Android手势识别类 GestureDetector
为了加强鼠标响应事件,Android提供了GestureDetector手势识别类。通过GestureDetector.OnGestureListener来获取当前被触发的操作手势(Single Tap Up、Show Press、Long Press、Scroll、Down、Fling),具体包括以下几种:
boolean onDoubleTap(MotionEvent e)
解释:双击的第二下Touch down时触发
boolean onDoubleTapEvent(MotionEvent e)
解释:双击的第二下Touch down和up都会触发,可用e.getAction()区分。
boolean onDown(MotionEvent e)
解释:Touch down时触发
boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY)
解释:Touch了滑动一点距离后,up时触发。
void onLongPress(MotionEvent e)
解释:Touch了不移动一直Touch down时触发
boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY)
解释:Touch了滑动时触发。
void onShowPress(MotionEvent e)
解释:Touch了还没有滑动时触发
(与onDown,onLongPress比较
onDown只要Touch down一定立刻触发。
而Touchdown后过一会没有滑动先触发onShowPress再是onLongPress。
所以Touchdown后一直不滑动,onDown->onShowPress->onLongPress这个顺序触发。
boolean onSingleTapConfirmed(MotionEvent e)
boolean onSingleTapUp(MotionEvent e)
解释:上面这两个函数都是在touch down后又没有滑动(onScroll),又没有长按(onLongPress),然后Touchup时触发。
点击一下非常快的(不滑动)Touchup:
onDown->onSingleTapUp->onSingleTapConfirmed
点击一下稍微慢点的(不滑动)Touchup:
onDown->onShowPress->onSingleTapUp->onSingleTapConfirmed
用一个图片切换的例子来说明手势识别类的使用。
java代码:
</div> </div>
package com.lovo; import android.app.Activity; import android.os.Bundle; import android.view.GestureDetector; import android.view.GestureDetector.OnGestureListener; import android.view.MotionEvent; import android.widget.ImageView; /** * 手势识别类 * 图片切换显示,实现接口OnGestureListener * @author Administrator * */ public class MyGestrueTest extends Activity implements OnGestureListener{ /**手势管理器*/ private GestureDetector detector; /**图片资源数组*/ private int [] imageId; /**图片视图*/ private ImageView imageView ; private ImageView[] imgView; /**图片下标计数器*/ private int count=0; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.my_gesture_test); //创建手势管理器 detector = new GestureDetector(this); //得到图片视图 imageView=(ImageView) findViewById(R.id.image_gestrue); //得到图片资源的Id imageId = new int[]{ R.drawable.whatsnew_fornew_01, R.drawable.whatsnew_fornew_02, R.drawable.whatsnew_fornew_03, R.drawable.whatsnew_fornew_04, R.drawable.whatsnew_fornew_05}; //得到图片视图 ImageView imgView = new ImageView []{ (ImageView) findViewById(R.id.small_image1), (ImageView) findViewById(R.id.small_image2), (ImageView) findViewById(R.id.small_image3), (ImageView) findViewById(R.id.small_image4), (ImageView) findViewById(R.id.small_image5)}; } @Override public boolean onTouchEvent(MotionEvent event) { //将touch事件交给手势管理器来处理 return detector.onTouchEvent(event); } @Override public boolean onDown(MotionEvent e) { return false; } /** * 手势滑动触发的事件 */ @Override public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) { //从右往左移动 if(e1.getX()-e2.getX()>50){ //下标++ count++; if(count<=4){ //切换到下一张 imageView.setImageResource(imageId[count]); //设置该张对应的高亮小图标 imgView[count].setImageResource(R.drawable.page_indicator_focused); //其他小图标均为非高亮 imgView[count-1].setImageResource(R.drawable.page_indicator_unfocused); }else{ //滑动到最后一张,该方向不会再滑动,就停留在最后一张 count=4; imageView.setImageResource(imageId[count]); } } //从左往右移动 if(e1.getX()-e2.getX()<50){ count--; if(count>=0){ imageView.setImageResource(imageId[count]); imgView[count].setImageResource(R.drawable.page_indicator_focused); imgView[count+1].setImageResource(R.drawable.page_indicator_unfocused); }else{ count=0; imageView.setImageResource(imageId[count]); } } return false; } @Override public void onLongPress(MotionEvent e) {} @Override public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) { return false; } @Override public void onShowPress(MotionEvent e) {} @Override public boolean onSingleTapUp(MotionEvent e) { return false; } }
XML:
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:background="#000"> <LinearLayout android:id="@+id/my_geture_test_1" android:layout_width="match_parent" android:layout_height="match_parent" > <ImageView android:id="@+id/image_gestrue" android:layout_width="match_parent" android:layout_height="match_parent" android:src="@drawable/whatsnew_fornew_01" > </ImageView> </LinearLayout> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:gravity="center_horizontal" android:layout_marginBottom="30dp" > <ImageView android:id="@+id/small_image1" android:padding="5dp" android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/page_indicator_focused" > </ImageView> <ImageView android:id="@+id/small_image2" android:padding="5dp" android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/page_indicator_unfocused" > </ImageView> <ImageView android:id="@+id/small_image3" android:padding="5dp" android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/page_indicator_unfocused" > </ImageView> <ImageView android:id="@+id/small_image4" android:padding="5dp" android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/page_indicator_unfocused" > </ImageView> <ImageView android:id="@+id/small_image5" android:padding="5dp" android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/page_indicator_unfocused" > </ImageView> </LinearLayout> </RelativeLayout>