我创建了一个应用程序，允许用户在外部存储上创建相册（文件夹）。现在我试图从所述目录中检索图像并将它们显示在GridView中。我正在使用AsyncTask使用listFiles（）遍历文件目录，然后在抓取每个图像后再创建一个位图，然后重新使用它。我的问题是我的GridView中没有出现任何内容。我已经设置了一些Log break，LogCat告诉我迭代确实发生了并且检索了图像。这让我觉得我在我的Adapter类中的某个地方犯了一个错误，它将位图绑定到Grid，可能在getView中？或者也许我错了。对我做错的任何帮助？我试图尽可能地评论代码，但我遗漏了不必要的部分。感谢
public class AlbumGridView extends Activity implements OnItemClickListener {
private GridView sdcardImages;
private ImageAdapter imageAdapter;
private Display display;
private Bitmap bitmap;
private Bitmap b;
File[] imageList;
private static final String TAG = "AlbumGridView";
String path;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
setContentView(R.layout.album_view);
//display =
//((Object) getSystemService(Context.WINDOW_SERVICE))).getDefaultDisplay();
path = getIntent().getStringExtra("key");
Toast.makeText(this, path, Toast.LENGTH_SHORT).show();
setupViews();
setProgressBarIndeterminateVisibility(true);
loadImages();
}
protected void onDestroy() {
super.onDestroy();
final GridView grid = sdcardImages;
final int count = grid.getCount();
ImageView v = null;
for (int i = 0; i < count; i++) {
v = (ImageView) grid.getChildAt(i);
((BitmapDrawable) v.getDrawable()).setCallback(null);
}
}
// Set up the GridView
private void setupViews() {
sdcardImages = (GridView) findViewById(R.id.gvAlbumView);
// sdcardImages.setNumColumns(display.getWidth()/95);
sdcardImages.setClipToPadding(false);
sdcardImages.setOnItemClickListener(AlbumGridView.this);
imageAdapter = new ImageAdapter(getApplicationContext());
// imageAdapter.setImageList(path);
sdcardImages.setAdapter(imageAdapter);
}
private void addImage(LoadedImage... value) {
for (LoadedImage image : value) {
imageAdapter.addPhoto(image);
imageAdapter.notifyDataSetChanged();
}
}
// Save Bitmap images to a list and return that list
@Override
public Object onRetainNonConfigurationInstance() {
final GridView grid = sdcardImages;
final int count = grid.getChildCount();
final LoadedImage[] list = new LoadedImage[count];
for (int i = 0; i < count; i++) {
final ImageView v = (ImageView) grid.getChildAt(i);
list[i] = new LoadedImage(
((BitmapDrawable) v.getDrawable()).getBitmap());
}
return list;
}
private void loadImages() {
// TODO Auto-generated method stub
final Object data = getLastNonConfigurationInstance();
if (data == null) {
new LoadImagesFromSDCard().execute();
} else {
final LoadedImage[] photos = (LoadedImage[]) data;
if (photos.length == 0) {
new LoadImagesFromSDCard().execute();
}
for (LoadedImage photo : photos) {
addImage(photo);
}
}
}
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
// TODO Auto-generated method stub
}
/ ------------------------------------------- ------------------------------------------ /
//Adapter for the GridView
public class ImageAdapter extends BaseAdapter {
private Context mContext;
private ArrayList<LoadedImage> photos = new ArrayList<LoadedImage>();
private String path;
private Bitmap bitmap;
public ImageAdapter(Context context) {
mContext = context;
}
public void addPhoto(LoadedImage photo) {
photos.add(photo);
}
public int getCount() {
return photos.size();
}
public Object getItem(int position) {
return photos.get(position);
}
public long getItemId(int position) {
return position;
}
/*
* public File[] setImageList(String path) {
*
* //this.path = path; //this.imageList = imageList; //File imagesDir =
* new File(path); //imageList = imagesDir.listFiles();
*
* File imagesDir = new File(path); imageList = imagesDir.listFiles();
* for (File image : imageList) try { bitmap =
* BitmapFactory.decodeStream(image.toURL().openStream()); //use bitmap
* and recycle afterwards LoadedImage lm = new LoadedImage(bitmap);
* this.addPhoto(lm); bitmap.recycle();
*
* } catch (IOException e) { e.printStackTrace(); } return imageList;
*
* }
*/
public View getView(int position, View convertView, ViewGroup parent) {
final ImageView imageView;
if (convertView == null) {
imageView = new ImageView(mContext);
} else {
imageView = (ImageView) convertView;
}
imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);
