如何获得ListView中某个项目的ImageView的图片呢

naohmurderer 2019-01-03 05:26:34
做是一个音乐播放器,每首歌曲在ListView中,其专辑图片已经读取出来了,如何实现在点击某首歌的时候将这首歌的专辑封面显示在MainActivity上。自己的思路就是读到ListView的位置,然后读取该位置的ImageView的内容返回给MainActivity的ImageView,但是不知道该如何下手,求解答。代码如下:
MainActivity:
package com.example.aw765.musicplayer;
public class MainActivity extends ListActivity {
private static final int UPDATE_FREQUENCY=500;
private static final int STEP_VALUE=4000;

private TextView selectedfile=null;
private SeekBar seekBar=null;
private MediaPlayer player=null;
private ImageButton prev=null;
private ImageButton play=null;
private ImageButton next=null;
private MediaCursorAdapter adapter=null;
private ImageView iv_album;

private boolean isStarted=true;
private String currentFile="";
private boolean isMovingSeekBar=false;
private final Handler handler=new Handler();
private Context context;

private final Runnable updatePositinRunnable=new Runnable() {
@Override
public void run() {
updatePosition();
}
};

private void updatePosition() {
handler.removeCallbacks(updatePositinRunnable);
seekBar.setProgress(player.getCurrentPosition());
handler.postDelayed(updatePositinRunnable, UPDATE_FREQUENCY);
}


@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
context=this;
selectedfile=(TextView) findViewById(R.id.selecteditem);
seekBar=(SeekBar) findViewById(R.id.seekBar);
prev=(ImageButton) findViewById(R.id.previous);
play=(ImageButton) findViewById(R.id.play);
next=(ImageButton) findViewById(R.id.next);
iv_album=(ImageView) findViewById(R.id.iv_album);

player=new MediaPlayer();
player.setOnCompletionListener(onCompletion);
player.setOnErrorListener(onError);
seekBar.setOnSeekBarChangeListener(seekBarChanged);

ContentResolver resolver = context.getContentResolver();
Cursor cursor=resolver.query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,null,null,null,null);



if (null !=cursor){
cursor.moveToFirst();
adapter=new MediaCursorAdapter(this,R.layout.item,cursor);
setListAdapter(adapter);
prev.setOnClickListener(OnButtonClick);
play.setOnClickListener(OnButtonClick);
next.setOnClickListener(OnButtonClick);
}

}

private Bitmap getAlbumArt(int album_id) {
String mUriAlbums = "content://media/external/audio/albums";
String[] projection = new String[]{"album_art"};
Cursor cur = context.getContentResolver().query(Uri.parse(mUriAlbums + "/" + Integer.toString(album_id)), projection, null, null, null);
String album_art = null;
if (cur.getCount() > 0 && cur.getColumnCount() > 0) {
cur.moveToNext();
album_art = cur.getString(0);
}
cur.close();
Bitmap bm = null;
if (album_art != null) {
bm = BitmapFactory.decodeFile(album_art);
} else {
bm = BitmapFactory.decodeResource(getResources(), R.drawable.default_album_art);
}
return bm;
}
@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
super.onListItemClick(l, v, position, id);
ContentResolver resolver = context.getContentResolver();
Cursor cursor=resolver.query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,null,null,null,null);
/*if (cursor!=null){
cursor.moveToFirst();
int album_id=cursor.getInt(cursor.getColumnIndex(MediaStore.Audio.Media.ALBUM_ID));
iv_album.setImageBitmap(getAlbumArt(album_id));
}*/
/*Bitmap bm = null;
if (album_art != null) {
bm = BitmapFactory.decodeFile(album_art);
} else {
bm = BitmapFactory.decodeResource(getResources(), R.drawable.default_album_art);
}*/
//iv_album.setImageDrawable(album_art);
adapter=new MediaCursorAdapter(this,R.layout.item,cursor);

currentFile = (String) v.getTag();
startPlay(currentFile);
}


private void startPlay(String file) {
Log.i("Selected: ", file);
selectedfile.setText(file);
seekBar.setProgress(0);
player.stop();
player.reset();

try {
player.setDataSource(file);
player.prepare();
player.start();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (IllegalStateException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
seekBar.setMax(player.getDuration());
play.setImageResource(android.R.drawable.ic_media_pause);
updatePosition();
isStarted = true;
}

private void stopPlay() {
player.stop();
player.reset();
play.setImageResource(android.R.drawable.ic_media_play);
handler.removeCallbacks(updatePositinRunnable);
seekBar.setProgress(0);
isStarted = false;
}

@Override
protected void onDestroy() {
super.onDestroy();
handler.removeCallbacks(updatePositinRunnable);
player.stop();
player.reset();
player.release();
player = null;
}

private View.OnClickListener OnButtonClick = new View.OnClickListener() {
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.play: {
if (player.isPlaying()) {
handler.removeCallbacks(updatePositinRunnable);
player.pause();
play.setImageResource(android.R.drawable.ic_media_play);
} else {
if (isStarted) {
player.start();
play.setImageResource(android.R.drawable.ic_media_pause);
updatePosition();
} else {
startPlay(currentFile);
}
}
break;
}

case R.id.next: {
int seekto = player.getCurrentPosition() + STEP_VALUE;
if (seekto > player.getDuration())
seekto = player.getDuration();
player.pause();
player.seekTo(seekto);
player.start();
break;
}

case R.id.previous: {
int seekto = player.getCurrentPosition() - STEP_VALUE;
if (seekto < 0)
seekto = 0;
player.pause();
player.seekTo(seekto);
player.start();
break;
}
}
}
};
private MediaPlayer.OnCompletionListener onCompletion = new MediaPlayer.OnCompletionListener() {
@Override
public void onCompletion(MediaPlayer mp) {
stopPlay();
}

;
};
private MediaPlayer.OnErrorListener onError = new MediaPlayer.OnErrorListener() {
@Override
public boolean onError(MediaPlayer mp, int what, int extra) {
return false;
}
};

private SeekBar.OnSeekBarChangeListener seekBarChanged =
new SeekBar.OnSeekBarChangeListener() {
@Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
if (isMovingSeekBar) {
player.seekTo(progress);
Log.i("OnSeekBarChangeListener", "OnProgressChanged");
}
}

@Override
public void onStartTrackingTouch(SeekBar seekBar) {
isMovingSeekBar = true;
}

@Override
public void onStopTrackingTouch(SeekBar seekBar) {
isMovingSeekBar = false;
}
};
}


Adapter主要部分代码:

album.setText(cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.ALBUM)));
title.setText(cursor.getString(cursor.getColumnIndex(MediaStore.MediaColumns.TITLE)));
int album_id=cursor.getInt(cursor.getColumnIndex(MediaStore.Audio.Media.ALBUM_ID));
long durationInMS=Long.parseLong(cursor.getString(cursor.getColumnIndex(MediaStore.Audio.AudioColumns.DURATION)));
double durationInMin=((double)durationInMS/1000.0)/60.0;
durationInMin=new BigDecimal(Double.toString(durationInMin)).setScale(2,BigDecimal.ROUND_UP).doubleValue();
duration.setText(""+durationInMin);
view.setTag(cursor.getString(cursor.getColumnIndex(MediaStore.MediaColumns.DATA)));

String mUriAlbums = "content://media/external/audio/albums";
String[] projection = new String[] { "album_art" };
Cursor cur = resolver.query(Uri.parse(mUriAlbums + "/" + Integer.toString(album_id)), projection, null, null, null);
String album_art = null;
if (cur.getCount() > 0 && cur.getColumnCount() > 0){
cur.moveToNext();
album_art = cur.getString(0);
}
cur.close();
cur = null;

Bitmap bitmap=null;
if (album_art==null){
iv_album_small.setBackgroundResource(R.drawable.default_album_art);
}else {
bitmap=BitmapFactory.decodeFile(album_art);
BitmapDrawable bitmapDrawable=new BitmapDrawable(bitmap);
((ImageView) iv_album_small).setImageDrawable(bitmapDrawable);

