import <Foundation/Foundation.h>

NS_ASSUME_NONNULL_BEGIN

@interface WebViewInjection : NSObject

• (void)allowDisplayingKeyboardWithoutUserAction;

@end

NS_ASSUME_NONNULL_END

import "WebViewInjection.h"

import <objc/runtime.h>

@implementation WebViewInjection

//+ (void)load {

• (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};
  if ([[NSProcessInfo processInfo] isOperatingSystemAtLeastVersion: iOS_13_0_0]) {
  SEL selector = sel_getUid("_elementDidFocus:userIsInteracting:blurPreviousNode:activityStateChanges: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, 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 if ([[NSProcessInfo processInfo] isOperatingSystemAtLeastVersion: iOS_12_2_0]) {
  SEL selector = sel_getUid("_elementDidFocus:userIsInteracting:blurPreviousNode:changingActivityState: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, 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 if ([[NSProcessInfo processInfo] isOperatingSystemAtLeastVersion: iOS_11_3_0]) {
  SEL selector = sel_getUid("_startAssistingNode:userIsInteracting:blurPreviousNode:changingActivityState: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, 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

可以在应用启动时执行allowDisplayingKeyboardWithoutUserAction
也可以直接写在 + load 里面