Android文字描边

实现文字描边原理不难，就是两个TextView叠在一起

package com.example.testproject;

 

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Paint.Style;

import android.text.TextPaint;

import android.util.AttributeSet;

import android.view.ViewGroup;

import android.widget.TextView;

/*

  * StrokeTextView的目标是给文字描边

  * 实现方法是两个TextView叠加,只有描边的TextView为底,实体TextView叠加在上面

  * 看上去文字就有个不同颜色的边框了

  */

public class StrokeTextView extends TextView {

 

     private TextView borderText = null ; ///用于描边的TextView

 

     public StrokeTextView(Context context) {

         super (context);

         borderText = new TextView(context);

         init();

     }

 

     public StrokeTextView(Context context, AttributeSet attrs) {

         super (context, attrs);

         borderText = new TextView(context,attrs);

         init();

     }

 

     public StrokeTextView(Context context, AttributeSet attrs,

             int defStyle) {

         super (context, attrs, defStyle);

         borderText = new TextView(context,attrs,defStyle);

         init();

     }

 

     public void init(){

         TextPaint tp1 = borderText.getPaint();

         tp1.setStrokeWidth( 4 );                                  //设置描边宽度

         tp1.setStyle(Style.STROKE);                             //对文字只描边

         borderText.setTextColor(getResources().getColor(R.color.border_text));  //设置描边颜色

         borderText.setGravity(getGravity());

     }

 

     @Override

     public void setLayoutParams (ViewGroup.LayoutParams params){

         super .setLayoutParams(params);

         borderText.setLayoutParams(params);

     }

 

     @Override

     protected void onMeasure( int widthMeasureSpec, int heightMeasureSpec) {

         CharSequence tt = borderText.getText();

         

         //两个TextView上的文字必须一致

         if (tt== null || !tt.equals( this .getText())){

             borderText.setText(getText());

             this .postInvalidate();

         }

         super .onMeasure(widthMeasureSpec, heightMeasureSpec);

         borderText.measure(widthMeasureSpec, heightMeasureSpec);

     }

 

     protected void onLayout ( boolean changed, int left, int top, int right, int bottom){

         super .onLayout(changed, left, top, right, bottom);

         borderText.layout(left, top, right, bottom);

     }

 

     @Override

     protected void onDraw(Canvas canvas) {

         borderText.draw(canvas);

         super .onDraw(canvas);

     }

 

}