JRAlertController

JRAlertController：基于apple的UIAlertController控件api，用swift重新打造的UI控件，更符合主流app的风格。

JRAlertController总体效果图

UIAlertController 历史

在日常iOS开发中，我们经常能遇到这种情况（我们需要在某个地方让用户做一个选择），比如说：一个博客，点击右上角的按钮后，你可以执行“修改博客”、“删除博客”两个操作。既然是这么常用的操作，Apple当然给我们提供了常用的控件，那就是UIAlertController。

UIAlertController自iOS8出现，在那之前，我们用的是UIAlertView和UIActionSheet。iOS8之后，UIAlertView与UIActionSheet合并为UIAlertController，并以一个style属性来区分原来的UIAlertView和UIActionSheet的作用，还有就是用闭包回调的方式代替了之前的代理（我觉得闭包回调的方式写起来方便多了）。

UIAlertController 不足

那么既然UIAlertController已经是在iOS8优化后的控件（至少api上优化了），那么为何还来个JRAlertController呢？

在开发中我们会发现，UIAlertController有以下几个不足之处：

1.无论是alert还是sheet下的界面，边角过于圆滑，尤其当style是sheet的时候，从底部弹出来那么一个过于圆滑的界面，反正我不觉得好看，不信你看微博、微信这些主流app是怎么做的
微博的效果：

2.点击背景部分，无法dismiss UIAlertController

3.alert样式下，添加过多的UITextField和Action后，界面显示丑陋。（虽然不会有这种需求，也不该在UIAlertController过量添加，毕竟UIAlertController适用于”短暂”操作，但是过多添加后，界面确实不好看，后面会有效果图）

基于以上几点不足，我认为足以自定义一个控件来代替UIAlertController，所以JRAlertController诞生了。

JRAlertController 与 UIAlertController 的不同

我在开头提到过UIAlertController的api,它的api还是不错的，所以我在写JRAlertController的时候，几乎完全采用了UIAlertController的api，一方面api不错，另一方面方便大家从UIAlertController迁移到JRAlertController，基本上你只需要把原来UIAlertController部分的UI开头的改成JR就可以了，我提供的Demo中，大家便能很清晰的看到这一点。

还有的几处不同点：

// UIAlertController 的初始化方法
public convenience init(title: String?, message: String?, preferredStyle: UIAlertControllerStyle)

// JRAlertController 的初始化方法
public convenience init(title: String? = nil, message: String? = nil, preferredStyle: JRAlertControllerStyle = .actionSheet)

你会发现，JRAlertController提供了title参数和message参数的默认值，恩……如果你不需要title或message中的某一个（或都不需要），这样可以帮你少写一点点代码。

// UIAlertController进入方法
// 这里的alertController为UIAlertController的实例，self为当前UIViewController
self.present(alertController, animated: true, completion: nil)

// JRAlertController进入方法
// 这里的alertController为JRAlertController的实例，self为当前UIViewController
alertController.jr_show(onRootView: self)

至于这里为什么要做，这里涉及到JRAlertController从底部上移的动画效果。（目前我能想到的方法是在JRAlertController的viewWillAppear中执行一个上移动画，如果调用系统的present进入的话，如果又给animated参数设置true，那么JRAlertController的进入效果会比较丑陋。可能有朋友会问，为什么不使用iOS的转场动画，我有尝试去用过，但是也需要第一个执行present的UIViewController做很多其他的动作，写更多的代码。如果有朋友看了我的代码后，有更好的方式来处理进入效果，欢迎到本项目的Github地址来Pull requests）

3.
UIAlertController里面有一个属性preferredAction，要求系统版本至少为iOS9。而在JRAlertController中，你只需要在iOS8下就可以使用了（如果不是UIViewController的modalPresentationStyle属性的.overCurrentContext值要求iOS8，我们就可以兼容到iOS7了）

JRAlertController 与 UIAlertController 相同点以及说明

因为JRAlertController是采用几乎和UIAlertController一样的api来实现的，所以JRAlertController的大体功能效果会和UIAlertController一样。同时也是为了方便打算使用JRAlertController的朋友们能够在迁移到JRAlertController的时候没有后顾之忧。

