我的应用程序完美适用于模拟器和设备。两者都运行android 2.3.X.当我尝试在Android 4.0+上运行它时，它会在第二个活动加载时崩溃，结果为NullPointerException。
这是我的logcat输出：
03-18 20:01:59.133: E/AndroidRuntime(611): FATAL EXCEPTION: main
03-18 20:01:59.133: E/AndroidRuntime(611): java.lang.NullPointerException
03-18 20:01:59.133: E/AndroidRuntime(611): at com.example.forsitefoodapp.lazyAdapter.getimage(lazyAdapter.java:106)
03-18 20:01:59.133: E/AndroidRuntime(611): at com.example.forsitefoodapp.lazyAdapter.getView(lazyAdapter.java:81)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.widget.AbsListView.obtainView(AbsListView.java:2033)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.widget.ListView.makeAndAddView(ListView.java:1772)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.widget.ListView.fillDown(ListView.java:672)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.widget.ListView.fillFromTop(ListView.java:732)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.widget.ListView.layoutChildren(ListView.java:1625)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.widget.AbsListView.onLayout(AbsListView.java:1863)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.view.View.layout(View.java:11278)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.view.ViewGroup.layout(ViewGroup.java:4224)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.widget.RelativeLayout.onLayout(RelativeLayout.java:925)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.view.View.layout(View.java:11278)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.view.ViewGroup.layout(ViewGroup.java:4224)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.widget.FrameLayout.onLayout(FrameLayout.java:431)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.view.View.layout(View.java:11278)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.view.ViewGroup.layout(ViewGroup.java:4224)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1628)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1486)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.widget.LinearLayout.onLayout(LinearLayout.java:1399)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.view.View.layout(View.java:11278)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.view.ViewGroup.layout(ViewGroup.java:4224)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.widget.FrameLayout.onLayout(FrameLayout.java:431)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.view.View.layout(View.java:11278)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.view.ViewGroup.layout(ViewGroup.java:4224)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1489)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2442)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.os.Handler.dispatchMessage(Handler.java:99)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.os.Looper.loop(Looper.java:137)
03-18 20:01:59.133: E/AndroidRuntime(611): at android.app.ActivityThread.main(ActivityThread.java:4424)
03-18 20:01:59.133: E/AndroidRuntime(611): at java.lang.reflect.Method.invokeNative(Native Method)
03-18 20:01:59.133: E/AndroidRuntime(611): at java.lang.reflect.Method.invoke(Method.java:511)
03-18 20:01:59.133: E/AndroidRuntime(611): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
03-18 20:01:59.133: E/AndroidRuntime(611): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
03-18 20:01:59.133: E/AndroidRuntime(611): at dalvik.system.NativeStart.main(Native Method)
我正在使用ActionBarSherlock。我不知道这是否与这个问题有关。
修改
lazyAdapter是一个扩展BaseAdapter的类。我用它来向ListView添加行。
以下是代码：
public class lazyAdapter extends BaseAdapter {
private Activity activity;
List<HashMap<String,String>> data ;
private static LayoutInflater inflater=null;
public lazyAdapter(Activity a, List<HashMap<String,String>> d) {
activity = a;
data=d;
inflater = (LayoutInflater)activity.getSystemService(activity.getApplicationContext().LAYOUT_INFLATER_SERVICE);
//imageLoader=new ImageLoader(activity.getApplicationContext());
}
public int getCount() {
return data.size();
}
public Object getItem(int position) {
HashMap<String, String> vid = new HashMap<String,String>();
vid = data.get(position);
return vid;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
View vi=convertView;
if(convertView==null)
vi = inflater.inflate(R.layout.list_row, null);
TextView title = (TextView)vi.findViewById(R.id.title); // title
// TextView artist = (TextView)vi.findViewById(R.id.artist); // artist name
// TextView duration = (TextView)vi.findViewById(R.id.duration); // duration
ImageView thumb_image=(ImageView)vi.findViewById(R.id.list_image); // thumb image
HashMap<String, String> song = new HashMap<String,String>();
song = data.get(position);
// Setting all values in listview
title.setText(song.get(MainActivity.KEY_tittle));
// artist.setText(song.get(VideoPage.KEY_description));
// duration.setText(song.get(VideoPage.KEY_playTime));
String imageUrl= song.get(MainActivity.KEY_image);
if (imageUrl != null){
URL imgURL;
try {
imgURL = new URL(imageUrl);
thumb_image.setImageBitmap(getimage (imgURL));
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
//imageLoader.DisplayImage(song.get(VideoPage.KEY_THUMB_URL), thumb_image);
return vi;
}
public Bitmap getimage (URL ImgURL){
InputStream is = null;
BufferedInputStream bis = null;
Bitmap bmp = null;
try {
URLConnection conn = ImgURL.openConnection();
conn.connect();
is = conn.getInputStream();
bis = new BufferedInputStream( is );
bmp = BitmapFactory.decodeStream( bis );
} catch (MalformedURLException e) {
} catch (IOException e) {
Log.i("error","io err");
} finally {
try {
is.close();
bis.close();
} catch (IOException e) {
}
}
return bmp;
}
}
答案 0 :(得分：2)
您必须在Lazy图像中创建另一个线程。下载不适用于主线程上的Android 3.0+。
您应该在getImage()中创建另一个帖子以开始下载。