我们用android经常使用的时候，手机的声音增大和缩小操作。在设定场景模式，它往往使用静音和振动运行，这通常是AudioManager来控制的。

今天我们就来看一下AudioManager
的使用。

首先要想操作声音必须取得这个服务。在前面我们学过取得系统服务的方法

AudioManager audio = (AudioManager) super.getSystemService(Context.AUDIO_SERVICE);

然后用这个类中的方法来操作声音组件。接下来用样例进行说明

xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:paddingBottom="@dimen/activity_vertical_margin"

    android:paddingLeft="@dimen/activity_horizontal_margin"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    tools:context=".MainActivity" >

    <ImageButton

        android:id="@+id/imageButton3"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignTop="@+id/imageButton4"

        android:layout_toLeftOf="@+id/imageButton4"

        android:src="@drawable/voiceup" />

    <ImageButton

        android:id="@+id/imageButton1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignParentLeft="true"

        android:layout_alignTop="@+id/imageButton2"

        android:src="@drawable/music" />

    <ImageButton

        android:id="@+id/imageButton2"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignTop="@+id/imageButton5"

        android:layout_toRightOf="@+id/imageButton1"

        android:src="@drawable/novoice" />

    <ImageButton

        android:id="@+id/imageButton4"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignParentRight="true"

        android:layout_alignParentTop="true"

        android:layout_marginTop="18dp"

        android:src="@drawable/voicedown" />

    <ImageButton

        android:id="@+id/imageButton5"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBottom="@+id/imageButton3"

        android:layout_alignTop="@+id/imageButton3"

        android:layout_toLeftOf="@+id/imageButton3"

        android:layout_toRightOf="@+id/imageButton2"

        android:src="@drawable/vibrate" />

</RelativeLayout>

JAVA文件

<span style="font-size:18px;">package com.example.audiomanager;

import java.io.IOException;

import android.app.Activity;

import android.content.Context;

import android.media.AudioManager;

import android.media.MediaPlayer;

import android.os.Bundle;

import android.view.View;

import android.widget.ImageButton;

import android.widget.Toast;

public class MainActivity extends Activity {

	private ImageButton voiceOn, voiceOff, voiceUp, voiceDown, vibate;

	private AudioManager audio;

	@Override

	protected void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);

		setContentView(R.layout.activity_main);

		voiceOn = (ImageButton) this.findViewById(R.id.imageButton1);

		voiceOff = (ImageButton) this.findViewById(R.id.imageButton2);

		voiceUp = (ImageButton) this.findViewById(R.id.imageButton3);

		voiceDown = (ImageButton) this.findViewById(R.id.imageButton4);

		vibate = (ImageButton) this.findViewById(R.id.imageButton5);

//		创建Mediaplayer对象，并设置播放资源

		MediaPlayer media = MediaPlayer.create(MainActivity.this, R.raw.fukua);

		try {

//		、准备播放

			media.prepare();

		} catch (IllegalStateException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		} catch (IOException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		}

//		进入软件自己主动播放音乐

		media.start();

//		取得AudioManager对象

		audio = (AudioManager) super.getSystemService(Context.AUDIO_SERVICE);

//		一下为各个button设置的监听事件

		voiceOn.setOnClickListener(new View.OnClickListener() {

			@Override

			public void onClick(View v) {

				// TODO Auto-generated method stub

				MainActivity.this.audio

						.setRingerMode(AudioManager.RINGER_MODE_NORMAL);

				Toast.makeText(MainActivity.this, "手机音量开启", Toast.LENGTH_SHORT).show();

			}

		});

		voiceOff.setOnClickListener(new View.OnClickListener() {

			@Override

			public void onClick(View v) {

				// TODO Auto-generated method stub

				MainActivity.this.audio

						.setRingerMode(AudioManager.RINGER_MODE_SILENT);

				Toast.makeText(MainActivity.this, "手机静音", Toast.LENGTH_SHORT).show();

			}

		});

		voiceUp.setOnClickListener(new View.OnClickListener() {

			@Override

			public void onClick(View v) {

				// TODO Auto-generated method stub

				MainActivity.this.audio.adjustVolume(AudioManager.ADJUST_RAISE,

						0);

				Toast.makeText(MainActivity.this, "手机音量增大", Toast.LENGTH_SHORT).show();

			}

		});

		voiceDown.setOnClickListener(new View.OnClickListener() {

			@Override

			public void onClick(View v) {

				// TODO Auto-generated method stub

				MainActivity.this.audio.adjustVolume(AudioManager.ADJUST_LOWER,

						0);

				Toast.makeText(MainActivity.this, "手机音量减小", Toast.LENGTH_SHORT).show();

			}

		});

		vibate.setOnClickListener(new View.OnClickListener() {

			@Override

			public void onClick(View v) {

				// TODO Auto-generated method stub

				MainActivity.this.audio

						.setRingerMode(AudioManager.RINGER_MODE_VIBRATE);

				Toast.makeText(MainActivity.this, "手机为振动模式", Toast.LENGTH_SHORT).show();

			}

		});

	}

}

</span>

点击屏幕上的几个button就能实现对应的操作。大家能够依据这几节学到的东西自己实现一个简单的音乐播放器。

根据第预测：Viewpaper使用组件