java - 向上滚动 ListView 时应用程序崩溃

Question

我有一个应用程序，它的 ListView 有 15 行。如果有新的查询要搜索，listivew 会被清理并向 ListView 添加新项目。但是在我的应用程序中进行一些搜索并将该项目添加到列表中后，我的应用程序正在被删除速度很慢，当我尝试向上滚动时它崩溃了。这是我的适配器

public class VideosAdapter extends BaseAdapter {

// The list of videos to display
public static List<Video> videos;
// An inflator to use when creating rows
private LayoutInflater mInflater;
private Context context;

/**
 * @param context this is the context that the list will be shown in - used to create new list rows
 * @param videos this is a list of videos to display
 */
public VideosAdapter(Context context, List<Video> videos) {
    VideosAdapter.videos = videos;
    this.mInflater = LayoutInflater.from(context);
    this.context = context;
}

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

@Override
public Object getItem(int position) {
    return videos.get(position);
}

@Override
public long getItemId(int position) {
    return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    final Video video = videos.get(position);

    if(video.getTitle()==null && video.getDuration()==-1)
    {
        convertView = mInflater.inflate(R.layout.more_results, null);
        View thumbnail = convertView.findViewById(R.id.thumbnail);
        thumbnail.setVisibility(View.INVISIBLE);
        return convertView;
    }
        //animation = AnimationUtils.loadAnimation(context, R.anim.push_up_in);
            // If convertView wasn't null it means we have already set it to our list_item_user_video so no need to do it again
    else if(convertView == null){
        // This is the layout we are using for each row in our list
        // anything you declare in this layout can then be referenced below
        convertView = mInflater.inflate(R.layout.list_item_user_video, null);
    }
    UrlImageView thumb = (UrlImageView) convertView.findViewById(R.id.list_image);
    //TextView size=(TextView) convertView.findViewById(R.id.size);
    TextView duration=(TextView) convertView.findViewById(R.id.duration);
    TextView title = (TextView) convertView.findViewById(R.id.userVideoTitleTextView); 


    int durationmin=video.getDuration()/60;
    int durationsec=video.getDuration()%60;

    if(durationsec<10) duration.setText(durationmin+":0"+durationsec);
    else{
        duration.setText(durationmin+":"+durationsec);
    }
     // thumb image

    // Get a single video from our list
    // Set the image for the list item
    thumb.setImageDrawable(video.getThumbUrl());
    // Set the title for the list item

    title.setText(video.getTitle());

    /*animation.setDuration(1000);
    convertView.startAnimation(animation);
    animation = null;*/

    return convertView;
}

我使用此代码设置适配器。

    VideosAdapter adapter = new VideosAdapter(getContext(), Allvideos);
    setAdapter(adapter);

我的logcat是这样的。

08-22 15:53:40.557: E/InputEventReceiver(619): Exception dispatching input event.
08-22 15:53:40.657: E/AndroidRuntime(619): FATAL EXCEPTION: main
08-22 15:53:40.657: E/AndroidRuntime(619): java.lang.NullPointerException
08-22 15:53:40.657: E/AndroidRuntime(619):  at com.skymaster.tut.ui.adapter.VideosAdapter.getView(VideosAdapter.java:108)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.widget.AbsListView.obtainView(AbsListView.java:2255)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.widget.ListView.makeAndAddView(ListView.java:1769)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.widget.ListView.fillUp(ListView.java:706)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.widget.ListView.fillGap(ListView.java:645)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.widget.AbsListView.trackMotionScroll(AbsListView.java:5040)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.widget.AbsListView.scrollIfNeeded(AbsListView.java:3197)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.widget.AbsListView.onTouchEvent(AbsListView.java:3471)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.View.dispatchTouchEvent(View.java:7127)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2170)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1905)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2176)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1919)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2176)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1919)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2176)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1919)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2176)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1919)
08-22 15:53:40.657: E/AndroidRuntime(619):  at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1925)
08-22 15:53:40.657: E/AndroidRuntime(619):  at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1379)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.app.Activity.dispatchTouchEvent(Activity.java:2396)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.support.v7.app.ActionBarActivityDelegateICS$WindowCallbackWrapper.dispatchTouchEvent(ActionBarActivityDelegateICS.java:268)
08-22 15:53:40.657: E/AndroidRuntime(619):  at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1873)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.View.dispatchPointerEvent(View.java:7307)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:3174)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:3119)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:4155)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:4134)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:4226)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:171)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.InputEventReceiver.nativeConsumeBatchedInputEvents(Native Method)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.InputEventReceiver.consumeBatchedInputEvents(InputEventReceiver.java:163)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.ViewRootImpl.doConsumeBatchedInput(ViewRootImpl.java:4205)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.ViewRootImpl$ConsumeBatchedInputRunnable.run(ViewRootImpl.java:4245)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.Choreographer$CallbackRecord.run(Choreographer.java:725)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.Choreographer.doCallbacks(Choreographer.java:555)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.Choreographer.doFrame(Choreographer.java:523)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:711)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.os.Handler.handleCallback(Handler.java:615)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.os.Handler.dispatchMessage(Handler.java:92)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.os.Looper.loop(Looper.java:137)
08-22 15:53:40.657: E/AndroidRuntime(619):  at android.app.ActivityThread.main(ActivityThread.java:4745)
08-22 15:53:40.657: E/AndroidRuntime(619):  at java.lang.reflect.Method.invokeNative(Native Method)
08-22 15:53:40.657: E/AndroidRuntime(619):  at java.lang.reflect.Method.invoke(Method.java:511)
08-22 15:53:40.657: E/AndroidRuntime(619):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
08-22 15:53:40.657: E/AndroidRuntime(619):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
08-22 15:53:40.657: E/AndroidRuntime(619):  at dalvik.system.NativeStart.main(Native Method)

正如您在我的代码中看到的那样，每行的布局中都有 URLIMAGEVIEW 使用此项目，我从每行的 url 加载不同的图像。并且在加载图像时会出现微调器，直到加载完成。URLIMAGEVIEW 可能是错误的原因，或者减慢我的应用程序的速度？

编辑:现在我发布了我原来的 logcat。错误就在这一行。

 duration.setText(durationmin+":"+durationsec);  

Answer 1

你使用notifyDataChanged()吗？它允许您在每次更改 View 内容时通知观察者，在您的情况下，每次列表视频更改时，您都必须使用 notifyDataChanged()。 http://developer.android.com/reference/android/widget/BaseAdapter.html#notifyDataSetChanged%28%29 。