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Canvas.drawText(…)不打印换行符

canvas text android

anon · 技术社区 · 15 年前

我试着在我创建的表面视图上写一些文字。如果title为false,并且文本中没有添加换行符,则它可以正常工作。但是如果我添加了一个标题和一个换行符,换行符就不会像预期的那样打印,而是打印了这个符号[]。

有什么线索吗?为什么?

@Override
public void drawObject() {
String text = "";
if (title) {
   text = getGameBoard().getGame().getForeignProfile().getName() + "\n";
}
text = text + getScoreAsString();
getGameBoard().getCanvas().drawText(text, 0, text.length(), getPosition().getX(), getPosition().getY(), getPaint());
}

4 回复 | 直到 15 年前

Trevor Johns 15 年前

[]符号可能是换行符。不管出于什么原因,drawText()都不知道如何处理换行符。

dbotha 13 年前

Rect bounds = new Rect();
void drawString(Canvas canvas, Paint paint, String str, int x, int y) {
    String[] lines = str.split("\n");

    int yoff = 0;
    for (int i = 0; i < lines.length; ++i) {
        canvas.drawText(lines[i], x, y + yoff, paint);
        paint.getTextBounds(lines[i], 0, lines[i].length(), bounds);
        yoff += bounds.height();
    }
}

FrinkTheBrave 12 年前

迪伊的回答很好。以下代码基于dee的答案,但对个人偏好进行了一些修改:

称之为drawMultilineText(因为它相当于drawText)
将参数按与drawText相同的顺序放置(text、x、y、paint和canvas在末尾)
在开始时获取一次行高,因为从边界返回的高度取决于字母的高度,即e没有e高

增加20%的线间距

void drawMultilineText(String str, int x, int y, Paint paint, Canvas canvas) {
    int      lineHeight = 0;
    int      yoffset    = 0;
    String[] lines      = str.split("\n");

    // set height of each line (height of text + 20%)
    paint.getTextBounds("Ig", 0, 2, mBounds);
    lineHeight = (int) ((float) mBounds.height() * 1.2);
    // draw each line
    for (int i = 0; i < lines.length; ++i) {
        canvas.drawText(lines[i], x, y + yoffset, paint);
        yoffset = yoffset + lineHeight;
    }
}

Community CDub 8 年前

继续改进迪伊和弗林克勇士的答案。我在方法中添加了一个Rect,以允许在特定宽度区域内绘制。将考虑修改它以选择适当的字体大小,并确保它适合正确的高度区域。

    private void drawMultilineText(String str, int x, int y, Paint paint, Canvas canvas, int fontSize, Rect drawSpace) {
    int      lineHeight = 0;
    int      yoffset    = 0;
    String[] lines      = str.split(" ");

    // set height of each line (height of text + 20%)
    lineHeight = (int) (calculateHeightFromFontSize(str, fontSize) * 1.2);
    // draw each line
    String line = "";
    for (int i = 0; i < lines.length; ++i) {

        if(calculateWidthFromFontSize(line + " " + lines[i], fontSize) <= drawSpace.width()){
            line = line + " " + lines[i];

        }else{
            canvas.drawText(line, x, y + yoffset, paint);
            yoffset = yoffset + lineHeight;
            line = lines[i];
        }
    }
    canvas.drawText(line, x, y + yoffset, paint);

}

private int calculateWidthFromFontSize(String testString, int currentSize)
{
    Rect bounds = new Rect();
    Paint paint = new Paint();
    paint.setTextSize(currentSize);
    paint.getTextBounds(testString, 0, testString.length(), bounds);

    return (int) Math.ceil( bounds.width());
}

private int calculateHeightFromFontSize(String testString, int currentSize)
{
    Rect bounds = new Rect();
    Paint paint = new Paint();
    paint.setTextSize(currentSize);
    paint.getTextBounds(testString, 0, testString.length(), bounds);

    return (int) Math.ceil( bounds.height());
}

这个答案包含了这个优秀的代码片段,这个代码片段可以在user850688以前的答案中找到 https://stackoverflow.com/a/11353080/1759409