他们的相同点说明：

1.只有alert样式下，才可以添加UITextField。

2.action也有样式，但是cancel样式的action只能添加一个，添加多了assert。

3.preferredAction属性也只能在alert样式下才能使用。

以上三点别问我为什么这么规定，Apple的UIAlertController就是这么定的。

其他说明：

1.JRAlertController的preferredAction属性补充说明：除了只能在alert样式下才能使用外，如果存在UITextField，那么在UITextField列表的最后一个UITextField的键盘中点击return按钮，将触发preferredAction回调，并且dismiss当前JRAlertController。

2.JRAlertController里面会有一个属性是这样的：open var textFields: [UITextField]?。所有你添加的UITextField都会在这里。注意的是，JRAlertController已经对所以添加的UITextField进行了代理操作。如果你覆盖了代理，影响也不是很大，但是至少会影响你以下两点：

①.在UITextField中点击键盘上return按钮时无法从当前UITextField进入到下一个UITextField。
②.如果当前UITextField已经是最后一个UITextField，同时你又设置了preferredAction，则无法触发preferredAction的回调，以及无法dismiss当前JRAlertController。

3.如果需要在JRAlertController里，主动dismiss，建议调用jr_dismiss()。

JRAlertController 与 UIAlertController Gif图效果对比

说了那么多，来几张效果图对比下JRAlertController与UIAlertController的区别

JRAlertController 实现效果图

JRAlertController在alert样式下简单显示

JRAlertController在alert样式下复杂显示

JRAlertController在sheet样式下简单显示

JRAlertController在sheet样式下复杂显示

UIAlertController 实现效果图

UIAlertController在alert样式下简单显示

UIAlertController在alert样式下复杂显示

UIAlertController在sheet样式下简单显示

UIAlertController在sheet样式下复杂显示

以上就是对JRAlertController的一些说明，下面放是官方性信息：

Requirements

iOS 8.0+
Xcode 8.0+
Swift 3.0+

Installation

CocoaPods

CocoaPods is a dependency manager for Cocoa projects. You can install it with the following command:

1	$ gem install cocoapods

CocoaPods 1.1.0+ is required to build JRAlertController 1.0.0

To integrate JRAlertController into your Xcode project using CocoaPods, specify it in your Podfile:

source 'https://github.com/CocoaPods/Specs.git'
platform :ios, '8.0'
use_frameworks!

target '<Your Target Name>' do
    pod 'JRAlertController', '~> 1.0。0'
end

Then, run the following command:

1	$ pod install

Manually

If you prefer not to use either of the aforementioned dependency managers, you can integrate JRAlertController into your project manually.

Embedded Framework

Open up Terminal, cd into your top-level project directory, and run the following command “if” your project is not initialized as a git repository:
1
$ git init
Add JRAlertController as a git submodule by running the following command:
1
$ git submodule add https://github.com/Jiar/JRAlertController.git
Open the new JRAlertController folder, and drag the JRAlertController.xcodeproj into the Project Navigator of your application’s Xcode project.

It should appear nested underneath your application’s blue project icon. Whether it is above or below all the other Xcode groups does not matter.
Select the JRAlertController.xcodeproj in the Project Navigator and verify the deployment target matches that of your application target.
Next, select your application project in the Project Navigator (blue project icon) to navigate to the target configuration window and select the application target under the “Targets” heading in the sidebar.
In the tab bar at the top of that window, open the “General” panel.
Click on the + button under the “Embedded Binaries” section.
You will see two different JRAlertController.xcodeproj folders each with two different versions of the JRAlertController.framework nested inside a Products folder.

It does not matter which Products folder you choose from, but it does matter whether you choose the top or bottom JRAlertController.framework.
Select the top JRAlertController.framework for iOS.
And that’s it!

The JRAlertController.framework is automagically added as a target dependency, linked framework and embedded framework in a copy files build phase which is all you need to build on the simulator and a device.

Usage

JRAlertController_alert_simple

let alertController = JRAlertController(title: "login tip", message: "please input account and password", preferredStyle: .alert)
let cancelAction = JRAlertAction(title: "cancel", style: .cancel, handler:  {
    (action: JRAlertAction!) -> Void in
    print("cancel")
})
let loginAction = JRAlertAction(title: "login", style: .default, handler: {
    (action: JRAlertAction!) -> Void in
    print("login")
})
alertController.addAction(cancelAction)
alertController.addAction(loginAction)
alertController.addTextField(configurationHandler: { (textField: UITextField) -> Void in
    textField.keyboardType = .default
    textField.placeholder = "please input account"
})
alertController.addTextField(configurationHandler: { (textField: UITextField) -> Void in
    textField.keyboardType = .default
    textField.isSecureTextEntry = true
    textField.placeholder = "please input password"
})
// must use this function to show JRAlertController
// self is a UIControllerView
alertController.jr_show(onRootView: self)

JRAlertController_alert_multiple

let alertController = JRAlertController(title: "I am title,I am title,I am title,I am title,I am title", message: "I am message, I am message, I am message, I am message, I am message, I am message, I am message, I am message, I am message", preferredStyle: .alert)
let cancelAction = JRAlertAction(title: "cancel", style: .cancel, handler:  {
    (action: JRAlertAction!) -> Void in
    print("cancel")
})
let deleteAction = JRAlertAction(title: "delete", style: .destructive, handler: {
    (action: JRAlertAction!) -> Void in
    print("delete")
})
let archiveAction = JRAlertAction(title: "archive", style: .default, handler: {
    (action: JRAlertAction!) -> Void in
    print("archive")
})
let archiveAction1 = JRAlertAction(title: "archive1", style: .default, handler: {
    (action: JRAlertAction!) -> Void in
    print("archive1")
})
let archiveAction2 = JRAlertAction(title: "archive2", style: .default, handler: {
    (action: JRAlertAction!) -> Void in
    print("archive2")
})
let archiveAction3 = JRAlertAction(title: "archive3", style: .default, handler: {
    (action: JRAlertAction!) -> Void in
    print("archive3")
})
let archiveAction4 = JRAlertAction(title: "archive4", style: .default, handler: {
    (action: JRAlertAction!) -> Void in
    print("archive4")
})
let archiveAction5 = JRAlertAction(title: "archive5", style: .default, handler: {
    (action: JRAlertAction!) -> Void in
    print("archive5")
})
let archiveAction6 = JRAlertAction(title: "archive6", style: .default, handler: {
    (action: JRAlertAction!) -> Void in
    print("archive6")
})
alertController.addAction(cancelAction)
alertController.addAction(deleteAction)
alertController.addAction(archiveAction)
alertController.addTextField(configurationHandler: { (textField: UITextField) -> Void in
    textField.textColor = .black
    textField.text = "black"
})
alertController.addTextField(configurationHandler: { (textField: UITextField) -> Void in
    textField.textColor = .darkGray
    textField.text = "darkGray"
})
alertController.addTextField(configurationHandler: { (textField: UITextField) -> Void in
    textField.textColor = .lightGray
    textField.text = "lightGray"
})
alertController.addTextField(configurationHandler: { (textField: UITextField) -> Void in
    textField.backgroundColor = .black
    textField.textColor = .white
    textField.text = "white"
})
alertController.addTextField(configurationHandler: { (textField: UITextField) -> Void in
    textField.textColor = .gray
    textField.text = "gray"
})
alertController.addTextField(configurationHandler: { (textField: UITextField) -> Void in
    textField.textColor = .red
    textField.text = "red"
})
alertController.addAction(archiveAction1)
alertController.addAction(archiveAction2)
alertController.addTextField(configurationHandler: { (textField: UITextField) -> Void in
    textField.textColor = .green
    textField.text = "green"
})
alertController.addTextField(configurationHandler: { (textField: UITextField) -> Void in
    textField.textColor = .blue
    textField.text = "blue"
})
alertController.addTextField(configurationHandler: { (textField: UITextField) -> Void in
    textField.textColor = .cyan
    textField.text = "cyan"
})
alertController.addTextField(configurationHandler: { (textField: UITextField) -> Void in
    textField.textColor = .yellow
    textField.text = "yellow"
})
alertController.addTextField(configurationHandler: { (textField: UITextField) -> Void in
    textField.textColor = .magenta
    textField.text = "magenta"
})
alertController.addTextField(configurationHandler: { (textField: UITextField) -> Void in
    textField.textColor = .orange
    textField.text = "orange"
})
alertController.addTextField(configurationHandler: { (textField: UITextField) -> Void in
    textField.textColor = .purple
    textField.text = "purple"
})
alertController.addTextField(configurationHandler: { (textField: UITextField) -> Void in
    textField.textColor = .brown
    textField.text = "brown"
})
alertController.addAction(archiveAction3)
alertController.addAction(archiveAction4)
alertController.addAction(archiveAction5)
alertController.addAction(archiveAction6)
alertController.preferredAction  = archiveAction6
// must use this function to show JRAlertController
// self is a UIControllerView
alertController.jr_show(onRootView: self)

JRAlertController_sheet_simple

      let alertController = JRAlertController(title: "blog tip", message: "Please select the option to use the corresponding option to operate your blog", preferredStyle: .actionSheet)
// let alertController = JRAlertController(title: "blog tip")
// let alertController = JRAlertController(message: "Please select the option to use the corresponding option to operate your blog")
// let alertController = JRAlertController()
      let addAction = JRAlertAction(title: "add", style: .default, handler: {
          (action: JRAlertAction!) -> Void in
          print("add blog")
      })
      let modifyAction = JRAlertAction(title: "modify", style: .default, handler: {
          (action: JRAlertAction!) -> Void in
          print("modify blog")
      })
      let deleteAction = JRAlertAction(title: "delete", style: .destructive, handler: {
          (action: JRAlertAction!) -> Void in
          print("delete blog")
      })
      let cancelAction = JRAlertAction(title: "cancel", style: .cancel, handler:  {
          (action: JRAlertAction!) -> Void in
          print("cancel")
      })
      alertController.addAction(addAction)
      alertController.addAction(modifyAction)
      alertController.addAction(deleteAction)
      alertController.addAction(cancelAction)
      // must use this function to show JRAlertController
      // self is a UIControllerView
      alertController.jr_show(onRootView: self)

JRAlertController_sheet_multiple

let alertController = JRAlertController(title: "I am title,I am title,I am title,I am title,I am title", message: "I am message, I am message, I am message, I am message, I am message, I am message, I am message, I am message, I am message", preferredStyle: .actionSheet)
let cancelAction = JRAlertAction(title: "cancel", style: .cancel, handler: nil)
let deleteAction = JRAlertAction(title: "delete", style: .destructive, handler: nil)
let archiveAction = JRAlertAction(title: "archive", style: .default, handler: {
    (action: JRAlertAction!) -> Void in
    print("archive")
})
let archiveAction1 = JRAlertAction(title: "archive1", style: .default, handler: {
    (action: JRAlertAction!) -> Void in
    print("archive1")
})
let archiveAction2 = JRAlertAction(title: "archive2", style: .default, handler: {
    (action: JRAlertAction!) -> Void in
    print("archive2")
})
let archiveAction3 = JRAlertAction(title: "archive3", style: .default, handler: {
    (action: JRAlertAction!) -> Void in
    print("archive3")
})
let archiveAction4 = JRAlertAction(title: "archive4", style: .default, handler: {
    (action: JRAlertAction!) -> Void in
    print("archive4")
})
let archiveAction5 = JRAlertAction(title: "archive5", style: .default, handler: {
    (action: JRAlertAction!) -> Void in
    print("archive5")
})
let archiveAction6 = JRAlertAction(title: "archive6", style: .default, handler: {
    (action: JRAlertAction!) -> Void in
    print("archive6")
})
alertController.addAction(cancelAction)
alertController.addAction(deleteAction)
alertController.addAction(archiveAction)
alertController.addAction(archiveAction1)
alertController.addAction(archiveAction2)
alertController.addAction(archiveAction3)
alertController.addAction(archiveAction4)
alertController.addAction(archiveAction5)
alertController.addAction(archiveAction6)
// must use this function to show JRAlertController
// self is a UIControllerView
alertController.jr_show(onRootView: self)

License

JRAlertController is released under the Apache-2.0 license. See LICENSE for details.

结束语

本文完，大家如何喜欢JRAlertController，欢迎来JRAlertController对本项目Star。读者在阅读本文时如有发现错误或不恰当指出，欢迎在评论中指出。如果读者还有一些相关方面的疑问，也欢迎在评论中提出。

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