MediaStore.Audio:存放音频信息
MediaStore.Image:存放图像信息
MediaStore.Video:存放视频信息
以下代码功能:
枚举所有内存卡中的图片缩略图,并显示在ImageView中
publicclass MainActivity extends Activity {
private ImageView image;
private Button btn;
privateint index;
privateint totalCount;
private ArrayList<String> imageSrcs =new ArrayList<String>();
@Override
publicvoid onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
image = (ImageView)findViewById(R.id.image);
btn = (Button)findViewById(R.id.btn);
//获取上下文
Context ctx = MainActivity.this;
//获取ContentResolver对象
ContentResolver resolver = ctx.getContentResolver();
//获得外部存储卡上的图片缩略图
Cursor c = resolver.query(MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI, null, null, null, null);
//为了for循环性能优化,用一变量存储数据条数
totalCount = c.getCount();
//将Cursor移动到第一位
c.moveToFirst();
//将缩略图数据添加到ArrayList中
for(int i=0; i<totalCount; i++){
int index = c.getColumnIndexOrThrow(MediaStore.Images.Thumbnails.DATA);
String src = c.getString(index);
imageSrcs.add(src);
index = i;
c.moveToNext();
}
//关闭游标
c.close();
//点击按钮,切换图片
btn.setOnClickListener(new OnClickListener(){
@Override
publicvoid onClick(View v) {
String src = imageSrcs.get(index);
image.setImageURI(Uri.parse(src));
index ++;
if(index == totalCount){
index =0;
}
}
});
}
}