iOS block里的self

1 self.block = ^(NSString *aString)
2 {
3     self.aLabel.text = aString;
4 });

 1 //例如：（无ARC）
 2 __block id safeSelf = self;
 3 self.block = ^(NSString *aString)
 4 {
 5     safeSelf.aLabel.text = aString;
 6 });
 7  
 8 //（有ARC）
 9 __weak id safeSelf = self;        //ios 5
10 // __unsafe_unretained id safeSelf = self; //ios 4
11 self.block = ^(NSString *aString)
12 {
13     safeSelf.aLabel.text = aString;
14 });