Dynamic change text size for maintain 1 line?

Question

I'm 17 and I'm italian. This is my first app.

I've foolishly thought this code for maintain 1 line on my switch independently from the screen:

Inside at OnCreate()
   
while(SWITCH.getLineCount()>1)
                SWITCH.setTextSize(SWITCH.getTextSize()-1);

obviously does not work.. why?

I've read a lot of ask but I have not yet figured out how to set the font size dynamically based on the size of the screen.

Thank you very much.

EDIT: for distraction I had written

(SWITCH.getLineCount()-1)

instead of

(SWITCH.getTextSize()-1),

but still does not work.

possible duplicate of [How to change the size of the font of a JLabel to take the maximum size](http://stackoverflow.com/questions/2715118/how-to-change-the-size-of-the-font-of-a-jlabel-to-take-the-maximum-size) — jbutler483, Sep 03 '14 at 11:03
You sure you want `getLineCount()` in `setTextSize()`? Wouldn't it be `getTextSize()`? — Mike M., Sep 03 '14 at 11:13
@mikeM. I've used getTextSize() to get the size and reduce it by one for loop. Do you understand me? — Leonardo Rignanese, Sep 03 '14 at 14:57
I understand what you're trying to do, but your logic is flawed. You want to decrement the size until the text fits on one line. `getLineCount()` does not return the text size, so subtracting 1 from that and setting it as the new size makes no sense. The line in the loop should be `SWITCH.setTextSize(SWITCH.getTextSize()-1);` — Mike M., Sep 03 '14 at 15:05
@mikeM. absolutely right! I'm a wimp and I was convinced that he had written getTextSize() , thanks boy. I'll try.. — Leonardo Rignanese, Sep 03 '14 at 15:10
I should mention, though, that I'm not sure this way will work. You might give cyanide's answer a shot, too. — Mike M., Sep 03 '14 at 15:16
@MikeM. SWITCH.setTextSize(SWITCH.getTextSize()-1) not work.. I want try the cyanide's code but i don't understand some things. — Leonardo Rignanese, Sep 03 '14 at 15:23

cyanide · Answer 1 · 2014-09-03T13:08:45.123

0

Assuming your TextView has android:maxWidth value.

The following function:

Gets Maximum width
Uses Paint.measureWidth to check the actual width
If the actual width is more than maximum, the font size is reduced proportionally.
The loop continues until the width becomes less than maximum.
For safety reason I introduced iterCount to ensure than the loop will eventually end.

I didn't test the code, but the idea should be clear:

private void adjustTextSize(TextView tv,  final String text) {
    float maxWidth = tv.getMaxWidth() * 0.9f;

    Paint p = tv.getPaint();
    float fontSize = p.getTextSize();
    float txtWidth;

    int iterCount = 10;

    while (--iterCount >= 0 &&  (txtWidth = p.measureText(text)) > maxWidth)  
        p.setTextSize(fontSize *= (maxWidth / txtWidth));

}

edited Sep 03 '14 at 13:08

answered Sep 03 '14 at 11:27

cyanide

3,885
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Correct, I have fixed that. Silly me! – cyanide Sep 03 '14 at 13:09
Thank you. But I don't understand how the text can get over the max width.. does not it impossible? – Leonardo Rignanese Sep 03 '14 at 14:59
I've try the code and the font resize . But i don't understand how much i must set the MaxWidth.. – Leonardo Rignanese Sep 03 '14 at 15:35
You can omit maxWidth and use layout_width="match_parent". The trouble is that in this case you don't know the size untill layout is complete. – cyanide Sep 03 '14 at 21:37

score 0 · Answer 2 · edited May 23 '17 at 12:00

You can omit maxWidth and use layout_width="match_parent". The trouble is that in this case you don't know the size until layout is complete. See How to know when an activity finishes a layout pass? about notification when layout is complete.

From onGlobalLayout() you can use tv.getWidth()

 final TextView tv= (TextView) findViewById(R.id.myView);

 tv.getViewTreeObserver().addOnGlobalLayoutListener(
       new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                float maxWidth = tv.getWidth() * 0.9f;

                String text = getResources().getString(R.string.myTextId); 
                float fontSize = tv.getTextSize();
                float txtWidth;

                int iterCount = 10;

                 while (--iterCount >= 0 &&  (txtWidth = tv.getPaint().measureText(text)) > maxWidth)  
                     tv.setTextSize(fontSize *= (maxWidth / txtWidth));

                 tv.setText(text);
             }
         });

I slightly changed the code to assign textSize to the TextView, rather than to the underlying Paint. It's more correct this way.

Daniel Santos · Answer 3 · 2017-02-27T22:02:54.883

0

Take a look at this library here later, it does what you want to do

Just add the compile to your gradle and replace the <TextView in xml with <me.grantland.widget.AutofitTextView, done, the magic is done, rs

edited Feb 27 '17 at 22:02

answered Feb 27 '17 at 21:58

Daniel Santos

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Dynamic change text size for maintain 1 line?

3 Answers3