Android 四大组件 之一 BroadcastReceiver

Android 四大组件 之一 BroadcastReceiver

在现代化Android开发当中广播一般只接收系统广播不做他用，不要滥用，不要使用LocalBroadcastManager。

在现代化Android开发当中如何使用BroadcastReceiver呢？

定义

/**
 * 只能使用于接收系统广播，不建议瞎jb使用广播和类似的EventBus这种框架
 */
internal fun Context.broadcastAsFlow(vararg actions: String): Flow<Intent> = callbackFlow<Intent> {
    val receiver = object : BroadcastReceiver(){
        override fun onReceive(context: Context?, intent: Intent?) {
            if (intent != null){
                val result: ChannelResult<Unit> = this@callbackFlow.trySendBlocking(element = intent)
                Log.i(TAG, "onReceive -> result: $result")
            }
        }
    }
    val filter: IntentFilter = IntentFilter().apply {
        actions.forEach {  action ->
            addAction(action)
        }
    }
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
        registerReceiver(receiver, filter, Context.RECEIVER_NOT_EXPORTED)
    } else {
        registerReceiver(receiver, filter)
    }
    awaitClose {
        Log.i(TAG, "broadcastAsFlow awaitClose ...")
        unregisterReceiver(receiver)
    }
}.buffer(capacity = Channel.UNLIMITED)

使用

方式1

coroutineScope.launch {
	context.broadcastAsFlow(Intent.ACTION_SCREEN_OFF, Intent.ACTION_SCREEN_ON)
		.collect { intent: Intent ->
			Log.i(TAG, "StoreScreen -> 屏幕关闭开启 intent: $intent")
		}
}

方式二

val intents: Intent by context.broadcastAsFlow(Intent.ACTION_SCREEN_OFF, Intent.ACTION_SCREEN_ON).collectAsStateWithLifecycle(initialValue = Intent())