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我對Android開發和StackOverflow都很新，我希望我不會問一個以前曾經問過的愚蠢問題，但我找不到任何東西。當使用向上按鈕onRestoreInstanceState不叫
我正在製作一個應用程序，該應用程序在連接到藍牙設備時啓動（初始未綁定）服務，並且應該只在我告訴它斷開連接或斷開連接時停止。 服務啓動後，主要活動會綁定到它，並在調用onDestroy（）時解除綁定。當onStart被調用並且mIsBound爲true時，它也重新綁定。 mIsBound布爾值與onRestoreInstanceState（）一起存儲。
*誤連接可能是mIsBound，但你的想法
當我重新打開應用程序通常，從多任務菜單或通過服務圖標mIsBound仍設置爲正確的值一個更好的名字。屏幕方向不是問題，當通過後退按鈕打開輔助活動並返回到主要活動時，所有操作仍然順利。 但是，當我在輔助活動中使用向上按鈕時，mIsBound值會丟失，並且不會調用onRestoreInstanceState（）。
我需要這個來確定服務是否已經運行，因爲如果它不是，我調用bindService（）它將啓動而不需要它，當它停止但仍然綁定時，我會得到錯誤。
服務：
public class BluetoothService extends Service {
@Override
public IBinder onBind(Intent intent) {
return mBinder;
}
public class LocalBinder extends Binder {
BluetoothService getService() {
return BluetoothService.this;
}
}
private void connectionLost() {
Log.e(TAG, "connection lost");
disconnect();
}
public synchronized void disconnect() {
Log.d(TAG, "disconnect");
stopSelf();
}
private void showNotification(String s) {
// Set the icon, scrolling text and timestamp
Notification notification = new Notification(R.drawable.ic_launcher, s,
System.currentTimeMillis());
// The PendingIntent to launch our activity if the user selects this notification
PendingIntent contentIntent = PendingIntent.getActivity(this, 0,
new Intent(this, LedAndIrControlActivity.class), 0);
// Set the info for the views that show in the notification panel.
notification.setLatestEventInfo(this, s, s, contentIntent);
// Send the notification.
startForeground(NOTIFICATION, notification);
}
mainActivity：
public class MainActivity extends Activity {
private static boolean mIsBound = false;
private BluetoothService Com;
@Override
public void onStart() {
super.onStart();
if(mIsBound){
doBindService();
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
Log.i(TAG, "onSaveInstanceState");
outState.putBoolean("mIsBound", mIsBound);
}
public void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
Log.i(TAG, "onRestoreInstanceState");
mIsBound = savedInstanceState.getBoolean("mIsBound");
if(mIsBound){
doBindService();
}
}
protected void onDestroy() {
super.onDestroy();
Log.i(TAG, "onDestroy");
doUnbindService();
}
public boolean onOptionsItemSelected(MenuItem item) {
Intent serverIntent = null;
switch (item.getItemId()) {
case android.R.id.home:
return true;
case R.id.item1:
// Launch the DeviceListActivity to see devices and do scan
serverIntent = new Intent(this, DeviceListActivity.class);
startActivityForResult(serverIntent, REQUEST_CONNECT_DEVICE);
startService(new Intent(this, BluetoothService.class));
doBindService();
return true;
case R.id.item2:
// Disconnect device
Com.disconnect();
doUnbindService();
return true;
case R.id.item3:
serverIntent = new Intent(this, SecondaryActivity.class);
//serverIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(serverIntent);
return true;
default:
return super.onOptionsItemSelected(item);
}
}
void doBindService() {
Log.d(TAG, "doBindService");
// Establish a connection with the service. We use an explicit
// class name because we want a specific service implementation that
// we know will be running in our own process (and thus won't be
// supporting component replacement by other applications).
bindService(new Intent(getBaseContext(), //Binding.this
BluetoothService.class), mConnection, Context.BIND_AUTO_CREATE);
mIsBound = true;
}
void doUnbindService() {
if (mIsBound) {
Log.d(TAG, "doUnbindService");
// Detach our existing connection.
unbindService(mConnection);
mIsBound = false;
}
Com = null;
}
private ServiceConnection mConnection = new ServiceConnection() {
public void onServiceConnected(ComponentName className, IBinder service) {
// This is called when the connection with the service has been
// established, giving us the service object we can use to
// interact with the service. Because we have bound to a explicit
// service that we know is running in our own process, we can
// cast its IBinder to a concrete class and directly access it.
Com = ((BluetoothService.LocalBinder)service).getService();
invalidateOptionsMenu();
Log.i(TAG, "Service connected");
// Tell the user about this for our demo.
Toast.makeText(getBaseContext(), "local_service_connected",//Binding.this
Toast.LENGTH_SHORT).show();
}
public void onServiceDisconnected(ComponentName className) {
// This is called when the connection with the service has been
// unexpectedly disconnected -- that is, its process crashed.
// Because it is running in our same process, we should never
// see this happen.
Com = null;
Toast.makeText(getBaseContext(), "local service_disconected",//Binding.this
Toast.LENGTH_SHORT).show();
}
};
secondaryActivity：
public class SecondaryActivity extends Activity {
@Override
public boolean onOptionsItemSelected(MenuItem item) {
Intent serverIntent = null;
switch (item.getItemId()) {
case android.R.id.home:
// app icon in action bar clicked; go home
serverIntent = new Intent(this, MainActivity.class);
serverIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(serverIntent);
return true;
default:
return super.onOptionsItemSelected(item);
}
}
我的問題是我怎麼能確保該mIsBound值總是恢復？ 我發現使用SharedPreferences是一個選項，但似乎並不像這樣做的正確方法。
有關如何綁定到服務的任何其他建議（如果它已正常運行），也是值得讚賞的！
謝謝！
UPDATE：
我想到的其他方式來解決問題，那就是簡單地檢查是否真正的服務已在運行，然後（重新）綁定。 這樣做的方式在這裏解釋： How to check if a service is running on Android?
我仍然沒有放棄相信這是這樣做的正確或最好的方式，但它會爲現在要做的。 如果您對此有評論，我們將不勝感激。
當您在第二個活動中的按鈕操作之後返回主活動時，主活動是否會調用onCreate？我看到你正在使用意向標誌，並且從我的經驗來看，我已經看到了使用它們的意外結果。如果正在調用onCreate，則不會調用restoreInstance，因爲實際上您正在獲取新實例！ – Mike
是的，當我按下輔助活動中的向上按鈕時，具有和不具有意圖標誌設置的onCreate被調用。 你知道如何使用這個按鈕並返回到現有的intent實例嗎？ – ZeroDay
經過一些測試，我相信這是onCreate在onRestore之前被調用的預期行爲，所以我的第一條評論可能是無關緊要的....作爲另一種途徑，在您的主要活動中，當onRestoreInstanceState未被調用但您期望它時，是onCreate非null的savedInstanceState包？如果出現這種情況，您可以使用您在onRestore – Mike