Android右滑返回上一个界面的实现方法

public class BaseActivity extends Activity implements OnTouchListener { 
 
  public ProgressDialog progressDialog; 
  public String states; 
  public RequestQueue mQueue; 
 
  /** 触摸时按下的点 **/ 
  PointF downP = new PointF(); 
  /** 触摸时当前的点 **/ 
  PointF curP = new PointF(); 
 
  @Override 
  protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    this.requestWindowFeature(Window.FEATURE_NO_TITLE); 
 
 
  } 
 
  @Override 
  protected void onResume() { 
    super.onResume(); 
  } 
 
   
  @Override 
  public boolean onTouchEvent(MotionEvent event) { 
 
 
     
    curP.x = event.getX(); 
    switch (event.getAction()) { 
     
     
    case MotionEvent.ACTION_DOWN: 
 
      downP.x = event.getX(); 
     
      break; 
    case MotionEvent.ACTION_MOVE: 
 
 
      if (curP.x- downP.x > 500) { 
        Log.i("TEST", "move-=-=-=--=-"); 
        finish(); 
       
      } 
 
      break; 
    case MotionEvent.ACTION_UP: 
 
      break; 
 
    default: 
      break; 
    } 
     
    return true; 
  } 
 
  @Override 
  protected void onPause() { 
    super.onPause(); 
  } 
 
  @Override 
  protected void onDestroy() { 
    super.onDestroy(); 
 
  } 
 
   
 
} 

public class BackScrollView extends ScrollView { 
 
  /** 触摸时按下的点 **/ 
  PointF downP = new PointF(); 
  /** 触摸时当前的点 **/ 
  PointF curP = new PointF(); 
 
  public BackScrollView(Context context) { 
    super(context); 
  } 
 
  public BackScrollView(Context context, AttributeSet attrs, int defStyle) { 
    super(context, attrs, defStyle); 
  } 
 
  public BackScrollView(Context context, AttributeSet attrs) { 
    super(context, attrs); 
  } 
 
  @Override 
  public boolean onTouchEvent(MotionEvent event) { 
 
    curP.x = event.getX(); 
    switch (event.getAction()) { 
 
    case MotionEvent.ACTION_DOWN: 
 
      downP.x = event.getX(); 
      Log.i("TEST", "downP.x-=-=-=--=-" + downP.x); 
      break; 
    case MotionEvent.ACTION_MOVE: 
      Log.i("TEST", "downP.x-=-=-=--=-" + curP.x); 
 
      if (downP.x < 200) { 
 
        if (curP.x - downP.x > 500) { 
 
          return false; 
 
        } 
      } 
 
      break; 
    case MotionEvent.ACTION_UP: 
 
      break; 
 
    default: 
      break; 
    } 
    return super.onTouchEvent(event); 
  }