Android 听筒模式的具体实现实例

一、利用距离感应器监听听筒靠近耳朵事件
准确的说距离感应器并不能监听到你是否把手机靠近耳朵，也许是你用手挡在了距离感应器前面，但这不是我们关心的，我们关心的是当你的耳朵靠近听筒时，我们要捕获到这个事件

step 1，新建实现sensoreventlistener接口的类并实现onsensorchanged(sensorevent event)方法

public class mainactivity extends activity implements sensoreventlistener

step 2，得到距离感应器的实例

audiomanager = (audiomanager) this
    .getsystemservice(context.audio_service);
  msensormanager = (sensormanager) getsystemservice

(context.sensor_service);
  msensor = msensormanager.getdefaultsensor(sensor.type_proximity);

step 3，在onsensorchanged方法中判断是否靠近听筒

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, "听筒模式", toast.length_long).show();
 }

step 4, 向sensormanager注册监听距离感应器

 @override
 protected void onresume() {
  msensormanager.registerlistener(this, msensor,
    sensormanager.sensor_delay_normal);
  super.onresume();
 }
 @override
 protected void onpause() {
  msensormanager.unregisterlistener(this);
  super.onpause();
 }

二、根据距离感应器改变audiomanager播放模式
默认情况下，播放语音都是用外置喇叭或者耳机，我们需要编码实现播放的切换。

step 1，在androidmanifest文件中添加权限声明

<uses-permission android:name="android.permission.modify_audio_settings" />

step 2，切换播放模式

 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, "听筒模式", toast.length_long).show();
    audiomanager.setmode(audiomanager.mode_in_call);
  }

完整代码：

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, "听筒模式", toast.length_long).show();
    audiomanager.setmode(audiomanager.mode_in_call);
  }
 }

 @override
 public void onaccuracychanged(sensor sensor, int accuracy) {
  // todo auto-generated method stub

 }

}