如何使用广播接收器检测到蓝牙状态变化？ [英] How to detect Bluetooth state change using a broadcast receiver?

问题描述

我试图让一个应用程序，显示敬酒时，该设备的蓝牙打开。我想执行，即使我的应用程序没有运行该操作。所以，我应该使用的广播接收机。 我知道我应该添加权限和意向过滤器的Andr​​oid清单，让一个Java类。

I am trying to make an app that shows a toast when the device's Bluetooth turned on. I wanna perform that action even when my app is not running. So I should use a broadcast receiver. I know I should add permissions and an intent-filter to android manifest and make a java class.

我应该怎么办？我应该使用什么权限？

What should I do? What permissions should I use?

推荐答案

据权限去，及时发现蓝牙的状态变化，你需要将其添加到您的Andr​​oidManifest.xml。

AS far as permissions go, to detect the state change of bluetooth you need to add this to your AndroidManifest.xml.

<uses-permission android:name="android.permission.BLUETOOTH" />

这是例子接收器应该是这样的，你加这个code到要处理的广播，例如活动：

An example receiver would look like this, you add this code to where you want to handle the broadcast, for example an activity:

    private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
            public void onReceive (Context context, Intent intent) {
                String action = intent.getAction();

                if (BluetoothAdapter.ACTION_STATE_CHANGED.equals(action)) {
                    if(intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, -1) 
    == BluetoothAdapter.STATE_OFF)
    // Bluetooth is disconnected, do handling here
}

}

        };

要使用接收器，你需要注册。你可以做如下。我注册在我的主要活动接收器。

To use the receiver, you need to register it. Which you can do as follows. I register the receiver in my main activity.

registerReceiver(this, new IntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED));

您也可以决定一切它添加到您的Andr​​oidManifest.xml。这种方式可以使接收机一类特殊和处理它。无需注册的接收器，才使这个类并添加下面的code到AndroidManifest

You could also decide to add all of it to your AndroidManifest.xml. This way you can make a special class for the receiver and handle it there. No need to register the receiver, just make the class and add the below code to the AndroidManifest

<receiver
        android:name=".packagename.NameOfBroadcastReceiverClass"
        android:enabled="true">
    <intent-filter>
        <action android:name="android.bluetooth.adapter.action.STATE_CHANGED"/>
    </intent-filter>
</receiver>

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