函数响应式编程及ReactiveObjC学习笔记 (四)

今天我们继续看其他的类别

UIImagePickerController+RACSignalSupport.h

#import <UIKit/UIKit.h>

@class RACDelegateProxy;
@class RACSignal<__covariant ValueType>;

NS_ASSUME_NONNULL_BEGIN

@interface UIImagePickerController (RACSignalSupport)

@property (nonatomic, strong, readonly) RACDelegateProxy *rac_delegateProxy;

- (RACSignal<NSDictionary *> *)rac_imageSelectedSignal;

@end

NS_ASSUME_NONNULL_END

可以看到它有一个代理属性, 一个信号

再看下它有帮我们代理哪些方法

- (RACSignal *)rac_imageSelectedSignal {
    RACSignal *pickerCancelledSignal = [[self.rac_delegateProxy
        signalForSelector:@selector(imagePickerControllerDidCancel:)]
        merge:self.rac_willDeallocSignal];

    RACSignal *imagePickerSignal = [[[[self.rac_delegateProxy
        signalForSelector:@selector(imagePickerController:didFinishPickingMediaWithInfo:)]
        reduceEach:^(UIImagePickerController *pickerController, NSDictionary *userInfo) {
            return userInfo;
        }]
        takeUntil:pickerCancelledSignal]
        setNameWithFormat:@"%@ -rac_imageSelectedSignal", RACDescription(self)];

    RACUseDelegateProxy(self);

    return imagePickerSignal;
}

一个取消按钮的代理, 一个选择完毕的代理,

我们用来试试看

// 创建一个RACDelegateProxy
    RACDelegateProxy *imgPickerDelegateProxy = [[RACDelegateProxy alloc] initWithProtocol:@protocol(UIImagePickerControllerDelegate)];

    // 绑定取消代理事件
    [[imgPickerDelegateProxy
     rac_signalForSelector:@selector(imagePickerControllerDidCancel:)]
     subscribeNext:^(RACTuple * _Nullable x) {

         NSLog(@"取消代理: %@", x);
         UIImagePickerController *imgPicker = x[];
         [imgPicker dismissViewControllerAnimated:YES completion:nil];
     }];

    // 绑定选择完毕事件
    [[imgPickerDelegateProxy
        rac_signalForSelector:@selector(imagePickerController:didFinishPickingImage:editingInfo:)]
        subscribeNext:^(RACTuple * _Nullable x) {

            NSLog(@"选择完成: %@", x);
            self.view.backgroundColor = [UIColor colorWithPatternImage:x[]];

            UIImagePickerController *imgPicker = x[];
            [imgPicker dismissViewControllerAnimated:YES completion:nil];
        }];

    // 创建UIImagePickerController
    UIImagePickerController *imgPickerController = [[UIImagePickerController alloc] init];
    imgPickerController.sourceType    = UIImagePickerControllerSourceTypePhotoLibrary;
    imgPickerController.allowsEditing = YES;

    // 设置代理为我们创建的delegateProxy
    // 这里注意一般UIImagePickerController需要实现UIImagePickerDelegate & UINavigationControllerDelegate, 但这里用RAC自带的方法只能设置一个代理
    // 不过其实RAC其实也只为UIImagePickerController处理了UIImagePickerControllerDelegate而已, 所以这里会有警告先不管它
    // 后面我们再想想其他方式,  是重新写一个UIImagePickerController分类还是重写方法什么的

    imgPickerController.delegate      = (id<UIImagePickerControllerDelegate>)imgPickerDelegateProxy;

    // retain delegateProxy
    objc_setAssociatedObject(imgPickerController, _cmd, imgPickerDelegateProxy, OBJC_ASSOCIATION_RETAIN_NONATOMIC);

    [self presentViewController:imgPickerController animated:YES completion:nil];

