问题
How is it possible to change my asyncTask into service because everytime i close the app or the restart the device my aysncTask not working . I have aysnc that sends Post request to php server and i got back an image on every request so i putted setting option to the user he can choose to the picture of wallpaper to change on every 1,5,10,..... min but like i said i want to be service so when the user choose the timing to change the wallpaper and closes (destroy) the application the server still countinue to change here is my code
public class MainActivity extends AppCompatActivity {
TextView txt;
Button btn;
String forecastJsonStr;
RadioButton rd1, rd2, rd3, rd4, rd5, rd6, rd7;
Handler mHandler;
RadioGroup radioGroup;
private final static int INTERVAL = 1000*60 * 1; //1 min
private final static int INTERVAL2 = 1000*60*5; // 5 min
private final static int INTERVAL3 = 1000 * 60 * 10; // 10 min
private final static int INTERVAL4 = 1000 * 60 * 15; // 15 min
private final static int INTERVAL5 = 1000 * 60 * 30; // 30 min
private final static int INTERVAL6 = 1000 * 60 * 60; // 1 hour
private final static int INTERVAL7 = 1000 * 60 * 1440; // 1 day
private final String hostName = "http://555.555.555.555";
private final String hostRequestName = "/yay.php";
private final String hostWallpaperName = "/wallpaper/";
private static int SELECTED_INTERVAL = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
txt = (TextView) findViewById(R.id.textView);
rd1 = (RadioButton) findViewById(R.id.radioButton);
rd2 = (RadioButton) findViewById(R.id.radioButton2);
rd3 = (RadioButton) findViewById(R.id.radioButton3);
rd4 = (RadioButton) findViewById(R.id.radioButton4);
rd5 = (RadioButton) findViewById(R.id.radioButton5);
rd6 = (RadioButton) findViewById(R.id.radioButton6);
rd7 = (RadioButton) findViewById(R.id.radioButton7);
radioGroup = (RadioGroup) findViewById(R.id.radiogroup);
mHandler = new Handler();
btn = (Button) findViewById(R.id.button);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(rd1.isChecked()) {
SELECTED_INTERVAL = INTERVAL;
} else if (rd2.isChecked()) {
SELECTED_INTERVAL = INTERVAL2;
}
startRepeatingTask();
}
});
}
void startRepeatingTask() {
mHandlerTask.run();
}
Runnable mHandlerTask = new Runnable() {
@Override
public void run() {
new WallpaperData().execute();
mHandler.postDelayed(mHandlerTask, SELECTED_INTERVAL);
}
};
private class WallpaperData extends AsyncTask<Void, Void, String> {
@Override
protected String doInBackground(Void... params) {
HttpURLConnection urlConnection = null;
BufferedReader reader = null;
try {
URL url = new URL("http://555.555.555.555/yay.php");
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("POST");
urlConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
urlConnection.setDoInput(true);
urlConnection.setDoOutput(true);
urlConnection.connect();
DataOutputStream wr = new DataOutputStream(
urlConnection.getOutputStream());
wr.write("method=get_random_wallpaper".getBytes());
wr.flush();
wr.close();
InputStream inputStream = urlConnection.getInputStream();
StringBuffer buffer = new StringBuffer();
if (inputStream == null) {
return null;
}
reader = new BufferedReader(new InputStreamReader(inputStream));
String line;
while ((line = reader.readLine()) != null) {
buffer.append(line + "\n");
Log.d("hey", buffer.toString());
}
if (buffer.length() == 0) {
return null;
}
forecastJsonStr = buffer.toString();
return forecastJsonStr;
} catch (IOException e) {
Log.e("PlaceholderFragment", "Error ", e);
return null;
} finally {
if (urlConnection != null) {
urlConnection.disconnect();
}
if (reader != null) {
try {
reader.close();
} catch (final IOException e) {
e.printStackTrace();
}
}
}
}
@Override
protected void onPostExecute(final String forecastJsonStr) {
txt.setText(forecastJsonStr);
Thread thread = new Thread(new Runnable() {
@Override
public void run() {
WallpaperManager wallpaperManager = WallpaperManager.getInstance(getApplicationContext());
try {
Bitmap result = Picasso.with(getBaseContext())
.load(hostName + hostWallpaperName + forecastJsonStr)
.get();
wallpaperManager.setBitmap(result);
} catch (IOException ex) {
ex.printStackTrace();
}
}
});
thread.start();
super.onPostExecute(forecastJsonStr);
}
}
}
回答1:
For time intervals larger than 30 secs you should use AlarmManager instead of Handler's .postDelayed method. See these tutorials: https://developer.android.com/training/scheduling/alarms.html, http://code4reference.com/2012/07/tutorial-on-android-alarmmanager/ . There is a JonScheduler for scheduling repeating tasks, Vogella has tutorial on it: http://www.vogella.com/tutorials/AndroidTaskScheduling/article.html . In a few words: you create Service (InteneService), create PendingIntent, pointing to that service and schedule AlarmManager, which will be sending that intent, which, in turn, sill be launcing your IntentService.
来源：https://stackoverflow.com/questions/40340422/how-i-can-change-my-asynctask-into-service