IOS 之 JavaScriptCore认识

JavaScriptCore是IOS7以后苹果为了解决JS和原生之间的交互问题 

1.非WebView环境下

  一般有两种方式解决JS -> OC

1.OC主动调用JS

-(void)OCCallJS{
    self.context = [[JSContext alloc] init];

    NSString *js = @"function add(a,b) {return a+b}";
    [self.context evaluateScript:js];
    JSValue *addJS = self.context[@"add"];

    JSValue *sum = [addJS callWithArguments:@[@(10),@(17)]];
    NSInteger intSum = [sum toInt32];
    NSLog(@"intSum: %zi",intSum);
}

2.JS中调用OC方法

a.通过block方式调用

-(NSInteger)add:(NSInteger)a and:(NSInteger)b{
    return  a+b;
}


-(void)JSCallOC_block{
    self.context = [[JSContext alloc] init];

    __weak typeof(self) weakSelf = self;
    self.context[@"add"] = ^NSInteger(NSInteger a, NSInteger b){
        return [weakSelf add:a and:b];
    };
    JSValue *sum = [self.context evaluateScript:@"add(4,5)"];
    NSInteger intSum = [sum toInt32];
    NSLog(@"intSum: %zi",intSum);
}

  b.js通过对象方式调用

#pragma mark - js通过对象方式调用
- (void)JSCallOC_JSExport
{
    NSLog(@"JSCallOC_JSExport");
    
    self.jsContext = [JSContext new];
    self.jsContext.exceptionHandler = ^(JSContext *context, JSValue *exception) {
        [JSContext currentContext].exception = exception;
        NSLog(@"exception:%@",exception);
    };
    
    self.addObj = [AddJSExportObj new];
    
    //self.jsContext[@"OCAddObj"] = self.addObj;//把oc对象映射成js对象 下面这句和这里效果是等价
    
    [self.jsContext setObject:self.addObj forKeyedSubscript:@"OCAddObj"];
    
    [self.jsContext evaluateScript:@"OCAddObj.token = OCAddObj.test()"];
    
    [self.jsContext evaluateScript:@"OCAddObj.addAnd(2,30)"];
    
    [self.jsContext evaluateScript:@"OCAddObj.TestTowParameter('参数A','参数B')"];
    
    NSLog(@"OCAddObj.token1:%@",self.addObj.token);
    
    //[self.jsContext evaluateScript:@"OCAddObj.testPromise('参数',function(resp){OCAddObj.token = resp})"];
    
    [self.jsContext evaluateScript:@"OCAddObj.testPromise1(function(resp){})"];
    
    //testPromise
    NSLog(@"OCAddObj.token2:%@",self.addObj.token);
}

自定义对象必须实现JSExport协议。

 

//
//  AddJSExportObj.h
//  JavaScriptCore的理解
//
//  Created by wangsheng on 2018/6/20.
//  Copyright © 2018年 wangsheng. All rights reserved.
//

#import <Foundation/Foundation.h>
#import <JavaScriptCore/JavaScriptCore.h>

@protocol AddJSExport <JSExport>
//JSExportAs 这样适用于多个参数的情况，对js方法重命名，如果不这样写JS那边 调用方式为addAnd(),
//JSExportAs(add, - (NSInteger)add:(NSInteger)a and:(NSInteger)b);
- (NSString *)test;
- (NSInteger)add:(NSInteger)a and:(NSInteger)b;
JSExportAs(TestTowParameter, -(void)TestTowParameter:(NSString *)message1 SecondParameter:(NSString *)message2);
JSExportAs(testPromise, - (void)testPromise:(NSString *)arg success:(void(^)(NSString *))success);
JSExportAs(testPromise1, - (void)testPromise1:(void(^)(NSString *))arg);
@property (nonatomic, copy) NSString *token;
@property (nonatomic, assign) NSInteger sum;
@end

@interface AddJSExportObj : NSObject <AddJSExport>
@property (nonatomic, assign) NSInteger sum;
@property (nonatomic,copy)NSString *token;
@end

#import "AddJSExportObj.h"

@implementation AddJSExportObj

- (NSString *)test{
    NSLog(@"js call oc method");
    return @"oc return value to js";
}

- (NSInteger)add:(NSInteger)a and:(NSInteger)b
{
    NSLog(@"come add:%li,b:%li",a,b);
    return a+b;
}

-(void)TestTowParameter:(NSString *)message1 SecondParameter:(NSString *)message2
{
    NSLog(@"TestTowParameter:%@,SecondParameter:%@",message1,message2);
}

- (void)testPromise:(NSString *)arg success:(void(^)(NSString *))success
{
    NSLog(@"testPromise come here:%@",arg);
    success(@"return value from oc to js");
}

- (void)testPromise1:(void(^)(NSString *))block
{
    NSLog(@"testPromise1:%@",block);
    block(@"11111");
}
@end

  2.WebView环境下

 1.通过拦截loadUrl方式实现JS -> OC

 

 2.动态

  1.获取JSContext上下文

 JSContext *context = [_webView valueForKeyPath:@"documentView.webView.mainFrame.javaScriptContext"];

 2.其他的同上面差不多

3.