Question

我正在尝试以编程方式绘制一个停车图标，作为地图上逐项列表的可绘制对象。

图标由一个蓝色方块组成，中间有一个白色的“P”，我想以编程方式更改方块的颜色，以表示不同的停车类型。

我尝试使用drawRect＆amp; amp; drawText但我找不到一种简单的方法将文本居中在广场上，我找不到将画布置于坐标中心的方法 - 它一直希望从左上角锚定。

我已经尝试过创建一个XML布局来转换为drawable，但也无法实现。

对于我想要实现的目标，是否有优雅的解决方案？

Answer 1

public class TextDrawable extends Drawable {

    private final static int    TEXT_PADDING           = 3;
    private final static int    ROUNDED_RECT_RADIUS    = 5;

    private final String    text;
    private final Paint     textPaint;
    private final Rect      textBounds;
    private final Paint     bgPaint;
    private final RectF     bgBounds;

    public TextDrawable(String text, String backgroundColor, int textHeight) {

        this.text = text;

        // Text
        this.textPaint = new Paint();
        this.textBounds = new Rect();
        textPaint.setColor(Color.WHITE);
        textPaint.setARGB(255, 255, 255, 255);
        textPaint.setAntiAlias(true);
        textPaint.setSubpixelText(true);
        textPaint.setTextAlign(Paint.Align.CENTER); // Important to centre horizontally in the background RectF
        textPaint.setTextSize(textHeight);
        textPaint.setTypeface(Typeface.DEFAULT_BOLD);
        // Map textPaint to a Rect in order to get its true height
        // ... a bit long-winded I know but unfortunately getTextSize does not seem to give a true height!
        textPaint.getTextBounds(text, 0, text.length(), textBounds);

        // Background
        this.bgPaint = new Paint();
        bgPaint.setAntiAlias(true);
        bgPaint.setColor(Color.parseColor(backgroundColor));
        float rectHeight  = TEXT_PADDING * 2 + textHeight;
        float rectWidth   = TEXT_PADDING * 2 + textPaint.measureText(text);
        //float rectWidth   = TEXT_PADDING * 2 + textHeight;  // Square (alternative)
        // Create the background - use negative start x/y coordinates to centre align the icon
        this.bgBounds = new RectF(rectWidth / -2, rectHeight / -2, rectWidth / 2, rectHeight / 2);
    }

    @Override
    public void draw(Canvas canvas) {
        canvas.drawRoundRect(bgBounds, ROUNDED_RECT_RADIUS, ROUNDED_RECT_RADIUS, bgPaint);
        // Position the text in the horizontal/vertical centre of the background RectF
        canvas.drawText(text, 0, (textBounds.bottom - textBounds.top)/2, textPaint);
    }

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

    @Override
    public void setColorFilter(ColorFilter cf) {
        bgPaint.setColorFilter(cf);
        textPaint.setColorFilter(cf);
    }

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

Answer 2

制作几张png图片＆amp;把它们放在res\drawable中，如果你有超过5种颜色，那么考虑少用。这让用户感到困惑。

以编程方式创建图标以用作ItemizedOverlay drawable - Android

2 个答案: