Android学习小记-Service

Service：实现程序在应用后台运行

1. 创建Service文件

// new Intent(MainActivity.this, MyService.class）创建当前和目标的Activity
 @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        findViewById(R.id.btnStartService).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startService(new Intent(MainActivity.this, MyService.class));
            }
        });

        findViewById(R.id.btnCloseService).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                stopService(new Intent(MainActivity.this, MyService.class));
            }
        });
    }

2. 在Service中重写 onStartCommand 方法

 // 在onStartCommand
    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {

        new Thread() {
            @Override
            public void run() {
                super.run();
                System.out.println("服务正在运行");
            }
        }.start();


        return super.onStartCommand(intent, flags, startId);
    }

通过绑定的方式实现启动Service

// ServiceConnection 实现当前的接口
public class MainActivity extends AppCompatActivity implements View.OnClickListener, ServiceConnection {
    Intent intent = nil;
    @Override
    protected void onCreate(Bundle savedInstanceState) {

        intent = new Intent(MainActivity.this, MyService.class);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
//        findViewById(R.id.btnStartService).setOnClickListener(new View.OnClickListener() {
//            @Override
//            public void onClick(View v) {
//                startService(new Intent(MainActivity.this, MyService.class));
//            }
//        });
//
//        findViewById(R.id.btnCloseService).setOnClickListener(new View.OnClickListener() {
//            @Override
//            public void onClick(View v) {
//                stopService(new Intent(MainActivity.this, MyService.class));
//            }
//        });
        findViewById(R.id.btnStartService).setOnClickListener(this);
        findViewById(R.id.btnCloseService).setOnClickListener(this);
        findViewById(R.id.btnBindService).setOnClickListener(this);
        findViewById(R.id.btnUnbindService).setOnClickListener(this);

    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case  R.id.btnStartService:
                startService(intent);
                break;
            case  R.id.btnCloseService:
                stopService(intent);
                break;
            case  R.id.btnBindService:
                bindService(intent,this, Context.BIND_AUTO_CREATE);
                break;
            case  R.id.btnUnbindService:
                unbindService(this);
                break;
        }
    }

    @Override
    public void onServiceConnected(ComponentName name, IBinder service) {
        // 服务被绑定时候执行
    }

    @Override
    public void onServiceDisconnected(ComponentName name) {
        // 服务崩溃的时候执行
    }
}

在MyService中 重写

  public IBinder onBind(Intent intent) {
        // TODO: Return the communication channel to the service.
        return  new Binder(); //
    }

public class MyService extends Service {
    public MyService() {

    }

    @Override
    public IBinder onBind(Intent intent) {
        // TODO: Return the communication channel to the service.
        return  new Binder(); //
    }


    // 在onStartCommand
    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {

        new Thread() {
            @Override
            public void run() {
                super.run();
                System.out.println("服务正在运行");
            }
        }.start();


        return super.onStartCommand(intent, flags, startId);
    }
}