这里大家需要注意下红色字体部分,

点击取消返回的x是imgPickerController本身, 转义后直接拿来dismiss即可

选择图片后x是一个数组, 第一个是imgPickerComtroller, 第二个是选择的image

UISegmentedControl+RACSignalSupport.h

#import <UIKit/UIKit.h>

@class RACChannelTerminal<ValueType>;

NS_ASSUME_NONNULL_BEGIN

@interface UISegmentedControl (RACSignalSupport)

- (RACChannelTerminal<NSNumber *> *)rac_newSelectedSegmentIndexChannelWithNilValue:(nullable NSNumber *)nilValue;

@end

NS_ASSUME_NONNULL_END

可以把分段选择器的选择结果直接绑定给其他空间, 或者拿去做别的 实例代码如下:

// 创建一个UISegementController
    UISegmentedControl *segmentController = [[UISegmentedControl alloc] initWithItems:@[@"One", @"Two"]];
    segmentController.frame = CGRectMake(, , , );
    segmentController.center = self.view.center;

    [self.view addSubview:segmentController];

    // 创建一个UITextField
    UITextField *textField = [[UITextField alloc] initWithFrame:CGRectMake(, , , )];
    textField.center = CGPointMake(self.view.center.x, self.view.center.y + );
    textField.layer.borderWidth = ;
    textField.layer.borderColor = [UIColor blueColor].CGColor;

    [self.view addSubview:textField];

    // 获取segement的channelTerminal
    RACChannelTerminal *segmentTerminal = [segmentController rac_newSelectedSegmentIndexChannelWithNilValue:];

    // 获取textField的channelTerminal
    RACChannelTerminal *textFieldTerminal = [textField rac_newTextChannel];

    // 把segementdeterminal结果处理后绑定给textfieldTerminal
    [[segmentTerminal
        map:^id _Nullable(id  _Nullable value) {

        if ([value  isEqual: @()]) {

            return @"选择了: Two";
        } else {

            return @"选择了: One";
        }
    }]
        subscribe:textFieldTerminal];

UISlider+RACSignalSupport.h

#import <UIKit/UIKit.h>

@class RACChannelTerminal<ValueType>;

NS_ASSUME_NONNULL_BEGIN

@interface UISlider (RACSignalSupport)

- (RACChannelTerminal<NSNumber *> *)rac_newValueChannelWithNilValue:(nullable NSNumber *)nilValue;

@end

NS_ASSUME_NONNULL_END

跟UISegement一样, 我们直接给上代码:

// 创建一个UISlider
    UISlider *slider = [[UISlider alloc] initWithFrame:CGRectMake(, , , )];
    slider.center = self.view.center;

    [self.view addSubview:slider];

    // 创建一个UITextField
    UITextField *textField = [[UITextField alloc] initWithFrame:CGRectMake(, , , )];
    textField.center = CGPointMake(self.view.center.x, self.view.center.y + );
    textField.layer.borderWidth = ;
    textField.layer.borderColor = [UIColor blueColor].CGColor;

    [self.view addSubview:textField];

    // 获取slider的channelTerminal
    RACChannelTerminal *sliderTerminal = [slider rac_newValueChannelWithNilValue:];

    // 获取textField的channelTerminal
    RACChannelTerminal *textFieldTerminal = [textField rac_newTextChannel];

    [[sliderTerminal
        map:^id _Nullable(id  _Nullable value) {

            return [NSString stringWithFormat:@"%@", value];
        }]
        subscribe:textFieldTerminal];

运行截图:

UIStepper+RACSignalSupport.h

#import <UIKit/UIKit.h>

@class RACChannelTerminal<ValueType>;

NS_ASSUME_NONNULL_BEGIN

@interface UIStepper (RACSignalSupport)

- (RACChannelTerminal<NSNumber *> *)rac_newValueChannelWithNilValue:(nullable NSNumber *)nilValue;

@end

NS_ASSUME_NONNULL_END

也是只有一个RACChannelTerminal, 我们直接上代码:

// 创建一个UIStepper
    UIStepper *stepper = [[UIStepper alloc] initWithFrame:CGRectMake(, , , )];
    stepper.center = self.view.center;

    [self.view addSubview:stepper];

    // 创建一个UITextField
    UITextField *textField = [[UITextField alloc] initWithFrame:CGRectMake(, , , )];
    textField.center = CGPointMake(self.view.center.x, self.view.center.y + );
    textField.layer.borderWidth = ;
    textField.layer.borderColor = [UIColor blueColor].CGColor;

    [self.view addSubview:textField];

    // 获取stepper的channelTerminal
    RACChannelTerminal *stepperTerminal = [stepper rac_newValueChannelWithNilValue:];

    // 获取textField的channelTerminal
    RACChannelTerminal *textFieldTerminal = [textField rac_newTextChannel];

    [[stepperTerminal
        map:^id _Nullable(id  _Nullable value) {

            return [NSString stringWithFormat:@"%@", value];
        }]
        subscribe:textFieldTerminal];

运行截图:

UISwitch+RACSignalSupport.h

#import <UIKit/UIKit.h>

@class RACChannelTerminal<ValueType>;

NS_ASSUME_NONNULL_BEGIN

@interface UISwitch (RACSignalSupport)

- (RACChannelTerminal<NSNumber *> *)rac_newOnChannel;

@end

NS_ASSUME_NONNULL_END

示例:

// 创建一个UISwitch
    UISwitch *aswitch = [[UISwitch alloc] initWithFrame:CGRectMake(, , , )];
    aswitch.center = self.view.center;

    [self.view addSubview:aswitch];

    // 创建一个UITextField
    UITextField *textField = [[UITextField alloc] initWithFrame:CGRectMake(, , , )];
    textField.center = CGPointMake(self.view.center.x, self.view.center.y + );
    textField.layer.borderWidth = ;
    textField.layer.borderColor = [UIColor blueColor].CGColor;

    [self.view addSubview:textField];

    // 获取aswitch的channelTerminal
    RACChannelTerminal *aswitchTerminal = [aswitch rac_newOnChannel];

    // 获取textField的channelTerminal
    RACChannelTerminal *textFieldTerminal = [textField rac_newTextChannel];

    [[aswitchTerminal
        map:^id _Nullable(id  _Nullable value) {

            if ([value boolValue]) {

                return @"";
            }

            return @"";
        }]
     subscribe:textFieldTerminal];

UITableViewCell+RACSignalSupport.h

#import <UIKit/UIKit.h>

@class RACSignal<__covariant ValueType>;
@class RACUnit;

NS_ASSUME_NONNULL_BEGIN

@interface UITableViewCell (RACSignalSupport)

@property (nonatomic, strong, readonly) RACSignal<RACUnit *> *rac_prepareForReuseSignal;

@end

NS_ASSUME_NONNULL_END

有一个rac_prepareForReuseSignal属性, 看字面意思就很清除准备复用时调用

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell"];
    if (!cell) {

        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"Cell"];
    }

    cell.textLabel.text = @"cell";

    [[cell
        rac_prepareForReuseSignal]
        subscribeNext:^(RACUnit * _Nullable x) {

            NSLog(@"开始复用");
        }];

    return cell;
}

UITableViewHeaderFooterView+RACSignalSupport.h

#import <UIKit/UIKit.h>

@class RACSignal<__covariant ValueType>;
@class RACUnit;

NS_ASSUME_NONNULL_BEGIN

// This category is only applicable to iOS >= 6.0.
@interface UITableViewHeaderFooterView (RACSignalSupport)

@property (nonatomic, strong, readonly) RACSignal<RACUnit *> *rac_prepareForReuseSignal;

@end

NS_ASSUME_NONNULL_END

这个也是一样就不举例了

今天先看这些,  后面我们再继续