Android编程自定义View时添加自己的监听器示例

这篇文章主要介绍了Android编程自定义View时添加自己的监听器,涉及Android自定义view中监听器的添加、设置与使用相关操作技巧,需要的朋友可以参考下

本文实例讲述了Android编程自定义View时添加自己的监听器。分享给大家供大家参考，具体如下：

监听器在Java中非常常用，在自定义控件时可能根据自己的需要去监听一些数据的改变，这时就需要我们自己去写监听器，Java中的监听器实际上就是C++中的回调函数，在初始化时设置了这个函数，由某个事件触发这个函数被调用，两个类之间的数据通信也可以通过监听器来实现。要定义监听器就要先定义一个接口，具体功能由设置监听器的类去实现

关键代码实现

 package com.example.listviewitem.widgets; import android.content.Context; import android.graphics.Canvas; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.View; /** * 在自定义的View中定义三个监听器 */ public class MyView extends View { private OnDownActionListener mDown = null; private OnMoveActionListener mMove = null; private OnUpActionListener mUp = null; public MyView(Context context) { super(context); } public MyView(Context context, AttributeSet attrs) { super(context, attrs); // TODO Auto-generated constructor stub } @Override protected void onDraw(Canvas canvas) { // TODO Auto-generated method stub super.onDraw(canvas); } @Override public boolean onTouchEvent(MotionEvent event) { // TODO Auto-generated method stub int x, y; if (event.getAction() == MotionEvent.ACTION_DOWN) { x = (int) event.getX(); y = (int) event.getY(); if (mDown != null) { mDown.OnDown(x, y); } return true; // 只有返回true这个控件的move和up才会响应 } else if (event.getAction() == MotionEvent.ACTION_MOVE) { x = (int) event.getX(); y = (int) event.getY(); if (mMove != null) { mMove.OnMove(x, y); } } else if (event.getAction() == MotionEvent.ACTION_UP) { x = (int) event.getX(); y = (int) event.getY(); if (mUp != null) { mUp.OnUp(x, y); } } return super.onTouchEvent(event); } // 为每个接口设置监听器 public void setOnDownActionListener(OnDownActionListener down) { mDown = down; } public void setOnMoveActionListener(OnMoveActionListener move) { mMove = move; } public void setOnUpActionListener(OnUpActionListener up) { mUp = up; } // 定义三个接口 public interface OnDownActionListener { public void OnDown(int x, int y); } public interface OnMoveActionListener { public void OnMove(int x, int y); } public interface OnUpActionListener { public void OnUp(int x, int y); } }

自定义View在xml中的定义

Activity中设置监听器

 package com.example.listviewitem; import com.example.listviewitem.widgets.MyView; import com.example.listviewitem.widgets.MyView.OnDownActionListener; import com.example.listviewitem.widgets.MyView.OnMoveActionListener; import com.example.listviewitem.widgets.MyView.OnUpActionListener; import android.app.Activity; import android.os.Bundle; public class TestListener extends Activity { private MyView view; @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); setContentView(R.layout.listener); view = (MyView) findViewById(R.id.my_view); view.setOnDownActionListener(new OnDownActionListener() { @Override public void OnDown(int x, int y) { // TODO Auto-generated method stub System.out.println("down x = " + x + " y = " + y); } }); view.setOnMoveActionListener(new OnMoveActionListener() { @Override public void OnMove(int x, int y) { // TODO Auto-generated method stub System.out.println("move x = " + x + " y = " + y); } }); view.setOnUpActionListener(new OnUpActionListener() { @Override public void OnUp(int x, int y) { // TODO Auto-generated method stub System.out.println("up x = " + x + " y = " + y); } }); } }

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