Android internal class monitoring and multi-object monitoring methods

Project directory:

1. Internal class monitor
MainActivity:

package com.example.demo_two;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        findViewById(R.id.button).setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) {
                Toast.makeText(MainActivity.this, "单击了Button1", Toast.LENGTH_SHORT).show();
            }
        });
        findViewById(R.id.button2).setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) {
                Toast.makeText(MainActivity.this, "单击了Button2", Toast.LENGTH_SHORT).show();
            }
        });
        findViewById(R.id.button3).setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) {
                Toast.makeText(MainActivity.this, "单击了Button3", Toast.LENGTH_SHORT).show();
            }
        });
    }
}

Layout:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <Button
            android:id="@+id/button"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Button1" />

        <Button
            android:id="@+id/button2"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Button2" />

        <Button
            android:id="@+id/button3"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Button3" />
    </LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

Two, multi-object monitoring
MainActivity:

package com.example.demo_two;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Button btn1=findViewById(R.id.button);
        btn1.setOnClickListener(this);
        Button btn2=findViewById(R.id.button2);
        btn2.setOnClickListener(this);
        Button btn3=findViewById(R.id.button3);
        btn3.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.button:
                Toast.makeText(this, "单击了Button1", Toast.LENGTH_SHORT).show();
                break;
            case R.id.button2:
                Toast.makeText(this, "单击了Button2", Toast.LENGTH_SHORT).show();
                break;
            case R.id.button3:
                Toast.makeText(this, "单击了Button3", Toast.LENGTH_SHORT).show();
                break;
        }
    }
}