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.
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();
}
}
