本文实例讲述了Android编程实现自动调整TextView字体大小以适应文字长度的方法。分享给大家供大家参考,具体如下:
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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;
private float 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);
}
}
}
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希望本文所述对大家Android程序设计有所帮助。