第一个安卓app——计算器

 

几天前，我花了一天时间，结合这段时间所学知识开发出了一个简单的计算器，它由两个TextView和23个Button组成，代码会放在文章结尾。

 

 

TextView

TextView：上面一个TextView的功能是记录运算过程，其中运算符的显示顺序是输入顺序也是运算顺序/*即1+2×3为（1+2）×3*/，

下面一个TextView功能是显示运算结果和显示输入的运算数据。

 

Button

AC键：功能是清除运算记录，将所有变量重置。

 

 

BC键：功能是返回上一步运算结果，在每一步运算结束后，会将这一步的运算结果存储在ArrayList中，BC之后会将Arraylist中最近一次的运算记录也就是返回的这步运算记录删除，以实现随意回调的效果。

 

 

+/-键：功能是将现在输入框中的数据转为它的相反数

 

DEL键：功能是退格，在输入数据不是小数时，退格的实现方式是输入框中数据除十得到结果，在输入数据是小数时退格的实现方式是获取输入框中的字符串减去末尾数字字符得到结果。

 

0~9数字键：进行数字键输入操作时，会对当前是否正在输入小数进行判断，如果是，则这样将

double num = 1;
pointnum++;//小数点后输入的位数
for (int i = 0; i < pointnum; i++)
    num /= 10;
init += key* num;//当前key的值*位数

的确是繁琐！

推荐第二种做法直接将key拼接到输入框字符串的尾部即可！

    

四则运算键：在四则运算前都会对前一个输入是否为其他四则运算符进行判断。如果是，则将前一个四则运算符替换为当前的。进行每一个运算符在被点击之后都会储存起来，在下一个运算符或等于键被点击时（即下一个需要运算的数据输入完毕时）进行运算，并将此时被点击的运算符存储起来以供下次运算使用。

 

%键：进行求余运算，与四则运算类似。

 

x²键：对当前输入框中的数据进行平方操作。

 

√x键：对当前输入框中的数据进行开平方操作。

 

 

小数点键：将当前输入状态设置为小数输入。

 

 

关于这个程序的反省：

*在这个程序中我对输入框中的输入等操作大多是以double数据的运算实现的，在写完之后我突然意识到其实输入等很多功能的实现用字符串操作会省很多功夫，像DEL退格的实现以及小数点的等等操作用字符串进行操作确实会容易很多，不需要做那么多运算，在用的时候直接把字符串转换为所需数据类型即可！

 

*关于界面布局的看法：

在刚开始写这个程序布局的时候我只用了一个RelativeLayout就写了下来，在虚拟机上看起来布局很好，但放到其他型号的手机里布局就不行了，今天我对它的布局做了优化，用的是一个大的LinearLayout里面框住两个文本框和一个小的LinearLayout框住五个更小的LinearLayout，然后为他们各自设置match_parent和layout_weight,五个更小的LinearLayout每个各占match_parent/5，在更小的的LinearLayout里为里面的键设置layoutweight，避免了直接使用dp等数字，保证它可以占满整个屏幕或者确定的那一部分，使之在其他机型上也能美观地展示。

 

activity_calculator.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.Appalication_Trial.Calculator">

    <TextView
        android:id="@+id/tv_cord"
        android:layout_width="match_parent"
        android:layout_height="99dp"
        android:background="@drawable/riple_btn_pink"
        android:gravity="right"
        android:textSize="30dp"></TextView>

