Android通过手势实现翻页效果

布局使用ViewFlipper装载图片，并通过showPrevious()和showNext()方法展示图片的上一页/下一页，布局文件如下：

<span style="font-size:14px;"><?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ViewFlipper
android:id="@+id/flipper"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout></span>

编写一个ChangePage的Activity实现OnGestureListener接口，在onFling()方法中编写核心的图片切换代码，通过ViewFlipper更换图片，还可以通过ViewFlipper的setInAnimation和setOutAnimation方法给图片切换设置切换动画，代码如下：

public class ChangePage extends Activity implements GestureDetector.OnGestureListener{
GestureDetector detector;
ViewFlipper flipper;
Animation animation[];
final int MINIMUM_DISTANCE = 50;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.flipper);
detector = new GestureDetector(this,this);
flipper = (ViewFlipper) findViewById(R.id.flipper);
flipper.addView(addImageView(R.drawable.one));
flipper.addView(addImageView(R.drawable.two));
flipper.addView(addImageView(R.drawable.three));
flipper.addView(addImageView(R.drawable.four));
flipper.addView(addImageView(R.drawable.five));
loadAnimation();

}

@Override
public boolean onTouchEvent(MotionEvent event) {
return detector.onTouchEvent(event);
}

@Override
public boolean onDown(MotionEvent e) {
return false;
}

@Override
public void onShowPress(MotionEvent e) {

}

@Override
public boolean onSingleTapUp(MotionEvent e) {
return false;
}

@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
return false;
}

@Override
public void onLongPress(MotionEvent e) {

}

@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
if(e2.getX()-e1.getX() > MINIMUM_DISTANCE){
flipper.setInAnimation(animation[0]);
flipper.setOutAnimation(animation[1]);
flipper.showPrevious();
return true;
}else if(e1.getX() - e2.getX() > MINIMUM_DISTANCE){
flipper.setInAnimation(animation[2]);
flipper.setOutAnimation(animation[3]);
flipper.showNext();
return false;
}
return false;
}
private ImageView addImageView(int resId){
ImageView imageView = new ImageView(this);
imageView.setImageResource(resId);
imageView.setScaleType(ImageView.ScaleType.CENTER);
return imageView;
}

private Animation[] loadAnimation(){
animation = new Animation[4];
animation[0] = AnimationUtils.loadAnimation(this,R.anim.left_in);
animation[1] = AnimationUtils.loadAnimation(this,R.anim.right_out);
animation[2] = AnimationUtils.loadAnimation(this,R.anim.right_in);
animation[3] = AnimationUtils.loadAnimation(this,R.anim.left_out);
return animation;
}
}
注：加载动画代码为：Animation animation = AnimationUtils.loadAnimation(context,R.anim.xx);