13使用MediaPlayer播放音频

基于Android的软件开发第13堂Android多媒体概述主要内容Android多媒体概述使用MediaPlayer

播放音频2Android多媒体概述Android支持的媒体格式3TypeFormatFileTypeAudioAACLC/LTP3GPPandMPEG-4(.mp4,.m4a).MP3MP3(.mp3)MIDIType0and1(.mid,.xmf,.mxmf)PCM/WAVEWAVE(.wav)Android多媒体概述Android支持的媒体格式4TypeFormatFileType(s)SupportedImageJPEGJPEG(.jpg)GIFGIF(.gif)PNGPNG(.png)BMPBMP(.bmp)Android多媒体概述Android支持的媒体格式5TypeFormatFileType(s)SupportedVideoH.2633GPP(.3gp)andMPEG-4(.mp4)H.264AVC3GPP(.3gp)andMPEG-4(.mp4)MPEG-4SP3GPP(.3gp)Android多媒体概述Android多媒体之音频处理播放声音：SoundPool类播放声音：MediaPlayer类录制声音：MediaRecorder采集6Android多媒体概述Android多媒体之播放视频VideoView播放视频简单、方便MediaPlayer类播放视频更加灵活Camera：一是拍照，二是摄像7使用MediaPlayer

播放音频8创建新项目13.1添加资源添加以下资源res/drawable-mdpi/armstrong_on_moon.jpgres/raw/one_small_step.wavres/raw/apollo_17_stroll.mpg添加字符串资源strings.xml<?xmlversion="1.0"encoding="utf-8"?><resources><stringname="app_name">HelloMoon</string><stringname="hello_world">Helloworld!</string><stringname="action_settings">Settings</string>

<stringname="hellomoon_play">Play</string><stringname="hellomoon_stop">Stop</string><stringname="hellomoon_description">NeilArmstrongsteppingontothemoon</string></resources>图解：HelloMoon应用的对象12使用MediaPlayer

播放音频应用开发步骤：定义fragment的布局创建fragment类修改activity及其布局，实现对fragment的托管创建AudioPlayer1313.2定义HelloMoonFragment布局文件fragment_hello_moon.xml<?xmlversion="1.0"encoding="utf-8"?><TableLayout

xmlns:android="http:///apk/res/android"

android:layout_width="match_parent"

android:layout_height="match_parent"><ImageView

android:src="@drawable/armstrong_on_moon"

android:contentDescription="@string/hellomoon_description"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:scaleType="centerInside"

android:layout_weight="1"/><TableRow

android:layout_weight="0"

android:gravity="center|bottom"><Button

android:id="@+id/hellomoon_playButton"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="@string/hellomoon_play"/><Button

android:id="@+id/hellomoon_stopButton"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="@string/hellomoon_stop"/></TableRow></TableLayout>fragment的布局手动设置应用主题AndroidManifest.xml<?xmlversion="1.0"encoding="utf-8"?><manifestxmlns:android="http:///apk/res/android"package=".zjicm.zhengjun.hellomoon13"

android:versionCode="1"

android:versionName="1.0">…<application

android:allowBackup="true"

android:icon="@drawable/ic_launcher"

android:label="@string/app_name"

android:theme="@style/AppTheme"><activity…</activity></application></manifest>手动设置应用主题修改res/values/styles.xml<stylename="AppBaseTheme"parent="android:Theme">修改res/values-v11/styles.xml<stylename="AppBaseTheme"parent="android:Theme.Holo">删除res/values-v13/目录13.3创建HelloMoonFragmentpublic

class

HelloMoonFragment

extendsFragment{

privateButtonmPlayButton;

privateButtonmStopButton;

@Override

publicViewonCreateView(LayoutInflater

inflater,ViewGroupparent,BundlesavedInstanceState){Viewv=inflater.inflate(R.layout.fragment_hello_moon,parent,false);

mPlayButton=(Button)v.findViewById(R.id.hellomoon_playButton);

mStopButton=(Button)v.findViewById(R.id.hellomoon_stopButton);

returnv;}}13.4使用布局fragment修改布局文件activity_hello_moon.xml<?xmlversion="1.0"encoding="utf-8"?><fragmentxmlns:android="http:///apk/res/android“

android:id="@+id/helloMoonFragment“

android:layout_width="match_parent"

android:layout_height="match_parent“

android:name=".zjicm.zhengjun.hellomoon.HelloMoonFragment"></fragment>修改HelloMoonActivity类将父类改为FragmentActivity删除onCreateOptionsMenu(…)和onOptionsItemSelected(…)方法Fragment的生命周期13.5播放音频创建AudioPlayer类public

class

AudioPlayer{

private

MediaPlayer

mPlayer;

public

voidstop(){

if(mPlayer!=null){

mPlayer.release();

mPlayer=null;}}

public

void

play(Contextc){

mPlayer=MediaPlayer.create(c,R.raw.one_small_step);

mPlayer.start();}}创建MediaPlayer对象，指定音频资源开始播放销毁MediaPlayer对象将mPlayer设为null修改AudioPlayer类public

void

play(Contextc){stop();

mPlayer=MediaPlayer.create(c,R.raw.one_small_step);

mPlayer.setOnCompletionListener(new

MediaPlayer.OnCompletionListener(){

public

void

onCompletion(MediaPlayermp){stop();}});

mPlayer.start();}避免多次单击Play按钮创建多个MediaPlayer对象添加MediaPlayer.OnCompletionListener监听器，在音频播放完后销毁MediaPlayer对象修改HelloMoonFragment类添加AudioPlayer变量为mPlayButton和mStopButton添加监听器重载onDestroy()方法public

class

HelloMoonFragment

extendsFragment{

privateAudioPlayer

mPlayer=newAudioPlayer();

…@Override

publicViewonCreateView(LayoutInflater

inflater,ViewGroupparent,Bu