Android霓虹灯文字控件

2020-07-03 11:03:31 浏览数 (1)

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
代码语言:javascript复制
    @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
代码语言:javascript复制
    @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

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