带有多行的画布绘制文本答案

【问题标题】：canvas drawtext with multiline带有多行的画布绘制文本
【发布时间】：2015-04-25 18:10:33
【问题描述】：

我正在开发一个图像评论应用程序。我用canvas.drawText(text, x, y, imgPaint);在画布上绘制文本

这出现在一行中。当文本跨越画布宽度时，我需要将行换成多行

提前致谢

【问题讨论】：

【解决方案1】：

你需要使用StaticLayout:

TextPaint mTextPaint=new TextPaint();
StaticLayout mTextLayout = new StaticLayout("my text\nNext line is very long text that does not definitely fit in a single line on an android device. This will show you how!", mTextPaint, canvas.getWidth(), Alignment.ALIGN_NORMAL, 1.0f, 0.0f, false);

canvas.save();
// calculate x and y position where your text will be placed

textX = 100;
textY = 100;

canvas.translate(textX, textY);
mTextLayout.draw(canvas);
canvas.restore();

【讨论】：

嘿，很好的处理方式。但是，当我必须将大文本拆分为页面并在画布上绘制时，如何解决这个问题？任何建议表示赞赏。

【解决方案2】：

您需要分割线并分别绘制每个片段，并根据字体高度增加 y。

例如：

var lines = text.split("\n"),
    x = 100, y = 100, fHeight = 16, // get x, y and proper font or line height here
    i = 0, line;

while(line = lines[i++]) {
    canvas.drawText(line, x, y, imgPaint);
    y += fHeight;
}

【讨论】：

我认为 OP 更关心确定换行符，而不是多行方面。

【解决方案3】：

好吧，添加另一个答案已经很晚了，但是如果有人不想使用 StaticLayout，那么他们可以尝试我的多行文本逻辑

注意：这段代码用在View的onSizeChanged()方法中，textArray是一个类变量，存储每一行

//This array will store all the words contained in input string
            val wordList = ArrayList<String>()

            //Temporary variable to store char or string
            var temp = ""

            it.trim().forEachIndexed { index, letter ->
                //Adding each letter to temp
                temp += letter

                //If letter is whiteSpace or last char then add it to wordList.
                //For example : Let input be "This is a Info text"
                //              since there is no whiteSpace after that last 't' then the last word
                //              will not be added to wordList there for checking for last letter is required
                //NOTE: the whiteSpace is also included in that word
                if (letter.isWhitespace() || index == it.length -1 ) {
                    wordList.add(temp)
                    //Resetting temp
                    temp = ""
                }
            }

            wordList.forEachIndexed { index, word ->
                //Measuring temp + word to check if their width in pixel is more than or equal to
                // the view's width + 60px(this is used so that word there is some space after each line. It can be changed)
                if (textPaint.measureText(temp + word) >= w - 60) {
                    textArray.add(temp)

                    //If adding last word to temp surpasses the required width then add the last word
                    // separately since the loop will be terminated after that
                    if (index == wordList.size - 1){
                        textArray.add(word)
                        return@forEachIndexed
                    }

                    //Resetting temp
                    temp = ""
                } else if (index == wordList.size - 1) {
                    //If adding last word to temp doesn't surpasses the required width the add that
                    // line to list
                    textArray.add(temp + word)
                    return@forEachIndexed
                }

                //Adding word to temp
                temp += word
            }

然后在 onDraw() 方法中

  textArray.forEachIndexed { index, singleLine ->
                    //x is set to 16f so that there is some space before first word
                    //y changes with each line i.e 1st line will be drawn at y = 60f, 2nd at 120f and so on
                    it.drawText(singleLine, 16f, (index + 1) * 60f, textPaint)
                }

【讨论】：