Question

我发现了一个奇怪的错误，当我在4.0以上的设备上吃午餐时，我在搜索我的视频时迷恋，当我在2.3上使用它时一切都好。

这是一个Youtube搜索/播放器。

这是我的错误：

 07-01 17:30:21.324: E/AndroidRuntime(23429): FATAL EXCEPTION: main
07-01 17:30:21.324: E/AndroidRuntime(23429): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.searcher1/com.example.searcher1.JsonParsingActivity}: java.lang.NullPointerException
07-01 17:30:21.324: E/AndroidRuntime(23429):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2198)
07-01 17:30:21.324: E/AndroidRuntime(23429):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2225)
07-01 17:30:21.324: E/AndroidRuntime(23429):    at android.app.ActivityThread.access$600(ActivityThread.java:151)
07-01 17:30:21.324: E/AndroidRuntime(23429):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1301)
07-01 17:30:21.324: E/AndroidRuntime(23429):    at android.os.Handler.dispatchMessage(Handler.java:99)
07-01 17:30:21.324: E/AndroidRuntime(23429):    at android.os.Looper.loop(Looper.java:153)
07-01 17:30:21.324: E/AndroidRuntime(23429):    at android.app.ActivityThread.main(ActivityThread.java:5070)
07-01 17:30:21.324: E/AndroidRuntime(23429):    at java.lang.reflect.Method.invokeNative(Native Method)
07-01 17:30:21.324: E/AndroidRuntime(23429):    at java.lang.reflect.Method.invoke(Method.java:511)
07-01 17:30:21.324: E/AndroidRuntime(23429):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
07-01 17:30:21.324: E/AndroidRuntime(23429):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
07-01 17:30:21.324: E/AndroidRuntime(23429):    at dalvik.system.NativeStart.main(Native Method)
07-01 17:30:21.324: E/AndroidRuntime(23429): Caused by: java.lang.NullPointerException
07-01 17:30:21.324: E/AndroidRuntime(23429):    at com.example.searcher1.JsonParsingActivity.onCreate(JsonParsingActivity.java:78)
07-01 17:30:21.324: E/AndroidRuntime(23429):    at android.app.Activity.performCreate(Activity.java:5207)
07-01 17:30:21.324: E/AndroidRuntime(23429):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1082)
07-01 17:30:21.324: E/AndroidRuntime(23429):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2162)
07-01 17:30:21.324: E/AndroidRuntime(23429):    ... 11 more

错误在：

for (Video l : lst)
            {
            alrts.add(l);   
            }

完整代码：

public class JsonParsingActivity extends Activity  {


        //ListView that will hold our items references back to main.xml
        ListView lstTest;
        //Array Adapter that will hold our ArrayList and display the items on the ListView
        AlertsAdapter arrayAdapter;

        //List that will  host our items and allow us to modify that array adapter
        ArrayList<Video> alrts=null;
        private TextView button;
        private EditText result;
        final Context context = this;

        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.search_tab);

            String username = null;      
            Bundle extras = getIntent().getExtras();

            if(extras != null)
            {
                username = extras.getString("searchterm");
            }

           //Initialize ListView
            lstTest= (ListView)findViewById(R.id.list);
            button = (TextView) findViewById(R.id.frontImage);
            result = (EditText) findViewById(R.id.editTextResult);


          //Initialize our ArrayList
            alrts = new ArrayList<Video>();

           //Initialize our array adapter notice how it references the listitems.xml layout
            arrayAdapter = new AlertsAdapter(JsonParsingActivity.this, R.layout.youtube_list_item,alrts);

          //Set the above adapter as the adapter of choice for our list
            lstTest.setAdapter(arrayAdapter);

            List<Video> lst = null;
            try {
                lst = new YouTube().getVideos(username);
            } catch (YouTubeException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }





            for (Video l : lst)
            {
            alrts.add(l);   
            }





            arrayAdapter.notifyDataSetChanged();



     // listening to single list item on click
        lstTest.setOnItemClickListener(new OnItemClickListener() {
          public void onItemClick(AdapterView<?> parent, View view,
              int position, long id) {

              String s = Video.getId(position);
              Intent intent = new Intent(Intent.ACTION_VIEW, 
                      Uri.parse("vnd.youtube://" 
                    + s ));
              startActivity(intent); 




}
        });

        button.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View arg0) {


                 String Data = result.getText().toString();

                 Intent i = new Intent(context,JsonParsingActivity.class);
                 Bundle extras = new Bundle();
                 extras.putString("searchterm", Data);
                 i.putExtras(extras);
                 startActivityForResult(i, 1);



}
});    



        }

        @Override
        public void onBackPressed() {
            // TODO Auto-generated method stub
            super.onBackPressed();

            Intent i = new Intent(context,SearchActivity.class);
            this.finish();
            startActivityForResult(i, 1);

        }

        @Override
        protected void onDestroy() {
            // TODO Auto-generated method stub
            super.onDestroy();
        }





    }

Answer 1

我发现了如何修复它：

StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);

由于Json异常，我不得不添加它。

在4.0设备上使用app时出错Json异常

1 个答案: