如何从Uri中获得位图对象(如果我成功地将它存储在 /data/data/MYFOLDER/myimage.png或文件///data/data/MYFOLDER/myimage.png)在我的应用程序中使用它?
有人知道怎么做到吗?
如何从Uri中获得位图对象(如果我成功地将它存储在 /data/data/MYFOLDER/myimage.png或文件///data/data/MYFOLDER/myimage.png)在我的应用程序中使用它?
有人知道怎么做到吗?
当前回答
下面是正确的方法,同时也要注意内存的使用情况:
protected void onActivityResult(int requestCode, int resultCode, Intent data)
{
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_OK)
{
Uri imageUri = data.getData();
Bitmap bitmap = getThumbnail(imageUri);
}
}
public static Bitmap getThumbnail(Uri uri) throws FileNotFoundException, IOException{
InputStream input = this.getContentResolver().openInputStream(uri);
BitmapFactory.Options onlyBoundsOptions = new BitmapFactory.Options();
onlyBoundsOptions.inJustDecodeBounds = true;
onlyBoundsOptions.inDither=true;//optional
onlyBoundsOptions.inPreferredConfig=Bitmap.Config.ARGB_8888;//optional
BitmapFactory.decodeStream(input, null, onlyBoundsOptions);
input.close();
if ((onlyBoundsOptions.outWidth == -1) || (onlyBoundsOptions.outHeight == -1)) {
return null;
}
int originalSize = (onlyBoundsOptions.outHeight > onlyBoundsOptions.outWidth) ? onlyBoundsOptions.outHeight : onlyBoundsOptions.outWidth;
double ratio = (originalSize > THUMBNAIL_SIZE) ? (originalSize / THUMBNAIL_SIZE) : 1.0;
BitmapFactory.Options bitmapOptions = new BitmapFactory.Options();
bitmapOptions.inSampleSize = getPowerOfTwoForSampleRatio(ratio);
bitmapOptions.inDither = true; //optional
bitmapOptions.inPreferredConfig=Bitmap.Config.ARGB_8888;//
input = this.getContentResolver().openInputStream(uri);
Bitmap bitmap = BitmapFactory.decodeStream(input, null, bitmapOptions);
input.close();
return bitmap;
}
private static int getPowerOfTwoForSampleRatio(double ratio){
int k = Integer.highestOneBit((int)Math.floor(ratio));
if(k==0) return 1;
else return k;
}
Mark Ingram的文章中的getBitmap()调用也调用decodeStream(),因此不会丢失任何功能。
引用:
Android:在SD卡上获取图像的缩略图,给定原始图像的Uri 处理大位图
其他回答
从移动库中获取图像uri的完整方法。
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == PICK_IMAGE_REQUEST && resultCode == RESULT_OK && data != null && data.getData() != null) {
Uri filePath = data.getData();
try { //Getting the Bitmap from Gallery
Bitmap bitmap = MediaStore.Images.Media.getBitmap(getContentResolver(), filePath);
rbitmap = getResizedBitmap(bitmap, 250);//Setting the Bitmap to ImageView
serImage = getStringImage(rbitmap);
imageViewUserImage.setImageBitmap(rbitmap);
} catch (IOException e) {
e.printStackTrace();
}
}
}
Bitmap bitmap = null;
ContentResolver contentResolver = getContentResolver();
try {
if(Build.VERSION.SDK_INT < 28) {
bitmap = MediaStore.Images.Media.getBitmap(contentResolver, imageUri);
} else {
ImageDecoder.Source source = ImageDecoder.createSource(contentResolver, imageUri);
bitmap = ImageDecoder.decodeBitmap(source);
}
} catch (Exception e) {
e.printStackTrace();
}
private fun setImage(view: ImageView, uri: Uri) {
val stream = contentResolver.openInputStream(uri)
val bitmap = BitmapFactory.decodeStream(stream)
view.setImageBitmap(bitmap)
}
MediaStore.Images.Media.getBitmap在API 29中已弃用。推荐的方法是使用ImageDecoder。在API 28中添加的createSource。
下面是如何获得位图:
val bitmap = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
ImageDecoder.decodeBitmap(ImageDecoder.createSource(requireContext().contentResolver, imageUri))
} else {
MediaStore.Images.Media.getBitmap(requireContext().contentResolver, imageUri)
}
重要:ImageDecoder.decodeBitmap读取EXIF方向,媒体。getBitmap不
下面是正确的做法:
protected void onActivityResult(int requestCode, int resultCode, Intent data)
{
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_OK)
{
Uri imageUri = data.getData();
Bitmap bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), imageUri);
}
}
如果你需要加载非常大的图像,下面的代码将以tile的形式加载它(避免大的内存分配):
BitmapRegionDecoder decoder = BitmapRegionDecoder.newInstance(myStream, false);
Bitmap region = decoder.decodeRegion(new Rect(10, 10, 50, 50), null);
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