Question

嗨，大家好我非常沮丧，因为我想改进代码，但我没有得到好结果这是我的代码

NSBlockOperation *blockOperation1 = [NSBlockOperation blockOperationWithBlock: ^{
        value1 = [self getDiferences:0.0 finx:width iniy:0.0 finy:cuartoheith image:imagen1 imagetoComapare:imagen2];
    }];
    [queue addOperation:blockOperation1];

NSBlockOperation *blockOperation2 = [NSBlockOperation blockOperationWithBlock: ^{
        value2 = [self getDiferences:0.0 finx:width iniy:0.0 finy:cuartoheith image:imagen1 imagetoComapare:imagen2];
    }];
    [queue addOperation:blockOperation2];

NSBlockOperation *blockOperation3 = [NSBlockOperation blockOperationWithBlock: ^{
        value3 = [self getDiferences:0.0 finx:width iniy:0.0 finy:cuartoheith image:imagen1 imagetoComapare:imagen2];
    }];
    [queue addOperation:blockOperation3];

NSBlockOperation *blockOperation4 = [NSBlockOperation blockOperationWithBlock: ^{
        value4 = [self getDiferences:0.0 finx:width iniy:0.0 finy:cuartoheith image:imagen1 imagetoComapare:imagen2];
    }];
    [queue addOperation:blockOperation4];

我希望在NSBlockOperation之外使用这个值，例如：valuetotal = value1 + value2 + value3 + value4;请帮助或帮助提供更好的解决方案

Answer 1

添加另一项操作，该操作取决于您的其他操作（使用addDependency:），并在那里添加您的代码。排队此操作。它将等待所有其他人完成，然后使用他们的输出。

例如，

NSBlockOperation *blockOperationFinal = [NSBlockOperation blockOperationWithBlock: ^{
    valueTotal = value1 + value2 + value3 + value4;
}];

[blockOperationFinal addDependency:blockOperation1];
[blockOperationFinal addDependency:blockOperation2];
[blockOperationFinal addDependency:blockOperation3];
[blockOperationFinal addDependency:blockOperation4];

[queue addOperation:blockOperationFinal];

Answer 2

一个块操作就足够了，因为它能够添加更多的块，并且可以同时执行，同时提供一个块来在所有块完成时触发，如下所示：

NSMutableArray *array = [[NSMutableArray alloc] init];
NSBlockOperation *operation = [NSBlockOperation blockOperationWithBlock:^{
    [array addObject:@"op1"];
}];
[operation addExecutionBlock:^{
    [array addObject:@"op2"];
}];

[[[NSOperationQueue alloc] init] addOperation:operation];
[operation setCompletionBlock:^{
    NSLog(@"array:%@", array);
}];

从NSBlockOperation获取价值？

2 个答案: