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我正在尝试以编程方式绘制一个停车图标，以作为地图上逐项叠加的可绘制对象。

该图标由一个蓝色正方形组成，其中心有一个白色“P”，我想以编程方式更改正方形的颜色以表示不同的停车类型。

我尝试使用 drawRect 和 drawText 通过画布创建它，但我找不到将文本居中在正方形中的简单方法，也找不到将画布居中在坐标上的方法 - 它一直想从左上角锚定手角。

我也尝试过创建一个 XML 布局以转换为可绘制对象，但也无法实现这一点。

对于我想要实现的目标，是否有一个优雅的解决方案？

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2 回答 2

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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;
    }
}
于 2012-03-30T01:57:03.627 回答
0

制作几个 png 图像并将它们放入res\drawable，如果你有超过 5 种颜色，那么考虑使用更少。这让用户感到困惑。

于 2012-03-23T01:00:36.910 回答