如果在android 4.x中运行合成模式,则如何处理屏幕方向更改

我试图实现以下代码来处理屏幕方向更改.

****DataBaseUpdateService.java****

public class DataBaseUpdateService extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState); 

        Updatetask Task = new Updatetask(this.getApplicationContext());
            if(Task.getStatus() == AsyncTask.Status.PENDING){
            Task.execute();};
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
    }

    @Override
    public void  onPause() {
        super.onPause();
    }

    @Override
    public void onResume() {
        super.onResume();
    }
}

================================================== ========================

****Androidmanifest.xml****
 <activity 
  android:name=".DataBaseUpdateService"
  android:configChanges="keyboardHidden|orientation"/>

这些代码与android 3.x或更低版本完美匹配.但是,它不能正常工作的android 4.x.

你有什么问题吗？

解决方法

解决方案1 – 如果您真的需要一个AsyncTask,请考虑两次.
解决方案2 – 将AsyncTask放入片段.
解决方案3 – 锁定屏幕方向
解决方案4 – 防止活动重新创建.

参考：http://androidresearch.wordpress.com/2013/05/10/dealing-with-asynctask-and-screen-orientation/

…..
发生问题的原因是当配置更改时重新创建活动,如方向更改等.
您可以锁定asyntask的onPreExecuted()方法中的方向更改,并在onPostExecuted()方法中解锁它.

import android.app.Activity;
import android.content.Context;
import android.content.pm.ActivityInfo;
import android.content.res.Configuration;
import android.os.AsyncTask;
import android.widget.Button;
import android.widget.ProgressBar;

public class MyAsyncTask extends AsyncTask<Void,Integer,Void> {
private Context context;
private ProgressBar progressBar;
private Button button;

public MyAsyncTask(ProgressBar progressBar,Context context,Button button){
    this.context=context;
    this.progressBar=progressBar;
    this.button=button;

}

private void lockScreenOrientation() {
    int currentOrientation =context.getResources().getConfiguration().orientation;
    if (currentOrientation == Configuration.ORIENTATION_PORTRAIT) {
        ((Activity) 
     context).setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
    } else {
        ((Activity) context). 
     setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
    }
}

private void unlockScreenOrientation() {
    ((Activity) context). 
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_SENSOR);
}

@Override
protected void onPreExecute() {
    // TODO Auto-generated method stub
    super.onPreExecute();
    progressBar.setMax(100);
    button.setEnabled(false);
    lockScreenOrientation();
}

@Override
protected Void doInBackground(Void... params) {
    // TODO Auto-generated method stub


    for(int i=0;i<=100;i++){
    try {
        Thread.sleep(200);
    } catch (InterruptedException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    publishProgress(i);

    }

return  null;   
}
@Override
protected void onProgressUpdate(Integer... values) {
    // TODO Auto-generated method stub
    super.onProgressUpdate(values);
    progressBar.setProgress(values[0]);
}
@Override
protected void onPostExecute(Void result) {
    // TODO Auto-generated method stub
    super.onPostExecute(result);
    button.setEnabled(true);
    unlockScreenOrientation();
}




}

如果在android 4.x中运行合成模式,则如何处理屏幕方向更改

解决方法

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