Ios 如何使用Bolts框架[Facebook+；Parse]

刚才我从Facebook上看到了关于IOS框架的内容

我可以将此视为主要概念：

bolt中的第一个组件是“任务”，它使复杂异步代码的组织更易于管理

但我没有得到这个。我对

螺栓框架

感到困惑。如何使用它（

它是否与web服务或JSON响应解析相关

）

他们用parse SDK提供了

ParseObject

的示例，但我不知道，他们也没有提供任何Xcode项目的示例

Facebook提供了这方面的信息。但我不知道如何与我的项目整合

他们提供的代码非常混乱：

[[object saveAsync:obj] continueWithBlock:^id(BFTask *task) {
  if (task.isCancelled) {
    // the save was cancelled.
  } else if (task.error) {
    // the save failed.
  } else {
    // the object was saved successfully.
    SaveResult *saveResult = task.result;
  }
  return nil;
}];

我们可以下载这个框架。有人能解释一下吗

更新：我收到了一些关于螺栓新问题的答案

示例：

---

假设您希望从AssertLibrary加载所有图像，并在加载时将所有图像调整为标准大小，因此如果使用主线程执行，则会被击中。在这里，如果你采用异步操作方式，如何使用BFTask呢？另一个例子。有一次，你试图用异步操作调用10个webservice并行，你怎么能把GCD与BFTask一起使用呢？

Bolt很棒。同意文档现在有点不集中。下面是一个简单的例子：

// the completion source is the *source* of the task...
BFTaskCompletionSource *source = [BFTaskCompletionSource taskCompletionSource];
[self asynchronousMethodWithCompletion:^(id response, NSError *error) {
   // your task completed; inform the completion source, which handles
   // the *completion* of the task
   error ? [source setError:error] : [source setResult:entity];
}];

[source.task continueWithBlock:^id(BFTask *task) {
   // this will be executed after the asynchronous task completes...
}];

我发现它对于组完成（半伪代码）特别有用：

这是一种更简洁的方法，可以使用调度组执行其他操作。不过，在串行和并行任务的排序等方面，还有很多

---

希望这能帮助您入门。

下面是一个完整的应用程序示例，它可以支持多个参与者在处理网络请求和用户交互时更改数据

我已经为自己设置了一个指导原则，在接触任何与线程安全相关的服务时，使用链接到串行调度队列的BFExecutor

指出其他最佳实践会很有用，谢谢

#import <Bolts/Bolts.h>

dispatch_queue_t serialQueue;
BFExecutor *serialExecutor;
BFTask *maintask;
int32_t key = 0;
BOOL initialized = FALSE;

@implementation yAppDelegate

- (void)setKey:(int32_t)key_ {
    // Don't worry about success, just appending to outstanding tasks
    maintask = [maintask continueWithExecutor:serialExecutor withBlock:^id(BFTask *task) {
        BFTaskCompletionSource *source = [BFTaskCompletionSource taskCompletionSource];

        key = key_;
        NSLog(@"set key to %d", key);
        [source setResult:nil];

        if (initialized) {
            [self initialize];
        }

        return source.task;
    }];
}

- (BFTask *)downloadConfig {
    BFTaskCompletionSource *source = [BFTaskCompletionSource taskCompletionSource];
    dispatch_async(serialQueue, ^{
        NSLog(@"working on init config, key = %d...", key);

        // Trigger from a different queue
        double delayInSeconds = 1.0;
        dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
        dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
            [source setResult:nil];
        });
    });
    return source.task;
}

- (BFTask *)initializeService {
    BFTaskCompletionSource *source = [BFTaskCompletionSource taskCompletionSource];
    dispatch_async(serialQueue, ^{
        NSLog(@"working on init service, key = %d...", key);

        // Trigger from a different queue
        double delayInSeconds = 1.0;
        dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
        dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
            [source setResult:nil];
        });

        // Set final state
        initialized = TRUE;
    });
    return source.task;
}

- (void)initialize {
    int32_t oldKey = key;
    __block bool reinit = false;

    // Start by chaining it to whatever task is in flight without regard to success
    // Everything should use the serialQueue or serialExecutor for thread safety
    maintask = [[[maintask continueWithExecutor:serialExecutor withBlock:^id(BFTask *task) {
        if (oldKey != key) {
            NSLog(@"key out of date (%d != %d).  reinitializing...", oldKey, key);
            reinit = true;
            return [BFTask cancelledTask];
        }
        return [self downloadConfig];
    }] continueWithExecutor:serialExecutor withSuccessBlock:^id(BFTask *task) {
        if (oldKey != key) {
            NSLog(@"key out of date (%d != %d).  reinitializing...", oldKey, key);
            reinit = true;
            return [BFTask cancelledTask];
        }
        return [self initializeService];
    }] continueWithExecutor:serialExecutor withBlock:^id(BFTask *task) {
        if (oldKey != key) {
            NSLog(@"key out of date (%d != %d).  reinitializing...", oldKey, key);
            reinit = true;
        }

        if (task.error || task.exception || task.isCancelled) {
            if (reinit) {
                [self initialize];
            }
            return nil;
        } else {
            NSLog(@"initService completed = %d", key);
            return nil;
        }
    }];
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    serialQueue = dispatch_queue_create("serial", NULL);
    serialExecutor = [BFExecutor executorWithDispatchQueue:serialQueue];

    // Start with an empty task so all tasks can be strung together without need to initialize
    maintask = [BFTask taskWithResult:nil];

