Android 聽筒模式 實現

一、利用距離感應器監聽聽筒靠近耳朵事件

step 1，新建實現SensorEventListener接口的類并實現onSensorChanged(SensorEvent event)方法

public class MainActivity extends Activity implements SensorEventListener

step 2，得到距離感應器的實例

audioManager = (AudioManager) this
                .getSystemService(Context.AUDIO_SERVICE);
        mSensorManager = (SensorManager) getSystemService

(Context.SENSOR_SERVICE);
        mSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);</pre> 
step 3，在onSensorChanged方法中判斷是否靠近聽筒

 public void onSensorChanged(SensorEvent event) {
        // TODO Auto-generated method stub
        float range = event.values[0];


    if (range == mSensor.getMaximumRange()) {
        Toast.makeText(this, "正常模式", Toast.LENGTH_LONG).show();
    } else {
        Toast.makeText(this, "聽筒模式", Toast.LENGTH_LONG).show();
    }</pre><br />

step 4, 向SensorManager注冊監聽距離感應器


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





二、根據距離感應器改變AudioManager播放模式
默認情況下，播放語音都是用外置喇叭或者耳機，我們需要編碼實現播放的切換。

step 1，在AndroidManifest文件中添加權限聲明
<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />


step 2，切換播放模式

 public void onSensorChanged(SensorEvent event) {
        // TODO Auto-generated method stub
        float range = event.values[0];


        if (range == mSensor.getMaximumRange()) {
            Toast.makeText(this, "正常模式", Toast.LENGTH_LONG).show();
             audioManager.setMode(AudioManager.MODE_NORMAL);
        } else {
            Toast.makeText(this, "聽筒模式", Toast.LENGTH_LONG).show();
             audioManager.setMode(AudioManager.MODE_IN_CALL);
        }


完整代碼：


package com.markjoker.sensortest;

import java.io.FileInputStream;
import java.io.IOException;

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.Bundle;
import android.app.Activity;
import android.content.Context;
import android.util.Log;
import android.view.Menu;
import android.widget.Toast;

public class MainActivity extends Activity implements SensorEventListener {
    private AudioManager audioManager;
    private SensorManager mSensorManager;
    private Sensor mSensor;

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

    private void init() {
        audioManager = (AudioManager) this
                .getSystemService(Context.AUDIO_SERVICE);
        mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
        mSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);

        MediaPlayer mPlayer = new MediaPlayer();
        try {
            mPlayer.reset();
            mPlayer.setDataSource(new FileInputStream("/sdcard/snow.mp3").getFD());
            mPlayer.prepare();
            mPlayer.start();
        } catch (IllegalArgumentException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SecurityException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IllegalStateException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

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

    @Override
    protected void onPause() {
        // TODO Auto-generated method stub
        mSensorManager.unregisterListener(this);
        super.onPause();
    }

    @Override
    public void onSensorChanged(SensorEvent event) {
        // TODO Auto-generated method stub
        float range = event.values[0];

        if (range == mSensor.getMaximumRange()) {
            Toast.makeText(this, "正常模式", Toast.LENGTH_LONG).show();
             audioManager.setMode(AudioManager.MODE_NORMAL);
        } else {
            Toast.makeText(this, "聽筒模式", Toast.LENGTH_LONG).show();
             audioManager.setMode(AudioManager.MODE_IN_CALL);
        }
    }

    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {
        // TODO Auto-generated method stub

    }

}