今天就跟大家聊聊有关Android中怎么利用Gallery实现多级联动，可能很多人都不太了解，为了让大家更加了解，小编给大家总结了以下内容，希望大家根据这篇文章可以有所收获。
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Gallery布局
主要的布局是有两个相对布局+两个Gallery组成的：
1: 2: 5: 6: 13: 14: 23:
Gallery的适配器
在android中适配器很好的实现了MVC思想，它很好的为某些组件提供了数据和view的实现。此处我们需要通过继承BaseAdapter，实现两个Gallery的适配器。
1: /** 2: * 专辑 3: * 4: * @author halzhang 5: */ 6: public class AlbumAdapter extends BaseAdapter { 7: 8: private Context context; 9: 10: private Cursor cursor; 11: 12: private Bitmap[] bitmaps; 13: 14: public AlbumAdapter(Context context) { 15: this.context = context; 16: this.cursor = context.getContentResolver().query( 17: MediaStore.Audio.Albums.EXTERNAL_CONTENT_URI, null, null, null, 18: MediaStore.Audio.Albums.DEFAULT_SORT_ORDER); 19: bitmaps = new Bitmap[cursor.getCount()]; 20: initBitmaps(); 21: } 22: 23: /** 24: * 初始化专辑封面图片 25: */ 26: private void initBitmaps() { 27: if (cursor.moveToFirst()) { 28: do { 29: bitmaps[cursor.getPosition()] = MusicUtils.getArtwork(context, -1, cursor 30: .getInt(cursor.getColumnIndexOrThrow(MediaStore.Audio.Albums._ID))); 31: } while (cursor.moveToNext()); 32: } 33: } 34: 35: public int getCount() { 36: if (cursor != null) { 37: return cursor.getCount(); 38: } 39: return 0; 40: } 41: 42: public Object getItem(int position) { 43: return position; 44: } 45: 46: public long getItemId(int position) { 47: if (cursor != null) { 48: cursor.moveToPosition(position); 49: return cursor.getInt(cursor.getColumnIndexOrThrow(MediaStore.Audio.Albums._ID)); 50: } 51: return 0; 52: } 53: 54: public View getView(int position, View convertView, ViewGroup parent) { 55: ImageView iv = new ImageView(context); 56: iv.setLayoutParams(new Gallery.LayoutParams(100, 100)); 57: iv.setAdjustViewBounds(true); 58: iv.setImageBitmap(bitmaps[position]); 59: return iv; 60: } 61: 62: } 1: /** 2: * 歌曲 3: * 4: * @author halzhang 5: */ 6: public class AudioAdapter extends BaseAdapter { 7: 8: private Context context; 9: 10: private Cursor cursor; 11: /**专辑ID*/ 12: private int albumId; 13: 14: public AudioAdapter(Context context, int albumId) { 15: this.context = context; 16: this.albumId = albumId; 17: this.cursor = context.getContentResolver().query( 18: MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, null, 19: MediaStore.Audio.Media.ALBUM_ID + "=" + albumId, null, 20: MediaStore.Audio.Media.DEFAULT_SORT_ORDER); 21: } 22: 23: public int getCount() { 24: if (cursor != null) { 25: return cursor.getCount(); 26: } 27: return 0; 28: } 29: 30: public Object getItem(int position) { 31: return position; 32: } 33: 34: public long getItemId(int position) { 35: if (cursor != null) { 36: cursor.moveToPosition(position); 37: return cursor.getInt(cursor.getColumnIndexOrThrow(MediaStore.Audio.Media._ID)); 38: } 39: return 0; 40: } 41: 42: public View getView(int position, View convertView, ViewGroup parent) { 43: cursor.moveToPosition(position); 44: TextView t = new TextView(context); 45: String title = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Audio.Media.TITLE)); 46: t.setLayoutParams(new Gallery.LayoutParams(LayoutParams.WRAP_CONTENT, 47: LayoutParams.WRAP_CONTENT)); 48: t.setText(title); 49: t.setTextColor(Color.BLACK); 50: return t; 51: } 52: 53: /** 54: * 当专辑改变了，调用此方法更新adapter的数据 55: * @param albumId 专辑ID 56: */ 57: public void notifyDataSetChanged(int albumId) { 58: this.cursor = context.getContentResolver().query( 59: MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, null, 60: MediaStore.Audio.Media.ALBUM_ID + "=" + albumId, null, 61: MediaStore.Audio.Media.DEFAULT_SORT_ORDER); 62: super.notifyDataSetChanged(); 63: } 64: 65: }Activity
1: public class MainActivity extends Activity implements AdapterView.OnItemSelectedListener { 2: 3: private Gallery album; 4: 5: private Gallery audio; 6: 7: private AlbumAdapter albumAdapter; 8: 9: private AudioAdapter audioAdapter; 10: 11: @Override 12: protected void onCreate(Bundle savedInstanceState) { 13: super.onCreate(savedInstanceState); 14: setContentView(R.layout.audio_player); 15: setupViews(); 16: } 17: 18: // 个人习惯 19: private void setupViews() { 20: album = (Gallery) findViewById(R.id.gallery); 21: audio = (Gallery) findViewById(R.id.gallery2); 22: 23: albumAdapter = new AlbumAdapter(this); 24: 25: album.setAdapter(albumAdapter); 26: 27: int aid = (int) albumAdapter.getItemId(0); 28: 29: audioAdapter = new AudioAdapter(this, aid); 30: audio.setAdapter(audioAdapter); 31: 32: audio.setOnItemSelectedListener(this); 33: album.setOnItemSelectedListener(this); 34: } 35: 36: public void onItemSelected(AdapterView parent, View view, int position, long id) { 37: if (parent == album) { 38: // 专辑被选中 39: int aid = (int) albumAdapter.getItemId(position); 40: // 更新歌曲Gallery 41: audioAdapter.notifyDataSetChanged(aid); 42: } else if (parent == audio) { 43: // TODO do something 44: } 45: 46: } 47: 48: public void onNothingSelected(AdapterView parent) { 49: 50: }看完上述内容，你们对Android中怎么利用Gallery实现多级联动有进一步的了解吗？如果还想了解更多知识或者相关内容，请关注创新互联行业资讯频道，感谢大家的支持。
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