    <TextView
        android:id="@+id/tv_calcul"
        android:layout_width="match_parent"
        android:layout_height="99dp"
        android:layout_below="@+id/tv_cord"
        android:background="@drawable/riple_btn_pink"
        android:gravity="right"
        android:textSize="30dp"></TextView>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_below="@id/tv_calcul"
        android:orientation="vertical"
        android:gravity="center">
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:orientation="horizontal"
            ><Button
            android:id="@+id/calcul_btn_ac"
            android:layout_width="70dp"
            android:layout_height="match_parent"
            android:layout_marginTop="0dp"
            android:background="@drawable/riple_btn_nocorner"
            android:fontFamily="宋体"
            android:text="AC"
            android:textSize="40dp"
            android:layout_weight="1"
            android:textColor="#169FDF"
            ></Button>
            <Button
                android:id="@+id/calcul_btn_back"
                android:layout_width="70dp"
                android:layout_height="match_parent"
                android:layout_marginTop="0dp"
                android:layout_toRightOf="@id/calcul_btn_ac"
                android:background="@drawable/riple_btn_nocorner"
                android:fontFamily="宋体"
                android:text="bc"
                android:textColor="#169FDF"
                android:layout_weight="1"
                android:textSize="40dp"></Button>
            <Button
                android:id="@+id/calcul_btn_neg"
                android:layout_width="70dp"
                android:layout_height="match_parent"
                android:layout_marginTop="0dp"
                android:background="@drawable/riple_btn_nocorner"
                android:text="+/-"
                android:textSize="40dp"
                android:textColor="#169FDF"
                android:layout_weight="1"
                android:fontFamily="宋体"></Button>
            <Button
                android:id="@+id/calcul_btn_del"
                android:layout_width="140dp"
                android:layout_height="match_parent"
                android:layout_marginTop="0dp"
                android:background="@drawable/riple_btn_nocorner"
                android:text="del"
                android:textSize="30dp"
                android:textColor="#169FDF"
                android:layout_weight="2"
                android:fontFamily="宋体"></Button>

        </LinearLayout>
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_weight="1"
            android:layout_height="0dp"
            android:orientation="horizontal"
            >
            <Button
                android:id="@+id/calcul_btn_1"
                android:layout_width="70dp"
                android:layout_height="match_parent"
                android:layout_marginTop="0dp"
                android:background="@drawable/riple_btn_nocorner"
                android:fontFamily="宋体"
                android:text="1"
                android:layout_weight="1"
                android:textColor="#169FDF"
                android:textSize="40dp"></Button>
            <Button
                android:id="@+id/calcul_btn_2"
                android:layout_width="70dp"
                android:layout_height="match_parent"
                android:layout_marginTop="0dp"
                android:background="@drawable/riple_btn_nocorner"
                android:text="2"
                android:layout_weight="1"
                android:textSize="40dp"
                android:textColor="#169FDF"
                android:fontFamily="宋体"></Button>
            <Button
                android:id="@+id/calcul_btn_3"
                android:layout_width="70dp"
                android:layout_height="match_parent"
                android:layout_marginTop="0dp"
                android:background="@drawable/riple_btn_nocorner"
                android:text="3"
                android:textSize="40dp"
                android:textColor="#169FDF"
                android:layout_weight="1"
                android:fontFamily="宋体"></Button>
            <Button
                android:id="@+id/calcul_btn_pf"
                android:layout_width="70dp"
                android:layout_height="match_parent"
                android:layout_below="@id/calcul_btn_back"
                android:layout_marginTop="0dp"
                android:layout_toRightOf="@id/calcul_btn_9"
                android:background="@drawable/riple_btn_nocorner"
                android:text="x²"
                android:textAllCaps="false"
                android:textSize="30dp"
                android:textColor="#169FDF"
                android:layout_weight="1"
                android:fontFamily="宋体"></Button>
            <Button
                android:id="@+id/calcul_btn_sqrt"
                android:layout_width="70dp"
                android:layout_height="match_parent"
                android:layout_below="@id/calcul_btn_back"
                android:layout_marginTop="0dp"
                android:layout_toRightOf="@id/calcul_btn_pf"
                android:background="@drawable/riple_btn_nocorner"
                android:text="√x"
                android:textAllCaps="false"
                android:textSize="30dp"
                android:textColor="#169FDF"
                android:layout_weight="1"
                android:fontFamily="宋体"></Button>

