Question

有些代码需要在大约10个类中进行重构班级有条件散落在整个班级的绘画中适当时将文字放到屏幕上。我想添加所有这些代码条件/绘画代码集成到一个集中位置。有适合的设计模式吗？

if (fontWidth == 100) {
    fontSize = large;
} else {
    fontSize = small;
}

if (fontWidth == 100) {
    graphics.drawText("100", xVal, yVal);
} else {
    xText = Utils.calculateXText(param1, param2);
    graphics.drawText("200", xVal, yVal);
}

对于委托是否意味着我需要编写不同的包装器对象，一个用于设置字体大小，另一个用于根据上面的代码绘制文本？

public void paint(Graphics graphics){

    super.paint(graphics);
    Font font;


    if(ScreenDimension.getFontWidth() == 320){
        font = Font.getDefault().derive(Font.PLAIN,10,Ui.UNITS_pt);
    }
    else {
        font = Font.getDefault().derive(Font.PLAIN,12,Ui.UNITS_pt);
    }

String strScore = String.valueOf(score);
    graphics.setFont(font); 
    int pixelWidth = font.getAdvance(strScore);


    if(ScreenDimension.getFontWidth() == 320){
        graphics.drawText(strScore, (int) (this.backgroundBitmap.getWidth() * 0.50) - (pixelWidth/2), 10);
    }
    else {
        graphics.drawText(strScore, (int) (this.backgroundBitmap.getWidth() * 0.50) - (pixelWidth/2), 20);
    }

    if(ScreenDimension.getFontWidth() == 320){
        font = Font.getDefault().derive(Font.PLAIN,6,Ui.UNITS_pt);
    }
    else {
        font = Font.getDefault().derive(Font.PLAIN,8,Ui.UNITS_pt);
    }

    int namePixelWidth = font.getAdvance(judgeName);
    graphics.setFont(font);

if(ScreenDimension.getFontWidth() == 320){
    graphics.drawText(judgeName, (int) (this.backgroundBitmap.getWidth() * 0.50) - (namePixelWidth/2), this.backgroundBitmap.getHeight() - font.getHeight() - 2);
}
    else {
        graphics.drawText(judgeName, (int) (this.backgroundBitmap.getWidth() * 0.50) - (namePixelWidth/2), this.backgroundBitmap.getHeight() - font.getHeight() - 15);
    }
}

Answer 1

您可以使用委托对象来检查您的10个类以正确地绘制文本。

你也可以简单地创建一个静态辅助函数来执行该代码（简单方便）。

事实上，如果没有看到更多代码，很难给出正确的意见。

Answer 2

您可能想要使用Strategy模式，定义类似

的内容

/**
 * Strategy to render some text, of two size variants, centered horizontally
 * at a specified position.
 */
public interface TextRenderer {
    public enum FontSize { LARGE, SMALL };
    public void render(String text, int x, int y, FontSize size);
}

/**
 * TextRenderer Factory that uses the ScreenDimension to determine sizes of LARGE
 * and SMALL fonts to use.
 */
public class ScreenDimensionAwareTextRendererFactory {
    public static TextRenderer getTextRenderer(Graphics gc) {
        Font baseFont = Font.getDefault();
        int fontWidth = ScreenDimension.getFontWidth();
        return fontWidth == 320
                ? new DefaultTextRenderer(gc, baseFont.derive(Font.PLAIN,10,Ui.UNITS_pt), baseFont.derive(Font.PLAIN,6,Ui.UNITS_pt))
                : new DefaultTextRenderer(gc, baseFont.derive(Font.PLAIN,12,Ui.UNITS_pt), baseFont.derive(Font.PLAIN,8,Ui.UNITS_pt));
    }
}

public class DefaultTextRenderer implements TextRenderer {
    protected Map<FontSize,Font> fontSizeMap = new HashMap<FontSize,Font>();
    protected Graphics gc;
    public DefaultTextRenderer(Graphics gc, Font largeFont, Font smallFont) {
        this.gc = gc;
        fontSizeMap.put(LARGE, largeFont);
        fontSizeMap.put(SMALL, smallFont);        
    }
    public void render(String text, int x, int y, FontSize size) {
        Font font = fontSizeMap.get(size)
        int pixelWidth = font.getAdvance(text);
        gc.setFont(font);

        // TODO: note here I'm not dealing with the vertical offsets you're using
        // which are dependent upon the font size. It would be possible, but
        // I suspect what you really ought to be doing is consistently rendering
        // text on a baseline.
        // The way you could adjust this to closer match what you appear to be doing
        // would be to have arguments to render() which indicate vertical alignment.
        // something like 
        // TextRenderer.VerticalAlignment = enum { BASELINE, TOP, BOTTOM }
        // and based on something like that you could compute here the y offset
        // based on the selected font.
        // I can't do that now because you're "magic numbers" hard coded don't explain
        // what they're trying to do
        gc.drawText(text, Math.round(x - (pixelWidth / 2)), y);
    }
}

// your example
public void paint(Graphics graphics) {
    super.paint(graphics);

    String strScore = String.valueOf(score);
    TextRenderer textRenderer = ScreenDimensionAwareTextRendererFactory.getTextRenderer(graphics);
    int middleX = Math.round(this.backgroundBitmap.getWidth() / 2);
    textRenderer.render(strScore, middleX, 10, TextRenderer.TextSize.LARGE);
    textRenderer.render(judgeName, middleX, this.backgroundBitmap.getHeight(), TextRenderer.TextSize.SMALL);
}

Answer 3

如果条件不变，则可以使用Servant设计模式。

http://en.wikipedia.org/wiki/Design_pattern_Servant

跨多个类分散的条件代码的设计模式代码

3 个答案: