如何检测应用/手机已连接Android Auto？是否有对应广播事件？

Hey there! Great question—yes, there are specific broadcast events you can listen to detect when your device connects or disconnects from Android Auto, and they work perfectly to trigger your existing car UI mode check code. Let's break this down:

Key Broadcasts for Android Auto #

Google Play Services provides two dedicated broadcast actions to track Android Auto connection state:

• com.google.android.gms.car.ACTION_CAR_CONNECTED: Fires when the device successfully connects to Android Auto
• com.google.android.gms.car.ACTION_CAR_DISCONNECTED: Fires when the device disconnects from Android Auto

Integrating with Your Existing Code #

You can create a dynamic broadcast receiver to listen for these events, then call your isCarUiMode() method whenever the connection state changes. Here's how to implement it:

Step 1: Create the Broadcast Receiver #

private BroadcastReceiver carConnectionReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if (com.google.android.gms.car.ACTION_CAR_CONNECTED.equals(action)) {
            // Trigger your car UI mode check when connected
            boolean isInCarMode = isCarUiMode(context);
            LogHelper.d(TAG, "Connected to Android Auto | Car UI Mode: " + isInCarMode);
        } else if (com.google.android.gms.car.ACTION_CAR_DISCONNECTED.equals(action)) {
            LogHelper.d(TAG, "Disconnected from Android Auto");
            // Optional: Re-check UI mode here if needed
            boolean isInCarMode = isCarUiMode(context);
            LogHelper.d(TAG, "Post-disconnect | Car UI Mode: " + isInCarMode);
        }
    }
};

// Your existing car UI mode check method
public static boolean isCarUiMode(Context c) {
    UiModeManager uiModeManager = (UiModeManager) c.getSystemService(Context.UI_MODE_SERVICE);
    if (uiModeManager.getCurrentModeType() == Configuration.UI_MODE_TYPE_CAR) {
        LogHelper.d(TAG, "Running in Car mode");
        return true;
    } else {
        LogHelper.d(TAG, "Running on a non-Car mode");
        return false;
    }
}

Step 2: Register/Unregister the Receiver #

Always register the receiver dynamically (static registration may not work reliably for these broadcasts) in your Activity or Fragment lifecycle:

@Override
protected void onResume() {
    super.onResume();
    IntentFilter filter = new IntentFilter();
    filter.addAction(com.google.android.gms.car.ACTION_CAR_CONNECTED);
    filter.addAction(com.google.android.gms.car.ACTION_CAR_DISCONNECTED);
    // Add system UI mode change broadcast for broader compatibility
    filter.addAction(Intent.ACTION_UIMODE_CHANGED);
    registerReceiver(carConnectionReceiver, filter);
}

@Override
protected void onPause() {
    super.onPause();
    unregisterReceiver(carConnectionReceiver);
}

Bonus: System-Level UI Mode Broadcast #

For better compatibility (including devices without Google Play Services), add Intent.ACTION_UIMODE_CHANGED to your filter. This system broadcast fires whenever the device's UI mode switches (e.g., entering/exiting car mode manually or via other car docks). You can handle it in the same receiver:

// Inside onReceive()
} else if (Intent.ACTION_UIMODE_CHANGED.equals(action)) {
    boolean isInCarMode = isCarUiMode(context);
    LogHelper.d(TAG, "UI Mode Updated | Car UI Mode: " + isInCarMode);
}

Notes #

• Ensure the device has Google Play Services installed to receive the Android Auto-specific broadcasts.
• Dynamic registration is recommended to avoid unnecessary background listening and comply with Android's broadcast restrictions.

内容的提问来源于stack exchange，提问作者Parth