android实现小球随着鼠标走之自定义View

初次学习android 如有不足之处希望大家指正

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layout 下布局文件

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:id="@+id/root"    android:orientation="vertical"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    >  </LinearLayout>

?自定义View 类

package com.android.imagebrowser;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.View;public class DrawView extends View {	public float currentX = 40;	public float currentY = 50;		// 定义创建画笔	Paint p = new Paint();		public DrawView(Context context) {		super(context);	}	public DrawView(Context context, AttributeSet set) {		super(context,set);	}		@Override	protected void onDraw(Canvas canvas) {		super.onDraw(canvas);		// 设置画笔的颜色		p.setColor(Color.RED);		// 绘制一个小园（作为小球）		canvas.drawCircle(currentX, currentY, 15, p);	}		// 为该组件的触发事件重写事件处理方法	@Override	public boolean onTouchEvent(MotionEvent event) {		// 修改currentX currentY		currentX = event.getX();		currentY = event.getY();		// 通知当前组件重绘自己		invalidate();		// 返回true 表明该处理方法已经处理该事件		return true;	}}

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MainActivity

package com.android.imagebrowser;import android.os.Bundle;import android.app.Activity;import android.view.Menu;import android.view.View;import android.view.View.OnClickListener;import android.widget.ImageView;import android.widget.LinearLayout;public class MainActivity extends Activity {	// 定义图片数组	static int [] images = new int[] {R.drawable.four,							   		  R.drawable.two,							   		  R.drawable.three,							   		  };	// 当前图片	static int currentImg = 0;		@Override	protected void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		setContentView(R.layout.activity_main);		// 获取LinearLayout 布局管理器		LinearLayout root = (LinearLayout) findViewById(R.id.root);		final DrawView draw = new DrawView(this);		draw.setMinimumHeight(500);		draw.setMinimumWidth(300);		root.addView(draw);	}	@Override	public boolean onCreateOptionsMenu(Menu menu) {		// Inflate the menu; this adds items to the action bar if it is present.		getMenuInflater().inflate(R.menu.main, menu);		return true;	}}

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