Question

UIColor有颜色方法，例如blackColor，whiteColor等。我想得到一个颜色列表，如：['blackColor','whiteColor'...]。但在检查method_list，ivar_list和property_list后，我发现列表中没有颜色方法。代码用Swift编写如下：

//: Playground - noun: a place where people can play

import UIKit

var ivarCount: UInt32 = 0
var propertyCount: UInt32 = 0
var methodCount: UInt32 = 0
let ivars = class_copyIvarList(UIColor.self, &ivarCount)
let properties = class_copyPropertyList(UIColor.self, &propertyCount)
let methods = class_copyMethodList(UIColor.self, &methodCount)

var ivarNames: [String] = []
var propertyNames: [String] = []
var methodNames: [String] = []

for var i = 0; i < Int(ivarCount); ++i {
    let ivar = ivars[i]
    let name = ivar_getName(ivar)
    ivarNames.append(String.fromCString(name)!);
}

for var i = 0; i < Int(propertyCount); ++i {
    let p = properties[i]
    let name = property_getName(p)
    propertyNames.append(String.fromCString(name)!)
}

for var i = 0; i < Int(methodCount); ++i {
    let m = methods[i]
    let name = sel_getName(method_getName(m))
    methodNames.append(String.fromCString(name)!)
}


NSLog("ivars:%@",ivarNames)
NSLog("properties:%@", propertyNames)
NSLog("methods:%@", methodNames)

结果如下：

2016-01-18 11:26:25.531 MyPlayground[42239:4975071] ivar:(
    "_systemColorName"
)
2016-01-18 11:26:25.531 MyPlayground[42239:4975071] properties:(
    CGColor,
    CIColor,
    systemColorName
)
2016-01-18 11:26:25.532 MyPlayground[42239:4975071] method:(
    "initWithColorLiteralRed:green:blue:alpha:",
    classForCoder,
    hash,
    "isEqual:",
    set,
    "initWithHue:saturation:brightness:alpha:",
    "_getWhite:alpha:",
    "_systemColorName",
    "initWithWhite:alpha:",
    "_getRed:green:blue:alpha:",
    "_colorBlendedWithColor:",
    styleString,
    isPatternColor,
    "getHue:saturation:brightness:alpha:",
    CIColor,
    "initWithPatternImage:",
    "_setSystemColorName:",
    "_luminance",
    "_colorBlendedWithColor:compositingFilter:",
    "_isSimilarToColor:withinPercentage:",
    "_colorDifferenceFromColor:",
    "_luminanceDifferenceFromColor:",
    "_colorBlendedWithColors:",
    dealloc,
    "copyWithZone:",
    "encodeWithCoder:",
    "initWithCoder:",
    cgColor,
    "initWithCGColor:",
    "initWithRed:green:blue:alpha:",
    CGColor,
    "getRed:green:blue:alpha:",
    setFill,
    "colorWithAlphaComponent:",
    setStroke,
    alphaComponent,
    "getWhite:alpha:",
    "initWithCIColor:"
)

Answer 1

那是因为颜色方法是类方法，它们绑定到UIColor的元类。并且class_copyMethodList返回作为参数传递的类的实例方法。

您可以通过object_getClass()调用UIColor来获取元类，因此您只需更改一行即可获得UIColor的所有类方法：

let methods = class_copyMethodList(object_getClass(UIColor.self), &methodCount)

object_getClass()适用于Class值，因为Objective-C每个类都有一个isa指针，这使得它有资格成为一个对象。

如何获得UIColor的所有Color方法？

1 个答案: