第二章实例：动态生成View控件例子—小球跟随手指滑动

package mydefault.packge;import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.view.View.OnTouchListener;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.ToggleButton;public class MainActivity extends Activity{    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        //布局管理器
        LinearLayout  layout  = new LinearLayout(MainActivity.this);        TextView tv = new TextView(MainActivity.this);
        tv.setText("这是代码生成的TextView");
        Button button = new  Button(MainActivity.this);
        ToggleButton tbtn = new ToggleButton(MainActivity.this);
        ///////////////////////////////////////////////
        //设置标题方法
        button.setText("动态生成的按钮");
        //设置布局方法
        button.setLayoutParams(new LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,ViewGroup.LayoutParams.WRAP_CONTENT));
        //设置背景
        button.setBackgroundColor(Color.CYAN);
        //------------
        tbtn.setTextOff("关机");
        layout.addView(tbtn);
        layout.addView(tv);
        layout.addView(button);        //layout.addView(new myView(MainActivity.this));
        this.setContentView(layout);    }
    public class myView extends View implements OnTouchListener{
        private float x;
        private float y;
        private Paint panter;
        public myView(Context context) {
            super(context);
            x = 0;
            y = 0;
            panter = new Paint();
            this.setOnTouchListener(this);
        }
        /////////////////////////////
        @Override
        public void draw(Canvas canvas) {
            super.draw(canvas);
            panter.setColor(Color.RED);
            canvas.drawCircle(x, y, 45, panter);        }
/*
        @Override
        public boolean onTouchEvent(MotionEvent event) {
            x = event.getX();
            y = event.getY();
            invalidate();            return super.onTouchEvent(event);
        }*/
        @Override
        public boolean onTouch(View arg0, MotionEvent event) {
            x = event.getX();
            y = event.getY();            invalidate();            return true;
        }    }}

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