android中SpannableString的使用

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView tv = (TextView) findViewById(R.id.tv);
//改变字体颜色
//先构造SpannableString
//将这个Span应用于指定范围的字体
tv.setText(spanString(20.085));
}

private  SpannableString spanString(double price) {
SpannableString spannableString = new SpannableString(getApplication().getString(R.string.dg_ticket_yuan,
Units.wrapPrice(price)));
int priceLength = spannableString.length() - 1;
//再构造一个改变字体颜色的Span
spannableString.setSpan(new ForegroundColorSpan(Color.BLUE), 0, 1, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
//再构造一个改变字体大小的Span
spannableString.setSpan(new AbsoluteSizeSpan(25, true), 0, 1, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
spannableString.setSpan(new AbsoluteSizeSpan(50, true), 1, priceLength, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
spannableString.setSpan(new AbsoluteSizeSpan(25, true), priceLength, spannableString.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
return spannableString;
}

}