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我使用延迟加载来下载图像,从而填充到水平列表视图中。但是滚动并不顺畅,特别是从右到左滚动时。这些是我的代码:

主页pg.xml

<ScrollView
            android:id="@+id/scrollView1"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:scrollbars="none" >

            <LinearLayout
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:orientation="vertical" > 

<RelativeLayout
                    android:id="@+id/Horizlistlatestnews"
                    android:layout_width="match_parent"
                    android:layout_height="105dp"
                      android:orientation="horizontal"
                      android:layout_below="@+id/Titlelatestnews"
                     >                   
                  <com.xxx.xxx.HorizontalView
            android:id="@+id/horizontallistln"
            android:layout_width="match_parent"
            android:layout_height="match_parent"  
            android:layout_marginLeft="2dp"         
            android:scrollbars="none"  


             >
        </com.xxx.xxx.HorizontalView>

                        </RelativeLayout>
                    </RelativeLayout>
                          <RelativeLayout
                    android:id="@+id/Boxoffice"
                    android:layout_width="match_parent"
                    android:layout_height="145dp"   
                    android:background="@drawable/bggray" >

                    <RelativeLayout
                    android:id="@+id/Titleboxofc"
                    android:layout_width="match_parent"
                    android:layout_height="30dp"                   

                     >

                        <TextView
                            android:id="@+id/textViewboxofc"
                            android:layout_width="wrap_content"
                            android:layout_height="wrap_content"
                            android:text="BOX OFFICE"
                            android:textColor="#FFFFFF"
                            android:textStyle="bold"
                            android:layout_alignParentLeft="true"
                            android:layout_marginLeft="5dp"
                            android:layout_centerVertical="true" />
                        <ProgressBar
                            android:id="@+id/progressBarboxofc"
                            android:layout_width="15dp"
                            android:layout_height="15dp"                            
                            android:visibility="gone"
                            android:layout_alignParentRight="true"
                            android:layout_marginRight="10dp"
                            android:layout_centerVertical="true"
                            />

                    </RelativeLayout>
                     <RelativeLayout
                    android:id="@+id/Horizlistboxofc"
                    android:layout_width="match_parent"
                    android:layout_height="105dp"
                      android:orientation="horizontal"
                      android:layout_below="@+id/Titleboxofc"
                     >                   
                  <com.xxx.xxx.HorizontalView
            android:id="@+id/horizontallistbo"
            android:layout_width="match_parent"
            android:layout_height="match_parent"  
            android:layout_marginLeft="2dp"         
            android:scrollbars="none"       

             >
        </com.xxx.xxx.HorizontalView>

                        </RelativeLayout>

 </LinearLayout>
        </ScrollView>

水平视图.java

package com.xxx.xxx;

import java.util.LinkedList;
import java.util.Queue;

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

public class HorizontalView extends AdapterView<Adapter> {

    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 mRemovedViewQueue = new LinkedList();
    private OnItemSelectedListener mOnItemSelected;
    private OnItemClickListener mOnItemClicked;
    private OnItemLongClickListener mOnItemLongClicked;
    private boolean mDataChanged = false;

    public HorizontalView(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 (HorizontalView.this) {
                mDataChanged = true;
            }
            invalidate();
            requestLayout();
        }

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

    };

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

    @Override
    public View getSelectedView() {
        return null;
    }

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

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

    @Override
    public void setSelection(int position) {

    }

    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 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() {
                @Override
                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,
                    (View) 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,
                    (View) mRemovedViewQueue.poll(), this);
            addAndMeasureChild(child, 0);
            leftEdge -= child.getMeasuredWidth();
            mLeftViewIndex--;
            mDisplayOffset -= child.getMeasuredWidth();
        }
    }

    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 (HorizontalView.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() {

        public boolean onDown(MotionEvent e) {
            return HorizontalView.this.onDown(e);
        }

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

        @Override
        public boolean onScroll(MotionEvent e1, MotionEvent e2,
                float distanceX, float distanceY) {
            synchronized (HorizontalView.this) {
                mNextX += (int) distanceX;
            }
            requestLayout();
            return true;
        }

