LHF Objective-C语法（11）写入和读取属性 对象的复制

1、

NSArray *array = [[NSArray arrayWithObjects:@"Apple",@"Google",@"Microsoft",nil];

[array writeToFile:@"plist.txt" atomically:NO];

会在当前文件夹下找到plist.txt，格式如下

(

      Apple,

      Google,

      Microsoft

)

NSArray *array2 = [NSArray arrayWithContentOfFile:@"plist.txt"];

NSLog(@"%@",[array2 objectAtIndex:1]);

2、如果持久化的类型不是数组，字典，缓冲区，那该怎么办。

objc里也有java一样的序列化，反序列化  使用NSCoding协议

    -(void) encodeWithCoder :(NSCoder*) coder; //编码对象

    -(id) initWithCoder :(NSCoder*) decoder; //解码

3、对象的复制

某个对象是否可以被复制，要看它的类型是否遵从NSCopying协议，这个协议有个复制方法需要我们去实现

//Engine.h======================================= #import <Foundation/Foundation.h>@interface Engine:NSObject <NSCopying>//遵从NSCopying协议 @end //Engine.m======================================= @implementation Engine -(id) copyWithZone:(NSZone*) zone{ Engine *engine = [[[self class] allocWithZone:zone] init]; return engine; } @end //======================================= @interface Tire:NSObject <NSCopying>{ int count; } -(Tire*) initWithCount:(int) count; -(void) setCount:(int) count; -(int) count; @end //======================================= @implementation Tire -(Tire*) initWithCount:(int) c{ self = [super init]; if(self){ count=c; } return self; } -(void) setCount:(int) c{ count = c; } -(int) count{ return count; } -(id) copyWithZone:(NSZone*) zone{ Tire *tire = [[[self class] allocWithZone:zone] initWithCount:count]; return tire; } @end //======================================== @interface Car : NSObject <NSCopying>{ Engine *engine; Tire *tire; } -(void) setEngine:(Engine*) engine; -(void) setTire:(Tire*) tire; -(Engine*) engine; -(Tire*) tire; @end //======================================== @implementation Car -(void) setEngine:(Engine*) e{ [e retain]; [engine release]; engine = e; } -(void) setTire:(Tire*) t{ [t retain]; [tire release]; tire = t; } -(Engine*) engine{ return engine; } -(Tire*) tire{ return tire; } -(id) copyWithZone:(NSZone*) zone{ Car *car = [[[self class] allocWithZone:zone] init]; Engine *engineCopy = [engine copy]; Tire *tireCopy = [tire copy]; [car setEngine:engineCopy]; [car setTire:tireCopy]; [engineCopy release]; [tireCopy release]; return car; } -(void) dealloc{ [engine release]; [tire release]; [super dealloc]; } @end int main (int argc, const char * argv[]) { @autoreleasepool { Engine *engine = [Engine new]; Tire *tire = [[Tire alloc] initWithCount:4]; Car *car = [Car new]; [car setEngine:engine]; [car setTire:tire]; [engine release]; [tire release]; Car *newCar = [car copy]; [car release]; NSLog(@"The car has %d tires",[[newCar tire] count]); [newCar release]; } return 0; }