Android开发 - 跟随手指的小球实现

     <p>今天要实现的是一个跟随手指的小球，说白了就是让小球按着手指滑动的轨迹运动，实现起来还是比较容易的。</p>    <p>用到的类是drawView，我们先自定义一个DrawView组件。</p>    <p>DrawView.java:</p>    <pre class="brush:java; toolbar: true; auto-links: false;">package cn.csdn.android.view;  import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.view.View;  public class DrawView extends View{   public float currentX = 300;  public float currentY = 500;    public DrawView(Context context) {   super(context);   // TODO Auto-generated constructor stub  }   @Override  protected void onDraw(Canvas canvas) {   // TODO Auto-generated method stub   super.onDraw(canvas);   Paint p = new Paint();   p.setColor(Color.RED);   canvas.drawCircle(currentX, currentY, 15, p);  }     }</pre>    <p></p>    <p>==================================</p>    <p>在main.xml文件中给一个android:id="@+id/root";</p>    <p>然后写java代码实现跟踪效果：</p>    <pre class="brush:java; toolbar: true; auto-links: false;">CustomView.java  package cn.csdn.android.view;  import android.app.Activity; import android.os.Bundle; import android.view.MotionEvent; import android.view.View; import android.view.View.OnTouchListener; import android.widget.LinearLayout;  public class CustomViewActivity extends Activity{   @Override  protected void onCreate(Bundle savedInstanceState) {   // TODO Auto-generated method stub   super.onCreate(savedInstanceState);   setContentView(R.layout.main);      LinearLayout main = (LinearLayout) findViewById(R.id.root);   final DrawView draw = new DrawView(this);      draw.setMinimumWidth(300);      draw.setMinimumHeight(500);           draw.setOnTouchListener(new OnTouchListener() {        @Override    public boolean onTouch(View v, MotionEvent event) {     draw.currentX = event.getX();     draw.currentY = event.getY();     draw.invalidate();     return true;    }   });      main.addView(draw);  }   }</pre>转自：    <a href="/misc/goto?guid=4959500610457750824" target="_blank">http://blog.csdn.net/yangbo_hbzjk/article/details/7193544</a>    <p></p>    <p></p>