小学数学测试题demo

目前只实现了重新出题和显示答案两个功能，其他功能以后完善

部分代码

package com.example.uidemo;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.*;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

import java.util.Random;

public class MainActivity extends AppCompatActivity {
    TextView textView;
    Button button3,button4;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView=findViewById(R.id.textView);
        button3=findViewById(R.id.button3);
        button4=findViewById(R.id.button4);

        Random r = new Random();
        int a=0;
        int d = 30;
        String s[] = new String[d];
        String b[]=new String[d];

        for (int i = 0; i < d; i++) {
            int ran1 = r.nextInt(100000) + 1;
            int ran2 = r.nextInt(100) + 1;
            while (ran1 < 10000 || ran2 < 11 || ran2 == 0 || ran1 % ran2 != 0 || ran1 <= ran2 || ran2 % 10 == 0) {
                ran1 = r.nextInt(100000) + 1;
                ran2 = r.nextInt(100) + 1;

            }
            String s1 = Integer.toString(ran1);
            String s2= Integer.toString(ran2);
            String s3 = Integer.toString(ran1 / ran2);

            if(s3.length()==3) continue;
            //System.out.println("---"+s3.substring(3, 4)+"---");
            if(a!=9) {
                s[i] = a + 1 +  ",      " + s1.substring(0, 3) + "." + s1.substring(3, 5) + " % " + s2.substring(0, 1) + "." + s2.substring(1, 2) + " = "
                        + s3.substring(0, 3) + "." + s3.substring(3, 4);
                b[i] =  a + 1 + ",      " + s1.substring(0, 3) + "." + s1.substring(3, 5) + " % " + s2.substring(0, 1) + "." + s2.substring(1, 2) + " = ";
            }
            else {
                s[i] =  a + 1 + ",    " + s1.substring(0, 3) + "." + s1.substring(3, 5) + " % " + s2.substring(0, 1) + "." + s2.substring(1, 2) + " = "
                        + s3.substring(0, 3) + "." + s3.substring(3, 4);
                b[i] =  a + 1 + ",    " + s1.substring(0, 3) + "." + s1.substring(3, 5) + " % " + s2.substring(0, 1) + "." + s2.substring(1, 2) + " = ";

            }

            a++;
            if(a==10) break;
        }
        String abc="";
        String da = "answer";
        String ab="";
        a=0;
        if (da.equals("answer")) {
            for (int i = 0; i < d; ++i) {
                if(s[i]!=null) {
                    ab+=s[i]+"
";
                    abc+=b[i]+"
";
                }

            }

        }
        textView.setText(abc);

        final String finalAbc = abc;
        final String finalAb = ab;
        button3.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View view) {
                textView.setText(finalAb);
            }


        });
        button4.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View view) {
                abcd();
            }


        });




        }

        public void abcd(){
            textView=findViewById(R.id.textView);
            button3=findViewById(R.id.button3);
            button4=findViewById(R.id.button4);

            Random r = new Random();
            int a=0;
            int d = 30;
            String s[] = new String[d];
            String b[]=new String[d];

            for (int i = 0; i < d; i++) {
                int ran1 = r.nextInt(100000) + 1;
                int ran2 = r.nextInt(100) + 1;
                while (ran1 < 10000 || ran2 < 11 || ran2 == 0 || ran1 % ran2 != 0 || ran1 <= ran2 || ran2 % 10 == 0) {
                    ran1 = r.nextInt(100000) + 1;
                    ran2 = r.nextInt(100) + 1;

                }
                String s1 = Integer.toString(ran1);
                String s2= Integer.toString(ran2);
                String s3 = Integer.toString(ran1 / ran2);

                if(s3.length()==3) continue;
                //System.out.println("---"+s3.substring(3, 4)+"---");
                if(a!=9) {
                    s[i] =  a + 1 + ",      " + s1.substring(0, 3) + "." + s1.substring(3, 5) + " % " + s2.substring(0, 1) + "." + s2.substring(1, 2) + " = "
                            + s3.substring(0, 3) + "." + s3.substring(3, 4);
                    b[i] =  a + 1 + ",      " + s1.substring(0, 3) + "." + s1.substring(3, 5) + " % " + s2.substring(0, 1) + "." + s2.substring(1, 2) + " = ";
                }
                else {
                    s[i] =  a + 1 + ",    " + s1.substring(0, 3) + "." + s1.substring(3, 5) + " % " + s2.substring(0, 1) + "." + s2.substring(1, 2) + " = "
                            + s3.substring(0, 3) + "." + s3.substring(3, 4);
                    b[i] =  a + 1 + ",    " + s1.substring(0, 3) + "." + s1.substring(3, 5) + " % " + s2.substring(0, 1) + "." + s2.substring(1, 2) + " = ";

                }

                a++;
                if(a==10) break;
            }
            String abc="";
            String da = "answer";
            String ab="";
            a=0;
            if (da.equals("answer")) {
                for (int i = 0; i < d; ++i) {
                    if(s[i]!=null) {
                        ab+=s[i]+"
";
                        abc+=b[i]+"
";
                    }

                }

            }
            textView.setText(abc);

            final String finalAbc = abc;
            final String finalAb = ab;
            button3.setOnClickListener(new View.OnClickListener(){
                @Override
                public void onClick(View view) {
                    textView.setText(finalAb);
                }


            });
            button4.setOnClickListener(new View.OnClickListener(){
                @Override
                public void onClick(View view) {
                    abcd();
                }


            });




        }
    }