[英]Android: What is the best way to implement a synchronization service (via http post) in background (service)
這是我在網絡服務(帶有一些HTTP POST請求)之間同步數據的基本服務的最新實現。
基本上,在應用程序執行期間,我想繼續將帖子(每1分鍾)發送到我的Web服務。
package com.example.testservice;
import android.app.Service;
import android.content.Intent;
import android.os.Handler;
import android.os.HandlerThread;
import android.os.IBinder;
import android.os.Looper;
import android.os.Message;
import android.util.Log;
import android.widget.Toast;
public class HelloService extends Service {
private Looper mServiceLooper;
private ServiceHandler mServiceHandler;
// Handler that receives messages from the thread
private final class ServiceHandler extends Handler {
public ServiceHandler(Looper looper) {
super(looper);
}
@Override
public void handleMessage(Message msg) {
// empty
}
}
@Override
public void onCreate() {
// Start up the thread running the service. Note that we create a
// separate thread because the service normally runs in the process's
// main thread, which we don't want to block. We also make it
// background priority so CPU-intensive work will not disrupt our UI.
HandlerThread thread = new HandlerThread("ServiceStartArguments",
android.os.Process.THREAD_PRIORITY_BACKGROUND);
thread.start();
// Get the HandlerThread's Looper and use it for our Handler
mServiceLooper = thread.getLooper();
mServiceHandler = new ServiceHandler(mServiceLooper);
Log.d("SERVICE TEST onCreate", "Service created first time");
Toast.makeText(this, "service created", Toast.LENGTH_SHORT).show();
final long oneMinuteMs = 60 * 1000;
Runnable eachMinute = new Runnable() {
@Override
public void run() {
Log.d("SERVICE TEST run", "Each minute task executing");
mServiceHandler.postDelayed(this, oneMinuteMs);
}
};
mServiceHandler.postDelayed(eachMinute, oneMinuteMs);
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
// empty
// If we get killed, after returning from here, restart
return START_STICKY;
}
@Override
public IBinder onBind(Intent intent) {
// We don't provide binding, so return null
return null;
}
@Override
public void onDestroy() {
Log.d("SERVICE TEST onDestroy", "Service destroyed");
}
}
編碼:
package com.ncfsistemi.testservice;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Intent intent = new Intent(this, HelloService.class);
startService(intent);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
注意:我也嘗試過
TimerTask syncTask = new TimerTask()
但我有一些奇怪的行為(任務多次生成且時間控制錯誤)。 Android創建者不鼓勵TimerTask ...對嗎?
如果要根據某些時間表定期同步數據,最好的方法是使用SyncAdapter 。 看一下文檔,有很好的示例如何使用它。
如果要按需同步數據(例如,按活動的onResume方法),則可以使用IntentService 。
無論您做什么,都不要運行TimerTask
。 正如您自己發現的那樣,可能會發生意外的行為。 您可以在此處閱讀有關在Android OS下如何管理進程和線程的信息,並發現TimerTask
很可能被殺死。 對於http操作,您必須使用Service
因為它們具有較高的優先級。
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