自定义editText有问题

Question

我正在创建具有自定义背景的自定义EditText。但它的工作原理错误。我在视图的底部创建了一条线。这条线是动画的。它运作良好。但是，如果我开始输入文字，那么就行了。

我的自定义视图：

public class DrawView extends EditText {

    private Paint paint;
    private Paint paintBefor;
    private float value;

    public DrawView(Context context) {
        super(context);
        init();
    }

    private void init() {
        paint = new Paint();
        paintBefor = new Paint();
        value = 0.0f;
        paint.setColor(Color.WHITE);
        paintBefor.setColor(Color.RED);
        paint.setStrokeWidth(10);
        paintBefor.setStrokeWidth(10);
    }

    public DrawView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        canvas.drawARGB(20, 102, 204, 255);
        int halfWidth = getWidth() / 2;
        canvas.drawLine(0,getHeight(),getWidth(),getHeight(), paintBefor);
        canvas.drawLine(halfWidth,getHeight(), halfWidth + value * halfWidth,getHeight(), paint);
        canvas.drawLine((1.0f - value) * halfWidth, getHeight(), halfWidth, getHeight(), paint);
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
    }

    public void startSkipAnimation() {
        ValueAnimator.AnimatorUpdateListener animatorUpdateListener = new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator valueAnimator) {
                setProgress((Float) valueAnimator.getAnimatedValue());
            }
        };

        ValueAnimator progressAnimator = ValueAnimator.ofFloat(0.0f,1.0f);
        progressAnimator.addUpdateListener(animatorUpdateListener);
        progressAnimator.setInterpolator(new DecelerateInterpolator());
        progressAnimator.setDuration(1500);
        progressAnimator.start();
    }

    private void setProgress(float value){
        this.value = value;
        invalidate();
    }

}

它看起来像这样： http://markevans.github.io/dragonfly/rails/

但是当我开始输入文字时：

我想在输入文字时显示背景线。