WKWebView 遇到 NSInternalInconsistencyException runJavaScriptAlertPanelWithMessage: was not called

Completion handler passed to -[xxx.BaseWebViewController webView:runJavaScriptAlertPanelWithMessage:initiatedByFrame:completionHandler:] was not called

从 crash 可以看出是 WKWebView 回调函数: runJavaScriptAlertPanelWithMessage中completionHandler 没有被调用导致的。

出现情况可能是WKWebView 退出的时候，JS刚好执行了window.alert(), alert 框可能弹不出来，completionHandler 最后没有被执行，导致 crash；另一种情况是在 WKWebView 一打开，JS就执行window.alert()，这个时候由于 WKWebView 所在的 UIViewController 出现（push或present）的动画尚未结束，alert 框可能弹不出来，completionHandler 最后没有被执行，导致 crash。

解决办法如下：

#pragma mark -- WKUIDelegate
- (void)webView:(WKWebView *)webView runJavaScriptAlertPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(void))completionHandler{
    if ([self.navigationController visibleViewController] != self)
    {
        completionHandler();
        return;
    }
    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"" message:message preferredStyle:UIAlertControllerStyleAlert];
    [alertController addAction:[UIAlertAction actionWithTitle:@"确认" style:UIAlertActionStyleCancel handler:^(UIAlertAction *action) {
        completionHandler();
        
    }]];
    if ([self.navigationController visibleViewController] == self)    {
        [self presentViewController:alertController animated:YES completion:nil];
    }else
    {
        completionHandler();
    }
    
}
// 显示两个按钮，通过completionHandler回调判断客户点击确实定还是取消按钮
- (void)webView:(WKWebView *)webView runJavaScriptConfirmPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(BOOL))completionHandler{
    if ([self.navigationController visibleViewController] != self)    {
        completionHandler(NO);
        return;
    }
    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:message message:nil preferredStyle:UIAlertControllerStyleAlert];
    [alertController addAction:[UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        completionHandler(YES);
        
    }]];
    [alertController addAction:[UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
        completionHandler(NO);
    }]];
    if ([self.navigationController visibleViewController] == self)    {
        [self presentViewController:alertController animated:YES completion:nil];
    }else{
        completionHandler(NO);
    }
    
}
// 显示一个带有输入框和一个确定按钮的，通过completionHandler回调客户输入的内容
- (void)webView:(WKWebView *)webView runJavaScriptTextInputPanelWithPrompt:(NSString *)prompt defaultText:(NSString *)defaultText initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(NSString * _Nullable))completionHandler{
    if ([self.navigationController visibleViewController] != self)    {
        completionHandler(@"error");
        return;
    }
    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"" message:nil preferredStyle:UIAlertControllerStyleAlert];
    [alertController addTextFieldWithConfigurationHandler:^(UITextField * _Nonnull textField) {
        
    }];
    [alertController addAction:[UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        completionHandler(alertController.textFields.lastObject.text);
        
    }]];
    if ([self.navigationController visibleViewController] == self)    {
        [self presentViewController:alertController animated:YES completion:nil];
        
    }
    else
    {
        completionHandler(@"error");
        
    }
    
}