Android Service和Activity通信

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一，通过startService(Intent service)启动服务

只能通过广播实现通信

二，通过bindService(Intent service,ServiceConnection conn,int flags)启动服务

第一个参数如果只是调用setAction(String action)方法实现隐式的Intent调用Service会出现Implicit intents with startService are not safe错误，这是引文从Lollipop开始，service服务必须采用显示方式启动。

Android源码

改进方法：

1) 直接在Intent中指定要启动的Service

Intent intent = new Intent(xxx.this,xxx.class);

bindService(intent,ServiceConnection,flags);

2) 设置Action和PackageName

Intent intent = new Intent();

intent.setAction("xxx.xxx.xxx");

intent.setPackage(getPackageName());

bindService(intent,ServiceConnection,flags);

在调用bindService的Activity中实现定义ServiceConnection，并实现其中的方法

public void onServiceConnected(ComponentName name,IBinder service);//强转成自己实现的Binder对象，即可实现通信

public void onServiceDisconnected(ComponentName name);

在Service类中定义内部类实现Binder，在onBind回调方法中将Binder的实例返回。

实例：

public class MyService extends Service {    private int count = 110;    private String TAG = "Service";    private MyBinder binder = new MyBinder();    public class MyBinder extends Binder {        public int getCount(){            return count;        }    }    public MyService() {    }    @Override    public void onCreate() {        super.onCreate();        Log.e(TAG,"onCreate");    }    @Override    public int onStartCommand(Intent intent, int flags, int startId) {        Log.e(TAG,"onStartCommand");        return super.onStartCommand(intent, flags, startId);    }    @Override    public void onDestroy() {        Log.e(TAG,"onDestroy");        super.onDestroy();    }    @Override    public boolean onUnbind(Intent intent) {        Log.e(TAG,"onUnbind");        return super.onUnbind(intent);    }    @Override    public IBinder onBind(Intent intent) {        Log.e(TAG,"onBind");        return binder;    }}

public class MainActivity extends Activity{    private Button bind,unbind;    private MyService.MyBinder binder;    ServiceConnection connectionn = new ServiceConnection(){        @Override        public void onServiceConnected(ComponentName name, IBinder service) {            Log.e(TAG,"onServiceConnected");            binder = (MyService.MyBinder)service;            Log.e(TAG,binder.getCount() + "");        }        @Override        public void onServiceDisconnected(ComponentName name) {            Log.e(TAG,"onServiceDisconnected is called");        }    };    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        bind= (Button)findViewById(R.id.bind);        bind.setOnClickListener(new View.OnClickListener(){            @Override            public void onClick(View v) {Intent intent = new Intent(MainActivity.this,MyService.class);            bindService(intent, connectionn, Service.BIND_AUTO_CREATE);
            }        
});
        unbind= (Button)findViewById(R.id.unbind);        unbind.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {
unbindService(connectionn);
            }        });    }}

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