主要解决在WKWebView加载H5，页面有输入框，让输入框称为第一响应者，前端H5开发同学需要原生配合解决，直接上代码：

1.在iOS原生中，让输入框弹起键盘，成为第一响应者，如下：

[self.textField becomeFirstResponder];

2.适配H5，新建WKWebView分类，命名为WebViewInjection,代码如下：

.h:

#import <WebKit/WebKit.h>

NS_ASSUME_NONNULL_BEGIN

@interface WKWebView (WebViewInjection)

+ (void)allowDisplayingKeyboardWithoutUserAction;

@end

NS_ASSUME_NONNULL_END

.m

#import "WKWebView+WebViewInjection.h"

@implementation WKWebView (WebViewInjection)

+ (void)allowDisplayingKeyboardWithoutUserAction {
    Class class = NSClassFromString(@"WKContentView");
    NSOperatingSystemVersion iOS_11_3_0 = (NSOperatingSystemVersion){11, 3, 0};
    NSOperatingSystemVersion iOS_12_2_0 = (NSOperatingSystemVersion){12, 2, 0};
    NSOperatingSystemVersion iOS_13_0_0 = (NSOperatingSystemVersion){13, 0, 0};
    char * methodSignature = "_startAssistingNode:userIsInteracting:blurPreviousNode:changingActivityState:userObject:";

    if ([[NSProcessInfo processInfo] isOperatingSystemAtLeastVersion: iOS_13_0_0]) {
        methodSignature = "_elementDidFocus:userIsInteracting:blurPreviousNode:activityStateChanges:userObject:";
    } else if ([[NSProcessInfo processInfo] isOperatingSystemAtLeastVersion: iOS_12_2_0]) {
        methodSignature = "_elementDidFocus:userIsInteracting:blurPreviousNode:changingActivityState:userObject:";
    }
    if ([[NSProcessInfo processInfo] isOperatingSystemAtLeastVersion: iOS_11_3_0]) {
            SEL selector = sel_getUid(methodSignature);
            Method method = class_getInstanceMethod(class, selector);
            IMP original = method_getImplementation(method);
            IMP override = imp_implementationWithBlock(^void(id me, void* arg0, BOOL arg1, BOOL arg2, BOOL arg3, id arg4) {
                ((void (*)(id, SEL, void*, BOOL, BOOL, BOOL, id))original)(me, selector, arg0, TRUE, arg2, arg3, arg4);
            });
            method_setImplementation(method, override);
        } else {
            SEL selector = sel_getUid("_startAssistingNode:userIsInteracting:blurPreviousNode:userObject:");
            Method method = class_getInstanceMethod(class, selector);
            IMP original = method_getImplementation(method);
            IMP override = imp_implementationWithBlock(^void(id me, void* arg0, BOOL arg1, BOOL arg2, id arg3) {
                ((void (*)(id, SEL, void*, BOOL, BOOL, id))original)(me, selector, arg0, TRUE, arg2, arg3);
            });
            method_setImplementation(method, override);
        }
}

@end

3.在使用WK加载H5的地方进行调用：

[WKWebView allowDisplayingKeyboardWithoutUserAction];

finish