Question

I have an xml file with a selector in it that defines the different states for a button:

<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_pressed="true" android:drawable="@drawable/custom_green_button_selected_state" />
<item android:state_enabled="false" android:drawable="@drawable/custom_green_button_disabled_state" />  
<item android:drawable="@drawable/custom_green_button_normal_state"/>
</selector>

Then in each of my drawable xmls I have information on how the button looks like this:

<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<gradient android:type="linear" android:gradientRadius="180"
    android:startColor="#6b9f41" android:endColor="#598a3d" />

<corners android:bottomRightRadius="7dp"
    android:bottomLeftRadius="7dp" android:topLeftRadius="7dp"
    android:topRightRadius="7dp" />
<padding android:left="15dp" android:right="15dp" android:top="10dp"
    android:bottom="10dp" />
</shape>

For most of the buttons in my app I just apply the first xml as the background and everything works fine. For a specific button, I’d like to use the same xmls but make the button skinnier by changing the padding of the drawables. I thought I’d try creating a new StateListDrawable in my code and adding a mutate of each of the individual state’s drawable xmls, however, these drawables show up as GradientDrawables which doesn’t seem to give me access to their padding properties. Any ideas?

Answer 1

Padding of background drawable are also set by setPadding in View class.

You can set padding by calling setPadding after setBackgroundDrawable.

Here is core/java/android/view/View.java:

/**
 * Set the background to a given Drawable, or remove the background. If the
 * background has padding, this View's padding is set to the background's
 * padding. However, when a background is removed, this View's padding isn't
 * touched. If setting the padding is desired, please use
 * {@link #setPadding(int, int, int, int)}.
 *
 * @param d The Drawable to use as the background, or null to remove the
 *        background
 */
public void setBackgroundDrawable(Drawable d) {
    boolean requestLayout = false;

    mBackgroundResource = 0;

    /*
     * Regardless of whether we're setting a new background or not, we want
     * to clear the previous drawable.
     */
    if (mBGDrawable != null) {
        mBGDrawable.setCallback(null);
        unscheduleDrawable(mBGDrawable);
    }

    if (d != null) {
        Rect padding = sThreadLocal.get();
        if (padding == null) {
            padding = new Rect();
            sThreadLocal.set(padding);
        }
        if (d.getPadding(padding)) {
            setPadding(padding.left, padding.top, padding.right, padding.bottom);
        }