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我的horizo​​ntallistview不滚动请帮我解决我以前的帖子如何在自定义ListView中加载动态图像 这个Horizo​​​​ntalListView类将显示图像但问题是如果我只添加3张图像1&half显示不滚动我如何在其中添加滚动视图这段代码请帮助我。一切都很好，只有水平列表视图不能滚动

import android.content.Context;
import android.database.DataSetObserver;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.util.Log;
import android.view.GestureDetector;
import android.view.GestureDetector.OnGestureListener;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.AdapterView;
import android.widget.ListAdapter;
import android.widget.Scroller;


public class HorizontalListView extends AdapterView<ListAdapter> {

  public boolean mAlwaysOverrideTouch = true;
  protected ListAdapter mAdapter;
  private int mLeftViewIndex = -1;
  private int mRightViewIndex = 0;
  protected int mCurrentX;
  protected int mNextX;
  private int mMaxX = Integer.MAX_VALUE;
  private int mDisplayOffset = 0;
  protected Scroller mScroller;
  private GestureDetector mGesture;
  private Queue<View> mRemovedViewQueue = new LinkedList<View>();
  private OnItemSelectedListener mOnItemSelected;
  private OnItemClickListener mOnItemClicked;
  private OnItemLongClickListener mOnItemLongClicked;
  private boolean mDataChanged = false;
  private boolean mMeasureHeightForVisibleOnly = true;


  public HorizontalListView(Context context, AttributeSet attrs) {
    super(context, attrs);
    initView();
  }

  private synchronized void initView() {
    mLeftViewIndex = -1;
    mRightViewIndex = 0;
    mDisplayOffset = 0;
    mCurrentX = 0;
    mNextX = 0;
    mMaxX = Integer.MAX_VALUE;
    mScroller = new Scroller(getContext());
    mGesture = new GestureDetector(getContext(), mOnGesture);
  }

  @Override
    public void setOnItemSelectedListener(AdapterView.OnItemSelectedListener listener) {
      mOnItemSelected = listener;
    }

  @Override
    public void setOnItemClickListener(AdapterView.OnItemClickListener listener){
      mOnItemClicked = listener;
    }

  @Override
    public void setOnItemLongClickListener(AdapterView.OnItemLongClickListener listener) {
      mOnItemLongClicked = listener;
    }

  private DataSetObserver mDataObserver = new DataSetObserver() {

    @Override
      public void onChanged() {
        synchronized(HorizontalListView.this){
          mDataChanged = true;
        }
        invalidate();
        requestLayout();
      }

    @Override
      public void onInvalidated() {
        reset();
        invalidate();
        requestLayout();
      }

  };

  @Override
    public ListAdapter getAdapter() {
      return mAdapter;
    }

  @Override
    public View getSelectedView() {
      //TODO: implement
      return null;
    }

  @Override
    public void setAdapter(ListAdapter adapter) {
      if(mAdapter != null) {
        mAdapter.unregisterDataSetObserver(mDataObserver);
      }
      mAdapter = adapter;
      mAdapter.registerDataSetObserver(mDataObserver);
      reset();
    }

  /**
   * @param visibleOnly - If set to true, then height is calculated
   * only using visible views. If set to false then height is
   * calculated using _all_ views in adapter. Default is true.
   * Be very careful when passing false, as this may result in
   * significant performance hit for larger number of views.
   */
  public void setHeightMeasureMode(boolean visibleOnly) {
    if(mMeasureHeightForVisibleOnly != visibleOnly) {
      mMeasureHeightForVisibleOnly = visibleOnly;
      requestLayout();
    }
  }

  private synchronized void reset(){
    initView();
    removeAllViewsInLayout();
    requestLayout();
  }

  @Override
    public void setSelection(int position) {
      //TODO: implement
    }

  private void addAndMeasureChild(final View child, int viewPos) {
    LayoutParams params = child.getLayoutParams();
    if(params == null) {
      params = new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);
    }

    addViewInLayout(child, viewPos, params, true);
    child.measure(MeasureSpec.makeMeasureSpec(getWidth(), MeasureSpec.AT_MOST),
        MeasureSpec.makeMeasureSpec(getHeight(), MeasureSpec.AT_MOST));
  }

  @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
      super.onMeasure(widthMeasureSpec, heightMeasureSpec);

      if(MeasureSpec.getMode(heightMeasureSpec) != MeasureSpec.EXACTLY) {
        int height = 0;

        if(mMeasureHeightForVisibleOnly) {
          int childCount = getChildCount();
          for(int i = 0; i < childCount; i++) {
            View v = getChildAt(i);
            v.measure(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED);
            if(v.getMeasuredHeight() > height) {
              height = v.getMeasuredHeight();
            }
          }
        } else {

