iOS thread dependent

The role of dependency: in iOS development, we often use a thread that needs to wait for another end to take place, a requirement that actually has a practical solution. Here are some of the methods that are currently used:

Requirements:: With nsopertion and nsopertionqueue processing a,b,c,d,e three threads, required to execute after a,b,d,e to execute C, how to do?

Create a queue

Nsoperationqueue *queue = [[Nsoperationqueue alloc] init];

Create 5 actions

Nsoperation *a = [Nsblockoperation blockoperationwithblock:^{

NSLog (@ "Operation---a");

}];

Nsoperation *b = [Nsblockoperation blockoperationwithblock:^{

NSLog (@ "Operation---b");

}];

Nsoperation *c = [Nsblockoperation blockoperationwithblock:^{

NSLog (@ "**************c");

}];

Nsoperation *d = [Nsblockoperation blockoperationwithblock:^{

NSLog (@ "Operation---d");

}];

Nsoperation *e = [Nsblockoperation blockoperationwithblock:^{

NSLog (@ "Operation---e");

}];

Add dependency

[C Adddependency:a];

[C ADDDEPENDENCY:B];

[C Adddependency:d];

[C Adddependency:e];

Perform actions

[Queue addoperation:a];

[Queue addoperation:b];

[Queue addoperation:c];

[Queue addoperation:d];

[Queue addoperation:e];

Printing results:

2017-08-17 18:38:02.040 Dependency [11633:750843] Operation---A

2017-08-17 18:38:02.040 Dependency [11633:757610] operation---b

2017-08-17 18:38:02.040 Dependency [11633:757611] operation---D

2017-08-17 18:38:02.040 Dependence [11633:757612] Operation---E

2017-08-17 18:38:02.042 dependence [11633:757610] **************c

iOS Thread dependency