为什么运行应用程序后绑定服务中的公共变量会发生变化？

Question

我在Android中使用绑定服务。我用按钮启动服务和停止服务，它工作正常。故事：我按下启动服务按钮，然后服务启动，我用showint按钮增加x，x增加，然后我关闭应用程序不停止服务然后再次运行应用程序，但公共 x 变为零并再次初始化。我需要没有重新初始化公共变量的服务。我该怎么做？怎么可能绑定。

public class MainActivity extends AppCompatActivity {
    BoundService mBoundService;
    boolean mServiceBound = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final TextView timestampText = (TextView) findViewById(R.id.timestamp_text);
        Button shownum = (Button) findViewById(R.id.shownum);
        Button stopService= (Button) findViewById(R.id.stop_service);
        Button start = (Button) findViewById(R.id.start);


        shownum.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                if (mServiceBound) {
                    timestampText.setText(mBoundService.shownum());
                }
            }
        });


        stopService.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                if (mServiceBound) {
                    unbindService(mServiceConnection);
                    mServiceBound = false;
                }
                Intent intent = new Intent(MainActivity.this,
                        BoundService.class);
                stopService(intent);

            }
        });


        start.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {

                Intent intent = new Intent(MainActivity.this, BoundService.class);
                startService(intent);
                bindService(intent, mServiceConnection, Context.BIND_AUTO_CREATE);

            }
        });

    }



    private ServiceConnection mServiceConnection = new ServiceConnection() {

        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            BoundService.MyBinder myBinder = (BoundService.MyBinder) service;
            mBoundService = myBinder.getService();
            mServiceBound = true;
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {
            mServiceBound = false;
        }


    };
}

和BoundService类：

public class BoundService extends Service {
    private IBinder mBinder = new MyBinder();
    public int x;

    @Override
        public void onCreate() {
//        super.onCreate();
        Toast.makeText(this,"onCreate",Toast.LENGTH_SHORT).show();
    }

    @Override
    public IBinder onBind(Intent intent) {
        Toast.makeText(this,"onBind",Toast.LENGTH_SHORT).show();
        return mBinder;
    }

    @Override
    public void onRebind(Intent intent) {
        Toast.makeText(this,"onRebind",Toast.LENGTH_SHORT).show();
        super.onRebind(intent);
    }

    @Override
    public boolean onUnbind(Intent intent) {
        Toast.makeText(this,"UUUUnbind",Toast.LENGTH_SHORT).show();
        return true;
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Toast.makeText(this,"onDestroy",Toast.LENGTH_SHORT).show();

    }

    public String shownum()
    {
        x++;
        return  String.valueOf(x);
    }

    public class MyBinder extends Binder {
        BoundService getService() {
            return BoundService.this;
        }
    }
}

Answer 1

从 Android 8 (Oreo) 开始，所有在应用关闭时应保持活动状态的服务应使用 startForegroundService() 启动，并应在运行时显示状态栏图标。

如果你不这样做，当应用程序关闭时服务会被杀死。

但是，您应该在 Logcat 中看到一些关于服务为何被终止的日志。