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我在尝试填写我的 listView 时遇到了一些问题。列表视图的条目有一个特殊的设计原因是用于 youtube 的视频。它们由两个字符串（标题和描述）和图像组成。我得到一个 nullPointerException，但我还没有找到原因。

listVideos 正确填充，使用与 youtube 连接的线程并使用 JSON 获取播放列表中的每个视频。videosListView 是一个普通的 listView，R.layout.entry 是一个包含图像和另一个线性布局（视频标题和描述）的线性布局。

YoutubeActivity 类：

public class YoutubeActivity extends YouTubeBaseActivity implements YouTubePlayer.OnInitializedListener  {

    YouTubePlayerView youTubeView; 
    String URL_VIDEO = "CaA-k1l0xa4";
    String KEY_DEVELOPER = MYKEY;


    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.videos_layout);     
        YouTubePlayerView youtubeView = (YouTubePlayerView) findViewById(R.id.youtube_view);  
        Youtube youtube = new Youtube(getApplicationContext(), youtubeView, KEY_DEVELOPER); 
        //youtube.reproduce(URL_VIDEO);
        ListView videosListView = (ListView) findViewById(R.id.listListView);
        youtube.loadListView(videosListView, "PLOhl4anP1Mp1vJKmmqGAcu10h5OSbx4zf");
    }

    @Override
    public void onInitializationFailure(Provider arg0,
            YouTubeInitializationResult arg1) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onInitializationSuccess(Provider arg0, YouTubePlayer arg1,
            boolean arg2) {
        // TODO Auto-generated method stub

    }
}

Youtube 类（FillListView INSIDE）

public class Youtube{

YouTubePlayerView youtubeView;
String keyDeveloper;
ListView videosListView;
LinearLayout videoEntryView;
Context context;
String urlVideo;

public Youtube(Context context, YouTubePlayerView youtubeView, String keyDeveloper){

    this.context = context;
    this.youtubeView = youtubeView;
    this.keyDeveloper = keyDeveloper;

}

public void loadListView(ListView videosListView, String channel){

    this.videosListView = videosListView;

    new Thread(new GetYouTubeUserVideosTask(myHandler, channel)).start();

}

Handler myHandler = new Handler(){
    public void handleMessage(Message msg){
        fillListView(msg);
    }
};

private void fillListView(Message msg){

    ArrayList<Video> listVideos = (ArrayList) msg.getData().get("VideosList");  

    videosListView.setAdapter(new AdapterList(context, R.layout.entry, listVideos){
        @Override
        public void onEntry(Object entry, View view) {
            if (entry != null) {
                TextView superiorText = (TextView) view.findViewById(R.id.textView_superior); 
                if (superiorText != null) 
                    superiorText.setText(((Video) entry).getTitle()); 

                TextView inferiorText = (TextView) view.findViewById(R.id.textView_inferior); 
                if (inferiorText != null)
                    inferiorText.setText(((Video) entry).getUrl()); 

                ImageView thumb = (ImageView) view.findViewById(R.id.imageView_imagen);

                String aux = ((Video)entry).getThumbUrl();
                ImageDownloader downloader = new ImageDownloader();
                downloader.download(aux, thumb);
            }
        }
    });


private void fillListView(Message msg){

    ArrayList<Video> listVideos = (ArrayList) msg.getData().get("VideosList");  

    videosListView.setAdapter(new AdapterList(context, R.layout.entry, listVideos){
        @Override
        public void onEntry(Object entry, View view) {
            if (entry != null) {
                TextView superiorText = (TextView) view.findViewById(R.id.textView_superior); 
                if (superiorText != null) 
                    superiorText.setText(((Video) entry).getTitle()); 

                TextView inferiorText = (TextView) view.findViewById(R.id.textView_inferior); 
                if (inferiorText != null)
                    inferiorText.setText(((Video) entry).getUrl()); 

                ImageView thumb = (ImageView) view.findViewById(R.id.imageView_imagen);

                String aux = ((Video)entry).getThumbUrl();
                ImageDownloader downloader = new ImageDownloader();
                downloader.download(aux, thumb);
            }
        }
    });`

以防万一，adapterList 类如下所示：

public abstract class AdapterList extends BaseAdapter{

private ArrayList<?> entries; 
private int R_layout_IdView; 
private Context context;

public AdapterList(Context context, int R_layout_IdView, ArrayList<?> entry){

    super();
    this.entries = entry;
    this.R_layout_IdView = R_layout_IdView;
    this.context = context;

}

@Override
public View getView(int posicion, View view, ViewGroup pariente) {
    if (view == null) {
        LayoutInflater vi = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
        view = vi.inflate(R_layout_IdView, null); 
    }
    onEntry (entries.get(posicion), view);
    return view; 
}

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

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

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

public abstract void onEntry(Object object, View view);

}

视频布局.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/LinearLayout1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@color/Blanco"
android:gravity="center"
android:orientation="vertical"
tools:context=".MainActivity" >

<ImageView
    android:id="@+id/header"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:contentDescription="@string/app_name"
/>

<TextView
    android:id="@+id/tituloTextView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:paddingBottom="6dp"
    android:text="@string/title"
    android:textColor="@color/Negro"
    android:textSize="20sp"
    android:textStyle="bold" />

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

<ListView
    android:id="@+id/listaListView"
    android:layout_width="match_parent"
    android:layout_height="136dp"
    android:background="@color/Blanco"
    android:paddingBottom="15dp" >

</ListView>

</LinearLayout>

<com.google.android.youtube.player.YouTubePlayerView
    android:id="@+id/youtube_view"
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_weight="0.83"
     />

入口.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/entryListView"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal" >

    <ImageView
        android:id="@+id/imageView_imagen"
        android:layout_width="50dp"
        android:layout_height="50dp"
        android:adjustViewBounds="true"
        android:scaleType="fitXY"
        android:contentDescription="@string/DescriptionImage"
        android:src="@android:drawable/ic_menu_gallery" />

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:orientation="vertical" >

        <TextView
            android:id="@+id/textView_superior"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/largeText"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:textSize="14sp" />

        <TextView
            android:id="@+id/textView_inferior"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/smallText"
            android:textAppearance="?android:attr/textAppearanceSmall"
            android:textSize="12sp" />

    </LinearLayout>

</LinearLayout>

错误日志：

08-24 13:34:51.828: E/AndroidRuntime(7580): FATAL EXCEPTION: main
08-24 13:34:51.828: E/AndroidRuntime(7580): java.lang.NullPointerException
08-24 13:34:51.828: E/AndroidRuntime(7580):     at guidelines.youtube.Youtube.fillListView(Youtube.java:67)
08-24 13:34:51.828: E/AndroidRuntime(7580):     at guidelines.youtube.Youtube.access$0(Youtube.java:63)
08-24 13:34:51.828: E/AndroidRuntime(7580):     at guidelines.youtube.Youtube$1.handleMessage(Youtube.java:59)
08-24 13:34:51.828: E/AndroidRuntime(7580):     at android.os.Handler.dispatchMessage(Handler.java:99)
08-24 13:34:51.828: E/AndroidRuntime(7580):     at android.os.Looper.loop(Looper.java:137)
08-24 13:34:51.828: E/AndroidRuntime(7580):     at android.app.ActivityThread.main(ActivityThread.java:4645)
08-24 13:34:51.828: E/AndroidRuntime(7580):     at java.lang.reflect.Method.invokeNative(Native Method)
08-24 13:34:51.828: E/AndroidRuntime(7580):     at java.lang.reflect.Method.invoke(Method.java:511)
08-24 13:34:51.828: E/AndroidRuntime(7580):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:809)
08-24 13:34:51.828: E/AndroidRuntime(7580):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:576)
08-24 13:34:51.828: E/AndroidRuntime(7580):     at dalvik.system.NativeStart.main(Native Method)

知道错误来自哪里吗？谢谢！

4

1 回答 1

1

解决了！经典的空指针愚蠢的错误...我在做 ListView list = ListView videosListView = (ListView) findViewById(R.id.listListView); 但是videos_layout.xml 中的listView 的ID 为listaListView ...该死的，我讨厌这些错误！浪费了这么多时间。

于 2013-11-04T18:39:48.150 回答