WebView上显示加载框（5种方案） 原创 精华

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方案5的效果图

问题现状

不管WebView在布局中哪个层级，都在最顶层显示。如下布局view_loading会被webview遮挡。

<?xml version="1.0" encoding="utf-8"?>
<DirectionalLayout
    xmlns:ohos="http://schemas.huawei.com/res/ohos"
    ohos:height="match_parent"
    ohos:width="match_parent"
    ohos:alignment="center"
    ohos:orientation="vertical">
    <ProgressBar
        ohos:id="$+id:progressbar"
        ohos:height="5vp"
        ohos:progress_width="5vp"
        ohos:max="100"
        ohos:progress="10"
        ohos:width="match_parent"
        ohos:progress_color="#47CC47"/>

    <DependentLayout
        xmlns:ohos="http://schemas.huawei.com/res/ohos"
        ohos:id="$+id:stack_layout"
        ohos:height="match_parent"
        ohos:width="match_parent">

        <ohos.agp.components.webengine.WebView
            ohos:id="$+id:webview"
            ohos:height="match_parent"
            ohos:width="match_parent"/>

        <include
            ohos:height="110vp"
            ohos:width="110vp"
            ohos:center_in_parent="true"
            ohos:layout="$layout:view_loading"/>
    </DependentLayout>
</DirectionalLayout>

解决方案有以下几种：

1. 用Dialog来显示，但是Dialog的特性，每次都得重新创建Dialog实例。见分支：dev_dialog

2. 隐藏WebView，从而可以显示出view_loading。这种方案有一个的缺点，当html加载出，但是js或css还没加载完成，WebView还是隐藏的状态。只有所有资源都加载完成后，loadingView才隐藏，WebView才显示。所以，这种方案在感觉上页面加载很慢。但是，优点就是最靠谱。见分支：dev_hide_webview

   ComponentContainer loadingView = (ComponentContainer) findComponentById(ResourceTable.Id_loadingView);
   
   private void showLoading() {
       if(loadingView !=null){
           mWebView.setVisibility(Component.HIDE);
           loadingView.setVisibility(Component.VISIBLE);
       }
   }
   
   private void hideLoading() {
       if(loadingView!=null){
           mWebView.setVisibility(Component.VISIBLE);
           loadingView.setVisibility(Component.HIDE);
       }
   }
   

3. 创建一个Window，类型指定为WindowManager.LayoutConfig.MOD_TOAST来显示。本质上和第一种方法一样。见分支：dev_window

   ComponentContainer progressBarDlg = (ComponentContainer) LayoutScatter.getInstance(getContext()).parse(ResourceTable.Layout_view_loading, null, false);
   
   
   private Window add2window(ComponentContainer progressBarDlg) {
       try {
           Window window = WindowManager.getInstance().addComponent(progressBarDlg, getContext(), WindowManager.LayoutConfig.MOD_TOAST);
   
           WindowManager.LayoutConfig layoutConfig = new WindowManager.LayoutConfig();
           layoutConfig.width = progressBarDlg.getLayoutConfig().width;
           layoutConfig.height = progressBarDlg.getLayoutConfig().height;
           window.setLayoutConfig(layoutConfig);
   
           return window;
       } catch (Exception e) {
           e.printStackTrace();
           L.i(TAG, e.getMessage());
       }
       return null;
   }
   

   private void showLoading() {
       if(dlgWindow==null && getLifecycle().getLifecycleState()== Lifecycle.Event.ON_ACTIVE){
           dlgWindow = add2window(progressBarDlg);
       }
   }
   
   private void hideLoading() {
       if(dlgWindow!=null){
           try {
               WindowManager.getInstance().destroyWindow(dlgWindow);
           } catch (Exception e) {
           }
           dlgWindow=null;
       }
   }
   

4. 用Android View来显示，可以调用setVisibility来显示或隐藏。效果最好，但是用到了Android的View元素。可能将来在鸿蒙系统上不再支持。代码见：主分支。参考：简单配置，使用Android API开发鸿蒙应用

5. 方案5是对方案4的优化
   回答了一个问题，题主顺便也分享了他的最终实现：https://developer.huawei.com/consumer/cn/forum/topic/0202621839353600065
   主要代码：

public static void bringToFront() {
    Activity activity = getCurrentActivity();
    FrameLayout decorView = (FrameLayout) activity.getWindow().getDecorView();
    FrameLayout contentView = decorView.findViewById(R.id.content);
    FrameLayout frameLayout = (FrameLayout) contentView.getChildAt(0);//和WebView并列在contentView下面
    SurfaceView agpContainerView = (SurfaceView) frameLayout.getChildAt(0);
    agpContainerView.setZOrderOnTop(true);
    agpContainerView.getHolder().setFormat(PixelFormat.TRANSPARENT);
}