【移动应用开发技术】Android如何实现音乐播放器

【移动应用开发技术】Android如何实现音乐播放器

/upload/information/20200623/125/124636.jpg<LinearLayout

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

xmlns:tools="/tools"

android:id="@+id/container"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical"

tools:context="com.example.musicplay.MainActivity"

>

<TextView

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="@string/filename"

/>

<EditText

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:layout_weight="0.00"

android:background="#B0C4DE"

android:text="Payphone.mp3"

android:id="@+id/filename"

/>

<LinearLayout

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:orientation="horizontal"

>

<Button

android:id="@+id/playbutton"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:onClick="mediaplay"

android:text="@string/playbutton"

/>

<Button

android:id="@+id/pausebutton"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:onClick="mediaplay"

android:text="@string/pausebutton"

/>

<Button

android:id="@+id/resetbutton"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:onClick="mediaplay"

android:text="@string/resetbutton"

/>

<Button

android:id="@+id/stopbutton"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:onClick="mediaplay"

android:text="@string/stopbutton"

/>

</LinearLayout>

</LinearLayout>package

com.example.musicplay;

import

java.io.File;

import

android.app.Activity;

import

android.content.Context;

import

android.media.MediaPlayer;

import

android.media.MediaPlayer.OnPreparedListener;

import

android.os.Bundle;

import

android.os.Environment;

import

android.telephony.PhoneStateListener;

import

android.telephony.TelephonyManager;

import

android.view.View;

import

android.widget.Button;

import

android.widget.EditText;

import

android.widget.Toast;

public

class

MainActivity

extends

Activity

{

private

EditText

nameText;

private

String

path;

private

int

position;

private

MediaPlayer

mediaplayer;

private

boolean

pause;

protected

void

onCreate(Bundle

savedInstanceState)

{

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

nameText=(EditText)

this.findViewById(R.id.filename);

mediaplayer=new

MediaPlayer();

}

//以下方法会造成只要应用在后台音乐都会停止播放

@Override

//当应用不在前台时，停止播放

protected

void

onPause()

{

if(mediaplayer.isPlaying()){

position=mediaplayer.getCurrentPosition();

mediaplayer.stop();

}

super.onPause();

}

@Override

protected

void

onResume()

{

if(position>0&&path!=null){

play();

mediaplayer.seekTo(position);

position=0;

}

super.onResume();

}

@Override

protected

void

onDestroy()

{

mediaplayer.release();

mediaplayer=null;

super.onDestroy();

}

public

void

mediaplay(View

v){

switch

(v.getId())

{

case

R.id.playbutton:

String

filename=nameText.getText().toString();

//Environment.getExternalStorageDirectory()检查外部存储设备的可用性

File

audio=new

File(Environment.getExternalStorageDirectory(),filename);

if(audio.exists()){

//获取SDCard目录,2.2的时候为:/mnt/sdcart

2.1的时候为：/sdcard，所以使用静态方法得到路径会好一点。

path=audio.getAbsolutePath();

play();

}

else{

path=null;

Toast.makeText(getApplicationContext(),

R.string.error,

1).show();

}

break;

case

R.id.pausebutton:

if(mediaplayer.isPlaying()){

mediaplayer.pause();

pause=true;

((Button)v).setText(R.string.continues);

}else{

if(pause){

mediaplayer.start();

pause=false;

((Button)v).setText(R.string.pausebutton);

}

}

break;

case

R.id.resetbutton:

if(mediaplayer.isPlaying()){

mediaplayer.seekTo(0);//从开始位置播放

}else{

if(path!=null){

play();

}

}

break;

case

R.id.stopbutton:

if(mediaplayer.isPlaying()){

mediaplayer.stop();

}

break;

default:

break;

}

}

private

void

play()

{

try

{

mediaplayer.reset();//把各项参数恢复到初始化状态

mediaplayer.setDataSource(path);

mediaplayer.prepare();//进行缓冲

//设置缓冲监听器

mediaplayer.setOnPr