Android GestureDetector手勢識別類

My鏡像站 2012-02-10

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為了加強鼠標響應(yīng)事件，Android提供了GestureDetector手勢識別類。通過GestureDetector.OnGestureListener來獲取當前被觸發(fā)的操作手勢（Single Tap Up、Show Press、Long Press、Scroll、Down、Fling），具體包括以下幾種：

boolean onDoubleTap(MotionEvent e)
解釋：雙擊的第二下Touch down時觸發(fā)
boolean onDoubleTapEvent(MotionEvent e)
解釋：雙擊的第二下Touch down和up都會觸發(fā)，可用e.getAction()區(qū)分。
boolean onDown(MotionEvent e)
解釋：Touch down時觸發(fā)
boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY)
解釋：Touch了滑動一點距離后，up時觸發(fā)。
void onLongPress(MotionEvent e)
解釋：Touch了不移動一直Touch down時觸發(fā)
boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY)
解釋：Touch了滑動時觸發(fā)。
void onShowPress(MotionEvent e)
解釋：Touch了還沒有滑動時觸發(fā)
（與onDown，onLongPress比較
onDown只要Touch down一定立刻觸發(fā)。
而Touchdown后過一會沒有滑動先觸發(fā)onShowPress再是onLongPress。
所以Touchdown后一直不滑動，onDown->onShowPress->onLongPress這個順序觸發(fā)。

boolean onSingleTapConfirmed(MotionEvent e)
boolean onSingleTapUp(MotionEvent e)
解釋：上面這兩個函數(shù)都是在touch down后又沒有滑動（onScroll），又沒有長按（onLongPress），然后Touchup時觸發(fā)。

點擊一下非?？斓模ú换瑒樱㏕ouchup：
onDown->onSingleTapUp->onSingleTapConfirmed
點擊一下稍微慢點的（不滑動）Touchup：
onDown->onShowPress->onSingleTapUp->onSingleTapConfirmed

使用GestureDetector需要在View中重寫onTouchEvent事件，例如：

[java] view plain copy print ?

GestureDetector mGesture = null;
@Override
public boolean onTouch(View v, MotionEvent event)
{
// TODO Auto-generated method stub
return mGesture.onTouchEvent(event);
}

詳細的測試例子如下：

[cpp] view plain copy print ?

package com.jiubang.android.gesturetest;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
import android.view.GestureDetector.SimpleOnGestureListener;
import android.view.View.OnTouchListener;
import android.widget.Button;
public class GestureActivity extends Activity
implements OnTouchListener
{
private Button mButton = null;
GestureDetector mGesture = null;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Log.i("TEST", "onCreate");
mButton = (Button)findViewById(R.id.button1);
mButton.setOnTouchListener(this);
mGesture = new GestureDetector(this, new GestureListener());
}
@Override
public boolean onTouch(View v, MotionEvent event)
{
// TODO Auto-generated method stub
return mGesture.onTouchEvent(event);
}
class GestureListener extends SimpleOnGestureListener
{
@Override
public boolean onDoubleTap(MotionEvent e)
{
// TODO Auto-generated method stub
Log.i("TEST", "onDoubleTap");
return super.onDoubleTap(e);
}
@Override
public boolean onDown(MotionEvent e)
{
// TODO Auto-generated method stub
Log.i("TEST", "onDown");
return super.onDown(e);
}
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
float velocityY)
{
// TODO Auto-generated method stub
Log.i("TEST", "onFling:velocityX = " + velocityX + " velocityY" + velocityY);
return super.onFling(e1, e2, velocityX, velocityY);
}
@Override
public void onLongPress(MotionEvent e)
{
// TODO Auto-generated method stub
Log.i("TEST", "onLongPress");
super.onLongPress(e);
}
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2,
float distanceX, float distanceY)
{
// TODO Auto-generated method stub
Log.i("TEST", "onScroll:distanceX = " + distanceX + " distanceY = " + distanceY);
return super.onScroll(e1, e2, distanceX, distanceY);
}
@Override
public boolean onSingleTapUp(MotionEvent e)
{
// TODO Auto-generated method stub
Log.i("TEST", "onSingleTapUp");
return super.onSingleTapUp(e);
}
}
}