Android实现EditText添加下划线

 
    
    @color/colorPrimary
    @color/colorPrimaryDark
    **@color/colorPrimaryDark**

//此时必须要设置其背景为空

//资源名称为 drawable/line

  
  

public class UnderLineEditText extends EditText {
  private Paint paint;

  public UnderLineEditText(Context context, AttributeSet attrs) {
    super(context, attrs);
    //设置画笔的属性
    paint = new Paint();
    paint.setStyle(Paint.Style.STROKE);
    //设置画笔颜色为红色
    paint.setColor(Color.RED);
  }

  @Override
  protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    /**canvas画直线，从左下角到右下角，this.getHeight()-2是获得父edittext的高度，但是必须要-2这样才能保证
     * 画的横线在edittext上面，和原来的下划线的重合
     */
    canvas.drawLine(0, this.getHeight()-2, this.getWidth()-2, this.getHeight()-2, paint);
  }
}