manager.setSpeakerphoneOn（true）不适用于平板电脑

Question

manager.setSpeakerphoneOn(true);

适用于手机但不适用于平板电脑。 声音不会从扬声器播放。有人知道为什么吗？ 请帮忙

在清单文件中还添加了MODIFY_AUDIO_SETTINGS权限。

我的代码

音频文件的路径 String mainpath =“android.resource：//com.example.texttospeech/raw/”;

 public void makeSound(String amount) {
            AudioManager m_amAudioManager;  
            m_amAudioManager = (AudioManager)getSystemService(Context.AUDIO_SERVICE);  
            m_amAudioManager.setMode(AudioManager.MODE_CURRENT); 
            m_amAudioManager.setSpeakerphoneOn(true); 

            int numInput = Integer.parseInt(amount);
            String amt = amount;
            Log.d("The amount is : ", amt);
            int length = amt.length();
            Log.d("Length of the String : ", Integer.toString(length));

            thousandsDigit = numInput / 1000;
            ths = numInput % 1000;
            hundredsDigit = ths / 100;
            hs = ths % 100;
            tensDigit = hs / 10;
            onesDigit = hs % 10;

            System.out.println(thousandsDigit);
            System.out.println(hundredsDigit);
            System.out.println(tensDigit);
            System.out.println(onesDigit);
            Log.d("Transaction type:",transactionType);
            if (transactionType.equals("WITHDRAW")){
                // withdraw();
                final MediaPlayer mp11 = new MediaPlayer();
                try {

                    mp11.setDataSource(AgentTransaction.this,
                            Uri.parse(mainpath + "withdraw"));
                    mp11.prepare();

                } catch (IllegalArgumentException | SecurityException
                        | IllegalStateException | IOException e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                }
                mp11.start();
                mp11.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
                    @Override
                    public void onCompletion(MediaPlayer mp) {
                        mp11.release();


                    }
                });
            }
}