Get specific drawable from state list drawable

Issue

I have a state list drawable, and i want to get a specific drawable from the state list drawable:

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android" xmlns:kplus="http://schemas.android.com/apk/res-auto">


    <item kplus:key_type_space_alt="true" android:state_pressed="true" android:drawable="@drawable/space_1_pressed" />
    <item kplus:key_type_space_alt="true" android:drawable="@drawable/space_1_normal" />

    <!-- TopNav keys. -->

    <item kplus:key_type_topnav="true" android:state_pressed="true" android:drawable="@drawable/tab_down" />
    <item kplus:key_type_topnav="true" android:state_selected="true" android:drawable="@drawable/tab_down" />
    <item kplus:key_type_topnav="true" android:drawable="@drawable/tab_normal" />

    <!-- TopRow keys. -->

    <item kplus:key_type_toprow="true" android:state_pressed="true" android:drawable="@drawable/numeric_presseed" />
    <item kplus:key_type_toprow="true" android:drawable="@drawable/numeric_normal" />
</selector>

I select the correct drawable state for each key, something like this:

if (keyIsNumbers) {
    if (KPlusInputMethodService.sNumbersState == 2) {
        drawableState = mDrawableStatesProvider.KEY_STATE_TOPNAV_CHECKED;
    }
}

Now the states are defined like this:

KEY_STATE_TOPNAV_NORMAL = new int[] {keyTypeTopNavAttrId};
KEY_STATE_TOPNAV_PRESSED = new int[] {keyTypeTopNavAttrId, android.R.attr.state_pressed};
KEY_STATE_TOPNAV_CHECKED = new int[] {keyTypeTopNavAttrId, android.R.attr.state_selected};

Now my question is how to extract the correct drawable for each state ? I need to get the 9patch padding of the drawable, because if the state have different padding on 9patch it will get the padding only for the top drawable, and i want to set the padding manually for each key (drawable.getPadding(rect)).

Solution

There is no public API to get the drawable from the state.

There are some methods in StateListDrawable but they are @hide with the comment "pending API council".

You can invoke them by reflection... but it's at your own risk !!!. (it may change in future releases)

Those methods are :

• getStateDrawableIndex
• getStateDrawable

Here is how to proceed (exceptions omitted) :

int[] currentState = view.getDrawableState();
StateListDrawable stateListDrawable = (StateListDrawable)view.getBackground();
Method getStateDrawableIndex = StateListDrawable.class.getMethod("getStateDrawableIndex", int[].class);
Method getStateDrawable = StateListDrawable.class.getMethod("getStateDrawable", int.class);
int index = (int) getStateDrawableIndex.invoke(stateListDrawable,currentState);
Drawable drawable = (Drawable) getStateDrawable.invoke(stateListDrawable,index);

Answered By - ben75