Les réservoirs de beaucoup de http://stackoverflow.com/users/234270/speedplane. Super réponse!
Ici est une version améliorée de sa réponse qui prennent également soin de hauteur et est livré avec un maxFontSize attribut de limiter la taille de la police (a été utile dans mon cas, donc je voulais le partager):
package com.<your_package>;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.widget.TextView;
public class FontFitTextView extends TextView
{
private Paint mTestPaint;
private float maxFontSize;
private static final float MAX_FONT_SIZE_DEFAULT_VALUE = 20f;
public FontFitTextView(Context context)
{
super(context);
initialise(context, null);
}
public FontFitTextView(Context context, AttributeSet attributeSet)
{
super(context, attributeSet);
initialise(context, attributeSet);
}
public FontFitTextView(Context context, AttributeSet attributeSet, int defStyle)
{
super(context, attributeSet, defStyle);
initialise(context, attributeSet);
}
private void initialise(Context context, AttributeSet attributeSet)
{
if(attributeSet!=null)
{
TypedArray styledAttributes = context.obtainStyledAttributes(attributeSet, R.styleable.FontFitTextView);
maxFontSize = styledAttributes.getDimension(R.styleable.FontFitTextView_maxFontSize, MAX_FONT_SIZE_DEFAULT_VALUE);
styledAttributes.recycle();
}
else
{
maxFontSize = MAX_FONT_SIZE_DEFAULT_VALUE;
}
mTestPaint = new Paint();
mTestPaint.set(this.getPaint());
//max size defaults to the initially specified text size unless it is too small
}
/* Re size the font so the specified text fits in the text box
* assuming the text box is the specified width.
*/
private void refitText(String text, int textWidth, int textHeight)
{
if (textWidth <= 0)
return;
int targetWidth = textWidth - this.getPaddingLeft() - this.getPaddingRight();
int targetHeight = textHeight - this.getPaddingTop() - this.getPaddingBottom();
float hi = maxFontSize;
float lo = 2;
// final float threshold = 0.5f; // How close we have to be
final float threshold = 1f; // How close we have to be
mTestPaint.set(this.getPaint());
Rect bounds = new Rect();
while ((hi - lo) > threshold)
{
float size = (hi + lo) / 2;
mTestPaint.setTextSize(size);
mTestPaint.getTextBounds(text, 0, text.length(), bounds);
if (bounds.width() >= targetWidth || bounds.height() >= targetHeight)
hi = size; // too big
else
lo = size; // too small
// if (mTestPaint.measureText(text) >= targetWidth)
// hi = size; // too big
// else
// lo = size; // too small
}
// Use lo so that we undershoot rather than overshoot
this.setTextSize(TypedValue.COMPLEX_UNIT_PX, lo);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int parentWidth = MeasureSpec.getSize(widthMeasureSpec);
int height = getMeasuredHeight();
refitText(this.getText().toString(), parentWidth, height);
this.setMeasuredDimension(parentWidth, height);
}
@Override
protected void onTextChanged(final CharSequence text, final int start, final int before, final int after)
{
refitText(text.toString(), this.getWidth(), this.getHeight());
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh)
{
if (w != oldw)
{
refitText(this.getText().toString(), w, h);
}
}
}
Correspondant /res/values/attr.xml fichier:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="FontFitTextView">
<attr name="maxFontSize" format="dimension" />
</declare-styleable>
</resources>
Exemple:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:res-auto="http://schemas.android.com/apk/res-auto"
android:id="@+id/home_Layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/background"
tools:ignore="ContentDescription" >
...
<com.<your_package>.FontFitTextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:singleLine="true"
android:text="Sample Text"
android:textSize="28sp"
res-auto:maxFontSize="35sp"/>
...
</RelativeLayout>
Tu utilisation du nouvel attribut, n'oubliez pas d'ajouter xmlns:res-auto="http://schemas.android.com/apk/res-auto" attribut xml par exemple.
