@Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        final int width = right - left;

        // layout display row
        final int displayRowWidth = displayRow.getMeasuredWidth();
        final int displayRowHeight = displayRow.getMeasuredHeight();
        final int displayRowX = (width - displayRowWidth) / 2;
        displayRow.layout(displayRowX, 0, displayRowX + displayRowWidth, displayRowHeight);

        // layout num pad
        final int numPadWidth = numPad.getMeasuredWidth();
        final int numPadHeight = numPad.getMeasuredHeight();
        final int numPadX = (width - numPadWidth) / 2;
        final int numPadY = displayRowHeight;
        numPad.layout(numPadX, numPadY, numPadX + numPadWidth, numPadY + numPadHeight);
    }
Sets the padding to be used for the number pad buttons.

@param padding padding in pixels
android/third_party/time-duration-picker/src/main/java/mobi/upod/timedurationpicker/TimeDurationPicker.java