Android – How to change the background color of a saved transparent bitmap

androidbitmaptransparency

I am opening a png image into a Bitmap, making some modifications to it and then saving it to disk as a jpg. In the case where the png has some transparent areas, they are saved as black. Is there a way to change this default behavior so the image is saved with a different color background such as white?

Thanks

Best Answer

You could draw it to a new bitmap, e.g.

   Bitmap newBitmap = Bitmap.createBitmap(image.getWidth(), 
    image.getHeight(), image.getConfig());
    Canvas canvas = new Canvas(newBitmap);
    canvas.drawColor(Color.WHITE);
    canvas.drawBitmap(image, 0F, 0F, null);

then save new bitmap instead

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Android – How to close/hide the Android soft keyboard programmatically

You can force Android to hide the virtual keyboard using the InputMethodManager, calling hideSoftInputFromWindow, passing in the token of the window containing your focused view.

// Check if no view has focus:
View view = this.getCurrentFocus();
if (view != null) {  
    InputMethodManager imm = (InputMethodManager)getSystemService(Context.INPUT_METHOD_SERVICE);
    imm.hideSoftInputFromWindow(view.getWindowToken(), 0);
}

This will force the keyboard to be hidden in all situations. In some cases, you will want to pass in InputMethodManager.HIDE_IMPLICIT_ONLY as the second parameter to ensure you only hide the keyboard when the user didn't explicitly force it to appear (by holding down the menu).

Note: If you want to do this in Kotlin, use: context?.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager

Kotlin Syntax

// Only runs if there is a view that is currently focused
this.currentFocus?.let { view ->
    val imm = getSystemService(Context.INPUT_METHOD_SERVICE) as? InputMethodManager
    imm?.hideSoftInputFromWindow(view.windowToken, 0)
}

Android – How to change colors of a Drawable in Android

I think you can actually just use Drawable.setColorFilter( 0xffff0000, Mode.MULTIPLY ). This would set white pixels to red but I don't think it would affect the transparent pixels.

See Drawable#setColorFilter

Best Answer

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Android – How to close/hide the Android soft keyboard programmatically

Android – How to change colors of a Drawable in Android

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