android RadioButton button drawable gravity

Question

I am generating RadioButtons dynamically with

RadioButton radioButton=new RadioButton(context);  

LayoutParams layoutParams=new LayoutParams(radioWidth,rad         


        

Answer 1

According to CompoundButton.onDraw() source code it's always left-aligned.

(Note the line buttonDrawable.setBounds(0, y, buttonDrawable.getIntrinsicWidth(), y + height);)

You will have to derive a new class from RadioButton and override onDraw().

EXAMPLE ADDED LATER:

Ok, so here's what you do. Firstly, here's a layout:

Secondly here's the custom-drawing RadioButtonCenter:

package org.test.TestProj;

import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.view.Gravity;
import android.widget.RadioButton;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;

public class RadioButtonCenter extends RadioButton {

    public RadioButtonCenter(Context context, AttributeSet attrs) {
        super(context, attrs);
        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CompoundButton, 0, 0);
        buttonDrawable = a.getDrawable(1);
        setButtonDrawable(android.R.color.transparent);
    }
    Drawable buttonDrawable;


     @Override
        protected void onDraw(Canvas canvas) {
            super.onDraw(canvas);

            if (buttonDrawable != null) {
                buttonDrawable.setState(getDrawableState());
                final int verticalGravity = getGravity() & Gravity.VERTICAL_GRAVITY_MASK;
                final int height = buttonDrawable.getIntrinsicHeight();

                int y = 0;

                switch (verticalGravity) {
                    case Gravity.BOTTOM:
                        y = getHeight() - height;
                        break;
                    case Gravity.CENTER_VERTICAL:
                        y = (getHeight() - height) / 2;
                        break;
                }

            int buttonWidth = buttonDrawable.getIntrinsicWidth();
            int buttonLeft = (getWidth() - buttonWidth) / 2;
            buttonDrawable.setBounds(buttonLeft, y, buttonLeft+buttonWidth, y + height);
                buttonDrawable.draw(canvas);
            }
        }   
}

Finally, here's an attrs.xml file you need to put in res/values so the code can get at platform-defined attributes.