}
}

求解答!!!
...全文
670 7 打赏 收藏 转发到动态 举报
写回复
用AI写文章
7 条回复
切换为时间正序
请发表友善的回复…
发表回复
南窗听雨88 2019-01-08
  • 打赏
  • 举报
回复
这个可以用控件下载,很多控件其实比自己开发用起来还更加方便快捷。推荐去 https://blog.csdn.net/john_dwh 这个博客找找你的需求看看有没有为你解答。
王能 2019-01-07
  • 打赏
  • 举报
回复
对的,根据MediaCursorAdapter获取专辑图的逻辑用arrayList保存(MediaCursorAdapter应该保存过了,其实你应该只需要把私有list改成protected的就行了),然后onItemClick时用list.get(position)来获取
王能 2019-01-04
  • 打赏
  • 举报
回复
楼上只是举个例子,意思是让你代码获取图片路径。 现在你需要得到音乐路径或直接得到图片路径就行了 如何得到路径:在你的MediaCursorAdapter里面找到查询逻辑把路径保存下来即可
naohmurderer 2019-01-04
  • 打赏
  • 举报
回复
引用 4 楼 王能 的回复:
楼上只是举个例子,意思是让你代码获取图片路径。 现在你需要得到音乐路径或直接得到图片路径就行了 如何得到路径:在你的MediaCursorAdapter里面找到查询逻辑把路径保存下来即可
主要是获取不到额。。因为在MediaCursorAdapter里获取了很多专辑图,具体要哪一张需要点击获取位置后再根据位置传回路径嘛,我回头改成BaseAdapter用getView方法来写一下吧。
naohmurderer 2019-01-04
  • 打赏
  • 举报
回复
引用 2 楼 无fucker说 的回复:
定义一个List<String> imgFilePaths; adapter=new MediaCursorAdapter(this,R.layout.item,imgFilePaths); setListAdapter(adapter); 开启子线程查询获取数据 ContentResolver resolver = context.getContentResolver(); Cursor cursor=resolver.query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,null,null,null,null); if (null !=cursor){ cursor.moveToFirst(); prev.setOnClickListener(OnButtonClick); play.setOnClickListener(OnButtonClick); next.setOnClickListener(OnButtonClick); ... //在这里获取所有封面图片途径 ... 然后Handler发消息 接收消息后adapter.notifyDatasetChanged() } ListView的item点击事件中 String imgPath=imgFilePaths.get(position); 然后就是Activity间传数据或者回传数据了
可是MediaCursorAdapter里第三个参数要求的是Cursor类的诶...
雕·不懒惰 2019-01-03
  • 打赏
  • 举报
回复
定义一个List<String> imgFilePaths;

adapter=new MediaCursorAdapter(this,R.layout.item,imgFilePaths);
setListAdapter(adapter);



开启子线程查询获取数据
ContentResolver resolver = context.getContentResolver();
Cursor cursor=resolver.query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,null,null,null,null);

if (null !=cursor){
cursor.moveToFirst();

prev.setOnClickListener(OnButtonClick);
play.setOnClickListener(OnButtonClick);
next.setOnClickListener(OnButtonClick);
... //在这里获取所有封面图片途径
...
然后Handler发消息 接收消息后adapter.notifyDatasetChanged()
}
ListView的item点击事件中
String imgPath=imgFilePaths.get(position);
然后就是Activity间传数据或者回传数据了
雕·不懒惰 2019-01-03
  • 打赏
  • 举报
回复
定义一个List<String> imgFilePaths;


ContentResolver resolver = context.getContentResolver();
Cursor cursor=resolver.query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,null,null,null,null);



if (null !=cursor){
cursor.moveToFirst();

setListAdapter(adapter);
prev.setOnClickListener(OnButtonClick);
play.setOnClickListener(OnButtonClick);
next.setOnClickListener(OnButtonClick);
}

80,337

社区成员

发帖
与我相关
我的任务
社区描述
移动平台 Android
androidandroid-studioandroidx 技术论坛(原bbs)
社区管理员
  • Android
  • yechaoa
  • 失落夏天
加入社区
  • 近7日
  • 近30日
  • 至今
社区公告
暂无公告

试试用AI创作助手写篇文章吧