[英]Cannot show in ImageView a picture exported from the gallery
我正在創建一個Android應用程序,該應用程序需要在內部存儲中存儲一些多媒體文件。 用戶可以從選擇器中選擇該多媒體文件。 即使用戶刪除了這些文件,這些文件也必須是可用的,因此它們會被復制到內部存儲器中。
這是我的代碼:
final Bitmap bitm = MediaStore.Images.Media.getBitmap( this.getContentResolver(), uri );
final int bitmapRawLength = bitm.getAllocationByteCount();
final ByteBuffer byteBuffer = ByteBuffer.allocate( bitmapRawLength );
bitm.copyPixelsToBuffer( byteBuffer );
data = byteBuffer.array();
final ByteArrayInputStream in = new ByteArrayInputStream( data );
db.store( in );
因此,組成圖像的字節通過InputStream復制到內部存儲中的平均文件中。 顯然它可以工作,因為該文件包含內容。
稍后將圖像加載到ImageView中 :
private void loadImage(File imgFile)
{
if ( imgFile.exists() ) {
final Bitmap bitmap = BitmapFactory.decodeFile( mediaFile.getPath() );
this.ivPictureBox.setImageBitmap( bitmap );
} else {
this.abortDueToMissingFile( imgFile );
}
return;
}
不幸的是,這不起作用。 是時候加載該圖像了, ImageView變成空白,什么也沒有顯示。
實際上,日志中顯示以下消息:
D/skia: --- Failed to create image decoder with message 'unimplemented'
如果我在Android Studio中使用文件資源管理器並將圖像導出到我的計算機,則GwenView失敗,並顯示消息“無法加載元數據”。
如何更容易或可行地正確存儲帶有完整信息的圖像,或正確顯示它?
在這種情況下,我已經開發並測試了一些代碼。 希望對您有幫助。
定義請求代碼:
private static final int REQUEST_CODE_KITKAT_PICK_PHOTO = 11;
private static final int REQUEST_CODE_PICK_PHOTO = 12;
調用圖像選擇器:
if (Build.VERSION.SDK_INT < 19) {
Intent intent = new Intent();
intent.setType("image/*");
intent.setAction(Intent.ACTION_GET_CONTENT);
startActivityForResult(Intent.createChooser(intent, "Choose a photo"), REQUEST_CODE_PICK_PHOTO);
} else {
Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
intent.addCategory(Intent.CATEGORY_OPENABLE);
intent.setType("image/*");
startActivityForResult(intent, REQUEST_CODE_KITKAT_PICK_PHOTO);
}
要接收選擇的圖像並將其復制,請在“ Activity
:
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == Activity.RESULT_OK) {
if (requestCode == REQUEST_CODE_PICK_PHOTO) {
if (data == null || data.getData() == null) {
Toast.makeText(getApplicationContext(), "Error in retrieving photo!", Toast.LENGTH_SHORT).show();
return;
}
Uri uri = data.getData();
String destPath = getFilesDir() + File.separator + "image.jpg"; // an example path
File imageFile = null;
try {
imageFile = copy(uri, destPath);
} catch (IOException e) {
e.printStackTrace();
}
if (imageFile != null) {
Bitmap bitmap = BitmapFactory.decodeFile(imageFile.getAbsolutePath());
ivPictureBox.setImageBitmap(bitmap);
}
} else if (requestCode == REQUEST_CODE_KITKAT_PICK_PHOTO) {
if (data == null || data.getData() == null) {
Toast.makeText(getApplicationContext(), "Error in retrieving photo!", Toast.LENGTH_SHORT).show();
return;
}
Uri originalUri = data.getData();
final int takeFlags = data.getFlags()
& (Intent.FLAG_GRANT_READ_URI_PERMISSION
| Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
// Check for the freshest data.