        </LinearLayout>
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_weight="1"
            android:layout_height="0dp"
            android:orientation="horizontal"
            >
            <Button
                android:id="@+id/calcul_btn_4"
                android:layout_width="70dp"
                android:layout_height="match_parent"
                android:layout_marginTop="0dp"
                android:background="@drawable/riple_btn_nocorner"
                android:text="4"
                android:textSize="40dp"
                android:layout_weight="1"
                android:textColor="#169FDF"
                android:fontFamily="宋体"></Button>
            <Button
                android:id="@+id/calcul_btn_5"
                android:layout_width="70dp"
                android:layout_height="match_parent"
                android:layout_marginTop="0dp"
                android:background="@drawable/riple_btn_nocorner"
                android:text="5"
                android:textSize="40dp"
                android:textColor="#169FDF"
                android:layout_weight="1"
                android:fontFamily="宋体"></Button>
            <Button
                android:id="@+id/calcul_btn_6"
                android:layout_width="70dp"
                android:layout_height="match_parent"
                android:layout_marginTop="0dp"
                android:background="@drawable/riple_btn_nocorner"
                android:text="6"
                android:textSize="40dp"
                android:textColor="#169FDF"
                android:layout_weight="1"
                android:fontFamily="宋体"></Button>
            <Button
                android:id="@+id/calcul_btn_add"
                android:layout_width="70dp"
                android:layout_height="match_parent"
                android:layout_marginTop="0dp"
                android:background="@drawable/riple_btn_nocorner"
                android:text="+"
                android:textSize="40dp"
                android:textColor="#169FDF"
                android:fontFamily="宋体"
                android:layout_weight="1"
                ></Button>
            <Button
                android:id="@+id/calcul_btn_multiply"
                android:layout_width="70dp"
                android:layout_height="match_parent"
                android:layout_weight="1"
                android:layout_marginTop="0dp"
                android:background="@drawable/riple_btn_nocorner"
                android:text="×"
                android:textSize="40dp"
                android:textColor="#169FDF"
                android:fontFamily="宋体"></Button></LinearLayout>
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_weight="1"
            android:layout_height="0dp"
            android:orientation="horizontal"
            >
          
            <Button
                android:id="@+id/calcul_btn_7"
                android:layout_width="70dp"
                android:layout_height="match_parent"
                android:layout_below="@id/calcul_btn_4"
                android:layout_marginTop="0dp"
                android:layout_toLeftOf="@id/calcul_btn_5"
                android:background="@drawable/riple_btn_nocorner"
                android:text="7"
                android:textSize="40dp"
                android:layout_weight="1"
                android:textColor="#169FDF"
                android:fontFamily="宋体"></Button>
            <Button
                android:id="@+id/calcul_btn_8"
                android:layout_width="70dp"
                android:layout_height="match_parent"
                android:layout_below="@id/calcul_btn_5"
                android:layout_marginTop="0dp"
                android:layout_toRightOf="@id/calcul_btn_7"
                android:background="@drawable/riple_btn_nocorner"
                android:text="8"
                android:layout_weight="1"
                android:textSize="40dp"
                android:textColor="#169FDF"
                android:fontFamily="宋体"></Button>
            <Button
                android:id="@+id/calcul_btn_9"
                android:layout_width="70dp"
                android:layout_height="match_parent"
                android:layout_below="@id/calcul_btn_6"
                android:layout_marginTop="0dp"
                android:layout_toRightOf="@id/calcul_btn_8"
                android:background="@drawable/riple_btn_nocorner"
                android:text="9"
                android:layout_weight="1"
                android:textColor="#169FDF"
                android:textSize="40dp"
                android:fontFamily="宋体"></Button>
            <Button
                android:id="@+id/calcul_btn_sub"
                android:layout_width="70dp"
                android:layout_height="match_parent"
                android:layout_marginTop="0dp"
                android:background="@drawable/riple_btn_nocorner"
                android:text="-"
                android:textSize="40dp"
                android:textColor="#169FDF"
                android:layout_weight="1"
                android:fontFamily="宋体"></Button>
            <Button
                android:id="@+id/calcul_btn_divide"
                android:layout_width="70dp"
                android:layout_height="match_parent"
                android:layout_marginTop="0dp"
                android:background="@drawable/riple_btn_nocorner"
                android:layout_weight="1"
                android:text="÷"
                android:textSize="40dp"
                android:textColor="#169FDF"
                android:fontFamily="宋体"></Button>
        </LinearLayout>
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_weight="1"
            android:layout_height="0dp"
            android:orientation="horizontal"
            >
            <Button
                android:id="@+id/calcul_btn_rem"
                android:layout_width="70dp"
                android:layout_height="match_parent"
                android:layout_below="@id/calcul_btn_divide"
                android:layout_marginTop="0dp"
                android:layout_toLeftOf="@id/calcul_btn_0"
                android:background="@drawable/riple_btn_nocorner"
                android:text="%"
                android:layout_weight="1"
                android:textSize="40dp"
                android:textColor="#169FDF"
                android:fontFamily="宋体"></Button>
            <Button
                android:id="@+id/calcul_btn_0"
                android:layout_width="70dp"
                android:layout_height="match_parent"
                android:layout_below="@id/calcul_btn_8"
                android:layout_marginTop="0dp"
                android:layout_toRightOf="@id/calcul_btn_7"
                android:background="@drawable/riple_btn_nocorner"
                android:text="0"
                android:textSize="40dp"
                android:layout_weight="1"
                android:fontFamily="宋体"
                android:textColor="#169FDF"
                ></Button>
            <Button
                android:id="@+id/calcul_btn_point"
                android:layout_width="70dp"
                android:layout_height="match_parent"
                android:layout_below="@id/calcul_btn_9"
                android:layout_marginTop="0dp"
                android:layout_toRightOf="@id/calcul_btn_0"
                android:background="@drawable/riple_btn_nocorner"
                android:text="."
                android:textAllCaps="false"
                android:layout_weight="1"
                android:textSize="70dp"
                android:textColor="#169FDF"
                android:fontFamily="宋体"></Button>
            <Button
                android:id="@+id/calcul_btn_equal"
                android:layout_width="140dp"
                android:layout_height="match_parent"
                android:layout_below="@id/calcul_btn_divide"
                android:layout_marginTop="0dp"
                android:layout_toRightOf="@id/calcul_btn_neg"
                android:background="@drawable/riple_btn_nocorner"
                android:text="="
                android:textSize="40dp"
                android:layout_weight="2"
                android:textColor="#169FDF"
                android:fontFamily="宋体"></Button>
        </LinearLayout>
    </LinearLayout>
</RelativeLayout>

