我正在尝试将文件解码为这样的位图 -
BitmapFactory.Options options = new BitmapFactory.Options();
try {
Bitmap bitmap = BitmapFactory.decodeFile(mCurrentPhotoPath, options);
cropImageView.setImageBitmap(bitmap);
Log.d("Musik","bitmap - "+bitmap+" "+mCurrentPhotoPath);
}
catch (Exception e){
Log.d("Musik",e.toString());
}
我的mCurrentPhotoPath是
file:/storage/sdcard0/Android/data/com.example.iaugmentor.iaugmentortestvers/files/Pictures/JPEG_20160805_161105_478260200.jpg
我无法找到为什么它返回null并且也没有捕获异常。
请帮忙。提前谢谢。
为了清楚说明，让我先说明如何首先保存图像我首先创建一个File对象，然后捕获图像并将其保存在给定的Uri中 -
// Create the File where the photo should go
File photoFile = null;
try {
photoFile = createImageFile();
} catch (IOException ex) {
// Error occurred while creating the File
}
if (items[which].equals("Take Photo")) {
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
if(intent.resolveActivity(getPackageManager()) != null) {
// Continue only if the File was successfully created
if (photoFile != null) {
profilePicUri = FileProvider.getUriForFile(ApplicationContext.getAppContext(),
"com.example.iaugmentor.iaugmentortestvers",
photoFile);
}
intent.putExtra(android.provider.MediaStore.EXTRA_OUTPUT, profilePicUri);
try {
intent.putExtra("return-data", true);
startActivityForResult(intent, RESULT_LOAD_IMG);
} catch (ActivityNotFoundException e) {
e.printStackTrace();
}
}
createImageFile（）方法就像这样`
private File createImageFile() throws IOException {
// Create an image file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
String imageFileName = "JPEG_" + timeStamp + "_";
File storageDir = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
File image = File.createTempFile(
imageFileName, /* prefix */
".jpg", /* suffix */
storageDir /* directory */
);
// Save a file: path for use with ACTION_VIEW intents
mCurrentPhotoPath = "file:" + image.getAbsolutePath();
return image;
}
然后我试图在变量 mCurrentPhotoPath
的帮助下从另一个活动中读取图像答案 0 :(得分：1)
在 createImageFile（）方法中创建/保存filePath：mCurrentPhotoPath。
File imageFile = new File(image.getAbsolutePath());
mCurrentPhotoPath = imageFile.toString();
答案 1 :(得分：1)
bitmap = BitmapFactory.decodeFile(capturedImageFilePath);
或
private static String filename;
public static Bitmap compressImage(String imageUri,Context mContext) {
String filePath = getRealPathFromURI(imageUri,mContext);
Bitmap scaledBitmap = null;
BitmapFactory.Options options = new BitmapFactory.Options();
// by setting this field as true, the actual bitmap pixels are not
// loaded in the memory. Just the bounds are loaded. If
// you try the use the bitmap here, you will get null.
options.inJustDecodeBounds = true;
Bitmap bmp = BitmapFactory.decodeFile(filePath, options);
int actualHeight = options.outHeight;
int actualWidth = options.outWidth;
// max Height and width values of the compressed image is taken as
// 816x612
float maxHeight = 816.0f;
float maxWidth = 612.0f;
float imgRatio = actualWidth / actualHeight;
float maxRatio = maxWidth / maxHeight;
// width and height values are set maintaining the aspect ratio of the
// image
if (actualHeight > maxHeight || actualWidth > maxWidth) {
if (imgRatio < maxRatio) {
imgRatio = maxHeight / actualHeight;
actualWidth = (int) (imgRatio * actualWidth);
actualHeight = (int) maxHeight;
} else if (imgRatio > maxRatio) {
imgRatio = maxWidth / actualWidth;
actualHeight = (int) (imgRatio * actualHeight);
actualWidth = (int) maxWidth;
} else {
actualHeight = (int) maxHeight;
actualWidth = (int) maxWidth;
}
}
// setting inSampleSize value allows to load a scaled down version of
// the original image
options.inSampleSize = calculateInSampleSize(options, actualWidth,
actualHeight);
// inJustDecodeBounds set to false to load the actual bitmap
options.inJustDecodeBounds = false;
// this options allow android to claim the bitmap memory if it runs low
// on memory
options.inPurgeable = true;
options.inInputShareable = true;
options.inTempStorage = new byte[16 * 1024];
try {
// load the bitmap from its path
bmp = BitmapFactory.decodeFile(filePath, options);
} catch (OutOfMemoryError exception) {
exception.printStackTrace();
}
try {
scaledBitmap = Bitmap.createBitmap(actualWidth, actualHeight,
Bitmap.Config.ARGB_8888);
} catch (OutOfMemoryError exception) {
exception.printStackTrace();
}
float ratioX = actualWidth / (float) options.outWidth;
float ratioY = actualHeight / (float) options.outHeight;
float middleX = actualWidth / 2.0f;
float middleY = actualHeight / 2.0f;
Matrix scaleMatrix = new Matrix();
scaleMatrix.setScale(ratioX, ratioY, middleX, middleY);
Canvas canvas = new Canvas(scaledBitmap);
canvas.setMatrix(scaleMatrix);
canvas.drawBitmap(bmp, middleX - bmp.getWidth() / 2,
middleY - bmp.getHeight() / 2, new Paint(
Paint.FILTER_BITMAP_FLAG));
// check the rotation of the image and display it properly
ExifInterface exif;
try {
exif = new ExifInterface(filePath);
int orientation = exif.getAttributeInt(
ExifInterface.TAG_ORIENTATION, 0);
Log.d("EXIF", "Exif: " + orientation);
Matrix matrix = new Matrix();
if (orientation == 6) {
matrix.postRotate(90);
Log.d("EXIF", "Exif: " + orientation);
} else if (orientation == 3) {
matrix.postRotate(180);
Log.d("EXIF", "Exif: " + orientation);
} else if (orientation == 8) {
matrix.postRotate(270);
Log.d("EXIF", "Exif: " + orientation);
}
scaledBitmap = Bitmap.createBitmap(scaledBitmap, 0, 0,
scaledBitmap.getWidth(), scaledBitmap.getHeight(), matrix,
true);
} catch (IOException e) {
e.printStackTrace();
}
FileOutputStream out = null;
filename = getFilename();
try {
out = new FileOutputStream(filename);
// write the compressed bitmap at the destination specified by
// filename.
//scaledBitmap.compress(Bitmap.CompressFormat.JPEG, 80, out);
if(filePath.contains(".png") || filePath.contains(".PNG")){
scaledBitmap.compress(Bitmap.CompressFormat.PNG, 100, out);
}else{
scaledBitmap.compress(Bitmap.CompressFormat.JPEG, 100, out);
}
// ContentValues values = new ContentValues();
//
// values.put(Images.Media.DATE_TAKEN,
// System.currentTimeMillis());
// values.put(Images.Media.MIME_TYPE, "image/jpeg");
// values.put(MediaStore.MediaColumns.DATA,filename);
//
// ((Activity)mContext).getContentResolver().insert(
// Images.Media.EXTERNAL_CONTENT_URI, values);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
return new BitmapFactory().decodeFile(filename);
}
public String getCompressedBitmapFilePath() {
return filename;
}