Android开发 广播

前言

本地广播只能在应用程序内部进行传递，并且只能通过动态注册.这种本地广播的好处是不会将一些隐蔽信息被全局广播出去.

全局静态与动态广播

在8.0版本以后，全局广播权限收紧，其实已经没有什么静态与动态的区别了.... 虽然还支持静态这种写法，但是实际上还是需要动态注册广播。下面就来讲解8.0之后的全局广播接收与发送

接收

class KeyReceiver : BroadcastReceiver() {

    override fun onReceive(context: Context, intent: Intent) {
        Log.e("zh", "接收到广播 : = ${intent.action} ", )
        when (intent.action){
            "com.zh.dev.KeyReceiver.enable" -> RemoteControlService.sIsEnableRemoteControlFunction = true
            "com.zh.dev.KeyReceiver.disable" -> RemoteControlService.sIsEnableRemoteControlFunction = false
        }
    }
}

AndroidManifest.xml

    <application>

        <receiver
            android:name=".KeyReceiver"
            android:enabled="true"
            android:exported="true">
            <intent-filter>
                <action android:name="com.zh.dev.KeyReceiver.enable"/>
                <action android:name="com.zh.dev.KeyReceiver.disable"/>
            </intent-filter>
        </receiver>
    </application>

千万记得要动态注册

       registerReceiver(KeyReceiver(), IntentFilter().apply {
            addAction("com.zh.dev.KeyReceiver.enable")
            addAction("com.zh.dev.KeyReceiver.disable")
        })

发送

val disableIntent = Intent("com.lwlx.dev.LwlxKeyReceiver.disable")
//现在必须添加component，以约束发送广播的范围。不添加会导致广播无法成功发送，下面第一个参数是目标apk包名，第二个参数是目标广播类
disableIntent.component = ComponentName("com.zh.dev", "com.zh.remotecontrol.KeyReceiver")
sendBroadcast(disableIntent)

本地广播

这种广播只作用app内部

创建广播接受类,继承BroadcastReceiver 

    public class MyReceiver extends BroadcastReceiver {

        @Override
        public void onReceive(Context context, Intent intent) {
            if (TextUtils.equals(intent.getAction(), DEMO_ACTION)){
                Toast.makeText(context, "触发本地广播", Toast.LENGTH_SHORT).show();

            }
        }
    }

注册广播,请注意,注册本地广播需要使用LocalBroadcastManager进行注册,这点与静态广播不通.

    private CloseDialogReceiver mCloseDialogReceiver;
    private void registerReceiver(){
        mCloseDialogReceiver = new CloseDialogReceiver();
        IntentFilter intentFilter = new IntentFilter();
        intentFilter.addAction(DEMO_ACTION);
        LocalBroadcastManager.getInstance(this).registerReceiver(mCloseDialogReceiver, intentFilter);
    }

发送广播,发送也需要使用LocalBroadcastManager发送 

    public void send(){
        Intent dismissDialog = new Intent(DEMO_ACTION);
        LocalBroadcastManager localBroadcastManager = LocalBroadcastManager.getInstance(this);
        localBroadcastManager.sendBroadcast(dismissDialog);
    }

注销广播

LocalBroadcastManager.getInstance(this).unregisterReceiver(mCloseDialogReceiver);