    // Everything related to changing service state should be contained with the serialQueue dispatch queue
    [self setKey:1];
    [self initialize];
    [self setKey:2];
    [self setKey:3];

    dispatch_async(dispatch_get_main_queue(), ^(void){
        [self setKey:4];
    });

    dispatch_async(serialQueue, ^(void){
        [self setKey:5];
    });

    [self setKey:6];

    // Override point for customization after application launch.
    return YES;
}

@end

有关示例，请参阅测试文件（即TaskTests.m）。Github上的示例是特定于解析的

---

一般来说，查看为软件编写的测试就足以学习如何使用代码。

对不起，我自己找不到太多信息，我还没有尝试将其与我自己的项目集成。谢谢@itsthejb查看此链接。你的答案和这个一样。请看这些评论。请解释它与异步操作的关系？Bolt旨在包装/封装任何类型的异步任务。您需要做的只是在操作完成时向任务完成源发送消息。我的想法是用这种方式来包装你的任何行动。是的，我知道。但是上面的任务在哪里可以找到异步任务呢？您是在异步任务完成后而不是在异步任务期间处理BFTask的？我说得对吗？我想知道，如何在异步任务中使用BFTask，特别是在哪里使用BFTask锁定和解锁资源？我会给你+1的方法吗？如果你不明白我的意思，请发表评论。或者在这方面做更多的研究并帮助我。谢谢：）我认为你误解了框架的目的。Bolts不帮助您编写异步操作。其目的是使用公共接口封装和排序操作

#import <Bolts/Bolts.h>

dispatch_queue_t serialQueue;
BFExecutor *serialExecutor;
BFTask *maintask;
int32_t key = 0;
BOOL initialized = FALSE;

@implementation yAppDelegate

- (void)setKey:(int32_t)key_ {
    // Don't worry about success, just appending to outstanding tasks
    maintask = [maintask continueWithExecutor:serialExecutor withBlock:^id(BFTask *task) {
        BFTaskCompletionSource *source = [BFTaskCompletionSource taskCompletionSource];

        key = key_;
        NSLog(@"set key to %d", key);
        [source setResult:nil];

        if (initialized) {
            [self initialize];
        }

        return source.task;
    }];
}

- (BFTask *)downloadConfig {
    BFTaskCompletionSource *source = [BFTaskCompletionSource taskCompletionSource];
    dispatch_async(serialQueue, ^{
        NSLog(@"working on init config, key = %d...", key);

        // Trigger from a different queue
        double delayInSeconds = 1.0;
        dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
        dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
            [source setResult:nil];
        });
    });
    return source.task;
}

- (BFTask *)initializeService {
    BFTaskCompletionSource *source = [BFTaskCompletionSource taskCompletionSource];
    dispatch_async(serialQueue, ^{
        NSLog(@"working on init service, key = %d...", key);

        // Trigger from a different queue
        double delayInSeconds = 1.0;
        dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
        dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
            [source setResult:nil];
        });

        // Set final state
        initialized = TRUE;
    });
    return source.task;
}

- (void)initialize {
    int32_t oldKey = key;
    __block bool reinit = false;

    // Start by chaining it to whatever task is in flight without regard to success
    // Everything should use the serialQueue or serialExecutor for thread safety
    maintask = [[[maintask continueWithExecutor:serialExecutor withBlock:^id(BFTask *task) {
        if (oldKey != key) {
            NSLog(@"key out of date (%d != %d).  reinitializing...", oldKey, key);
            reinit = true;
            return [BFTask cancelledTask];
        }
        return [self downloadConfig];
    }] continueWithExecutor:serialExecutor withSuccessBlock:^id(BFTask *task) {
        if (oldKey != key) {
            NSLog(@"key out of date (%d != %d).  reinitializing...", oldKey, key);
            reinit = true;
            return [BFTask cancelledTask];
        }
        return [self initializeService];
    }] continueWithExecutor:serialExecutor withBlock:^id(BFTask *task) {
        if (oldKey != key) {
            NSLog(@"key out of date (%d != %d).  reinitializing...", oldKey, key);
            reinit = true;
        }

        if (task.error || task.exception || task.isCancelled) {
            if (reinit) {
                [self initialize];
            }
            return nil;
        } else {
            NSLog(@"initService completed = %d", key);
            return nil;
        }
    }];
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    serialQueue = dispatch_queue_create("serial", NULL);
    serialExecutor = [BFExecutor executorWithDispatchQueue:serialQueue];

    // Start with an empty task so all tasks can be strung together without need to initialize
    maintask = [BFTask taskWithResult:nil];

    // Everything related to changing service state should be contained with the serialQueue dispatch queue
    [self setKey:1];
    [self initialize];
    [self setKey:2];
    [self setKey:3];

    dispatch_async(dispatch_get_main_queue(), ^(void){
        [self setKey:4];
    });

    dispatch_async(serialQueue, ^(void){
        [self setKey:5];
    });

    [self setKey:6];

    // Override point for customization after application launch.
    return YES;
}

@end

set key to 1
key out of date (0 != 1).  reinitializing...
key out of date (0 != 1).  reinitializing...
set key to 2
set key to 3
set key to 6
set key to 5
key out of date (1 != 5).  reinitializing...
key out of date (1 != 5).  reinitializing...
working on init config, key = 5...
working on init service, key = 5...
initService completed = 5
set key to 4
working on init config, key = 4...
working on init service, key = 4...
initService completed = 4