解决ViewFlipper与ScrollView滑动响应事件拦截的问题

最近在做一个简单的展示界面时，遇到了一个比较棘手的问题。由于要展示多项内容，所以使用ViewFlipper作为水平滑动容器；而每项内容中由于许多文本较长，因此需要使用ScrollView作为垂直滑动容器。基本的界面布局大致如下：

外部文件common_list_view.xml：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/geyan_query_view_layout"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:background="@drawable/mid_bg">
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_marginTop="43dip"
android:orientation="vertical"
android:gravity="top"
android:layout_gravity="top">
<Gallery
android:id="@+id/gallery_data"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="top"
android:layout_gravity="top"
android:spacing="60dip"
android:paddingLeft="6dip"
android:paddingRight="6dip"
>
</Gallery>
</LinearLayout>
<ImageView
android:id="@+id/main_background"
android:layout_width="fill_parent"
android:layout_height="fill_parent"/>
<include layout="@layout/common_title_view"
android:id="@+id/title"/>
</RelativeLayout>

内部文件common_info_view.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:id="@+id/linear">
<TextView
android:id="@+id/text_title"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:padding="5dip"
android:layout_marginTop="5dip"
android:gravity="center"
android:textSize="20sp"
android:textStyle="bold"
android:textColor="#181712"
/>
<ScrollView
android:id="@+id/scroll"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_marginBottom="5dip"
android:fadeScrollbars="true"
>
<TextView
android:id="@+id/text_detail"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:lineSpacingMultiplier="1.3"
android:textSize="18sp"
android:textColor="#181712"
android:singleLine="false"
/>
</ScrollView>
</LinearLayout>

由于ViewFlipper在外，ScrollView在内，因此一般的做法是定义一个手势响应类来处理响应事件，并将响应事件的处理交给内层的ScrollView。大致代码如下：

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.GestureDetector;
import android.view.GestureDetector.SimpleOnGestureListener;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MotionEvent;
import android.view.View;
import android.view.Window;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.ViewFlipper;
 
public class Test1 extends Activity {
 
	private ViewFlipper viewFlipper;
 
	private String[] descriptionsArray;
	private String[] titleArray;
 
	private int selectedPosition;
 
	private TextView textViewTitle;
	private TextView textViewContent;
	private FriendlyScrollView scroll;
 
	private LayoutInflater mInflater;
 
	private GestureDetector gestureDetector;
 
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
 
		requestWindowFeature(Window.FEATURE_NO_TITLE);
		setContentView(R.layout.common_info_list_view);
 
		InitUI();
 
		super.onCreate(savedInstanceState);
 
		Toast.makeText(this, R.string.hello, Toast.LENGTH_SHORT).show();
	}
 
	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// TODO Auto-generated method stub
        super.onCreateOptionsMenu(menu);
        return false;
	}
 
	@Override
	public void onBackPressed() {
		// TODO Auto-generated method stub
		finish();
	}
 
	private void InitUI(){
 
		viewFlipper = (ViewFlipper) findViewById(R.id.viewflipper_data);
 
		mInflater = LayoutInflater.from(this);
 
		fillDate();
 
		viewFlipper.addView(getContentView());
	}
 
	private void fillDate(){
		selectedPosition = 0;
 
		titleArray = getResources().getStringArray(R.array.title_array);
		descriptionsArray = getResources().getStringArray(R.array.description_array);
 
		gestureDetector = new GestureDetector(new CommonGestureListener());
	}
 
	private View getContentView() {
		View contentView = new View(this);
		contentView = mInflater.inflate(R.layout.common_info_item_view, null);
 
		textViewTitle = (TextView) contentView.findViewById(R.id.text_title);
		textViewContent = (TextView) contentView.findViewById(R.id.text_detail);
 
		textViewTitle.setText(titleArray[selectedPosition]);
		textViewTitle.setPadding(10, 0, 10, 0);
		textViewContent.setText(descriptionsArray[selectedPosition]);
		textViewContent.setPadding(10, 5, 10, 5);
 
		scroll = (FriendlyScrollView) contentView.findViewById(R.id.scroll);
		scroll.setOnTouchListener(onTouchListener);
		scroll.setGestureDetector(gestureDetector);
 
		return contentView;
	}
 
	private View.OnTouchListener onTouchListener = new View.OnTouchListener() {
 
		public boolean onTouch(View v, MotionEvent event) {
			// TODO Auto-generated method stub
			return gestureDetector.onTouchEvent(event);
		}
	};
 
	public class CommonGestureListener extends SimpleOnGestureListener {
 
		@Override
		public boolean onDown(MotionEvent e) {
			// TODO Auto-generated method stub
			Log.d("QueryViewFlipper", "====> Jieqi: do onDown...");
			return false;
		}
 