imageView.setPadding(2, 2, 2, 2);
// imageView.setImageBitmap(photos.get(position).getBitmap());
try {
imageView
.setImageBitmap(BitmapFactory
.decodeStream(imageList[position].toURL()
.openStream()));
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return imageView;
}
}
/*-------------------------------------------------------------------------*/
//AsyncTask to get the images
class LoadImagesFromSDCard extends AsyncTask<Object, LoadedImage, Object> {
@Override
protected Object doInBackground(Object... arg0) {
// Load images from SD card in Background
// Display each image on the screen
File imagesDir = new File(path);
imageList = imagesDir.listFiles();
for (File image : imageList)
try {
if (bitmap != null) {
bitmap.recycle();
bitmap = null;
}
bitmap = BitmapFactory.decodeStream(image.toURL()
.openStream());
Log.e(TAG, "Grabbed Image " + image.getName());
// use bitmap then recycle after
LoadedImage lm = new LoadedImage(bitmap);
// addImage(lm);
// imageAdapter.addPhoto(lm);
// imageAdapter.setImageList(path);
// imageAdapter.addPhoto(lm);
// imageAdapter.setImageList(path);
// bitmap.recycle();
// addImage(lm);
// imageAdapter.addPhoto(lm);
Log.e(TAG, "Added Image " + lm.toString());
// imageAdapter.setImageList(path);
addImage(lm);
// bitmap.recycle();
// bitmap.recycle();
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
答案 0 :(得分：1)
这是解决方案顺便说一句，对不起，我花了很长时间才意识到其他人都在等待答案。抱歉。相关代码如下。
这是AsyncTask，它将查询设备的MediaStore并检索所有照片。请注意，这是检索缩略图而不是全尺寸图像，更具体地说，它是MICRO_KIND。还有一个Thumbnail.MINI_KIND。
/*----------------------------ASYNC TASK TO LOAD THE PHOTOS--------------------------------------------------------*/
public class LoadPhotos extends AsyncTask<Object, Object, Object> {
@Override
protected Object doInBackground(Object... params) {
try {
final String[] columns = { MediaStore.Images.Media._ID };
final String orderBy = MediaStore.Images.Media._ID;
Cursor imagecursor = managedQuery(
MediaStore.Images.Media.EXTERNAL_CONTENT_URI, columns,
null, null, orderBy);
int image_column_index = imagecursor
.getColumnIndex(MediaStore.Images.Media._ID);
AllPhotosActivity.count = imagecursor.getCount();
AllPhotosActivity.windows = new Bitmap[AllPhotosActivity.count];
for (int i = 0; i < AllPhotosActivity.count; i++) {
imagecursor.moveToPosition(i);
// i = index;
int id = imagecursor.getInt(image_column_index);
windows[i] = MediaStore.Images.Thumbnails.getThumbnail(
getApplicationContext().getContentResolver(), id,
MediaStore.Images.Thumbnails.MICRO_KIND, null);
}
imagecursor.close();
} catch (Exception e) {
e.printStackTrace();
Log.d("AllPhotosActivity",
"Error occured while fetching all photos on device.");
}
return null;
}
@Override
protected void onPostExecute(Object result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
Handler mHandler = new Handler();
mHandler.post(new Runnable() {
public void run() {
pd.dismiss();
// imageAdapter.notifyDataSetChanged();
// sdcardImages.setAdapter(imageAdapter);
}
});
// pd.dismiss();
imagegrid.setAdapter(imageAdapter);
// pd.dismiss();
}
@Override
protected void onProgressUpdate(Object... values) {
// TODO Auto-generated method stub
super.onProgressUpdate(values);
}
}
这是GridView的适配器，它将缩略图绑定到gridview。我的问题只是在我的ImageAdapter的getView方法中，注意我是从Bitmaps数组的不同索引设置我的ImageView资源我称之为windows。
public class ImageAdapter extends BaseAdapter {
private Context mContext;
public ImageAdapter(Context c) {
mContext = c;
}
public Object getItem(int position) {
// TODO Auto-generated method stub
return position;
}
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ImageView i = (ImageView) convertView;
if (i != null) {
i.setImageBitmap(windows[position]);
} else {
i = new ImageView(mContext.getApplicationContext());
// i.setPadding(3, 3, 3, 3);
// i.setScaleType(ImageView.ScaleType.FIT_CENTER);
i.setAdjustViewBounds(true);
// i.setMaxHeight(200);
// i.setMaxWidth(200);
i.setPadding(3, 3, 3, 3);
i.setLayoutParams(new GridView.LayoutParams(92, 92));
i.setImageBitmap(windows[position]);
}
return i;
}
public int getCount() {
// TODO Auto-generated method stub
return count;
}
}