此答案基于 Pedro 的答案,但经过编辑,因此在 text 属性已设置好时也可以使用:
package nl.raakict.android.spc.widget;
import android.content.Context;
import android.text.Spannable;
import android.text.SpannableString;
import android.text.style.ScaleXSpan;
import android.util.AttributeSet;
import android.widget.TextView;
public class LetterSpacingTextView extends TextView {
private float letterSpacing = LetterSpacing.BIGGEST;
private CharSequence originalText = "";
public LetterSpacingTextView(Context context) {
super(context);
}
public LetterSpacingTextView(Context context, AttributeSet attrs){
super(context, attrs);
originalText = super.getText();
applyLetterSpacing();
this.invalidate();
}
public LetterSpacingTextView(Context context, AttributeSet attrs, int defStyle){
super(context, attrs, defStyle);
}
public float getLetterSpacing() {
return letterSpacing;
}
public void setLetterSpacing(float letterSpacing) {
this.letterSpacing = letterSpacing;
applyLetterSpacing();
}
@Override
public void setText(CharSequence text, BufferType type) {
originalText = text;
applyLetterSpacing();
}
@Override
public CharSequence getText() {
return originalText;
}
private void applyLetterSpacing() {
StringBuilder builder = new StringBuilder();
for(int i = 0; i < originalText.length(); i++) {
String c = ""+ originalText.charAt(i);
builder.append(c.toLowerCase());
if(i+1 < originalText.length()) {
builder.append("\u00A0");
}
}
SpannableString finalText = new SpannableString(builder.toString());
if(builder.toString().length() > 1) {
for(int i = 1; i < builder.toString().length(); i+=2) {
finalText.setSpan(new ScaleXSpan((letterSpacing+1)/10), i, i+1, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
}
}
super.setText(finalText, BufferType.SPANNABLE);
}
public class LetterSpacing {
public final static float NORMAL = 0;
public final static float NORMALBIG = (float)0.025;
public final static float BIG = (float)0.05;
public final static float BIGGEST = (float)0.2;
}
}