          /* Traverses _all_ views! Bypasses view recycler! */

          HashMap<Integer, View> mRecycler = new HashMap<Integer, View>();
          int childCount = getAdapter().getCount();
          for(int i = 0; i < childCount; i++) {
            int type = getAdapter().getItemViewType(i);
            View convertView = mRecycler.get(type);
            View v = getAdapter().getView(i, convertView, this);
            mRecycler.put(type, v);

            v.measure(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED);
            if(v.getMeasuredHeight() > height) {
              height = v.getMeasuredHeight();
            }
          }
        }

        if(MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.AT_MOST) {
          int maxHeight = MeasureSpec.getSize(heightMeasureSpec);
          if(maxHeight < height) {
            height = maxHeight;
          }
        }

        setMeasuredDimension(getMeasuredWidth(), height);
      }
    }

  @Override
    protected synchronized void onLayout(boolean changed, int left, int top,
        int right, int bottom) {
      super.onLayout(changed, left, top, right, bottom);

      if(mAdapter == null){
        return;
      }

      if(mDataChanged){
        int oldCurrentX = mCurrentX;
        initView();
        removeAllViewsInLayout();
        mNextX = oldCurrentX;
        mDataChanged = false;
      }

      if(mScroller.computeScrollOffset()){
        int scrollx = mScroller.getCurrX();
        mNextX = scrollx;
      }

      if(mNextX <= 0){
        mNextX = 0;
        mScroller.forceFinished(true);
      }
      if(mNextX >= mMaxX) {
        mNextX = mMaxX;
        mScroller.forceFinished(true);
      }

      int dx = mCurrentX - mNextX;

      removeNonVisibleItems(dx);
      fillList(dx);
      positionItems(dx);

      mCurrentX = mNextX;

      if(!mScroller.isFinished()){
        post(new Runnable(){
            public void run() {
            requestLayout();
            }
            });

      }
    }

  private void fillList(final int dx) {
    int edge = 0;
    View child = getChildAt(getChildCount()-1);
    if(child != null) {
      edge = child.getRight();
    }
    fillListRight(edge, dx);

    edge = 0;
    child = getChildAt(0);
    if(child != null) {
      edge = child.getLeft();
    }
    fillListLeft(edge, dx);


  }

  private void fillListRight(int rightEdge, final int dx) {
    while(rightEdge + dx < getWidth() && mRightViewIndex < mAdapter.getCount()) {

      View child = mAdapter.getView(mRightViewIndex, mRemovedViewQueue.poll(), this);
      addAndMeasureChild(child, -1);
      rightEdge += child.getMeasuredWidth();

      if(mRightViewIndex == mAdapter.getCount()-1) {
        mMaxX = mCurrentX + rightEdge - getWidth();
      }

      if (mMaxX < 0) {
        mMaxX = 0;
      }
      mRightViewIndex++;
    }

  }

  private void fillListLeft(int leftEdge, final int dx) {
    while(leftEdge + dx > 0 && mLeftViewIndex >= 0) {
      View child = mAdapter.getView(mLeftViewIndex, mRemovedViewQueue.poll(), this);
      addAndMeasureChild(child, 0);
      leftEdge -= child.getMeasuredWidth();
      mLeftViewIndex--;
      mDisplayOffset -= child.getMeasuredWidth();
    }
  }

  private void removeNonVisibleItems(final int dx) {
    View child = getChildAt(0);
    while(child != null && child.getRight() + dx <= 0) {
      mDisplayOffset += child.getMeasuredWidth();
      mRemovedViewQueue.offer(child);
      removeViewInLayout(child);
      mLeftViewIndex++;
      child = getChildAt(0);

    }

    child = getChildAt(getChildCount()-1);
    while(child != null && child.getLeft() + dx >= getWidth()) {
      mRemovedViewQueue.offer(child);
      removeViewInLayout(child);
      mRightViewIndex--;
      child = getChildAt(getChildCount()-1);
    }
  }

  private void positionItems(final int dx) {
    if(getChildCount() > 0){
      mDisplayOffset += dx;
      int left = mDisplayOffset;
      for(int i=0;i<getChildCount();i++){
        View child = getChildAt(i);
        int childWidth = child.getMeasuredWidth();
        child.layout(left, 0, left + childWidth, child.getMeasuredHeight());
        left += childWidth;
      }
    }
  }

  public synchronized void scrollTo(int x) {
    mScroller.startScroll(mNextX, 0, x - mNextX, 0);
    requestLayout();
  }

