ContentProvider--实现在本地获取音乐显示在ListView

我用的逍遥安卓，数据库的路径：在data/data/com.android.providers.media/database/external(手机SDK)

效果：



实现步骤：

1.创建一个类继承Adapter(由于获取的东西比较多，所以我们可以创建一个对象)

2.在Activity中实现对应的方法

创建对象：

public class MusicContent {
String _data,_display_name,mime_type,title,artist,album;
long _size,date_added,duration;

public MusicContent(String _data, String _display_name, String mime_type, String title, String artist, String album, long _size, long date_added, long duration) {
this._data = _data;
this._display_name = _display_name;
this.mime_type = mime_type;
this.title = title;
this.artist = artist;
this.album = album;
this._size = _size;
this.date_added = date_added;
this.duration = duration;
}

public String get_data() {
return _data;
}

public void set_data(String _data) {
this._data = _data;
}

public String get_display_name() {
return _display_name;
}

public void set_display_name(String _display_name) {
this._display_name = _display_name;
}

public String getMime_type() {
return mime_type;
}

public void setMime_type(String mime_type) {
this.mime_type = mime_type;
}

public String getTitle() {
return title;
}

public void setTitle(String title) {
this.title = title;
}

public String getArtist() {
return artist;
}

public void setArtist(String artist) {
this.artist = artist;
}

public String getAlbum() {
return album;
}

public void setAlbum(String album) {
this.album = album;
}

public long get_size() {
return _size;
}

public void set_size(long _size) {
this._size = _size;
}

public long getDate_added() {
return date_added;
}

public void setDate_added(long date_added) {
this.date_added = date_added;
}

public long getDuration() {
return duration;
}

public void setDuration(long duration) {
this.duration = duration;
}
}MusicAdapte:
public class MusicAdapter extends BaseAdapter {
Context context;
LayoutInflater mInflater;
ArrayList<MusicContent> arrayList;

public MusicAdapter(Context context, ArrayList<MusicContent> arrayList) {
this.context = context;
this.arrayList = arrayList;
this.mInflater = LayoutInflater.from(context);
}

@Override
public int getCount() {
return arrayList.size();
}

@Override
public Object getItem(int position) {
return arrayList.get(position);
}

@Override
public long getItemId(int position) {
return position;
}

@Override
public View getView(int positi
9c21
on, View convertView, ViewGroup parent) {
ViewHolder viewHolder;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.activity_main, null);
TextView tv = (TextView) convertView.findViewById(R.id.tv);
viewHolder = new ViewHolder(tv);
convertView.setTag(viewHolder);
}
viewHolder = (ViewHolder) convertView.getTag();
MusicContent musicContent = (MusicContent) getItem(position);
viewHolder.textView.setText(musicContent.get_data());
return convertView;
}
}

class ViewHolder {
TextView textView;

public ViewHolder(TextView textView) {
this.textView = textView;
}
}

MainActivity：
public class MainActivity extends AppCompatActivity {
ContentResolver resolver;
ArrayList<MusicContent> arrayList;
ListView lv;
Button but;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_listview);
lv = (ListView) findViewById(R.id.lv_music);
arrayList = new ArrayList<>();
resolver = getContentResolver();

/**
* 参数一：Uri uri
* 参数二：String[] projection 列名
* 参数三：String selection 查询条件
* 参数四：String[] selectionArgs 查询条件的值
* 参数五：String sortOrder 排序
*/
Cursor cursor = resolver.query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, null, null, null, null);
if (cursor != null) {
while (cursor.moveToNext()) {
String _date = cursor.getString(cursor.getColumnIndex("_data"));
String _display_name = cursor.getString(cursor.getColumnIndex("_display_name"));
String mime_type = cursor.getString(cursor.getColumnIndex("mime_type"));
String title = cursor.getString(cursor.getColumnIndex("title"));
String artist = cursor.getString(cursor.getColumnIndex("artist"));
String album = cursor.getString(cursor.getColumnIndex("album"));
long _size = cursor.getInt(cursor.getColumnIndex("_data"));
long date_added = cursor.getInt(cursor.getColumnIndex("_data"));
long duration = cursor.getInt(cursor.getColumnIndex("_data"));
MusicContent musicContent = new MusicContent(_date, _display_name, mime_type, title, artist, album, _size, date_added, duration);
arrayList.add(musicContent);
}
}
MusicAdapter musicAdapter = new MusicAdapter(this, arrayList);
lv.setAdapter(musicAdapter);
}
}activity_mian.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
>
<TextView
android:id="@+id/tv"
android:layout_width="match_parent"
android:layout_height="match_parent" />

</LinearLayout>activity_listview.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ListView
android:id="@+id/lv_music"
android:layout_width="match_parent"
android:layout_height="match_parent">

</ListView>
</LinearLayout>
这里我只是简单的在ListView显示了一个属性，写得比较粗糙，大致实现是这样的