我想通过AsynTask的代码更改屏幕的方向,但我注意到如果我把我的应用程序崩溃
getActivity().setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
在public String doInBackground(String... params)
或public void onPostExecute(String s)
相反,此方法适用于TabbedActivity类或Fragment类。为什么这种方法在AsynTask中不起作用?我真的需要用它!
这是logcat
01-01 18:03:40.953 3646-3783/com.example.utente.progettigscorsipa E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #1
Process: com.example.utente.progettigscorsipa, PID: 3646
java.lang.RuntimeException: An error occurred while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:318)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:354)
at java.util.concurrent.FutureTask.setException(FutureTask.java:223)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:243)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
at java.lang.Thread.run(Thread.java:761)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v4.app.FragmentActivity.setRequestedOrientation(int)' on a null object reference
at com.example.utente.progettigscorsipa.FotoCuboActivity$PlaceholderFragment$MultiplyTask.doInBackground(FotoCuboActivity.java:165)
at com.example.utente.progettigscorsipa.FotoCuboActivity$PlaceholderFragment$MultiplyTask.doInBackground(FotoCuboActivity.java:142)
at android.os.AsyncTask$2.call(AsyncTask.java:304)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:243)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
at java.lang.Thread.run(Thread.java:761)
01-01 18:03:41.340 3646-3682 / com.example.utente.progettigscorsipa E / EGL_emulation:tid 3682:eglSurfaceAttrib(1146):错误0x3009(EGL_BAD_MATCH) 01-01 18:03:41.340 3646-3682 / com.example.utente.progettigscorsipa W / OpenGLRenderer:无法在表面0x9637ab60上设置EGL_SWAP_BEHAVIOR,错误= EGL_BAD_MATCH
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
private boolean ciclo=true;
private Activity activity;
public PlaceholderFragment() {
}
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
{
switch (getArguments().getInt(ARG_SECTION_NUMBER))
{
case 1:
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getContext());
SharedPreferences.Editor editor = prefs.edit();
editor.putInt("i",0);
editor.commit();
new MultiplyTask().execute();
View rootView = inflater.inflate(R.layout.fragment_foto_cubo, container, false);
return rootView;
case 2:
View rootView2 = inflater.inflate(R.layout.fragment_foto_cubo4, container, false);
return rootView2;
case 3:
View rootView3 = inflater.inflate(R.layout.fragment_foto_cubo5, container, false);
return rootView3;
case 4:
View rootView4 = inflater.inflate(R.layout.fragment_foto_cubo6, container, false);
return rootView4;
case 5:
View rootView5 = inflater.inflate(R.layout.fragment_foto_cubo7, container, false);
return rootView5;
case 6:
View rootView6 = inflater.inflate(R.layout.fragment_foto_cubo8, container, false);
return rootView6;
case 7:
View rootView7 = inflater.inflate(R.layout.fragment_foto_cubo2, container, false);
return rootView7;
case 8:
prefs = PreferenceManager.getDefaultSharedPreferences(getContext());
editor = prefs.edit();
editor.putInt("i",7);
editor.commit();
new MultiplyTask().execute();
View rootView8 = inflater.inflate(R.layout.fragment_foto_cubo3, container, false);
return rootView8;
default:
View rootView0 = inflater.inflate(R.layout.fragment_foto_cubo, container, false);
return rootView0;
}
}
@Override
public void onAttach(Activity activity1)
{
super.onAttach(activity1);
activity = activity1;
}
public class MultiplyTask extends AsyncTask<String,String,String>
{
@Override
public void onPreExecute()
{
super.onPreExecute();
Toast.makeText(getActivity(),"Sto eseguendo",Toast.LENGTH_LONG).show();
}
@Override
public void onPostExecute(String s)
{
super.onPostExecute(s);
}
@Override
public String doInBackground(String... params)
{
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getContext());
while(ciclo)
{
if(prefs.getInt("i",0)==7)
activity.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
else
activity.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
}
return null;
}
}
}
答案 0 :(得分:0)
使用AsyncTask时,我在锁定当前方向的屏幕方面取得了更大的成功,而不是强制方向(就像你使用横向一样)。
//lock screen orientation
private void lockScreenOrientation() {
int currentOrientation = getResources().getConfiguration().orientation;
if (currentOrientation == Configuration.ORIENTATION_PORTRAIT) setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
else setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
}