android中Activity与service之间相互通信的实现方式

1. 使用intent代参，intent可以带基础数据类型，基础数据类型的数组，序列化对象，集合
2. 使用广播
3. 使用单例模式，在activity与service中少用
4. bindService获取引用，AIDL（进程中通信）基础，推荐使用

activity生命周期

下面是代码：

MainActivity

public class MainActivity extends AppCompatActivity {


    MyService myservice;

    private static MainActivity instance;
    //静态的他一直持有MainActivity的引用，activity是不会退的，也就是程序都退出了，这个引用还在里面，会造成内层泄露
    //activity和service都少用单例模式

    public static MainActivity getInstance() {

        return instance;
    }


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        instance = this;
        IntentFilter filter = new IntentFilter("activity");
        //上面的activity是用来过滤的service发送广播中所用的intent
        registerReceiver(receiver, filter);
    }


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


    public void myIntent(View v) {
        Intent intent = new Intent(this, MyService.class);
        intent.putExtra("msg", "activity向service传参用intent方式：hello service");
        startService(intent);
    }

    public void guangbo(View v) {
        sendBroadcast(new Intent("service").putExtra("msg", "你好，服务器"));
    }

    BroadcastReceiver receiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            Log.e("TAG", "接收到Service发来的广播" + intent.getStringExtra("msg"));
        }
    };

    public void danli(View v) {
        //必须保证service不能为空
        //静态变量，最后释放,不用的时候要手动的将static变量=null；
        if (MyService.getInstance() != null) {
            MyService.getInstance().print("activity调用service中的单例");
        }
    }

    //使用BiandService
    public void bind(View v) {

        bindService(new Intent(this, MyService.class), conn, BIND_AUTO_CREATE);
    }

    ServiceConnection conn = new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            //这边的IBinder就是MyService中的onBind 中return的那个IBinder
            MyService.MyBind bind = (MyService.MyBind) service;
            myservice = bind.getService();//拿到我们的MyService
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {

        }
    };


    public void send(View v){
        myservice.startMusic();
    }
}

自己定义的MyService类

public class MyService extends Service {

    private static MyService instance;

    public static MyService getInstance() {
        return instance;
    }

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {

        return new MyBind();//这里不能return this 是应为Service不是IBinder的子类,需要自己定义
    }

    class MyBind extends Binder{
        public MyService getService(){
            return MyService.this;//内部类使用外部类的引用,把service返回回去
        }
    }

    public void startMusic(){
        //随便写一个方法
        Toast.makeText(this,"音乐开始播放",Toast.LENGTH_SHORT).show();
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        //service接受activity用intent方式传来的参数
        String msg = intent.getStringExtra("msg");
        Toast.makeText(getBaseContext(), msg, Toast.LENGTH_SHORT).show();
        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public void onCreate() {
        super.onCreate();
        //注册广播
        IntentFilter filter = new IntentFilter("service");
        registerReceiver(receiver, filter);
        instance = this;
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        //解绑广播
        unregisterReceiver(receiver);
    }

    BroadcastReceiver receiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            Log.e("TAG", "接收到activity发来的广播" + intent.getStringExtra("msg"));
            sendBroadcast(new Intent("activity").putExtra("msg", "发送给activity的消息"));
        }
    };

    public void print(String msg) {
        Log.e("TAG", msg);
    }

}

Layout布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.example.servicesendactivity_11_10.MainActivity">

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="myIntent"
        android:text="intent传参" />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="guangbo"
        android:text="广播传参" />
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="danli"
        android:text="单例模式" />
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="bind"
        android:text="绑定service" />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="send"
        android:text="使用service实例调用方法" />
LinearLayout>

最后不要忘记要在Androidmanifest中注册

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.servicesendactivity_11_10">

    <application android:allowBackup="true" android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name" android:supportsRtl="true" android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            intent-filter>
        activity>
        <service android:name=".MyService"/>
    application>

manifest>

需要注意的是上面的下面几个方法都需要先把Intent传参打开 ，这个程序中有启动service的程序，如果连service都没打开还怎么传