		@Override
		public void onShowPress(MotionEvent e) {
			// TODO Auto-generated method stub
			Log.d("QueryViewFlipper", "====> Jieqi: do onShowPress...");
			super.onShowPress(e);
		}
 
		@Override
	    public void onLongPress(MotionEvent e) {
	        // TODO Auto-generated method stub
			Log.d("QueryViewFlipper", "----> Jieqi: do onLongPress...");
	    }
 
		@Override
		public boolean onSingleTapConfirmed(MotionEvent e) {
			// TODO Auto-generated method stub
			Log.d("QueryViewFlipper", "====> Jieqi: do onSingleTapConfirmed...");
			return false;
		}
 
		@Override
		public boolean onSingleTapUp(MotionEvent e) {
			// TODO Auto-generated method stub
			Log.d("QueryViewFlipper", "====> Jieqi: do onSingleTapUp...");
			return false;
		}
 
		@Override
		public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
				float velocityY){
			// TODO Auto-generated method stub
			Log.d("QueryViewFlipper", "====> Jieqi: do onFling...");
			if (e1.getX() - e2.getX() > 100 && Math.abs(velocityX) > 50) {
				//向左
				selectedPosition = selectedPosition + 1 < titleArray.length ? (selectedPosition + 1) : 0;
				viewFlipper.addView(getContentView());
				viewFlipper.setInAnimation(AnimationControl.inFromRightAnimation());
                viewFlipper.setOutAnimation(AnimationControl.outToLeftAnimation());
                viewFlipper.showNext();
                viewFlipper.removeViewAt(0);
			} else if (e2.getX() - e1.getX() > 100 &amp;&amp; Math.abs(velocityX) > 50) {
				//向右
				selectedPosition = selectedPosition > 0 ? (selectedPosition - 1) : (titleArray.length - 1);
				viewFlipper.addView(getContentView());
				viewFlipper.setInAnimation(AnimationControl.inFromLeftAnimation());
                viewFlipper.setOutAnimation(AnimationControl.outToRightAnimation());
				viewFlipper.showNext();
				viewFlipper.removeViewAt(0);
			}
			return true;
		}
 
		@Override
		public boolean onScroll(MotionEvent e1, MotionEvent e2,
				float distanceX, float distanceY) {
			// TODO Auto-generated method stub
			Log.d("QueryViewFlipper", "====> Jieqi: do onScroll...");
			return super.onScroll(e1, e2, distanceX, distanceY);
		}
 
    }
}

这个时候问题出现了，通过Log显示，当ScrollView中内容太短的时候，ScrollView不会触发OnScroll和OnFling事件，导致ViewFlipper左右滑动不响应。（当然后来的另一个测试表明这个问题在ListView上不存在）

为了解决这一个问题，我重新自定义了一个FriendlyScrollView类，来重写ScrollView的onTouchEvent和dispatchTouchEvent方法，具体如下：

import android.content.Context;
import android.util.AttributeSet;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.widget.ScrollView;
 
public class FriendlyScrollView extends ScrollView {
 
	GestureDetector gestureDetector;
 
    public FriendlyScrollView(Context context) {
		super(context);
		// TODO Auto-generated constructor stub
	}
 
	public FriendlyScrollView(Context context, AttributeSet attrs) {
		super(context, attrs);
		// TODO Auto-generated constructor stub
	}
 
	public FriendlyScrollView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		// TODO Auto-generated constructor stub
	}
 
	public void setGestureDetector(GestureDetector gestureDetector) {
		this.gestureDetector = gestureDetector;
	}
 
	@Override
	public boolean onTouchEvent(MotionEvent event) {
	    super.onTouchEvent(event);
	    return gestureDetector.onTouchEvent(event);
	}
 
	@Override
	public boolean dispatchTouchEvent(MotionEvent ev){
	    gestureDetector.onTouchEvent(ev);
	    super.dispatchTouchEvent(ev);
	    return true;
	} 
 
}

然后将common_info_view.xml和程序中的ScrollView改成FriendlyScrollView，终于解决了这个问题。

http://disanji.net/2011/02/19/solve-viewflipper-scrollview-flip-problem/