Android – How write a program to connect to a a2dp bluetooth device using pre 3.0 Android

androidaudiobluetoothprofile

My application needs to connect to a a2dp device over bluetooth and I want to "be able to query for the visible bluetooth devices, then, select a a2dp device and have it 'connect via a2dp' so that audio starts playing through the connected device" but my phone is running gingerbread (2.3.3).

I went through the basic bluetooth tutorial at http://developer.android.com/guide/topics/wireless/bluetooth.html and got to the part I need to connect to the bluetooth device and then I read the bottom of the page:

"Starting in Android 3.0, the Bluetooth API includes support for working with Bluetooth profiles." -> does this mean that I am S.O.L.? Is there any way to programmatically (why does stackoverflow mark programmatically as being misspelled?!) connect to a a2dp device using a pre-3.0 version of Android? Is my only option to direct the user to go into their settings/pull up the settings programmatically?? Because I'm able to do it through the settings, I guess I just assumed it would be possible via my application as well.

Help?

Best Answer

Some of the Bluetooth classes (profiles like BluetoothA2dp) are hidden in Gingerbread. It means that their declaration is annotated by @hide, and they are not included into the SDK (Android.jar). This is done intentionally, since these APIs are likely to be changed in newer Android versions. Generally it is not a good idea to use hidden APIs, since your App can stop working on newer Android versions, but if you are sure you want to, follow http://devmaze.wordpress.com/2011/01/18/using-com-android-internal-part-1-introduction/

Once you get access to them do something like (just a hint):

BluetoothA2dp mBluetoothA2dp = new BluetoothA2dp(context);
BluetoothDevice device = BluetoothAdapter.getDefaultAdapter().
// Loop through paired devices
for (BluetoothDevice device : mBluetoothAdapter.getBondedDevices()) {
    if (device.getName().contains("whatyouwant")) {
        mBluetoothA2dp.addSink(device);
    }
}

Related Solutions

Android – How to close/hide the Android soft keyboard programmatically

You can force Android to hide the virtual keyboard using the InputMethodManager, calling hideSoftInputFromWindow, passing in the token of the window containing your focused view.

// Check if no view has focus:
View view = this.getCurrentFocus();
if (view != null) {  
    InputMethodManager imm = (InputMethodManager)getSystemService(Context.INPUT_METHOD_SERVICE);
    imm.hideSoftInputFromWindow(view.getWindowToken(), 0);
}

This will force the keyboard to be hidden in all situations. In some cases, you will want to pass in InputMethodManager.HIDE_IMPLICIT_ONLY as the second parameter to ensure you only hide the keyboard when the user didn't explicitly force it to appear (by holding down the menu).

Note: If you want to do this in Kotlin, use: context?.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager

Kotlin Syntax

// Only runs if there is a view that is currently focused
this.currentFocus?.let { view ->
    val imm = getSystemService(Context.INPUT_METHOD_SERVICE) as? InputMethodManager
    imm?.hideSoftInputFromWindow(view.windowToken, 0)
}

Android – Programmatically connect to paired Bluetooth device

Okay, since this was driving me crazy, I did some digging into the source code and I've found a 100% reliable (at least on my Nexus 4, Android 4.3) solution to connect to a paired A2DP device (such as a headset or Bluetooth audio device). I've published a fully working sample project (easily built with Android Studio) that you can find here on Github.

Essentially, what you need to do is:

Get an instance of the BluetoothAdapter
Using this instance, get a profile proxy for A2DP:

adapter.getProfileProxy (context, listener, BluetoothProfile.A2DP);

where listener is a ServiceListener that will receive a BluetoothProfile in its onServiceConnected() callback (which can be cast to a BluetoothA2dp instance)

Use reflection to acquire the connect(BluetoothDevice) method on the proxy:

Method connect = BluetoothA2dp.class.getDeclaredMethod("connect", BluetoothDevice.class);

Find your BluetoothDevice:

String deviceName = "My_Device_Name";

BluetoothDevice result = null;

Set<BluetoothDevice> devices = adapter.getBondedDevices();
if (devices != null) {
    for (BluetoothDevice device : devices) {
        if (deviceName.equals(device.getName())) {
            result = device;
            break;
        }
    }
}

And invoke the connect() method:

connect.invoke(proxy, result);

Which, at least for me, caused an immediate connection of the device.

Best Answer

Related Solutions

Android – How to close/hide the Android soft keyboard programmatically

Android – Programmatically connect to paired Bluetooth device

Related Topic