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
getContentResolver().takePersistableUriPermission(originalUri, takeFlags);
}
String destPath = getFilesDir() + File.separator + "image.jpg"; // an example path
File imageFile = null;
try {
imageFile = copy(originalUri, destPath);
} catch (IOException e) {
e.printStackTrace();
}
if (imageFile != null) {
Bitmap bitmap = BitmapFactory.decodeFile(imageFile.getAbsolutePath());
ivPictureBox.setImageBitmap(bitmap);
}
}
}
}
// To copy the file:
private File copy(Uri inputUri, String destPath) throws IOException {
File inputFile = new File(ImageUtils.getPathFromUri(getApplicationContext(), inputUri));
File outputFile = new File(destPath);
if (!outputFile.exists()) {
outputFile.createNewFile();
}
FileInputStream inStream = new FileInputStream(inputFile);
FileOutputStream outStream = new FileOutputStream(outputFile);
FileChannel inChannel = inStream.getChannel();
FileChannel outChannel = outStream.getChannel();
inChannel.transferTo(0, inChannel.size(), outChannel);
inStream.close();
outStream.close();
return outputFile;
}
ImageUtils.java:
import android.annotation.SuppressLint;
import android.content.ContentUris;
import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
import android.os.Build;
import android.os.Environment;
import android.provider.DocumentsContract;
import android.provider.MediaStore;
public class ImageUtils {
@SuppressLint("NewApi")
public static String getPathFromUri(final Context context, final Uri uri) {
final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;
// DocumentProvider
if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {
// ExternalStorageProvider
if (isExternalStorageDocument(uri)) {
final String docId = DocumentsContract.getDocumentId(uri);
final String[] split = docId.split(":");
final String type = split[0];
if ("primary".equalsIgnoreCase(type)) {
return Environment.getExternalStorageDirectory() + "/" + split[1];
}
// TODO handle non-primary volumes
}
// DownloadsProvider
else if (isDownloadsDocument(uri)) {
final String id = DocumentsContract.getDocumentId(uri);
final Uri contentUri = ContentUris.withAppendedId(
Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));
return getDataColumn(context, contentUri, null, null);
}
// MediaProvider
else if (isMediaDocument(uri)) {
final String docId = DocumentsContract.getDocumentId(uri);
final String[] split = docId.split(":");
final String type = split[0];
Uri contentUri = null;
if ("image".equals(type)) {
contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
} else if ("video".equals(type)) {
contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
} else if ("audio".equals(type)) {
contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
}
final String selection = "_id=?";
final String[] selectionArgs = new String[]{
split[1]
};
return getDataColumn(context, contentUri, selection, selectionArgs);
}
}
// MediaStore (and general)
else if ("content".equalsIgnoreCase(uri.getScheme())) {
// Return the remote address
if (isGooglePhotosUri(uri))
return uri.getLastPathSegment();
return getDataColumn(context, uri, null, null);
}
// File
else if ("file".equalsIgnoreCase(uri.getScheme())) {
return uri.getPath();
}
return null;
}
public static String getDataColumn(Context context, Uri uri, String selection, String[] selectionArgs) {
Cursor cursor = null;
final String column = "_data";
final String[] projection = {
column
};
try {
cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs,
null);
if (cursor != null && cursor.moveToFirst()) {
final int index = cursor.getColumnIndexOrThrow(column);
return cursor.getString(index);
}
} finally {
if (cursor != null)
cursor.close();
}
return null;
}
/**
* @param uri The Uri to check.
* @return Whether the Uri authority is ExternalStorageProvider.
*/
public static boolean isExternalStorageDocument(Uri uri) {
return "com.android.externalstorage.documents".equals(uri.getAuthority());
}
/**
* @param uri The Uri to check.
* @return Whether the Uri authority is DownloadsProvider.
*/
public static boolean isDownloadsDocument(Uri uri) {
return "com.android.providers.downloads.documents".equals(uri.getAuthority());
}
/**
* @param uri The Uri to check.
* @return Whether the Uri authority is MediaProvider.
*/
public static boolean isMediaDocument(Uri uri) {
return "com.android.providers.media.documents".equals(uri.getAuthority());
}
/**
* @param uri The Uri to check.
* @return Whether the Uri authority is Google Photos.
*/
public static boolean isGooglePhotosUri(Uri uri) {
return "com.google.android.apps.photos.content".equals(uri.getAuthority());
}
}
結果如下:
我真傻!
它很簡單:
final InputStream in = this.getContentResolver().openInputStream( uri );
...並復制到任何您想要的位置。
這適用於具有SCHEME_CONTENT和SCHEME_FILE方案的URI。
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