Calculater.java

package com.Appalication_Trial;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import com.example.myapplication5.R;

import java.util.ArrayList;

import static java.lang.Math.pow;
import static java.lang.Math.sqrt;

public class Calculator extends AppCompatActivity {
    private Button btn_0, btn_1, btn_2, btn_3, btn_4, btn_5, btn_6, btn_7, btn_8, btn_9, btn_add,
            btn_del, btn_mul, btn_neg, btn_ac, btn_sub, btn_equal, btn_divide, btn_sqrt, btn_rem,
            btn_point, btn_pf, btn_back;
    private TextView tv_cord, tv_calcul;
    private double init = 0;//当前输入数据
    private char calcul = '#';//运算符
    private double nowsum = 0;//当前运算结果
    private int pointnum = 0;//小数点输入次数
    boolean isaheadchar = false, isnowpoint = false, isaheadequal = false, isaheadsqr = false;
    //isaheadchar: 是否输入过运算符
    //isnowpoint：小数点状态
    //isaheadequal：前一个运算符是否为=
    //isaheadsqr：前一个运算符是否为平方，主要为setText方便而设置
    ArrayList<Double> arr = new ArrayList<>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_calculator);
        btn_0 = findViewById(R.id.calcul_btn_0);
        btn_1 = findViewById(R.id.calcul_btn_1);
        btn_2 = findViewById(R.id.calcul_btn_2);
        btn_3 = findViewById(R.id.calcul_btn_3);
        btn_4 = findViewById(R.id.calcul_btn_4);
        btn_5 = findViewById(R.id.calcul_btn_5);
        btn_6 = findViewById(R.id.calcul_btn_6);
        btn_7 = findViewById(R.id.calcul_btn_7);
        btn_8 = findViewById(R.id.calcul_btn_8);
        btn_9 = findViewById(R.id.calcul_btn_9);
        btn_point = findViewById(R.id.calcul_btn_point);
        btn_pf = findViewById(R.id.calcul_btn_pf);
        btn_back = findViewById(R.id.calcul_btn_back);
        btn_sqrt = findViewById(R.id.calcul_btn_sqrt);
        btn_sub = findViewById(R.id.calcul_btn_sub);
        btn_ac = findViewById(R.id.calcul_btn_ac);
        btn_add = findViewById(R.id.calcul_btn_add);
        btn_equal = findViewById(R.id.calcul_btn_equal);
        btn_del = findViewById(R.id.calcul_btn_del);
        btn_divide = findViewById(R.id.calcul_btn_divide);
        btn_mul = findViewById(R.id.calcul_btn_multiply);
        btn_rem = findViewById(R.id.calcul_btn_rem);
        btn_neg = findViewById(R.id.calcul_btn_neg);
        tv_calcul = findViewById(R.id.tv_calcul);
        tv_cord = findViewById(R.id.tv_cord);
        tv_calcul.setText("0");
        tv_cord.setText("");
        for (int i = 0; i <= 9; i++)
            btn_0.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if (!isnowpoint)
                        init = init * 10 + 0;
                    else {
                        double num = 1;
                        pointnum++;
                        for (int i = 0; i < pointnum; i++)
                            num /= 10;
                        init += 0 * num;
                    }
                    tv_calcul.setText("" + init);
                    isaheadequal = false;
                    isaheadchar = false;
                }
            });
        btn_1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (!isnowpoint)
                    init = init * 10 + 1;
                else {
                    double num = 1;
                    pointnum++;
                    for (int i = 0; i < pointnum; i++)
                        num /= 10;
                    init += 1 * num;
                }
                tv_calcul.setText("" + init);
                isaheadequal = false;
                isaheadchar = false;
            }
        });
        btn_2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (!isnowpoint)
                    init = init * 10 + 2;
                else {
                    double num = 1;
                    pointnum++;
                    for (int i = 0; i < pointnum; i++)
                        num /= 10;
                    init += 2 * num;
                }
                tv_calcul.setText("" + init);
                isaheadequal = false;
