iam使用以下代码，它不在gridview中显示拇指图像，但在模拟器中显示请建议我如何在sdcard中显示gridview中的拇指图像
String[] projection = {MediaStore.Images.Media._ID};
final String orderBy = MediaStore.Images.Media._ID+" DESC";
// Create the cursor pointing to the SDCard
Cursor cursor = managedQuery( MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
projection, // Which columns to return
null, // Return all rows
null,
orderBy);
int columnIndex = cursor.getColumnIndexOrThrow(MediaStore.Images.Media._ID);
int size = cursor.getCount();
// If size is 0, there are no images on the SD Card.
if (size == 0) {
//No Images available, post some message to the user
}
int imageID = 0;
for (int i = 0; i < size; i++) {
cursor.moveToPosition(i);
imageID = cursor.getInt(columnIndex);
uri = Uri.withAppendedPath(MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI, "" + imageID);
try {
bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(uri));
if (bitmap != null) {
newBitmap = Bitmap.createScaledBitmap(bitmap, 86, 96, true);
bitmap.recycle();
if (newBitmap != null) {
publishProgress(new LoadedImage(newBitmap));
}
}
} catch (IOException e) {
}
}
答案 0 :(得分：0)
试试这段代码，它会起作用
package com.video;
import android.app.Activity;
import android.content.Context;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.Toast;
import android.widget.AdapterView.OnItemClickListener;
public class StartActivity extends Activity {
//set constants for MediaStore to query, and show videos
private final static Uri MEDIA_EXTERNAL_CONTENT_URI = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
private final static String _ID = MediaStore.Video.Media._ID;
private final static String MEDIA_DATA = MediaStore.Video.Media.DATA;
//flag for which one is used for images selection
private GridView _gallery;
private Cursor _cursor;
private int _columnIndex;
private int[] _videosId;
private Uri _contentUri;
protected Context _context;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
_context = getApplicationContext();
setContentView(R.layout.main);
//set GridView for gallery
_gallery = (GridView) findViewById(R.id.videoGrdVw);
//set default as external/sdcard uri
_contentUri = MEDIA_EXTERNAL_CONTENT_URI;
//initialize the videos uri
//showToast(_contentUri.getPath());
initVideosId();
//set gallery adapter
setGalleryAdapter();
}
private void setGalleryAdapter() {
_gallery.setAdapter(new VideoGalleryAdapter(_context));
_gallery.setOnItemClickListener(_itemClickLis);
}
private AdapterView.OnItemClickListener _itemClickLis = new OnItemClickListener()
{
public void onItemClick(AdapterView parent, View v, int position, long id)
{
// Now we want to actually get the data location of the file
String [] proj={MEDIA_DATA};
// We request our cursor again
_cursor = managedQuery(_contentUri,
proj, // Which columns to return
null, // WHERE clause; which rows to return (all rows)
null, // WHERE clause selection arguments (none)
null); // Order-by clause (ascending by name)
// We want to get the column index for the data uri
int count = _cursor.getCount();
//
_cursor.moveToFirst();
//
_columnIndex = _cursor.getColumnIndex(MEDIA_DATA);
// Lets move to the selected item in the cursor
_cursor.moveToPosition(position);
// And here we get the filename
String filename = _cursor.getString(_columnIndex);
//*********** You can do anything when you know the file path :-)
showToast(filename);
//
}
};
private void initVideosId() {
try
{
//Here we set up a string array of the thumbnail ID column we want to get back
String [] proj={_ID};
// Now we create the cursor pointing to the external thumbnail store
_cursor = managedQuery(_contentUri,
proj, // Which columns to return
null, // WHERE clause; which rows to return (all rows)
null, // WHERE clause selection arguments (none)
null); // Order-by clause (ascending by name)
int count= _cursor.getCount();
// We now get the column index of the thumbnail id
_columnIndex = _cursor.getColumnIndex(_ID);
//initialize
_videosId = new int[count];
//move position to first element
_cursor.moveToFirst();
for(int i=0;i<count;i++)
{
int id = _cursor.getInt(_columnIndex);
//
_videosId[i]= id;
//
_cursor.moveToNext();
//
}
}catch(Exception ex)
{
showToast(ex.getMessage().toString());
}
}
protected void showToast(String msg)
{
Toast.makeText(_context, msg, Toast.LENGTH_LONG).show();
}
//
private class VideoGalleryAdapter extends BaseAdapter
{
public VideoGalleryAdapter(Context c)
{
_context = c;
}
public int getCount()
{
return _videosId.length;
}
public Object getItem(int position)
{
return position;
}
public long getItemId(int position)
{
return position;
}
public View getView(int position, View convertView, ViewGroup parent)
{
ImageView imgVw= new ImageView(_context);;
try
{
if(convertView!=null)
{
imgVw= (ImageView) convertView;
}
imgVw.setImageBitmap(getImage(_videosId[position]));
imgVw.setLayoutParams(new GridView.LayoutParams(96, 96));
imgVw.setPadding(8, 8, 8, 8);
}
catch(Exception ex)
{
System.out.println("StartActivity:getView()-135: ex " + ex.getClass() +", "+ ex.getMessage());
}
return imgVw;
}
// Create the thumbnail on the fly
private Bitmap getImage(int id) {
Bitmap thumb = MediaStore.Video.Thumbnails.getThumbnail(
getContentResolver(),
id, MediaStore.Video.Thumbnails.MICRO_KIND, null);
return thumb;
}
}
}