How to scale/resize text to fit a TextView?

Question

I'm trying to create a method for resizing multi-line text in a TextView such that it fits within the bounds (both the X and Y dimensions) of the TextView.

At present, I have something, but all it does is resize the text such that just the first letter/character of the text fills the dimensions of the TextView (i.e. only the first letter is viewable, and it's huge). I need it to fit all the lines of the text within the bounds of the TextView.

Here is what I have so far:

public static void autoScaleTextViewTextToHeight(TextView tv) {     final float initSize = tv.getTextSize();     //get the width of the view's back image (unscaled)....      float minViewHeight;     if(tv.getBackground()!=null)     {       minViewHeight = tv.getBackground().getIntrinsicHeight();     }     else     {       minViewHeight = 10f;//some min.     }     final float maxViewHeight = tv.getHeight() - (tv.getPaddingBottom()+tv.getPaddingTop())-12;// -12 just to be sure     final String s = tv.getText().toString();      //System.out.println(""+tv.getPaddingTop()+"/"+tv.getPaddingBottom());      if(minViewHeight >0 && maxViewHeight >2)     {       Rect currentBounds = new Rect();       tv.getPaint().getTextBounds(s, 0, s.length(), currentBounds);       //System.out.println(""+initSize);       //System.out.println(""+maxViewHeight);       //System.out.println(""+(currentBounds.height()));        float resultingSize = 1;       while(currentBounds.height() < maxViewHeight)       {         resultingSize ++;         tv.setTextSize(resultingSize);          tv.getPaint().getTextBounds(s, 0, s.length(), currentBounds);         //System.out.println(""+(currentBounds.height()+tv.getPaddingBottom()+tv.getPaddingTop()));         //System.out.println("Resulting: "+resultingSize);       }       if(currentBounds.height()>=maxViewHeight)       {         //just to be sure, reduce the value         tv.setTextSize(resultingSize-1);       }     } } 

I think the problem is in the use of tv.getPaint().getTextBounds(...). It always returns small numbers for the text bounds... small relative to the tv.getWidth() and tv.getHeight() values... even if the text size is far larger than the width or height of the TextView.

Answer 1

The AutofitTextView library from MavenCentral handles this nicely. The source hosted on Github(1k+ stars) at https://github.com/grantland/android-autofittextview

Add the following to your app/build.gradle

repositories {     mavenCentral() }  dependencies {     implementation 'me.grantland:autofittextview:0.2.+' } 

Enable any View extending TextView in code:

AutofitHelper.create(textView); 

Enable any View extending TextView in XML:

<me.grantland.widget.AutofitLayout     android:layout_width="match_parent"     android:layout_height="wrap_content"     >     <Button         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:singleLine="true"         /> </me.grantland.widget.AutofitLayout> 

Use the built in Widget in code or XML:

<me.grantland.widget.AutofitTextView     android:layout_width="match_parent"     android:layout_height="wrap_content"     android:singleLine="true"     /> 

Answer 2

New since Android O:

https://developer.android.com/preview/features/autosizing-textview.html

<TextView   android:layout_width="wrap_content"   android:layout_height="wrap_content"   android:autoSizeTextType="uniform"   android:autoSizeMinTextSize="12sp"   android:autoSizeMaxTextSize="100sp"   android:autoSizeStepGranularity="2sp" />