A drawable which draws borders as background of a view

BorderDrawable.java

/* The MIT License (MIT)
 
Copyright (c) 2014, Marty Glaubitz
 
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
 
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE. */

public class BorderDrawable extends Drawable {

    private Paint   _PaintLeft;
    private Paint   _PaintTop;
    private Paint   _PaintRight;
    private Paint   _PaintBottom;

    public BorderDrawable(int color, int border) {
        this(color, color, color, color, border, border, border, border);
    }

    public BorderDrawable(Integer colorLeft, Integer colorTop, Integer colorRight, Integer colorBottom, int borderWidthLeft, int borderWidthTop, int borderWidthRight, int borderWidthBottom) {
        super();
        if (colorLeft != null) {
            _PaintLeft = new Paint();
            _PaintLeft.setStrokeWidth(borderWidthLeft);
            _PaintLeft.setStyle(Paint.Style.STROKE);
            _PaintLeft.setColor(colorLeft);
        }

        if (colorTop != null) {
            _PaintTop = new Paint();
            _PaintTop.setStrokeWidth(borderWidthTop);
            _PaintTop.setStyle(Paint.Style.STROKE);
            _PaintTop.setColor(colorTop);
        }

        if (colorRight != null) {
            _PaintRight = new Paint();
            _PaintRight.setStrokeWidth(borderWidthRight);
            _PaintRight.setStyle(Paint.Style.STROKE);
            _PaintRight.setColor(colorRight);
        }

        if (colorBottom != null) {
            _PaintBottom = new Paint();
            _PaintBottom.setStrokeWidth(borderWidthBottom);
            _PaintBottom.setStyle(Paint.Style.STROKE);
            _PaintBottom.setColor(colorBottom);
        }
    }


    @Override
    public void draw(Canvas canvas) {
        if (_PaintLeft != null) {
            final float X = _PaintLeft.getStrokeWidth() / 2;
            canvas.drawLine(X, 0, X, canvas.getHeight(), _PaintLeft);
        }

        if (_PaintTop != null) {
            final float Y = _PaintTop.getStrokeWidth() / 2;
            canvas.drawLine(0, Y, canvas.getWidth(), Y, _PaintTop);
        }

        if (_PaintRight != null) {
            final float X = canvas.getWidth() - (_PaintRight.getStrokeWidth() / 2);
            canvas.drawLine(X, 0, X, canvas.getHeight(), _PaintRight);
        }

        if (_PaintBottom != null) {
            final float Y = canvas.getHeight() - _PaintBottom.getStrokeWidth();
            canvas.drawLine(0, Y, canvas.getWidth(), Y, _PaintBottom);
        }

    }

    @Override
    public void setAlpha(int alpha) {
        if (_PaintLeft != null) {
            _PaintLeft.setAlpha(alpha);
        }

        if (_PaintTop != null) {
            _PaintTop.setAlpha(alpha);
        }

        if (_PaintRight != null) {
            _PaintRight.setAlpha(alpha);
        }

        if (_PaintBottom != null) {
            _PaintBottom.setAlpha(alpha);
        }
    }

    @Override
    public void setColorFilter(ColorFilter cf) {
        if (_PaintLeft != null) {
            _PaintLeft.setColorFilter(cf);
        }

        if (_PaintTop != null) {
            _PaintTop.setColorFilter(cf);
        }

        if (_PaintRight != null) {
            _PaintRight.setColorFilter(cf);
        }

        if (_PaintBottom != null) {
            _PaintBottom.setColorFilter(cf);
        }
    }

    @Override
    public int getOpacity() {
        return 0;
    }
}

usage example, draws black borders ontop and at the bottom which are 3 pixels wide:

viewWhichNeedsBorders.setBackground(new BorderDrawable(null, Color.Black, null, Color.Black, 0, 3, 0, 3))

change: now uses lines to draw borders
fix: bottom line was half to thin