android View的一些学习记录

1，View是所有控件的父类

2，View可以关联很多个listenner。就像一个女孩有很多个男人对她好一样。有为她卖苦力的穷叼丝，也有她拿得出手的高副帅。当女孩发生需要搬宿舍的事件的时候，这个时候穷叼丝监听到了该事件的发生，于是帮搬宿舍，当她需要去看电影和开房的时候，高副帅男友监听到了该事件，于是就跟她完成了一个很美好的夜晚。

View 的事件监听，举个例子

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);    }}

然后在layout的xml文件中加入该自定义控件

<!--?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">     <com.example.listviewitem.widgets.myview android:id="@+id/my_view" android:layout_width="wrap_content" android:layout_height="wrap_content" android:background="@drawable/area_point_bg"> </com.example.listviewitem.widgets.myview></linearlayout>

然后用一个activity来用它

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);            }        });    }}

这样就完成了一个自定义控件的时间监听。