使用gsap实现加载进度条功能

最终动画效果

动画开始前

动画结束后

代码如下

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <script src="https://cdnjs.cloudflare.com/ajax/libs/gsap/3.11.0/gsap.min.js"></script>
    <title>Document</title>
    <style>
        body {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
            display: flex;
            justify-content: center;
            align-items: center;
            height: 100vh;
        }

        .circle-progress {
            position: relative;
            width: 200px;
            height: 200px;
        }

        .circle-progress svg {
            transform: rotate(-90deg);
        }

        .circle-progress .track {
            fill: none;
            stroke: #f0f0f0;
            stroke-width: 8;
        }

        .circle-progress .progress {
            fill: none;
            stroke: #4CAF50;
            stroke-width: 8;
            stroke-linecap: round;
            stroke-dasharray: 0 314; /* 314 是周长 2 * π * 50 */
            transition: stroke-dasharray 0.5s ease;
        }

        .progress-percentage {
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            font-size: 24px;
            font-weight: bold;
        }
    </style>
</head>

<body>
    <div class="circle-progress">
        <svg width="100%" height="100%">
            <circle class="track" cx="50%" cy="50%" r="50"></circle>
            <circle class="progress" cx="50%" cy="50%" r="50"></circle>
        </svg>
        <!-- 添加显示百分比的元素 -->
        <div class="progress-percentage" id="progressPercentage">0%</div>
    </div>

    <script>
        document.addEventListener("DOMContentLoaded", () => {
            const progressCircle = document.querySelector('.circle-progress .progress');
            const progressPercentage = document.getElementById('progressPercentage');
            const circleCircumference = 314; // 2 * π * 50

            gsap.to(progressCircle, {
                duration: 5,
                strokeDasharray: `${circleCircumference} ${circleCircumference}`,
                ease: "linear",
                // repeat: -1,
                yoyo: true,
                // 在动画更新时触发回调函数
                onUpdate: () => {
                    const computedDasharray = gsap.getProperty(progressCircle, "strokeDasharray");
                    const currentDash = parseFloat(computedDasharray.split(' ')[0]);
                    let progress = currentDash / circleCircumference;

                    // 处理精度误差，当进度接近 1 时，直接设置为 1
                    if (progress > 0.99) {
                        progress = 1;
                    }

                    const percentage = Math.round(progress * 100);
                    progressPercentage.textContent = `${percentage}%`;
                }
            });
        });
    </script>
</body>

</html>