自动调整TextView字体大小以适应文字长度

package com.test.android.textview;


import android.content.Context;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.widget.TextView;


public class CustomTextView extends TextView {


private static float DEFAULT_MIN_TEXT_SIZE = 10;
private static float DEFAULT_MAX_TEXT_SIZE = 20;


// Attributes
private Paint testPaint;
private float minTextSize, maxTextSize;


public CustomTextView(Context context, AttributeSet attrs) {
super(context, attrs);
initialise();
}


private void initialise() {
testPaint = new Paint();
testPaint.set(this.getPaint());


// max size defaults to the intially specified text size unless it is
// too small
maxTextSize = this.getTextSize();


if (maxTextSize <= DEFAULT_MIN_TEXT_SIZE) {
maxTextSize = DEFAULT_MAX_TEXT_SIZE;
}


minTextSize = DEFAULT_MIN_TEXT_SIZE;
};


/**
* 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) {
if (textWidth > 0) {
int availableWidth = textWidth - this.getPaddingLeft()
- this.getPaddingRight();
float trySize = maxTextSize;
testPaint.setTextSize(trySize);
while ((trySize > minTextSize)
&& (testPaint.measureText(text) > availableWidth)) {
trySize -= 1;
if (trySize <= minTextSize) {
trySize = minTextSize;
break;
}
testPaint.setTextSize(trySize);
}
this.setTextSize(trySize);
}
};


@Override
protected void onTextChanged(CharSequence text, int start, int before,
int after) {
super.onTextChanged(text, start, before, after);
refitText(text.toString(), this.getWidth());
}


@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
if (w != oldw) {
refitText(this.getText().toString(), w);
}
}
}