IOS开发之Block的使用和内存管理

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使用Block可简化回调；

Block 形式：返回类型(^ Block名)(形式参数){实体;};

Block Pointer指针：返回类型(^Block名)(形式参数);

可用typedof申明；

Block按在内存中的位置分为 NSGlobalBlock、NSStackBlock、NSMallocBlock；

ARC中将会自动把NSStackBlock复制到NSMallocBlock；

NSMallocBlock只需要对NSStackBlock进行copy操作就可以获取，但是retain操作就不行,

小Demo如下：

<span style="font-size:18px;">#import "ViewController.h"typedef void(^MyBlock)(void);@interface ViewController()@property (nonatomic, strong) MyBlock myblock;@property (nonatomic, assign)int globalData ;@end@implementation ViewController- (void)viewDidLoad {        int i = 0;    static int staticI = 0;        __weak ViewController *viewCon = self;        _myblock = ^(void){        NSLog(@"\ni = %d\n staticI = %d\n globaldata = %d",i,staticI,viewCon.globalData);            };        i++;    staticI++;    _globalData++;                _myblock();        }-(void)showMessage{    NSLog(@"this is private method showMessage");}@end</span>

输出结果为：

i = 0

staticI = 1

globaldata = 1

参考文献：

Block入门：http://www.jianshu.com/p/17872da184fb

Block内存管理：http://www.knowsky.com/883942.html

http://www.cocoachina.com/bbs/read.php?tid=87593&keyword=block
http://www.cocoachina.com/bbs/read.php?tid=88591&keyword=block
http://www.cocoachina.com/bbs/read.php?tid=9222&keyword=block

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