[移动开发]Android应用--简、美音乐播放器获取专辑图片（自定义列表适配器

首先介绍布局吧：

列表布局有稍微的改变,也没什么好说的，看代码吧

/SimpleBeautyMusicPlayer/res/layout/music_list_item_layout.xml

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

android:id="@+id/RelativeLayout1"

android:layout_width=“match_parent”

android:layout_height=“wrap_content”

android:descendantFocusability=“blocksDescendants”

android:orientation=“vertical” >

<ImageView

android:id="@+id/albumImage"

android:layout_width=“64.0dip”

android:layout_height=“64.0dip”

android:layout_alignParentLeft=“true”

android:layout_centerInParent=“true”

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

<TextView

android:id="@+id/music_duration"

android:layout_width=“wrap_content”

android:layout_height=“wrap_content”

android:layout_alignParentRight=“true”

android:layout_alignParentTop=“true”

android:layout_marginRight=“5.0dp”

android:textColor="@android:color/white"

android:text="@string/time" />

<TextView

android:id="@+id/music_title"

android:layout_width=“wrap_content”

android:layout_height=“wrap_content”

android:layout_alignParentTop=“true”

android:layout_marginLeft=“5dp”

android:layout_toRightOf="@+id/albumImage"

android:focusable=“true”

android:text="@string/siger"

android:textColor="@android:color/white"

android:textSize=“18sp”

/>

<TextView

android:id="@+id/music_Artist"

android:layout_width=“wrap_content”

android:layout_height=“wrap_content”

android:layout_alignLeft="@+id/music_title"

android:layout_marginTop=“5.0dip”

android:layout_below="@id/music_title"

android:textColor="@android:color/white"

android:text="@string/artist" />

自定义ListView适配器

/SimpleBeautyMusicPlayer/src/com/wwj/sb/adapter/MusicListAdapter.java

package com.wwj.sb.adapter;

import java.util.List;

import android.content.Context;

import android.graphics.Bitmap;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.BaseAdapter;

import android.widget.ImageView;

import android.widget.TextView;

import com.wwj.sb.activity.R;

import com.wwj.sb.domain.Mp3Info;

import com.wwj.sb.utils.MediaUtil;

/**

• 自定义的音乐列表适配器

• 为了方便扩展，因为之前没有考虑到显示专辑封面

• @author wwj

*/

public class MusicListAdapter extends BaseAdapter{

private Context context; //上下文对象引用

private List mp3Infos; //存放Mp3Info引用的集合

private Mp3Info mp3Info; //Mp3Info对象引用

private int pos = -1; //列表位置

/**

• 构造函数

• @param context 上下文

• @param mp3Infos 集合对象

*/

public MusicListAdapter(Context context, List mp3Infos) {

this.context = context;

this.mp3Infos = mp3Infos;

}

@Override

public int getCount() {

return mp3Infos.size();

}

@Override

public Object getItem(int position) {

return position;

}

@Override

public long getItemId(int position) {

return position;

}

@Override

public View getView(int position, View convertView, ViewGroup parent) {

ViewHolder viewHolder = null;

if(convertView == null)

{

viewHolder = new ViewHolder();

convertView = LayoutInflater.from(context).inflate(R.layout.music_list_item_layout, null);

viewHolder.albumImage = (ImageView) convertView.findViewById(R.id.albumImage);

viewHolder.musicTitle = (TextView) convertView.findViewById(R.id.music_title);

viewHolder.musicArtist = (TextView) convertView.findViewById(R.id.music_Artist);

viewHolder.musicDuration = (TextView) convertView.findViewById(R.id.music_duration);

convertView.setTag(viewHolder); //表示给View添加一个格外的数据，

} else {

viewHolder = (ViewHolder)convertView.getTag();//通过getTag的方法将数据取出来

}

mp3Info = mp3Infos.get(position);

if(position == pos) {

viewHolder.albumImage.setImageResource(R.drawable.item);

} else {

Bitmap bitmap = MediaUtil.getArtwork(context, mp3Info.getId(),mp3Info.getAlbumId(), true, true);

viewHolder.albumImage.setImageBitmap(bitmap);

}

viewHolder.musicTitle.setText(mp3Info.getTitle()); //显示标题

viewHolder.musicArtist.setText(mp3Info.getArtist()); //显示艺术家

viewHolder.musicDuration.setText(MediaUtil.formatTime(mp3Info.getDuration()));//显示时长

return convertView;

}

/**

• 定义一个内部类

• 声明相应的控件引用

• @author wwj

*/

public class ViewHolder {

//所有控件对象引用

public ImageView albumImage; //专辑图片

public TextView musicTitle; //音乐标题

public TextView musicDuration; //音乐时长

public TextView musicArtist; //音乐艺术家

}

}

自定义适配器需要继承BaseAdapter类，主要是为了实现图片显示的显示，而不是单纯的字符串。

增加代码的MediaUtil类，主要包含获取专辑封面图片的方法，需要对图片做稍微的处理

/SimpleBeautyMusicPlayer/src/com/wwj/sb/utils/MediaUtil.java

package com.wwj.sb.utils;

import java.io.FileDescriptor;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.InputStream;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.Iterator;

import java.util.List;

import android.content.ContentResolver;

import android.content.ContentUris;

import android.content.Context;

import android.database.Cursor;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.graphics.BitmapFactory.Options;

import android.net.Uri;

import android.os.ParcelFileDescriptor;

import android.provider.MediaStore;

import com.wwj.sb.activity.R;

import com.wwj.sb.domain.Mp3Info;

public class MediaUtil {

//获取专辑封面的Uri

private static final Uri albumArtUri = Uri.parse(“content://media/external/audio/albumart”);

/**

• 用于从数据库中查询歌曲的信息，保存在List当中

• @return

*/

public static List getMp3Infos(Context context) {

Cursor cursor = context.getContentResolver().query(

MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, null, null, null,

MediaStore.Audio.Media.DEFAULT_SORT_ORDER);

List mp3Infos = new ArrayList();

for (int i = 0; i < cursor.getCount(); i++) {

cursor.moveToNext();

Mp3Info mp3Info = new Mp3Info();

long id = cursor.getLong(cursor

.getColumnIndex(MediaStore.Audio.Media._ID)); //音乐id

String title = cursor.getString((cursor

.getColumnIndex(MediaStore.Audio.Media.TITLE))); // 音乐标题

String artist = cursor.getString(cursor

.getColumnIndex(MediaStore.Audio.Media.ARTIST)); // 艺术家

String album = cursor.getString(cursor

.getColumnIndex(MediaStore.Audio.Media.ALBUM)); //专辑

long albumId = cursor.getInt(cursor.getColumnIndex(MediaStore.Audio.Media.ALBUM_ID));

long duration = cursor.getLong(cursor

.getColumnIndex(MediaStore.Audio.Media.DURATION)); // 时长

long size = cursor.getLong(cursor

.getColumnIndex(MediaStore.Audio.Media.SIZE)); // 文件大小

String url = cursor.getString(cursor

.getColumnIndex(MediaStore.Audio.Media.DATA)); // 文件路径

int isMusic = cursor.getInt(cursor

.getColumnIndex(MediaStore.Audio.Media.IS_MUSIC)); // 是否为音乐

if (isMusic != 0) { // 只把音乐添加到集合当中

mp3Info.setId(id);

mp3Info.setTitle(title);

mp3Info.setArtist(artist);

mp3Info.setAlbum(album);

mp3Info.setAlbumId(albumId);

mp3Info.setDuration(duration);

mp3Info.setSize(size);

mp3Info.setUrl(url);

mp3Infos.add(mp3Info);

}

}

return mp3Infos;

