3.1按钮

Button控件的实现形式主要分三种:

1.button控件匿名类实现OnClickListener监听 重写onClick方法

2.布局文件定义android:onClick="方法名" 不需要加括号 再定义public void 方法名(View view)

3.Activity类实现OnClickListener监听 重写onClick方法 再根据id定位控件

优先度(由高到底执行顺序):1>3>2

界面:

样式:

<?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:id="@+id/mainview"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.liang.buttonndemo.MainActivity">

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="button1"
        android:id="@+id/button1"
        android:layout_alignParentTop="true"
        android:layout_alignParentStart="true" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="button2"
        android:id="@+id/button2"
        android:layout_below="@+id/button1"
        android:layout_alignParentStart="true"
        android:onClick="xmlClick"
        android:layout_marginTop="25dp" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="button3"
        android:id="@+id/button3"
        android:layout_below="@+id/button2"
        android:layout_alignParentStart="true"
        android:layout_marginTop="26dp" />

    <ImageButton
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/imageButton"
        android:src="@drawable/androidbtn"
        android:layout_below="@+id/button3"
        android:layout_alignParentStart="true"
        android:layout_marginTop="29dp" />
</RelativeLayout>

代码:

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.Toast;

//按钮的三种方法 优先度 方法1>方法三>方法二 监听方法>实现方法>xml定义onclick方法
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private View view;
    private Button button1;
    private Button button2;
    private Button button3;
    private ImageButton imageButton;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        view = this.findViewById(R.id.mainview);
        button1 = (Button) this.findViewById(R.id.button1);
        button2 = (Button) this.findViewById(R.id.button2);
        button3 = (Button) this.findViewById(R.id.button3);
        imageButton = (ImageButton) this.findViewById(R.id.imageButton);
        button1.setOnClickListener(this);
        button2.setOnClickListener(this);
        button3.setOnClickListener(this);
        imageButton.setOnClickListener(this);

        //只有view有onclicklistener事件
        view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(MainActivity.this, "view click", 1).show();
            }
        });

        //方法1 设置监听
        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(MainActivity.this, "button1 click", 1).show();
            }
        });

        //长按监听
        button1.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View v) {
                Toast.makeText(MainActivity.this, "button1 long click", 1).show();
                return false;
            }
        });

        imageButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(MainActivity.this, "imagebutton click", 1).show();
            }
        });

    }

    //方法二 响应按钮点击
    //xml里面设置android:onclick里面方法只需要名字 不需要括号
    //1.必须public 2.必须void 3.形参必须只有一个 而且为View对象
    public void xmlClick(View view) {
        Toast.makeText(MainActivity.this, "button2 click", 1).show();
    }

    //方法三
    //实现OnClickListener接口 重写onclick方法  控件设置监听方法setOnClickListener(this)
    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.button1:
                Toast.makeText(MainActivity.this, "method 3 button1 click", 1).show();
                break;
            case R.id.button2:
                Toast.makeText(MainActivity.this, "method 3 button2 click", 1).show();
                break;
            case R.id.button3:
                Toast.makeText(MainActivity.this, "method 3 button3 click", 1).show();
                break;
            case R.id.imageButton:
                Toast.makeText(MainActivity.this, "method 3 imagebutton click", 1).show();
                break;
            default:
                Toast.makeText(MainActivity.this, "others click", 1).show();
                break;
        }
    }
}