I am doing an application where for example when i click on the image(it is a searchView)
I just met the same problem, here are some reference links.
http://blog.luxteam.net/2013/11/04/styling-appcompat-searchview/
https://android.googlesource.com/platform/frameworks/support.git/+/android-support-lib-19.1.0/v7/appcompat/src/android/support/v7/widget/SearchView.java
The key is in the following function, it sets the icon as an ImageSpan.
private CharSequence getDecoratedHint(CharSequence hintText) {
// If the field is always expanded, then don't add the search icon to the hint
if (!mIconifiedByDefault) return hintText;
SpannableStringBuilder ssb = new SpannableStringBuilder(" "); // for the icon
ssb.append(hintText);
Drawable searchIcon = getContext().getResources().getDrawable(getSearchIconId());
int textSize = (int) (mQueryTextView.getTextSize() * 1.25);
searchIcon.setBounds(0, 0, textSize, textSize);
ssb.setSpan(new ImageSpan(searchIcon), 1, 2, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
return ssb;
}