android

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关于安卓BindService 绑定问题

BindService 主要用于当用户想要将活动activity与service进行绑定，当activity结束时（调用者）service也跟着一起结束了；而startService()只能用来启动服务，当服务启动后，就与前台活动没有了关系；

当我们要从service外部获得service中的方法内容时，我们必须要Ibinder返回的service对象才能操作；所以我们必须利用bindservice的方式去绑定服务获取binder对象，利用binder的方式去获取service的方法内容；

使用bindservice的具体过程如下：

1）创建意图：Intent intent = new Intent(MainActivity.this,BindService.class);

2）创建bindservice对象：bindService(intent,conn,BIND_AUTO_CREATE);

3）创建内部类MyBinder、新建mybinder对象：

private  MyBinder myBinder = new MyBinder();    class MyBinder extends Binder{        public BindService getService(){            return BindService.this;        }    }

4）onBind()返回mybinder对象：

public IBinder onBind(Intent intent) {        return myBinder;    }

5）通过serviceconnection获取Binder对象进一步来获取service对象，最后调用service中的方法：

ServiceConnection conn = new ServiceConnection() {        @Override        public void onServiceConnected(ComponentName name, IBinder service) {            BindService.MyBinder binder = (BindService.MyBinder)service;            BindService bindService = binder.getService();            bindService.print();        }        @Override        public void onServiceDisconnected(ComponentName name) {        }    };

示例代码：

MainActivity

public class MainActivity extends AppCompatActivity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        initEvent();    }    ServiceConnection conn = new ServiceConnection() {        @Override        public void onServiceConnected(ComponentName name, IBinder service) {            BindService.MyBinder binder = (BindService.MyBinder)service;            BindService bindService = binder.getService();            bindService.print();        }        @Override        public void onServiceDisconnected(ComponentName name) {        }    };    private void initEvent() {        findViewById(R.id.button4).setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                Intent intent = new Intent(MainActivity.this,BindService.class);                bindService(intent,conn,BIND_AUTO_CREATE);            }        });        findViewById(R.id.button5).setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                unbindService(conn);            }        });    }}

BindService

public class BindService extends Service {        public void print(){        Log.d(TAG, "print: BindService");    }    @Override    public void onCreate() {        super.onCreate();        Log.d(TAG, "onCreate");    }    @Override    public void onStart(Intent intent, int startId) {        super.onStart(intent, startId);        Log.d(TAG, "onStart");    }    @Override    public int onStartCommand(Intent intent, int flags, int startId) {        Log.d(TAG, "onStartCommand");        return super.onStartCommand(intent, flags, startId);            }    @Override    public void onDestroy() {        super.onDestroy();        Log.d(TAG, "onDestroy");    }    @Override    public boolean onUnbind(Intent intent) {        Log.d(TAG, "onUnbind:");        return super.onUnbind(intent);    }    @Override    public void onRebind(Intent intent) {        Log.d(TAG, "onRebind");        super.onRebind(intent);    }    private  MyBinder myBinder = new MyBinder();    @Nullable    @Override    public IBinder onBind(Intent intent) {        return myBinder;    }    class MyBinder extends Binder{        public BindService getService(){            return BindService.this;        }    }}

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