Develop Reference

how to sample the bitmap for memory management in android?

i have made a demo for image editing,I am facing issue when i pass the image to another activity(Grow heap size),and my app crashed,Please tell me how cani sample and resize my bitmap directly (not from resources) to solve memory issue ,My code is as below:
code
if (Global.photo_editor_bitmap != null) {
ByteArrayOutputStream stream = new ByteArrayOutputStream();
Global.photo_editor_bitmap.compress(Bitmap.CompressFormat.PNG,
100, stream);
byte[] byteArray = stream.toByteArray();
i = new Intent(PhotoEditor.this, Enhance.class);
i.putExtra("bitmap_image", byteArray);
i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);
} else {
Toast.makeText(getApplicationContext(), "No Image", 1).show();
}
static int calculateInSampleSize(BitmapFactory.Options options,
int reqWidth, int reqHeight) {
int inSampleSize = 1; // Default subsampling size
// See if image raw height and width is bigger than that of required
// view
if (options.outHeight > reqHeight || options.outWidth > reqWidth) {
// bigger
final int halfHeight = options.outHeight / 2;
final int halfWidth = options.outWidth / 2;
// Calculate the largest inSampleSize value that is a power of 2 and
// keeps both
// height and width larger than the requested height and width.
while ((halfHeight / inSampleSize) > reqHeight
&& (halfWidth / inSampleSize) > reqWidth) {
inSampleSize *= 2;
}
}
return inSampleSize;
}
static Bitmap decodeSampledBitmapFromResource(Resources res, int resId,
int reqWidth, int reqHeight) {
// First decode with inJustDecodeBounds=true to check dimensions
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(res, resId, options);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth,
reqHeight);
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
return BitmapFactory.decodeResource(res, resId, options);
}
I got solution of decodebitmapFromresources,But my bitmap is available,SO how to use this direclty.

I have the same problem the app gets crashed and showing message in log for heap size, allocation size and bitmap size, what i have done is checked the device width & height and on the basis of that scaled the bitmap or calculate sample size.
int screenHeight = getResources().getDisplayMetrics().heightPixels;
int screenWidth = getResources().getDisplayMetrics().widthPixels;
get the width and height and then put it in reqWidth and reqHeight

OutOfMemoryError android Bitmap listview

In my application I use an SQLite database to store the data of a lot of images. Some images can be up to 600x600 pixels. I use a custom list to create the bitmaps. I know there is a method bitmap.recycle(); but I'm not sure how to use that with a listview.

Here is the solution to handle bitmaps in android
First, you should calculate the sampleBitmapSize of the bitmap ( to load the lower version of the same bitmap )
public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId,
int reqWidth, int reqHeight) {
// First decode with inJustDecodeBounds=true to check dimensions
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(res, resId, options);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
return BitmapFactory.decodeResource(res, resId, options);
}
Below is the util function to calculate InSampleSize ( an integer that defines the value (rating) of quality of a bitmap).
public static int calculateInSampleSize(
BitmapFactory.Options options, int reqWidth, int reqHeight) {
// Raw height and width of image
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 1;
if (height > reqHeight || width > reqWidth) {
final int halfHeight = height / 2;
final int halfWidth = width / 2;
// Calculate the largest inSampleSize value that is a power of 2 and keeps both
// height and width larger than the requested height and width.
while ((halfHeight / inSampleSize) > reqHeight
&& (halfWidth / inSampleSize) > reqWidth) {
inSampleSize *= 2;
}
}
Log.i("ImageUtil", "InSampleSize: "+inSampleSize);
return inSampleSize;
}

How to load high resolution image

I hava a high resolution(1188 * 17617 2.35MB) image and I want to load it in my Android APP.
If I use WebView, the image can display. But it is indistinct. I open it with browser in Android OS, it also indistinct.
If I use ImageView, it just display nothing.

You can scale down your bitmaps before loading them into the memory if they are too large. You can accomplish that by using BitmapFactory.Options and scale down as per your requirement.
public static Bitmap decodeSampledBitmapFromPath(String path, int reqWidth,
int reqHeight) {
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(path, options);
options.inSampleSize = calculateInSampleSize(options, reqWidth,
reqHeight);
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
Bitmap bmp = BitmapFactory.decodeFile(path, options);
return bmp;
}
public static int calculateInSampleSize(BitmapFactory.Options options,
int reqWidth, int reqHeight) {
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 1;
if (height > reqHeight || width > reqWidth) {
if (width > height) {
inSampleSize = Math.round((float) height / (float) reqHeight);
} else {
inSampleSize = Math.round((float) width / (float) reqWidth);
}
}
return inSampleSize;
}

Use the Picasso library. http://square.github.io/picasso/.
It deals with everything for you including downloading, caching and most importantly for you downsampling via a resize function. It also works with a standard ImageView with very little code:
Picasso.with(context)
.load(url)
.resize(50, 50)
.centerCrop()
.into(imageView)

Android Bitmap for Performance

I have this
Bitmap appWidgetBitmap = Bitmap.createBitmap(availableWidth, availableHeight, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(appWidgetBitmap);
And in the log console I see this
"dalvikvm-heap Grow heap (frag case) to......byte allocation
How can I make Bitmap with the lowest resources possible?
I saw something on BitmapFactory, but how to do it because the code above is createBitmap, not from resources.