                isaheadchar = false;
            }
        });
        btn_3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (!isnowpoint)
                    init = init * 10 + 3;
                else {
                    double num = 1;
                    pointnum++;
                    for (int i = 0; i < pointnum; i++)
                        num /= 10;
                    init += 3 * num;
                }
                tv_calcul.setText("" + init);
                isaheadequal = false;
                isaheadchar = false;
            }
        });
        btn_4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (!isnowpoint)
                    init = init * 10 + 4;
                else {
                    double num = 1;
                    pointnum++;
                    for (int i = 0; i < pointnum; i++)
                        num /= 10;
                    init += 4 * num;
                }
                tv_calcul.setText("" + init);
                isaheadequal = false;
                isaheadchar = false;
            }
        });
        btn_5.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (!isnowpoint)
                    init = init * 10 + 5;
                else {
                    double num = 1;
                    pointnum++;
                    for (int i = 0; i < pointnum; i++)
                        num /= 10;
                    init += 5 * num;
                }
                tv_calcul.setText("" + init);
                isaheadequal = false;
                isaheadchar = false;
            }
        });
        btn_6.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (!isnowpoint)
                    init = init * 10 + 6;
                else {
                    double num = 1;
                    pointnum++;
                    for (int i = 0; i < pointnum; i++)
                        num /= 10;
                    init += 6 * num;
                }
                tv_calcul.setText("" + init);
                isaheadequal = false;
                isaheadchar = false;
            }
        });
        btn_7.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (!isnowpoint)
                    init = init * 10 + 7;
                else {
                    double num = 1;
                    pointnum++;
                    for (int i = 0; i < pointnum; i++)
                        num /= 10;
                    init += 7 * num;
                }
                tv_calcul.setText("" + init);
                isaheadequal = false;
                isaheadchar = false;
            }
        });
        btn_8.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (!isnowpoint)
                    init = init * 10 + 8;
                else {
                    double num = 1;
                    pointnum++;
                    for (int i = 0; i < pointnum; i++)
                        num /= 10;
                    init += 8 * num;
                }
                tv_calcul.setText("" + init);
                isaheadequal = false;
                isaheadchar = false;
            }
        });
        btn_9.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (!isnowpoint)
                    init = init * 10 + 9;
                else {
                    double num = 1;
                    pointnum++;
                    for (int i = 0; i < pointnum; i++)
                        num /= 10;
                    init += 9 * num;
                }
                tv_calcul.setText("" + init);
                isaheadequal = false;
                isaheadchar = false;
            }
        });
        btn_add.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                switch (calcul) {
                    case '+': {
                        nowsum += init;
                        arr.add(nowsum);
                        break;
                    }
                    case '-': {
                        nowsum -= init;
                        arr.add(nowsum);

