How to get all Color methods of UIColor?

问题

UIColor has color methods such as blackColor, whiteColor and so on. I would like to get a color list of them like:['blackColor','whiteColor'...]. But after checking the method_list, ivar_list and property_list, I find no color method in the lists. The code is written in Swift as following:

//: 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)

The result is as following:

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:"
)

回答1:

That's because the color methods are class methods, which are bound to UIColor's metaclass. And class_copyMethodList returns the instance methods of the class passed as argument.

You can obtain the metaclass by calling object_getClass() on UIColor, so you'll need to change only one line to get all class methods of UIColor:

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

object_getClass() works on Class values as in Objective-C every class has an isa pointer, which qualifies it for being an object.

来源：https://stackoverflow.com/questions/34846964/how-to-get-all-color-methods-of-uicolor

标签

swift

runtime

uicolor