基于AS3.0简易音乐播放器

功能：实现音乐播放器的上一首、下一首、播放、暂停功能

平台：Android Studio 3.0.1

直接见代码：

app配置文件

apply plugin: 'com.android.application'

android {
    compileSdkVersion 27
    buildToolsVersion "27.0.3"
    defaultConfig {
        applicationId "com.example.lenovo.design3application"
        minSdkVersion 21
        targetSdkVersion 27
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.1'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
    implementation 'com.android.support:support-v4:27.1.1'
}

//注意要导入v4:27.1.1包

相应的.xml文件

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.lenovo.design3application">
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />     //添加访问sd卡权限

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

MyFilter.java类：

ackage com.example.lenovo.design3application;

import java.io.File;
import java.io.FilenameFilter;

/**
 * Created by lenovo on 2018/4/22.
 */

public class MyFilter implements FilenameFilter {
    private String type;
    public MyFilter(String type){ //构造函数
        this.type = type;
    }
    @Override //实现FilenameFilter接口accept()方法
    public boolean accept(File dir, String name) { //dir当前目录, name文件名
        return name.endsWith(type); //返回true的文件则合格
    }
}

activity_main.xml:   //里面的图片自行改换

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">


    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:orientation="horizontal">

        <ImageView
            android:id="@+id/imageView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:src="@drawable/bgpic" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:orientation="horizontal">

        <Button
            android:id="@+id/button1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="上一首" />

        <ImageButton
            android:id="@+id/btn_pause"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:src="@drawable/begin" />

        <Button
            android:id="@+id/button3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="下一首" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="300dp"
        android:orientation="horizontal">

        <ListView
            android:id="@+id/listView"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />
    </LinearLayout>

</LinearLayout>

MainActivity.java

package com.example.lenovo.design3application;

import android.Manifest;
import android.app.Activity;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.media.MediaPlayer;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.os.Environment;
import android.os.StrictMode;
import android.support.v4.app.ActivityCompat;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.ListView;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;

import java.io.File;
import java.util.ArrayList;

public class MainActivity extends Activity {

    MediaPlayer mp=new MediaPlayer();
    String song_path="";
    int i=1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        if (ActivityCompat.checkSelfPermission( MainActivity.this, Manifest.permission.READ_EXTERNAL_STORAGE)
                != PackageManager.PERMISSION_GRANTED ) {
            ActivityCompat.requestPermissions(MainActivity.this,
                    new String[] { Manifest.permission.READ_EXTERNAL_STORAGE }, 123);
            return;
        }

        if ( Build.VERSION.SDK_INT >= Build.VERSION_CODES.N ) {
            StrictMode.VmPolicy.Builder builder = new StrictMode.VmPolicy.Builder();
            StrictMode.setVmPolicy(builder.build());
        }
//两个if用来解决android 6.0 7.0 权限问题


        ArrayList<String> list = new ArrayList<String>(); //音乐列表
        File sdpath= Environment.getExternalStorageDirectory(); //获得手机SD卡路径
        File path=new File(sdpath+"//mp3//"); //获得SD卡的mp3文件夹
        //返回以.mp3结尾的文件 (自定义文件过滤)
        File[ ] songFiles = path.listFiles( new MyFilter(".mp3") );
        for (File file :songFiles){
            list.add( file.getAbsolutePath() ); //获取文件的绝对路径
        }



        ArrayAdapter<String> adapter = new ArrayAdapter<String>(
                MainActivity.this,
                android.R.layout.simple_list_item_single_choice,
                list );
        ListView li=(ListView)findViewById(R.id.listView);
        li.setAdapter(adapter);
        li.setChoiceMode(ListView.CHOICE_MODE_SINGLE); //单选


        li.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                song_path=((TextView)view).getText().toString();
                try{
                    mp.reset(); //重置
                    mp.setDataSource(song_path);
                    mp.prepare(); //准备
                    mp.start(); //播放
                }catch (Exception e){ }
            }
        });


        final ImageButton btnpause=(ImageButton)findViewById(R.id.btn_pause);
        btnpause.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if( song_path.isEmpty() )
                    Toast.makeText(getApplicationContext(), "先选收歌曲先听听",
                            Toast.LENGTH_SHORT).show();
                if( mp.isPlaying() ){
                    mp.pause(); //暂停
                    btnpause.setImageResource(R.drawable.stop);
                }else if( !song_path.isEmpty() ){
                    mp.start(); //继续播放
                    btnpause.setImageResource(R.drawable.begin);
                }
            }
        });


        Button bt2=(Button)findViewById(R.id.button1);
        bt2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if( mp.isPlaying() )
                    mp.pause();
                i--;

                ArrayList<String> list1 = new ArrayList<String>(); //音乐列表
                File sdpath= Environment.getExternalStorageDirectory(); //获得手机SD卡路径
                File path=new File(sdpath+"//mp3//"); //获得SD卡的mp3文件夹
                //返回以.mp3结尾的文件 (自定义文件过滤)
                File[ ] songFiles = path.listFiles( new MyFilter(".mp3") );
                for (File file :songFiles){
                    list1.add( file.getAbsolutePath() ); //获取文件的绝对路径
                }

                if(i<0)
                    i=list1.size()-1;

                song_path=(String) list1.get(i);
                try{
                    mp.reset(); //重置
                    mp.setDataSource(song_path);
                    mp.prepare(); //准备
                    mp.start(); //播放
                }catch (Exception e){ }


                }

        });



        Button bt3=(Button)findViewById(R.id.button3);
        bt3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if( mp.isPlaying() )
                    mp.pause();
                i++;

                ArrayList<String> list1 = new ArrayList<String>(); //音乐列表
                File sdpath= Environment.getExternalStorageDirectory(); //获得手机SD卡路径
                File path=new File(sdpath+"//mp3//"); //获得SD卡的mp3文件夹
                //返回以.mp3结尾的文件 (自定义文件过滤)
                File[ ] songFiles = path.listFiles( new MyFilter(".mp3") );
                for (File file :songFiles){
                    list1.add( file.getAbsolutePath() ); //获取文件的绝对路径
                }

                if(i>=list1.size())
                    i=0;

                song_path=(String) list1.get(i);
                try{
                    mp.reset(); //重置
                    mp.setDataSource(song_path);
                    mp.prepare(); //准备
                    mp.start(); //播放
                }catch (Exception e){ }


            }

        });



    }

    @Override
    protected void onDestroy() {
        super.onDestroy();

        if(mp!=null ){
            mp.stop();
            mp.release();
        }
        Toast.makeText(getApplicationContext(), "退出啦", Toast.LENGTH_SHORT).show();

    }
}

运行效果见截图：

本人在自己android 6.0 手机上运行，没问题，建议在自己手机上运行

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