RichTextEditor

iOS 13 之后不再支持 UIWebView,所以将之前一篇文章iOS 富文本编辑器-UIWebView中 UIWebView 替换为 WKWebView。以下为更换到 WKWebView 的一些知识点。

富文本编辑器设计的知识点

Objective-C 语言调用 JavaScript 语言

通过WKWebView的

- (void)evaluateJavaScript:(NSString *)javaScriptString completionHandler:(void (^ _Nullable)(_Nullable id, NSError * _Nullable error))completionHandler;

方法来实现的。这样我们就可以实现文字的加粗、下划线、斜体等等一切我们想要的样式。

详见项目中 WKWebView+VJJSTool 文件。

JavaScript 语言调用 Objective-C 语言

第一步：我们需要在WKWebView创建的过程中初始化添加ScriptMessageHandler

WKWebViewConfiguration *configuration = [[WKWebViewConfiguration alloc] init];
WKUserContentController *userController = [[WKUserContentController alloc] init];
configuration.userContentController = userController;
_mainWebView = [[WKWebView alloc] initWithFrame:CGRectMake(0, 0, KMainWidth, KMainHeight) configuration:configuration];
[userController addScriptMessageHandler:self name:@"currentCookies"];

然后实现代理方法.监听JS的回调.

//JS调用的OC回调方法
- (void)userContentController:(WKUserContentController *)userContentController didReceiveScriptMessage:(WKScriptMessage *)message{
    
    if ([message.name isEqualToString:@"jsMethod"]) {
        //
    }
}

然后在Html文件中添加点击方法.

<div id="button_div" onclick="buttonDivAction()">
      点击调用OC方法
</div>

紧接着.在js文件中实现点击事件.这时候要注意的是ScriptMessageHandler的名称要与上面定义的一致.

function buttonDivAction() {
    window.webkit.messageHandlers. jsMethod.postMessage({
        "body": "buttonActionMessage"
    });
}

输入文字时，插入符号位置计算

ZSSRichTextEditor.js

zss_editor.calculateEditorHeightWithCaretPosition = function() {}

新增标题与副标题

editor.html

<div id="vj_title">
     <input id="vj_article_title" maxlength="70" type="text" placeholder="请输入标题">
</div>
<div id="vj_abstract-title">
    <input id="vj_article_abstract" maxlength="35" type="text" placeholder="请输入文章摘要">
</div>

去掉键盘自带的工具条

WKWebView+HackishAccessoryHiding.h

@property (nonatomic, assign) BOOL hidesInputAccessoryView;

自动弹出键盘

实现和 UIWebView 中 keyboardDisplayRequiresUserAction 相同功能。即在 web 页面 focus 获得焦点状态下弹出键盘，UIWebView 中 keyboardDisplayRequiresUserAction 设置为 NO 就可以实现，但是WKWebView 中没有此属性，可以通过以下方式实现：

WKWebView+HackishAccessoryHiding.m

-(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);
        }

}

详细代码请看项目 https://github.com/Vergil-wj/RichTextEditor

参考资料：

ZSSRichTextEditor

WGEditor

浅谈WKWebView使用、JS的交互