                        break;
                    }
                    case '*': {
                        nowsum *= init;
                        arr.add(nowsum);

                        break;
                    }
                    case '/': {
                        if (init != 0) {
                            nowsum /= init;
                            arr.add(nowsum);
                        } else
                            Toast.makeText(getApplicationContext(), "不能除0！", Toast.LENGTH_LONG).show();
                        break;
                    }
                    case '士': {
                        nowsum *= -1;
                        arr.add(nowsum);
                        break;
                    }
                    case '%': {
                        nowsum %= init;
                        arr.add(nowsum);
                        break;
                    }
                    default: {
                        nowsum += init;
                    }
                }
                if (isaheadchar) {
                    if (!isaheadsqr)
                        tv_cord.setText(tv_cord.getText().subSequence(0, tv_cord.getText().length() - 1));
                    calcul = '+';

                }
                if (!isaheadequal) {
                    if (!isaheadchar)
                        tv_cord.setText(tv_cord.getText() + "" + init + "+");
                    else tv_cord.setText(tv_cord.getText() + "+");
                    tv_calcul.setText("" + nowsum);
                } else {
                    tv_cord.setText("" + nowsum + "+");
                    tv_calcul.setText("" + nowsum);
                }
                calcul = '+';
                init = 0;
                isaheadequal = false;
                isaheadchar = true;
                isaheadsqr = false;
                isnowpoint = false;
                pointnum = 0;
            }
        });
        btn_sub.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (isaheadequal) {
                    tv_cord.setText("");
                }
                switch (calcul) {
                    case '+': {
                        nowsum += init;
                        arr.add(nowsum);

                        break;
                    }
                    case '-': {
                        nowsum -= init;
                        arr.add(nowsum);

                        break;
                    }
                    case '*': {
                        nowsum *= init;
                        arr.add(nowsum);

                        break;
                    }
                    case '/': {
                        if (init != 0) {
                            nowsum /= init;
                            arr.add(nowsum);
                        } else
                            Toast.makeText(getApplicationContext(), "不能除0！", Toast.LENGTH_LONG).show();
                        break;
                    }
                    case '士': {
                        nowsum *= -1;
                        arr.add(nowsum);
                        break;
                    }
                    case '%': {
                        nowsum %= init;
                        arr.add(nowsum);
                        break;
                    }
                    default: {
                        nowsum += init;
                    }
                }
                if (isaheadchar) {
                    if (!isaheadsqr)
                        tv_cord.setText(tv_cord.getText().subSequence(0, tv_cord.getText().length() - 1));
                    calcul = '-';
                }
                if (!isaheadequal) {
                    if (!isaheadchar)
                        tv_cord.setText(tv_cord.getText() + "" + init + "-");
                    else tv_cord.setText(tv_cord.getText() + "-");
                    tv_calcul.setText("" + nowsum);
                } else {
                    tv_cord.setText("" + nowsum + "-");
                    tv_calcul.setText("" + nowsum);
                }
                calcul = '-';
                init = 0;
                isaheadequal = false;
                isaheadchar = true;
                isaheadsqr = false;
                isnowpoint = false;
                pointnum = 0;
            }
        });
        btn_mul.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (isaheadequal) {
                    tv_cord.setText("");
                }
                switch (calcul) {
                    case '+': {
                        nowsum += init;
                        arr.add(nowsum);

