Android and setting alpha for (image) view alpha

Question

Is there really no XML attribute counterpart to setAlpha(int)?

If not, what alternatives are there?

Answer 1

No, there is not, see how the "Related XML Attributes" section is missing in the ImageView.setAlpha(int) documentation. The alternative is to use View.setAlpha(float) whose XML counterpart is android:alpha. It takes a range of 0.0 to 1.0 instead of 0 to 255. Use it e.g. like

<ImageView android:alpha="0.4">

However, the latter in available only since API level 11.

Answer 2

setAlpha(int) is deprecated as of API 16: Android 4.1

Please use setImageAlpha(int) instead

Answer 3

I am not sure about the XML but you can do it by code in the following way.

ImageView myImageView = new ImageView(this);
myImageView.setAlpha(xxx);

In pre-API 11:

• range is from 0 to 255 (inclusive), 0 being transparent and 255 being opaque.

In API 11+:

• range is from 0f to 1f (inclusive), 0f being transparent and 1f being opaque.