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android View的一些學習記錄
1，View是所有控件的父類
2，View可以關聯很多個listenner。就像一個女孩有很多個男人對她好一樣。有為她賣苦力的窮叼絲，也有她拿得出手的高副帥。當女孩發生需要搬宿舍的事件的時候，這個時候窮叼絲監聽到了該事件的發生，於是幫搬宿舍，當她需要去看電影和開房的時候，高副帥男友監聽到了該事件，於是就跟她完成了一個很美好的夜晚。
View 的事件監聽，舉個例子
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;
/**
* 在自定義的View中定義三個監聽器
*/
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; // 隻有返回true這個控件的move和up才會響應
} 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);
}
// 為每個接口設置監聽器
public void setOnDownActionListener(OnDownActionListener down) {
mDown = down;
}
public void setOnMoveActionListener(OnMoveActionListener move) {
mMove = move;
}
public void setOnUpActionListener(OnUpActionListener up) {
mUp = up;
}
// 定義三個接口
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);
}
}
然後在layout的xml文件中加入該自定義控件
<!--?xml version="1.0" encoding="utf-8"?-->
<linearlayout xmlns:andro android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical">
<com.example.listviewitem.widgets.myview android: android:layout_width="wrap_content" android:layout_height="wrap_content" android:background="@drawable/area_point_bg">
</com.example.listviewitem.widgets.myview></linearlayout>
然後用一個activity來用它
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);
}
});
}
}
這樣就完成了一個自定義控件的時間監聽。
最後更新：2017-04-03 05:39:57