安卓bindservice [英] android bindservice

问题描述

我得到空指针异常在行mService.start（），当我尝试结合已启动的服务。我从不同的活动（该服务被启动），同样的事情everythig去的权利。所有这些活动都是一个应用程序的一部分。

你觉得我做错了什么？

 公共类RouteOnMap扩展MapActivity {
    私有静态最终诠释NEW_LOCATION = 1;
    私有静态最终诠释GPS_OFF = 2;

    私人MapView类mMapView;
    私人ILocService MSERVICE;
    私人布尔mServiceStarted;
    私人布尔mBound;
    私人意图mServiceIntent;
    私人双人mLatitude，mLongitude;

    私人ServiceConnection连接=新ServiceConnection（）{
        公共无效onServiceConnected（组件名的className，的IBinder iservice）{
            MSERVICE = ILocService.Stub.asInterface（iservice）;
            mBound = TRUE;
        }

        公共无效onServiceDisconnected（组件名的className）{
            MSERVICE = NULL;
            mBound = FALSE;
        }

    };

    公共无效的onCreate（包savedInstanceState）{
        super.onCreate（savedInstanceState）;
        的setContentView（R.layout.mapview）;

        mMapView =（图形页面）findViewById（R.id.mapview）;
        mMapView.setBuiltInZoomControls（真正的）;
        mServiceIntent =新意图（）;
        mLatitude = 0.0;
        mLongitude = 0.0;
        mBound = FALSE;
    }

    @覆盖
    公共无效的OnStart（）{
        super.onStart（）;

        mServiceIntent.setClass（这一点，LocationService.class）;
        // startService（mServiceIntent）;
        如果（！mBound）{
            mBound = TRUE;
            this.bindService（mServiceIntent，连接，Context.BIND_AUTO_CREATE）;
        }
    }

    @覆盖
    公共无效onResume（）{
        super.onResume（）;


        尝试 {
            mService.start（）;
        }赶上（RemoteException的E）{
            e.printStackTrace（）;
        }

    }

    @覆盖
    公共无效的onPause（）{
        super.onPause（）;

        如果（mBound）{
            this.unbindService（连接）;
        }
    }

    @覆盖
    保护的布尔isRouteDisplayed（）{
        // TODO自动生成方法存根
        返回false;
    }

}
 

解决方案

您有没有办法知道，如果该服务被绑定 onResume的（）。 bindService（）是不是阻塞调用。呼叫 mService.start（）从 onServiceConnected（）方法。

I get null pointer exception at line mService.start() when i try to bind to an already started service. I do the same thing from different activity(where the service gets started) everythig goes right. All these activities are part of one application.

What do you think I do wrong?

public class RouteOnMap extends MapActivity{
    private static final int NEW_LOCATION = 1;
    private static final int GPS_OFF = 2;

    private MapView mMapView;
    private ILocService mService;
    private boolean mServiceStarted;
    private boolean mBound;
    private Intent mServiceIntent;
    private double mLatitude, mLongitude;

    private ServiceConnection connection = new ServiceConnection() {
        public void onServiceConnected(ComponentName className, IBinder iservice) {
            mService = ILocService.Stub.asInterface(iservice);
            mBound = true;
        }

        public void onServiceDisconnected(ComponentName className) {
            mService = null;
            mBound = false;
        }

    };

    public void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.mapview);

        mMapView = (MapView) findViewById(R.id.mapview);
        mMapView.setBuiltInZoomControls(true);      
        mServiceIntent = new Intent();
        mLatitude = 0.0;
        mLongitude = 0.0;
        mBound = false;
    }

    @Override
    public void onStart(){
        super.onStart();

        mServiceIntent.setClass(this, LocationService.class);
        //startService(mServiceIntent);
        if(!mBound){
            mBound = true;
            this.bindService(mServiceIntent, connection, Context.BIND_AUTO_CREATE);
        }
    }

    @Override
    public void onResume(){
        super.onResume();


        try {
            mService.start();
        } catch (RemoteException e) {
            e.printStackTrace();
        }

    }

    @Override
    public void onPause(){
        super.onPause();

        if(mBound){
            this.unbindService(connection);
        }
    }

    @Override
    protected boolean isRouteDisplayed() {
        // TODO Auto-generated method stub
        return false;
    }

}

解决方案

You have no way of knowing if the service is bound by onResume(). bindService() is not a blocking call. Call mService.start() from your onServiceConnected() method.

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