Android四大组件之Service的介绍

package com.servicedemo;
import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log;

/**
 * Created by YK on 2016/8/26.
 */
public class MyService extends Service {
    //当其他组件调用bindService()方法请求绑定Service时，该方法被回调。（默认为null）
    @Override
    public IBinder onBind(Intent intent) {
        Log.e("kaka", "onBind");
        return new MyBinder();
    }

    //当Service第一次创建时，回调该方法（只一次）。
    @Override
    public void onCreate() {
        super.onCreate();
        Log.e("kaka", "onCreate");
    }

    //当其他组件调用startService()方法请求启动Service时，该方法被回调（每次）。
    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Log.e("kaka", "onStartCommand");
        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public boolean onUnbind(Intent intent) {
        Log.e("kaka", "onUnbind");
        return super.onUnbind(intent);
    }

    //当Service被销毁时回调，在该方法中应清除一些占用的资源。
    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.e("kaka", "onDestroy");
    }

    class MyBinder extends Binder {
        public void doSomething(){
            Log.e("kaka","doSomething");
        }
    }
}

• 修改MainActivity中的代码，让MainActivity和MyService之间建立关联：

<span style="color:#2f2f2f;">package com.servicedemo;
import android.content.ComponentName;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.IBinder;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private Button mStartService, mStopService;
    private MyService.MyBinder myBinder;
    private ServiceConnection conn = new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            Log.e("kaka", "onServiceConnected");
            myBinder = (MyService.MyBinder) service;
            myBinder.doSomething();
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {
            Log.e("kaka", "onServiceDisconnected");
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        mStartService.setOnClickListener(this);
        mStopService.setOnClickListener(this);
    }

    private void initView() {
        mStartService = (Button) findViewById(R.id.start);
        mStopService = (Button) findViewById(R.id.stop);
    }


    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.start:
                //这里传入BIND_AUTO_CREATE，表示在Activity和Service关联后自动创建Service，
                //</span><span style="color:#ff0000;">这会使得MyService中的onCreate()方法得到执行，但onStartCommand()方法不会执行。</span><span style="color:#2f2f2f;">
                Intent startIntent = new Intent(this, MyService.class);
                bindService(startIntent, conn, BIND_AUTO_CREATE);
                break;
            case R.id.stop:
                //如果没有绑定服务就执行unbindService是会报错， java.lang.IllegalArgumentException: Service not registered:
                unbindService(conn);
                break;
            default:
                break;
        }
    }
}
</span>

运行结果及说明：

@Override
    protected void onDestroy(){
        super.onDestroy();
        unbindService(conn);
    }

Service生命周期总结