Use below methods for resizing the image as aspect ratio:
public static int calculateInSampleSize(BitmapFactory.Options options,
int reqWidth, int reqHeight) {
// Raw height and width of image
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 1;
if (height > reqHeight || width > reqWidth) {
final int halfHeight = height / 2;
final int halfWidth = width / 2;
// Calculate the largest inSampleSize value that is a power of 2 and
// keeps both
// height and width larger than the requested height and width.
while ((halfHeight / inSampleSize) > reqHeight
&& (halfWidth / inSampleSize) > reqWidth) {
inSampleSize *= 2;
}
}
return inSampleSize;
}
public static Bitmap decodeSampledBitmapFromResource(Resources res,
int resId, int reqWidth, int reqHeight) {
// First decode with inJustDecodeBounds=true to check dimensions
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(res, resId, options);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth,
reqHeight);
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
// BitmapFactory.decodeResource(res, resId, options);
return Bitmap.createScaledBitmap(
BitmapFactory.decodeResource(res, resId, options), reqWidth,
reqHeight, true);
}
Then decode your image into bitmap format and set into the Canvas:
Bitmap src = decodeSampledBitmapFromResource(getResources(),
R.drawable.ic_bg_box, imgWidth, imgHeight);
Canvas canvas = new Canvas(src);
I hope this will help you.

MediaStore.Images.Media.getBitmap and out of memory error

My code code is:
public Bitmap loadPhoto(Uri uri) {
Bitmap scaled = null;
try {
scalled = Bitmap.createBitmap(
MediaStore.Images.Media.getBitmap(getContentResolver(), uri),
0,0,90, 90);
if (scaled == null) { return null; }
} catch(Exception e) { }
return scaled;
}
After this. I display scaled in ImageView. Every image comes from the device camera.
Every time, I get error: out of memory after I display three photos from camera. How to solve this?

Answer of Praveen Katha will always return null. Here is the updated answer.
Here is the trick, close the input stream after every use. Input Stream means to be used one time. For more information, please follow this answer
private static int calculateInSampleSize(
BitmapFactory.Options options, int reqWidth, int reqHeight) {
// Raw height and width of image
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 1;
if (height > reqHeight || width > reqWidth) {
final int halfHeight = height / 2;
final int halfWidth = width / 2;
// Calculate the largest inSampleSize value that is a power of 2 and keeps both
// height and width larger than the requested height and width.
while ((halfHeight / inSampleSize) >= reqHeight
&& (halfWidth / inSampleSize) >= reqWidth) {
inSampleSize *= 2;
}
}
return inSampleSize;
}
public static Bitmap decodeSampledBitmapFromUri(Context context, Uri imageUri, int reqWidth, int reqHeight) throws FileNotFoundException {
Bitmap bitmap = null;
try {
// Get input stream of the image
final BitmapFactory.Options options = new BitmapFactory.Options();
InputStream iStream = context.getContentResolver().openInputStream(imageUri);
// First decode with inJustDecodeBounds=true to check dimensions
options.inJustDecodeBounds = true;
BitmapFactory.decodeStream(iStream, null, options);
if (iStream != null) {
iStream.close();
}
iStream = context.getContentResolver().openInputStream(imageUri);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
bitmap = BitmapFactory.decodeStream(iStream, null, options);
if (iStream != null) {
iStream.close();
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return bitmap;
}

Try using BitmapFactory to fix the problem http://developer.android.com/reference/android/graphics/BitmapFactory.html

The MediaStore.getBitmap method is a convenience method that does not specify a sample size when obtaining the bitmap. If you are using getBitmap(ContentResolver, Uri), and want to use a sample size, just use the ContentResolver to get the input stream, and decode the bitmap as you would normally (calculating sample size first, and then loading it with the appropriate sample size).

For those who are looking for code sample:
private static int calculateInSampleSize(
BitmapFactory.Options options, int reqWidth, int reqHeight) {
// Raw height and width of image
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 1;
if (height > reqHeight || width > reqWidth) {
final int halfHeight = height / 2;
final int halfWidth = width / 2;
// Calculate the largest inSampleSize value that is a power of 2 and keeps both
// height and width larger than the requested height and width.
while ((halfHeight / inSampleSize) >= reqHeight
&& (halfWidth / inSampleSize) >= reqWidth) {
inSampleSize *= 2;
}
}
return inSampleSize;
}
public static Bitmap decodeSampledBitmapFromUri(Context context, Uri imageUri, int reqWidth, int reqHeight) throws FileNotFoundException {
// Get input stream of the image
final BitmapFactory.Options options = new BitmapFactory.Options();
InputStream iStream = context.getContentResolver().openInputStream(imageUri);
// First decode with inJustDecodeBounds=true to check dimensions
options.inJustDecodeBounds = true;
BitmapFactory.decodeStream(iStream, null, options);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
return BitmapFactory.decodeStream(iStream, null, options);
}