Android Recording Incoming and Outgoing Calls

First off, you have to be careful with recording calls as there are legal requirements depending on the country.

Here is a blog post on how to record audio using the MediaRecorder.

I haven't tried recording phone call's but there is a option in MediaRecorder AudioSource for:

• VOICE_CALL - Voice call uplink + downlink audio source
• VOICE_DOWNLINK - Voice call downlink (Rx) audio source
• VOICE_UPLINK - Voice call uplink (Tx) audio source

As long as the audio source options work, you should be good to go.

I am using mic to record calls for better support and compatibility.

MediaRecorder recorder = new MediaRecorder();
recorder.reset();
recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
recorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
recorder.setOutputFile(your_desired_folder_path);
 try {
    recorder.prepare();
} catch (java.io.IOException e) {
    recorder = null;
    return;
}
recorder.start();

I am using mic to record phone audio and also use the Telephony manager to find the calling state.

private MediaRecorder recorder;

  recorder = new MediaRecorder();
        try {
            recorder.setAudioSource(MediaRecorder.AudioSource.VOICE_COMMUNICATION);
            recorder.setOutputFormat(MediaRecorder.OutputFormat.AMR_NB);
            recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
            recorder.setAudioSamplingRate(44100);
            recorder.setOutputFile(your_desired_files_absoulte_path);
} catch (Exception e) {
e.printstacktrace ;
}

after that, you can easily start recording anywhere you want

recorder.prepare();
recorder.start();

and after finishing recording you can easily also stop the recording

recorder.stop();
recorder.reset();
recorder.release();