我试图从SD卡中获取所有图像并将其显示在gridview中(包含在片段中)。但是,虽然没有抛出任何异常,但gridview中只显示任何内容,只是一个普通的黑屏。我不确定问题出在哪里,视图绑定或将数据提取到光标中。这是片段的当前代码:
public class PhotoGridFragment extends Fragment implements LoaderManager.LoaderCallbacks<Cursor> {
// member variables for
private static final int PHOTO_LIST_LOADER = 0x01;
private ImageCursorAdapter adapter;
private Cursor c;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getLoaderManager().initLoader(PHOTO_LIST_LOADER, null, this);
adapter = new ImageCursorAdapter(getActivity().getApplicationContext(), c);
}
/* R.layout.grid_item,
null, new String[] { MediaStore.Images.Thumbnails.DATA }, new int[] {R.id.grid_item},
CursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER); */
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.photo_item, container, false);
}
// Loader manager methods
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
String[] projection = { MediaStore.Images.Thumbnails._ID, MediaStore.Images.Thumbnails.DATA };
CursorLoader cursorLoader = new CursorLoader(getActivity(),
MediaStore.Images.Media.EXTERNAL_CONTENT_URI, projection,
null, null, null);
return cursorLoader;
}
public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
adapter.swapCursor(cursor);
}
public void onLoaderReset(Loader<Cursor> cursor) {
adapter.swapCursor(null);
}
private class ImageCursorAdapter extends CursorAdapter {
private LayoutInflater mLayoutInflater;
private Context mContext;
public ImageCursorAdapter(Context context, Cursor c) {
super(context, c);
mContext = context;
mLayoutInflater = LayoutInflater.from(context);
}
@Override
public void bindView(View view, Context context, Cursor cursor) {
ImageView newView = (ImageView) view.findViewById(R.layout.grid_item);
String imagePath = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Images.Thumbnails._ID));
if (imagePath != null && imagePath.length() != 0 && newView != null) {
newView.setVisibility(ImageView.VISIBLE);
}
}
@Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
View v = mLayoutInflater.inflate(R.layout.grid_item, parent, false);
return v;
}
}
项目的布局文件如下:
photo_item.xml:
<?xml version="1.0" encoding="UTF-8"?>
<GridView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/photo_item"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:textSize="24dp"
android:padding="6dp" />
grid_item.xml:
<?xml version="1.0" encoding="utf-8"?>
<ImageView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/grid_item"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:textSize="24dp"
android:padding="6dp"
/>
答案 0 :(得分:1)
答案 1 :(得分:1)
试试此代码
sdcard.java
public class Sdcard extends Activity {
// Cursor used to access the results from querying for images on the SD card.
private Cursor cursor;
// Column index for the Thumbnails Image IDs.
private int columnIndex;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sdcard);
// Set up an array of the Thumbnail Image ID column we want
String[] projection = {MediaStore.Images.Thumbnails._ID};
// Create the cursor pointing to the SDCard
cursor = managedQuery( MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI,
projection, // Which columns to return
null, // Return all rows
null,
MediaStore.Images.Thumbnails.IMAGE_ID);
// Get the column index of the Thumbnails Image ID
columnIndex = cursor.getColumnIndexOrThrow(MediaStore.Images.Thumbnails._ID);
GridView sdcardImages = (GridView) findViewById(R.id.gridView1);
sdcardImages.setAdapter(new ImageAdapter(this));
}
private class ImageAdapter extends BaseAdapter {
private Context context;
public ImageAdapter(Context localContext) {
context = localContext;
}
public int getCount() {
return cursor.getCount();
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ImageView picturesView;
if (convertView == null) {
picturesView = new ImageView(context);
// Move cursor to current position
cursor.moveToPosition(position);
// Get the current value for the requested column
int imageID = cursor.getInt(columnIndex);
// Set the content of the image based on the provided URI
picturesView.setImageURI(Uri.withAppendedPath(
MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI, "" + imageID));
picturesView.setScaleType(ImageView.ScaleType.FIT_XY);
picturesView.setPadding(10, 10, 10, 10);
picturesView.setLayoutParams(new GridView.LayoutParams(100, 100));
}
else {
picturesView = (ImageView)convertView;
}
return picturesView;
}
}
}