Canvas.drawText(...) does not print linebreak

Question

I tried to write some text on a surface view I created. It works fine, if title is false, and there is no linebreak added to the text. But if I add a title and therefore a linebreak, the linebreak isn't printed as expected, but instead there is this symbol [] printed.

Any hints why?

@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());
}

See my answer here: https://stackoverflow.com/a/63098776/5730321 — Leo DroidCoder, Jul 26 '20 at 10:36

score 27 · Answer 1 · answered Nov 23 '11 at 12:29

You could try something like the following to draw text with linebreaks:

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();
    }
}

score 11 · Answer 2 · answered Nov 08 '12 at 21:15

dee's answer is brilliant. The code below is based on dee's answer, but with some amendments for personal preferences:

Call it drawMultilineText (as it's sort of equivalent to drawText
Put the parameters in the same order as drawText (text, x, y, paint and canvas on the end)
Get the line height once at the start as the height returned from the bounds depends on the height of the letters, i.e. e is not as tall as E

Add 20% height gap between lines

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;
    }
}

Brilliant..Saved me lot of headache. – Jitendra Surve May 12 '20 at 20:38 — Jitendra Surve, May 12 '20 at 20:38

score 4 · Answer 3 · edited May 23 '17 at 10:30

Continuing to improve on both Dee's and FrinkTheBrave's answers. I've added a Rect to the method to allow for drawing within particular width area. Will look at modifying it to select an appropriate font size and ensure it fits within the correct height area.

This will let you specify the width of the lines that you want to write which is very useful for breaking up an unformatted string of text into similar length lines and drawing them to a canvas.

    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());
}

This answer includes this excellent code snippet found here in a previous answer by user850688 https://stackoverflow.com/a/11353080/1759409

drawSpace is a Rect variable that you send to the method so that the method knows how large an area is available to be filled with text. — Music Monkey, Mar 24 '13 at 11:07
@MusicMonkey isn't the height of each line the exact same as the font size? — android developer, Jul 11 '13 at 14:21
@android developer yes it is. But for text to look naturally spaced our eye normally works on spacing of approximately 20% above and below... Otherwise each line of text will appear to touch the line above and below. I could rewrite that line again so that linespacing can be passed in as a constant but I found that 'x 1.2' gave me a consistent and pleasant visual layout. — Music Monkey, Jul 11 '13 at 23:18

score 1 · Accepted Answer · answered Jun 30 '10 at 23:05

1

The [] symbol is probably your newline character. For whatever reason, drawText() doesn't know how to handle newlines.

Either strip the newline, or call drawText() twice with an offset Y-position to simulate a newline.

answered Jun 30 '10 at 23:05

Trevor Johns

15,682
3
55
54

thanks. I didn't know it doesn0t supports newline. thats really annoying. what do you mean with strip the newline? – RoflcoptrException Jun 30 '10 at 23:08
Use String.replace() to replace all instances of "\n" with "" (an empty string). – Trevor Johns Jun 30 '10 at 23:15
1

ah yes that's not the problem, the code above is the single situation where i need it ;) and as you can see it added the "\n" by myself – RoflcoptrException Jul 01 '10 at 06:22

score 0 · Answer 5 · answered Aug 12 '22 at 06:54

And I also add and ellipsize for each line:

Rect mBounds = new Rect();
void drawMultiLineString(Canvas canvas, TextPaint paint, String str, Rect drawingRect) {
    int lineHeight = 0;
    int yOffset    = 0;

    String[] lines = str.split("\n");
    for (String line : lines) {
        CharSequence txt = TextUtils.ellipsize(line, mTextPaint, drawingRect.right - drawingRect.left, TextUtils.TruncateAt.END);
        canvas.drawText(txt, 0, txt.length(), drawingRect.left, drawingRect.top + yOffset, paint);
        paint.getTextBounds(line, 0, line.length(), mBounds);
        lineHeight = (int) ((float) mBounds.height() * 1.2);
        yOffset += lineHeight;
    }
}

Canvas.drawText(...) does not print linebreak

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