                        break;
                    }
                    case '-': {
                        nowsum -= init;
                        arr.add(nowsum);

                        break;
                    }
                    case '*': {
                        nowsum *= init;
                        arr.add(nowsum);
                        break;
                    }
                    case '/': {
                        if (init != 0) {
                            nowsum /= init;
                            arr.add(nowsum);
                        } else
                            Toast.makeText(getApplicationContext(), "不能除0！", Toast.LENGTH_LONG).show();
                        break;
                    }
                    case '士': {
                        nowsum *= -1;
                        arr.add(nowsum);
                        break;
                    }
                    case '%': {
                        nowsum %= init;
                        arr.add(nowsum);
                        break;
                    }
                    default: {
                        nowsum += init;
                    }
                }
                //if ptr calcul is calcul change it
                if (isaheadchar) {
                    if (!isaheadsqr)
                        tv_cord.setText(tv_cord.getText().subSequence(0, tv_cord.getText().length() - 1));
                    calcul = '*';
                }
                if (!isaheadequal) {
                    if (!isaheadchar)
                        tv_cord.setText(tv_cord.getText() + "" + init + "×");
                    else tv_cord.setText(tv_cord.getText() + "×");
                    tv_calcul.setText("" + nowsum);
                } else {
                    tv_cord.setText("" + nowsum + "×");
                    tv_calcul.setText("" + nowsum);
                }
                calcul = '*';
                init = 0;
                isaheadchar = true;
                isaheadequal = false;
                isaheadsqr = false;
                isnowpoint = false;
                pointnum = 0;
            }
        });
        btn_divide.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (isaheadequal) {
                    tv_cord.setText("");
                }
                switch (calcul) {
                    case '+': {
                        nowsum += init;
                        arr.add(nowsum);

                        break;
                    }
                    case '-': {
                        nowsum -= init;
                        arr.add(nowsum);

                        break;
                    }
                    case '*': {
                        nowsum *= init;
                        arr.add(nowsum);

                        break;
                    }
                    case '/': {
                        if (init != 0) {
                            nowsum /= init;
                            arr.add(nowsum);
                        } else
                            Toast.makeText(getApplicationContext(), "不能除0！", Toast.LENGTH_LONG).show();
                        break;
                    }
                    case '士': {
                        nowsum *= -1;
                        arr.add(nowsum);
                        break;
                    }
                    case '%': {
                        nowsum %= init;
                        arr.add(nowsum);
                        break;
                    }
                    default: {
                        nowsum += init;
                    }
                }
                if (isaheadchar) {
                    if (!isaheadsqr)
                        tv_cord.setText(tv_cord.getText().subSequence(0, tv_cord.getText().length() - 1));
                    calcul = '/';
                }
                if (!isaheadequal) {
                    if (!isaheadchar)
                        tv_cord.setText(tv_cord.getText() + "" + init + "÷");
                    else tv_cord.setText(tv_cord.getText() + "÷");
                    tv_calcul.setText("" + nowsum);
                } else {
                    tv_cord.setText("" + nowsum + "÷");
                    tv_calcul.setText("" + nowsum);
                }
                calcul = '/';
                init = 0;
                isaheadequal = false;
                isaheadchar = true;
                isaheadsqr = false;
                isnowpoint = false;
                pointnum = 0;
            }
        });
        btn_rem.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (isaheadequal) {
                    tv_cord.setText("");
                }
                switch (calcul) {
                    case '+': {
                        nowsum += init;
                        arr.add(nowsum);

                        break;
                    }
                    case '-': {
                        nowsum -= init;
                        arr.add(nowsum);

                        break;
                    }
                    case '*': {
                        nowsum *= init;
                        arr.add(nowsum);

                        break;
                    }
                    case '/': {
                        if (init != 0) {
                            nowsum /= init;
                            arr.add(nowsum);
                        } else
                            Toast.makeText(getApplicationContext(), "不能除0！", Toast.LENGTH_LONG).show();
                        break;
                    }
                    case '士': {
                        nowsum *= -1;
                        arr.add(nowsum);
                        break;
                    }
                    case '%': {
                        nowsum %= init;
                        arr.add(nowsum);
                        break;
                    }
                    default: {
                    }
                }
                if (!isaheadequal) {
                    tv_cord.setText(tv_cord.getText() + "" + init + "%");
                    tv_calcul.setText("" + nowsum);
                } else {
                    tv_cord.setText("" + nowsum + "%");
                    tv_calcul.setText("" + nowsum);
                    isaheadequal = false;
                }
                calcul = '%';
                init = 0;
                isnowpoint = false;
                pointnum = 0;
            }
        });
        btn_neg.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                double nowcal = Double.parseDouble(tv_calcul.getText().toString());
                nowcal *= -1;
                init = nowcal;
                tv_calcul.setText("" + init);
                isnowpoint = false;
                pointnum = 0;
            }
        });
        btn_point.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                isnowpoint = true;
            }
        });
        btn_equal.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (isaheadequal) {
                    tv_cord.setText("");
                }
                switch (calcul) {
                    case '+': {
                        nowsum += init;
                        arr.add(nowsum);
                        break;
                    }
                    case '-': {
                        nowsum -= init;
                        arr.add(nowsum);
                        break;
                    }
                    case '*': {
                        nowsum *= init;
                        arr.add(nowsum);

                        break;
                    }
                    case '/': {
                        if (init != 0) {
                            nowsum /= init;
                            arr.add(nowsum);
                        } else
                            Toast.makeText(getApplicationContext(), "不能除0！", Toast.LENGTH_LONG).show();
                        break;
                    }
                    case '士': {
                        nowsum *= -1;
                        arr.add(nowsum);
                        break;
                    }
                    case '%': {
                        nowsum %= init;
                        arr.add(nowsum);
                        break;
                    }
                    default: {
                        nowsum = init;
                    }
                }
                if (!isaheadsqr)
                    tv_cord.setText(tv_cord.getText() + "" + init + "=");
                else tv_cord.setText(tv_cord.getText() + "=");
                tv_calcul.setText("" + nowsum);
                calcul = '#';
                init = 0;
                isaheadequal = true;
                isaheadsqr = false;
                isnowpoint = false;
                pointnum = 0;
            }
        });
        btn_ac.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                tv_calcul.setText("");
                tv_cord.setText("");
                calcul = '#';
                init = 0;
                nowsum = 0;
                isaheadchar = false;
                isnowpoint = false;
                isaheadequal = false;
                isaheadsqr = false;
                pointnum = 0;
                arr.removeAll(arr);
            }
        });
        btn_del.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                if (!isnowpoint)
                    init = (int) init / 10;
                else {
                    if (tv_calcul.getText().length() > 2) {
                        tv_calcul.setText(tv_calcul.getText().subSequence(0, tv_calcul.getText().length() - 1));
                        init = Double.parseDouble(tv_calcul.getText().toString());
                    } else {
                        isnowpoint = false;
                        pointnum = 0;
                    }
                }
                tv_calcul.setText("" + init);
            }
        });
        btn_pf.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                double ptr;
                double nowcal = Double.parseDouble(tv_calcul.getText().toString());
                nowcal *= nowcal;
                ptr = init;
                init = nowcal;
                tv_calcul.setText("" + init);
                tv_cord.setText(tv_cord.getText() + "" + ptr + "²");
                isaheadsqr = true;
                isaheadchar = true;
                pointnum = 0;
            }
        });
        btn_sqrt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                double ptr;
                double nowcal = Double.parseDouble(tv_calcul.getText().toString());
                nowcal = sqrt(nowcal);
                ptr = init;
                init = nowcal;
                tv_calcul.setText("" + init);
                tv_cord.setText(tv_cord.getText() + "√" + ptr);
                isaheadsqr = true;
                isaheadchar = true;
                pointnum = 0;
            }
        });
        btn_back.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (arr.size()>=1) {
                    Log.d("A","111");
                    arr.remove(arr.size()-1);
                    nowsum = arr.get(arr.size()-1);
                    init = 0;
                    tv_cord.setText("" + nowsum);
                    tv_calcul.setText("" + nowsum);
                }
            }
        });

    }
}