Meme App with UIKit

APP里用到的相关的UIKit

• UIImagePickerController
• UIActivityViewController
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隐藏status bar

在info.plist中添加属性
1.View controller-based status bar appearance 并设置为No

2. 在代码内开关statusBar

UIApplication.sharedApplication().statusBarHidden = true

UIImagePickerController

用来呈现相册或者直接调用摄像头
通过调整sourceType来切换相册或者摄像头

private func pickUpAnImage(source:UIImagePickerControllerSourceType){        let imagePickerVC = UIImagePickerController()        imagePickerVC.delegate = self        imagePickerVC.sourceType = source        presentViewController(imagePickerVC, animated: true, completion: nil)    }

设置textField文本属性

利用defaultTextAttributes属性

let memeTextAttributes = [        NSStrokeColorAttributeName: UIColor.blackColor(),        NSForegroundColorAttributeName: UIColor.whiteColor(),        NSFontAttributeName: UIFont(name: "HelveticaNeue-CondensedBlack", size: 40)!,        NSStrokeWidthAttributeName: -3.0    ]topTextField.defaultTextAttributes = memeTextAttributes

在 Nav Bar中添加button item

1. 在 storyboard中添加navigation item 并且与对应的viewController作outlet
2. 调用navItem来添加button

navItem.leftBarButtonItem = UIBarButtonItem(barButtonSystemItem: .Action, target: self, action: #selector(shareYourMeme))        navItem.rightBarButtonItem = UIBarButtonItem(title: "Cancel", style: .Plain, target: self, action: #selector(cancelMeme))

使用UIGraphics来绘图制作UIImage

private func generateMemedImage() -> UIImage {        //hide toolbar and navbar        configureBars(true)        //UIGraphicsBeginImageContext(self.view.frame.size)        UIGraphicsBeginImageContextWithOptions(self.view.frame.size, false, 0)        view.drawViewHierarchyInRect(self.view.frame, afterScreenUpdates: true)        let memedImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()        UIGraphicsEndImageContext()        //show navbar and toolbar        configureBars(false)        return memedImage    }

利用NSNotification来处理屏幕和键盘的关系

普通Notification流程
1. 定义通知的Key
2. 将通知 Post到NSNotificationCenter.defaultCenter()上
3. 添加在NSNotificationCenter.defaultCenter()上添加observers
4. 定义Observer收到Notification时的方法

在这里我们用系统定义好的

UIKeyboardWillShowNotification
UIKeyboardWillHideNotification

//compute keyboard height and change frame    var oldKeyboard:CGFloat = CGFloat(0)    func keyboardWillShow(notification: NSNotification){        if  bottomTextField.isFirstResponder(){            let newKeyBoard = getKeyboardHeight(notification)            if keyboardHasOnScreen{                view.frame.origin.y += oldKeyboard            }            view.frame.origin.y -= newKeyBoard            oldKeyboard = newKeyBoard            keyboardHasOnScreen = true        }    }    func keyboardWillHide(notification: NSNotification){        if keyboardHasOnScreen && bottomTextField.isFirstResponder(){            view.frame.origin.y += getKeyboardHeight(notification)            keyboardHasOnScreen = false        }    }    private func getKeyboardHeight(notification: NSNotification) -> CGFloat {        let userInfo = notification.userInfo        let keyboardSize = userInfo![UIKeyboardFrameEndUserInfoKey] as! NSValue        return keyboardSize.CGRectValue().height    }    //noticifations    func subscribeToKeyboardNotifications(){        NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(MemeEditorViewController.keyboardWillShow(_:)), name: UIKeyboardWillShowNotification, object: nil)        NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(MemeEditorViewController.keyboardWillHide(_:)), name: UIKeyboardWillHideNotification, object: nil)    }    func unsubscribeFromKeyboardNotifications() {        NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillShowNotification, object: nil)        NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillHideNotification, object: nil)    }

TableViewController & CollectionView

自定义化Cell

1. 在storyBoard中在tableViewcell中设置为custom，设置Identifier,并且摆放部件. 在collectionViewCell中设置Identifier,并且摆放部件
2. 添加一个对应的Cell的文件，并且与刚刚在storyBoard创建的view建立outlets
3. 在各自设置cell的delegate函数中使用刚刚定义的identifier来取得cell并且转化成对应的type

let cell = tableView.dequeueReusableCellWithIdentifier("SentMemesTableViewCell") as! SentMemesTableViewCelllet cell = collectionView.dequeueReusableCellWithReuseIdentifier(reuseIdentifier, forIndexPath: indexPath) as! SentMemesCollectionViewCell

经常需要完成的delegate（前俩是必须要完成的）

设置collectionView Item之间的布局

使用UICollectionViewFlowLayout

将storyboard中的collectionViewCell的flowLayout与你的controller先做出outlet

//MARK: Outlets    @IBOutlet weak var flowLayout: UICollectionViewFlowLayout!

然后通过flowLayout来定义Item之间的最小间距，行/列最小间距，以及ItemSize

flowLayout.minimumLineSpacing = itemSpcaeflowLayout.minimumInteritemSpacing = itemSpcae

利用
UIInterfaceOrientationIsLandscape(UIApplication.sharedApplication().statusBarOrientation)来判断屏幕旋转后的方向

private func adjustCellSize(space: CGFloat){        var dimensison = (view.frame.size.width - 2 * space) / 3        if UIInterfaceOrientationIsLandscape(UIApplication.sharedApplication().statusBarOrientation){            dimensison = (view.frame.size.width - 4 * space) / 5        }        flowLayout.itemSize = CGSizeMake(dimensison, dimensison)    }

用viewWillLayoutSubviews()来相应屏幕旋转并重新利用flowLayout来调节itemSize

override func viewWillLayoutSubviews() {        adjustCellSize(itemSpcae)    }

unwind Segue

1.在目的地controller中做一个@IBaction

@IBAction func backToMemeList(segue: UIStoryboardSegue){        self.navigationController?.popViewControllerAnimated(true)    }

1. 在storyboard中创建unwind segue
   

3.调用segue,

self.performSegueWithIdentifier("backToMemeList", sender: self)