延迟应用程序关闭并发送消息

Question

>实际上我有一个TCP客户端，它onStart连接到服务器并将设备IP和号码发送到它，但现在我希望当应用程序关闭时(onDestroy(延迟几秒钟(重新打开连接并发送另一条消息的正确时间(并发送另一条消息，其中我说设备处于脱机状态。

我尝试过在销毁方法上执行此操作，但可能这很疯狂，显然 这不起作用(我试图在销毁上做以下事情：

protected void onDestroy() {
new ConnectTask().execute("");
if (client != null) {
client.sendMessage(trm + "OFFLINE");
}
if (client != null) {
client.stopClient();
}
super.onDestroy();
server.onDestroy();
}

这是我的主活动代码，我在其中唤起TCP客户端并发送启动消息：

public class MainActivity extends AppCompatActivity {
Server server;
static Client client;
settings Settings;
public static TextView terminale, indr, msg;
TextView log;
static TextView msgServer;
static String ipp;
static String trm;
static DataBaseHandler myDB;
allert Allert;
SharedPreferences prefs;
String s1 = "GAB Tamagnini SRL © 2017 n" +
"Via Beniamino Disraeli, 17,n" +
"42124 Reggio Emilia n" +
"Telefono: 0522 / 38 32 22 n" +
"Fax: 0522 / 38 32 72 n" +
"Partita IVA, Codice Fiscale n" +
"Reg. Impr. di RE 00168780351 n" +
"Cap. soc. € 50.000,00 i.v. n" + "" +
"REA n. RE-107440 n" +
"presso C.C.I.A.A. di Reggio Emilia";
ImageButton settings, helps, allerts, home;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Utils.darkenStatusBar(this, R.color.colorAccent);
server = new Server(this);
myDB = DataBaseHandler.getInstance(this);
msg = (TextView) findViewById(R.id.msg);
log = (TextView) findViewById(R.id.log_avviso);
settings = (ImageButton) findViewById(R.id.impo);
helps = (ImageButton) findViewById(R.id.aiut);
allerts = (ImageButton) findViewById(R.id.msge);
home = (ImageButton) findViewById(R.id.gab);
terminale = (TextView) findViewById(R.id.terminal);
indr = (TextView) findViewById(R.id.indr);
msgServer = (TextView) findViewById(R.id.serverMSG);
final Cursor cursor = myDB.fetchData();
if (cursor.moveToFirst()) {
do {
indr.setText(cursor.getString(1));
terminale.setText(cursor.getString(2));
Client.SERVER_IP = cursor.getString(1);
trm = cursor.getString(2);
} while (cursor.moveToNext());
}

startService(new Intent(MainActivity.this,FinalizingOperationsService.class));
WifiManager wm = (WifiManager) getSystemService(WIFI_SERVICE);
ipp = Formatter.formatIpAddress(wm.getConnectionInfo().getIpAddress());
startConnection.postDelayed(runnableConnection,5000);
startMessage.postDelayed(runnableMessage,5500);
cursor.close();
server.Parti();

home.setOnClickListener(new View.OnClickListener() {
int counter = 0;
@Override
public void onClick(View view) {
counter++;
if (counter == 10) {
AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
builder.setCancelable(true);
builder.setMessage(s1);
builder.show();
counter = 0;
}
}
});
settings.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent impostazioni = new Intent(getApplicationContext(), settingsLogin.class);
startActivity(impostazioni);
}
});
helps.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent pgHelp = new Intent(getApplicationContext(), help.class);
startActivity(pgHelp);
}
});
allerts.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Server.count = 0;
SharedPreferences prefs = getSharedPreferences("MY_DATA", MODE_PRIVATE);
SharedPreferences.Editor editor = prefs.edit();
editor.clear();
editor.apply();
msg.setVisibility(View.INVISIBLE);
Intent pgAlert = new Intent(getApplicationContext(), allert.class);
startActivity(pgAlert);
}
});
}
@Override
protected void onDestroy() {
super.onDestroy();
server.onDestroy();
}
public static class ConnectTask extends AsyncTask<String, String, Client> {
@Override
protected Client doInBackground(String... message) {

client = new Client(new Client.OnMessageReceived() {
@Override
public void messageReceived(String message) {
publishProgress(message);
}
});
client.run();
return null;
}
@Override
protected void onProgressUpdate(String... values) {
super.onProgressUpdate(values);
msgServer.setTextColor(Color.parseColor("#00FF00"));
msgServer.setText("ONLINE");
Log.d("test", "response " + values[0]);
}
}
static Handler startConnection = new Handler();
static Runnable runnableConnection = new Runnable() {
@Override
public void run() {
new ConnectTask().execute("");
}
};
static Handler startMessage = new Handler();
static Runnable runnableMessage = new Runnable() {
@Override
public void run() {
final Cursor cursor = myDB.fetchData();
if (cursor.moveToFirst()) {
do {
Client.SERVER_IP = cursor.getString(1);
trm = cursor.getString(2);
} while (cursor.moveToNext());
}
if (client != null) {
client.sendMessage(ipp + "#" + trm);
}
}
};
static Handler startMessageClose = new Handler();
static Runnable runnableMessageClose = new Runnable() {
@Override
public void run() {
if (client != null) {
client.sendMessage(trm + "IS OFFLINE");
}
}
};

}

用于打开连接的正确命令是new ConnectTask().execute("");当我发送消息时if (client != null) { client.sendMessage(ipp + "#" + trm); }

FinalizingOperationsService.java 代码：

public class FinalizingOperationsService extends Service {
@Override
public IBinder onBind(Intent intent) {
return null;
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.d("FOService", "Service Started");
return START_STICKY;
}
@Override
public void onDestroy() {
super.onDestroy();
Log.d("FOService", "Service Destroyed");
}
@Override
public void onTaskRemoved(Intent rootIntent) {
Log.e("FOService", "Service Ends");
MainActivity.startConnection.removeCallbacks(MainActivity.runnableConnection);
MainActivity.startConnection.postDelayed(MainActivity.runnableConnection,100);
MainActivity.startMessageClose.removeCallbacks(MainActivity.runnableMessageClose);
MainActivity.startMessageClose.postDelayed(MainActivity.runnableMessageClose,110);
stopSelf();
}
}

Answer 1

创建一个这样的新服务，

public class FinalizingOperationsService extends Service {
@Override
public IBinder onBind(Intent intent) {
return null;
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.d("FOService", "Service Started");
return START_STICKY;
}
@Override
public void onDestroy() {
super.onDestroy();
Log.d("FOService", "Service Destroyed");
}
@Override
public void onTaskRemoved(Intent rootIntent) {
Log.e("FOService", "Service Ends");
// write server updation code here
// after completing code perform stopself() to stop this service;
}
}

并在清单文件中定义此服务，如下所示，

<service android:name=". FinalizingOperationsService" android:stopWithTask="false"/>

最后在主要活动的onCreate方法中启动服务

startService(newIntent(getContext(),FinalizingOperationsService.class));

说明：当应用程序被杀死或销毁时，将调用服务的onTaskRemoved((方法，因此在此方法中，您可以执行最终操作以通知服务器并在操作完成后停止服务。希望对您有所帮助。