About Switching AudioManager Play Mode Between earpiece and speakerphone Delay

The code intent to play an audio, and switch the play mode, when i close to the phone,the sound play in earpiece,play in speakerphone when far away phone.

Question:

1.When switch the mode, the sound delay about 1~2 seconds.

2.When switch to earpiece, about 1 second sound lost.

Below is my code:

package com.ballfund.audioplaymodedemo;

import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

import java.io.File;
import java.io.FileInputStream;


public class MainActivity extends ActionBarActivity implements SensorEventListener, View.OnClickListener{

    private AudioManager audioManager;
    private SensorManager mSensorManager;
    private Sensor mSensor;

    private MediaPlayer mMediaPlayer;
    private Button btnPlay;

    private String mediaUrl = "";
    private MyHandle myHandle = new MyHandle();
    private final int PLAY_MSG_FLAG = 0XFF;

    public class MyHandle extends Handler {
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what)
            {
                case PLAY_MSG_FLAG:
                    try {
                        mMediaPlayer.reset();
                        mMediaPlayer.setDataSource(new FileInputStream(mediaUrl).getFD());
                        mMediaPlayer.prepare();
                        mMediaPlayer.start();
                    }catch (Exception e)
                    {
                        e.printStackTrace();
                    }
                    break;
                default:
                    break;
            }
            super.handleMessage(msg);
        }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initManager();

        btnPlay = (Button) findViewById(R.id.btnPlay);
        btnPlay.setOnClickListener(this);
        mediaUrl = Environment.getExternalStorageDirectory() + "/123.mp3";

    }


    @Override
    protected void onResume() {
        mSensorManager.registerListener(this,mSensor,SensorManager.SENSOR_DELAY_FASTEST);
        super.onResume();
    }

    @Override
    protected void onPause() {
        mSensorManager.unregisterListener(this);
        super.onPause();
    }

    private void initManager()
    {
        audioManager = (AudioManager) this.getSystemService(Context.AUDIO_SERVICE);
        mSensorManager = (SensorManager) this.getSystemService(Context.SENSOR_SERVICE);

        mMediaPlayer = new MediaPlayer();
        mSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onSensorChanged(SensorEvent event) {
        float range = event.values[0];

        if(range == mSensor.getMaximumRange())
        {
            mMediaPlayer.reset();
            audioManager.setMode(AudioManager.MODE_NORMAL);
            myHandle.sendEmptyMessage(PLAY_MSG_FLAG);
        }else{
            mMediaPlayer.reset();
            audioManager.setMode(AudioManager.MODE_IN_CALL);
            myHandle.sendEmptyMessage(PLAY_MSG_FLAG);
        }
    }

    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {

    }

    @Override
    public void onClick(View v) {
        if(v.equals(btnPlay))
        {
            if(mMediaPlayer.isPlaying())
            {
                mMediaPlayer.stop();
                mMediaPlayer.reset();
            }else
            {
                myHandle.sendEmptyMessage(PLAY_MSG_FLAG);
            }
        }
    }
}