Android霓虹灯文字控件

霓虹灯文字.gif

首先自定义一个控件继承TextView，使用LinearGradient进行渲染

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

        String text = getText().toString();
        textMaxWidth = getPaint().measureText(text);
        float onceWidth = textMaxWidth / text.length() * gradientCount;

        linearGradient = new LinearGradient(onceWidth, 0, 0, 0, new int[]{getCurrentTextColor(), 0xff000000, getCurrentTextColor()},
                null, Shader.TileMode.CLAMP);
        getPaint().setShader(linearGradient);
    }

效果：

LinearGradient.jpg

实现动起来的效果，在onDraw中处理

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        postix += FACTOR;
        if (postix > textMaxWidth || postix < -1) {
            FACTOR = -FACTOR;
        }
        matrix.setTranslate(postix, 0);
        linearGradient.setLocalMatrix(matrix);

        postInvalidateDelayed(50);
    }

项目地址：https://gitee.com/aruba/ShaderApplication.git