  @Override
    public boolean dispatchTouchEvent(MotionEvent ev) {
      boolean handled = super.dispatchTouchEvent(ev);
      handled |= mGesture.onTouchEvent(ev);
      return handled;
    }

  protected boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
      float velocityY) {
    synchronized(HorizontalListView.this){
      mScroller.fling(mNextX, 0, (int)-velocityX, 0, 0, mMaxX, 0, 0);
    }
    requestLayout();

    return true;
  }

  protected boolean onDown(MotionEvent e) {
    mScroller.forceFinished(true);
    return true;
  }

  private OnGestureListener mOnGesture = new GestureDetector.SimpleOnGestureListener() {

    @Override
      public boolean onDown(MotionEvent e) {
        return HorizontalListView.this.onDown(e);
      }

    @Override
      public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
          float velocityY) {
        return HorizontalListView.this.onFling(e1, e2, velocityX, velocityY);
      }

    @Override
      public boolean onScroll(MotionEvent e1, MotionEvent e2,
          float distanceX, float distanceY) {

        synchronized(HorizontalListView.this){
          mNextX += (int)distanceX;
        }
        requestLayout();

        return true;
      }

    @Override
      public boolean onSingleTapConfirmed(MotionEvent e) {
        Rect viewRect = new Rect();
        for(int i=0;i<getChildCount();i++){
          View child = getChildAt(i);
          int left = child.getLeft();
          int right = child.getRight();
          int top = child.getTop();
          int bottom = child.getBottom();
          viewRect.set(left, top, right, bottom);
          if(viewRect.contains((int)e.getX(), (int)e.getY())){
            if(mOnItemClicked != null){
              mOnItemClicked.onItemClick(HorizontalListView.this, child, mLeftViewIndex + 1 + i, mAdapter.getItemId( mLeftViewIndex + 1 + i ));
            }
            if(mOnItemSelected != null){
              mOnItemSelected.onItemSelected(HorizontalListView.this, child, mLeftViewIndex + 1 + i, mAdapter.getItemId( mLeftViewIndex + 1 + i ));
            }
            break;
          }

        }
        return true;
      }

    @Override
      public void onLongPress(MotionEvent e) {
        Rect viewRect = new Rect();
        int childCount = getChildCount();
        for (int i = 0; i < childCount; i++) {
          View child = getChildAt(i);
          int left = child.getLeft();
          int right = child.getRight();
          int top = child.getTop();
          int bottom = child.getBottom();
          viewRect.set(left, top, right, bottom);
          if (viewRect.contains((int) e.getX(), (int) e.getY())) {
            if (mOnItemLongClicked != null) {
              mOnItemLongClicked.onItemLongClick(HorizontalListView.this, child, mLeftViewIndex + 1 + i, mAdapter.getItemId(mLeftViewIndex + 1 + i));
            }
            break;
          }

        }
      }

  };



}
















               <?xml version="1.0" encoding="utf-8"?>
  <LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"

>

<ImageView
android:id="@+id/image"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#fff"
android:src="@drawable/icon"
/>

<TextView
android:id="@+id/title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#000"
android:gravity="center_horizontal"
/>



    </LinearLayout>












              <com.schoollunchapp.HorizontalListView
           android:id="@+id/listview"
           android:layout_width="wrap_content"
           android:layout_height="0dp"
              android:layout_weight="0.6"

           android:background="#EEEEEE">

 </com.schoollunchapp.HorizontalListView>
4

1 回答 1

1 
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
    boolean handled = super.dispatchTouchEvent(ev);
    handled |= mGesture.onTouchEvent(ev); //this is always true during scrolling
    return handled; //returning true will stop the listview functions to scroll it
}

@Override
  public boolean onScroll(MotionEvent e1, MotionEvent e2,
      float distanceX, float distanceY) {

    synchronized(HorizontalListView.this){
      mNextX += (int)distanceX;
    }
    requestLayout();

    return true;
  }

上面的代码是问题

根据我的说法，如果您在 dispatchTouchEvent 函数中返回 true，则列表视图将不会滚动，在您的情况下滚动时始终为 true。onScroll 手势始终返回 true，并且列表视图从不滚动。

您正在尝试手动执行滚动。尝试返回 false 并且不要手动处理滚动。

我无法阅读您的完整代码，因为它太长了，但我已经为您发现了问题，现在您可以以任何您想要的方式处理它。

于 2013-07-18T11:12:15.267 回答