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。