mms
Quartz2D 二维绘图引擎(绘制图形|绘制文字|读取生成 PDF|裁剪图片|自定义 UI 控件)
继承 UIView 重写 drawRect.(viewDidLoad->viewWillAppear->drawRect)
view 相关联的上下文,直接找 UIGraphics开头
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VFL http://www.cnblogs.com/developer-ios/p/4991073.html
功能 表达式
水平方向 H:
垂直方向 V:
Views [view]
SuperView |
关系 >=,==,<=
空间,间隙 -
优先级 @value
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Method swizzling指的是改变一个已存在的选择器对应的实现的过程，它依赖于Objectvie-C中方法的调用能够在运行时进改变——通过改变类的调度表（dispatch table）中选择器到最终函数间的映射关系。
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NSString *string = @”origion”; //0x100001038—-origion
NSString *stringCopy = [string copy];// 0x100001038—-origion
NSMutableString *stringMCopy = [string mutableCopy];//0x100300500—-origion
[stringMCopy appendString:@”!!”]; //0x100300500—-origion!!
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NSMutableString *string = [NSMutableString stringWithString: @”origion”];//0x100206980–A–origion
NSString *xx=@”origion”;//0x100001038–xx–origion
NSString *stringCopy = [string copy]; //0x6e6f696769726f75–B–origion
NSMutableString *stringCopyMM = [string copy]; //0x6e6f696769726f75–M–origion
[string appendString:@”123″];
NSMutableString *mStringCopy = [string copy];//0x100107500–C–origion123
NSMutableString *stringMCopy = [string mutableCopy];//0x1001067c0–D–origion123
// [mStringCopy appendString:@”mm”];//error
[string appendString:@” origion!”];// 0x100206980–E–origion123 origion!
[stringMCopy appendString:@”!!”];//0x1001067c0–F–origion123!!
NSLog(@”===string====>%@”,string.class); //===string====>__NSCFString
NSLog(@”====mStringCopy===>%@”,mStringCopy.class);//====mStringCopy===>__NSCFString
NSLog(@”====stringCopy===>%@”,stringCopy.class);//====stringCopy===>NSTaggedPointerString
NSLog(@”====xx===>%@”,xx.class);//====xx===>__NSCFConstantString
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