}

/**

• 往List集合中添加Map对象数据，每一个Map对象存放一首音乐的所有属性

• @param mp3Infos

• @return

*/

public static List<HashMap<String, String>> getMusicMaps(

List mp3Infos) {

List<HashMap<String, String>> mp3list = new ArrayList<HashMap<String, String>>();

for (Iterator iterator = mp3Infos.iterator(); iterator.hasNext()😉 {

Mp3Info mp3Info = (Mp3Info) iterator.next();

HashMap<String, String> map = new HashMap<String, String>();

map.put(“title”, mp3Info.getTitle());

map.put(“Artist”, mp3Info.getArtist());

map.put(“album”, mp3Info.getAlbum());

map.put(“albumId”, String.valueOf(mp3Info.getAlbumId()));

map.put(“duration”, formatTime(mp3Info.getDuration()));

map.put(“size”, String.valueOf(mp3Info.getSize()));

map.put(“url”, mp3Info.getUrl());

mp3list.add(map);

}

return mp3list;

}

/**

• 格式化时间，将毫秒转换为分:秒格式

• @param time

• @return

*/

public static String formatTime(long time) {

String min = time / (1000 * 60) + “”;

String sec = time % (1000 * 60) + “”;

if (min.length() < 2) {

min = “0” + time / (1000 * 60) + “”;

} else {

min = time / (1000 * 60) + “”;

}

if (sec.length() == 4) {

sec = “0” + (time % (1000 * 60)) + “”;

} else if (sec.length() == 3) {

sec = “00” + (time % (1000 * 60)) + “”;

} else if (sec.length() == 2) {

sec = “000” + (time % (1000 * 60)) + “”;

} else if (sec.length() == 1) {

sec = “0000” + (time % (1000 * 60)) + “”;

}

return min + “:” + sec.trim().substring(0, 2);

}

/**

• 获取默认专辑图片

• @param context

• @return

*/

public static Bitmap getDefaultArtwork(Context context,boolean small) {

BitmapFactory.Options opts = new BitmapFactory.Options();

opts.inPreferredConfig = Bitmap.Config.RGB_565;

if(small){ //返回小图片

return BitmapFactory.decodeStream(context.getResources().openRawResource(R.drawable.music5), null, opts);

}

return BitmapFactory.decodeStream(context.getResources().openRawResource(R.drawable.defaultalbum), null, opts);

}

/**

• 从文件当中获取专辑封面位图

• @param context

• @param songid

• @param albumid

• @return

*/

private static Bitmap getArtworkFromFile(Context context, long songid, long albumid){

Bitmap bm = null;

if(albumid < 0 && songid < 0) {

throw new IllegalArgumentException(“Must specify an album or a song id”);

}

try {

BitmapFactory.Options options = new BitmapFactory.Options();

FileDescriptor fd = null;

if(albumid < 0){

Uri uri = Uri.parse(“content://media/external/audio/media/”

• songid + “/albumart”);

ParcelFileDescriptor pfd = context.getContentResolver().openFileDescriptor(uri, “r”);

if(pfd != null) {

fd = pfd.getFileDescriptor();

}

} else {

Uri uri = ContentUris.withAppendedId(albumArtUri, albumid);

ParcelFileDe

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scriptor pfd = context.getContentResolver().openFileDescriptor(uri, “r”);

if(pfd != null) {

fd = pfd.getFileDescriptor();

}

}

options.inSampleSize = 1;

// 只进行大小判断

options.inJustDecodeBounds = true;

// 调用此方法得到options得到图片大小

BitmapFactory.decodeFileDescriptor(fd, null, options);

// 我们的目标是在800pixel的画面上显示

// 所以需要调用computeSampleSize得到图片缩放的比例

options.inSampleSize = 100;

// 我们得到了缩放的比例，现在开始正式读入Bitmap数据

options.inJustDecodeBounds = false;

options.inDither = false;

options.inPreferredConfig = Bitmap.Config.ARGB_8888;

//根据options参数，减少所需要的内存

bm = BitmapFactory.decodeFileDescriptor(fd, null, options);

} catch (FileNotFoundException e) {

e.printStackTrace();

}