源码解析，了解View的事件分发

先执行Listener再是onTouckEvent

1. dispatchTouchEvent->setOnTouchListener->onTouchEvent
2. onClick/onLongClick来自onTouchEvent的处理
3. //OnLongClickListen返回false还会接着触发onClick事件
   //如果返回的是true，点击事件就被消费掉了

---

MyButton

package com.example.test0508.widget;

import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.widget.Button;

import androidx.appcompat.widget.AppCompatButton;

public class MyButton extends AppCompatButton {
    public MyButton(Context context) {
        super(context);
    }

    public MyButton(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public MyButton(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()){
            case MotionEvent.ACTION_DOWN:
                Log.d("MyButton" , "--onTouchEvent");
                break;
        }
        return super.onTouchEvent(event);
    }

    /**
     * 这是一个入口方法
     */
    @Override
    public boolean dispatchTouchEvent(MotionEvent event) {
        Log.d("MyButton","这是入口方法dispatchTouchEvent");
        return super.dispatchTouchEvent(event);

    }
}

---

EventActivity和布局文件

package com.example.test0508;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;


import com.example.test0508.widget.MyButton;

//通过事件源所在的类实现，让Activity实现这个Listener
public class EventActivity extends AppCompatActivity {

    private MyButton myButton;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_event);
        myButton = findViewById(R.id.btn_my_button);
        myButton.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View view, MotionEvent motionEvent) {
                switch (motionEvent.getAction()){
                    case MotionEvent.ACTION_DOWN:
                        Log.d("Listener","onTouchEvent");
                        break;
                }
                return false;
            }
        });
        myButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Log.d("Listener","onClick");
            }
        });
        myButton.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View view) {
                //OnLongClickListen返回false还会接着触发onClick事件
                //如果返回的是true，点击事件就被消费掉了
                return true;
            }
        });
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()){
            case MotionEvent.ACTION_DOWN :
                Log.d("Activity","onTouchEvent");
                break;
        }

        return false;
    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingBottom="15dp"
    >

    <Button
        android:id="@+id/btn_event1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="click me"
        android:textAllCaps="false"
        />

    <com.example.test0508.widget.MyButton
        android:id="@+id/btn_my_button"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="自己定义的button"
        android:textAllCaps="false"
        />

</LinearLayout>