## ImagePreview 图片预览

### 使用范例

```
import 'package:flutter_vant_kit/main.dart';

List<Widget> images = [
  Image.network("https://img.yzcdn.cn/vant/apple-1.jpg"),
  Image.network("https://img.yzcdn.cn/vant/apple-2.jpg"),
  ...
];

showDialog(
  context: context,
  barrierDismissible: true,
  builder: (BuildContext context) {
    return ImagePreview(
      images: images,
    );
  }
);
```

更多例子请参考[Demo](https://github.com/benjaken/flutter_vant_kit/blob/master/example/lib/routes/demoImagePreview.dart)

### API

| 参数 | 说明 | 类型 | 默认值 |
| ------------ | ------------ | ------------ | ------------ |
| images | 需要预览的图片数组 | `List<Widget>` | - |
| startPosition | 图片预览起始位置索引 | `int` | `0` |
| showIndex | 是否显示页数 | `bool` | `true` |
| showIndicators | 是否显示轮播指示器 | `bool` | `false` |
| swipeDuration | 动画时长| `Duration` | `Duration(seconds: 1)` |
| onChange | 切换图片时的回调函数 | `Function(int val)` | - |
