Android Shadow未在ActionBar中显示

Question

I have problem with shadow of ActionBar it doesn't show when i add this : android:hardwareAccelerated="false" in my AndroidManifest.xml but when i delete this line it show shadow well and show other problem in my Activity which has Recycleview with items of images(small size images) it be very slow when i scroll the Recycleview , but when add android:hardwareAccelerated="false" scrolling be normal.

Please anyone could help me with this?

Answer 1

According to google documentation

Beginning in Android 3.0 (API level 11), the Android 2D rendering pipeline supports hardware acceleration, meaning that all drawing operations that are performed on a View's canvas use the GPU. Because of the increased resources required to enable hardware acceleration, your app will consume more RAM.

So i guess writing android:hardwareAccelerated="false" stops the app from making use of the GPU, hence reducing GPU rendered effects like shadows.

A couple of things that you can do is

1. Add the android:hardwareAccelerated="false" for the specific activity where you want to load heavy images. Click here to check that.

2. Try and reduce the size of the images that you are loading. This can be done using the following two functions as documented in the developer documentation for android. Click here for the complete documentation.

Function 1

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;
}

Function 2

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);
}

Set Image in ImageView

mImageView.setImageBitmap(
decodeSampledBitmapFromResource(getResources(), R.id.myimage, 100, 100));

Also refer this link for a another reference about Image Resizing.