TextDrawable.java

package org.wheelmap.android.utils;

import android.databinding.BindingAdapter;
import android.graphics.Canvas;
import android.graphics.ColorFilter;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.annotation.NonNull;
import android.support.v7.widget.ViewUtils;
import android.widget.ImageView;

public class TextDrawable extends Drawable {

    private Paint mPaint;
    private CharSequence mText;
    private int mIntrinsicWidth;
    private int mIntrinsicHeight;

    public TextDrawable(CharSequence text, int color, int textSize) {
        mText = text;
        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mPaint.setColor(color);
        mPaint.setTextAlign(Paint.Align.CENTER);
        mPaint.setTextSize(textSize);
        mIntrinsicWidth = (int) (mPaint.measureText(mText, 0, mText.length()) + .5);
        mIntrinsicHeight = mPaint.getFontMetricsInt(null);
    }

    @Override
    public void draw(@NonNull Canvas canvas) {
        Rect bounds = getBounds();
        canvas.drawText(mText, 0, mText.length(),
                bounds.centerX(), bounds.centerY() + (mIntrinsicHeight / 4), mPaint);
    }

    @Override
    public int getOpacity() {
        return PixelFormat.TRANSLUCENT;
    }

    @Override
    public int getIntrinsicWidth() {
        return mIntrinsicWidth;
    }

    @Override
    public int getIntrinsicHeight() {
        return mIntrinsicHeight;
    }

    @Override
    public void setAlpha(int alpha) {
        mPaint.setAlpha(alpha);
    }

    @Override
    public void setColorFilter(ColorFilter filter) {
        mPaint.setColorFilter(filter);
    }

    @BindingAdapter({"app:drawableText", "app:drawableTextColor", "app:drawableTextSize"})
    public static void textDrawable(ImageView imageView, String text, int color, int size) {
        int fontSize = (int) UtilsMisc.dbToPx(imageView.getResources(), size);
        imageView.setImageDrawable(new TextDrawable(text, color, fontSize));
    }

}