正在实施一项服务以从服务器获取更新，如下所示：
public class Myupdates extends Service {
private static final String TAG = "AutoUpdates";
private static final int started = 0;
static SQLiteDatabase db;
private boolean isRunning = false;
private CountDownTimer timer;
@Override
public void onCreate() {
this.db = openOrCreateDatabase("db", Context.MODE_PRIVATE, null);
//Log.i(TAG, "Service onCreate");
isRunning = true;
}
int mCount = 1;
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
//Log.i(TAG, "Service onStartCommand");
//Creating new thread for my service
//Always write your long running tasks in a separate thread, to avoid ANR
new Thread(new Runnable() {
@Override
public void run() {
if (isRunning) {
new Timer().scheduleAtFixedRate(new TimerTask() {
@Override
public void run() {
updates();
}
}, 0, 30000);
}
//Stop service once it finishes its task
//stopSelf();
}
}).start();
return Service.START_STICKY;
}
@Override
public IBinder onBind(Intent arg0) {
//Log.i(TAG, "Service onBind");
return null;
}
@Override
public void onDestroy() {
isRunning = false;
//Log.i(TAG, "Service onDestroy");
}
/*
HANDLE ADVERTS
*/
protected void updates() {
/*
JSON
*/
final JSONObject json = new JSONObject();
final JSONObject manJson = new JSONObject();
try {
manJson.put("userid", "4444");
manJson.put("version", "6.0");
final String j = json.put("UPDATE", manJson).toString();
final String base_url = "https://myweburl.com";
// Instantiate the RequestQueue.
RequestQueue queue = Volley.newRequestQueue(this);
// Request a string response from the provided URL.
StringRequest stringRequest = new StringRequest(Request.Method.POST, base_url, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
//Log.i(TAG, "received "+response);
try {
JSONObject object = (JSONObject) new JSONTokener(response).nextValue();
String update = object.getString("UPDATE");
} catch (JSONException e) {
return;
}
return;
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
//perform operation here after getting error
return;
}
}) {
@Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
//pack message into json
try {
params.put("data", j.toString());
} catch (Exception e) {
//Log.i(TAG,"Map error: Unable to compile post");
}
return params;
}
@Override
public Map<String, String> getHeaders() throws AuthFailureError {
Map<String, String> params = new HashMap<String, String>();
params.put("Content-Type", "application/x-www-form-urlencoded");
return params;
}
};
// Add the request to the RequestQueue.
queue.add(stringRequest);
// ends here
return;
} catch (Exception e) {
//Log.i(TAG,"ERROR: Unable to get setup settings");
} // end exception write
return;
}
}
但是，在长时间运行服务后，应用程序崩溃并出现以下错误：
03-08 00:19:41.570 11239-11253/com.mobiledatabook.com.dialcode E/AndroidRuntime：FATAL EXCEPTION：Timer-0 Process：com.mobiledatabook.com.dialcode，PID：11239 java.lang.OutOfMemoryError：pthread_create（堆栈大小16384字节）失败：再试一次java.lang.VMThread.create（本地方法）at java.lang.Thread.start（Thread.java:1029）atcom.android.volley.Request estQueue.start（RequestQueue.java:152）atcom.android.volley.toolbox.Volley.newRequest estQueue（Volley.java:66）atcom.android.dialde.Myupdate.iDialAutoUpdate（Myupdates.java:128）atcom.mobiledatabook.com.dialde.Myupdates1美元1.run（Myupdates.java:74）at java.util.TimerTimerImpl.run美元（Timer.java:284）
错误：java. lang.OutOfMemoryError。
有人可以帮助我改进此代码，以避免在长时间运行服务后导致应用程序崩溃吗？
发生这种情况是因为您通过传递Activitycontext多次创建RequestQueue实例。您应该使用Application类创建一次实例，然后在需要时一次又一次地使用它。像这样创建一个应用程序类，
public class AppController extends Application {
private static AppController sInstance;
private RequestQueue mRequestQueue;
@Override
public void onCreate() {
super.onCreate();
sInstance = this;
}
public static synchronized AppController getInstance() {
return sInstance;
}
public RequestQueue getRequestQueue() {
if (mRequestQueue == null) {
mRequestQueue = Volley.newRequestQueue(getApplicationContext());
}
return mRequestQueue;
}
}
那就这样用吧
RequestQueue queue=AppController.getInstance().getRequestQueue();
注意：通过一次又一次地将上下文传递给请求队列，您正在填满您的ram，这会导致无法分配更多空间时出现OutOfMemoryException
正如android官方文档中提到的，
一个关键概念是，Request estQueue必须使用Application上下文来实例化，而不是使用Activity上下文。这确保了Request estQueue将在您的应用程序的生命周期内持续，而不是每次重新创建Activity时都重新创建（例如，当用户旋转设备时）。