        @Override
        public boolean onSingleTapConfirmed(MotionEvent e) {
            for (int i = 0; i < getChildCount(); i++) {
                View child = getChildAt(i);
                if (isEventWithinView(e, child)) {
                    if (mOnItemClicked != null) {
                        mOnItemClicked.onItemClick(HorizontalView.this, child,
                                mLeftViewIndex + 1 + i,
                                mAdapter.getItemId(mLeftViewIndex + 1 + i));
                    }
                    if (mOnItemSelected != null) {
                        mOnItemSelected.onItemSelected(HorizontalView.this,
                                child, mLeftViewIndex + 1 + i,
                                mAdapter.getItemId(mLeftViewIndex + 1 + i));
                    }
                    break;
                }
            }
            return true;
        }

        @Override
        public void onLongPress(MotionEvent e) {
            int childCount = getChildCount();
            for (int i = 0; i < childCount; i++) {
                View child = getChildAt(i);
                if (isEventWithinView(e, child)) {
                    if (mOnItemLongClicked != null) {
                        mOnItemLongClicked.onItemLongClick(HorizontalView.this,
                                child, mLeftViewIndex + 1 + i,
                                mAdapter.getItemId(mLeftViewIndex + 1 + i));
                    }
                    break;
                }
            }
        }

        private boolean isEventWithinView(MotionEvent e, View child) {
            Rect viewRect = new Rect();
            int[] childPosition = new int[2];
            child.getLocationOnScreen(childPosition);
            int left = childPosition[0];
            int right = left + child.getWidth();
            int top = childPosition[1];
            int bottom = top + child.getHeight();
            viewRect.set(left, top, right, bottom);
            return viewRect.contains((int) e.getRawX(), (int) e.getRawY());
        }
    };


}

Horizo​​ntalImageAdapter.java

package com.xxx.xxx;

import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.content.Context;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.ImageView.ScaleType;

public class HorizontalImageAdapter extends ArrayAdapter<RSSItem> {

    //private Context context;
            private List<RSSItem> objectsln = new ArrayList<RSSItem>();
            int ResourceId;
            private Activity activity;
            public ImageManager imageManager1;

    private static ViewHolder holder;


    public HorizontalImageAdapter(Activity a, int textViewResourceId, List<RSSItem> objectsln) {

        super(a, textViewResourceId, objectsln);
        System.out.println("LISTVIEW Constructor Called");
        activity = a;
        this.objectsln = objectsln;
        this.ResourceId = textViewResourceId;
        imageManager1 = new ImageManager(activity.getApplicationContext());
    }

    @Override
    public int getCount() {
        return this.objectsln.size();
    }

    @Override
    public RSSItem getItem(int position) {
        return this.objectsln.get(position);

    }

    @Override
    public long getItemId(int position) {
        System.out.println("LISTVIEW POSITION Called: "+position);
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        if (convertView == null) {
            holder = new ViewHolder();
             LayoutInflater infleter = (LayoutInflater) this.getContext().getSystemService(Context.
                       LAYOUT_INFLATER_SERVICE);
             convertView = infleter.inflate(ResourceId, parent, false);         
            holder = new ViewHolder();
            holder.imageViewln = (ImageView) convertView.findViewById(R.id.imageViewhlist);
            holder.textviewln=(TextView)convertView.findViewById(R.id.textViewhlist);
            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
        }
        RSSItem dataln = null ;

            //get the item
            if(objectsln.size() !=0){
                dataln = getItem(position);
            }else{
                Log.i("test TAG", "Size zero found");
            }

            if (dataln != null) {
                holder.textviewln.setText(dataln.title); // For taking the title from
                                                    // Web Services and set into text view
                System.out.println("TITLE LATEST NEWS - "+position+": "+dataln.title);  

                holder.imageViewln.setScaleType(ScaleType.FIT_XY);

                holder.imageViewln.setTag(dataln.imageurl);
                imageManager1.displayImage(dataln.imageurl, activity,
                        holder.imageViewln);
            }
        return convertView;
    }

    private static class ViewHolder {
        ImageView imageViewln;
        TextView textviewln;
    }

}
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