在 iOS 11 使用 webview 发现顶部会有一个空白条，怎么也去不掉，通过设置 contentInsetAdjustmentBehavior = UIScrollViewContentInsetAdjustmentNever 就可以解决了，具体的代码如下：
//
// ViewController.m
// webView
//
// Created by exchen on 18/7/14.
// Copyright © 2018年 exchen. All rights reserved.
//
#import "ViewController.h"
@interface ViewController () <UIWebViewDelegate>
@property(nonatomic, strong) UIWebView* webView;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
CGRect screen = [[UIScreen mainScreen] bounds];
//添加 UIWebView
self.webView = [[UIWebView alloc] initWithFrame: CGRectMake(0, 0, screen.size.width, screen.size.height)];
[self.view addSubview: self.webView];
NSURL * url = [NSURL URLWithString: @"https://www.exchen.net"];
NSURLRequest * request = [NSURLRequest requestWithURL:url];
[self.webView loadRequest:request];
self.webView.delegate = self;
//解决 iOS 11 屏幕顶部显示不全
if ([[UIDevice currentDevice].systemVersion floatValue] >= 11.0) {
self.webView.scrollView.contentInsetAdjustmentBehavior = UIScrollViewContentInsetAdjustmentNever;
}
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (void)webViewDidStartLoad:(UIWebView *)webView {
NSLog(@"%@",NSStringFromSelector(_cmd));
}
//加载失败时调用
- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error {
NSLog(@"%@",NSStringFromSelector(_cmd));
NSLog(@"error: %@",error);
UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"信息" message:@"连接服务器失败，请检查网络" preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleCancel handler:^(UIAlertAction *action){
exit(0);
}];
[alertController addAction:cancelAction];
[self presentViewController:alertController animated:YES completion:nil];
}
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType{
return true;
}
@end