Swift学习笔记(4)使用UIImagePickerController实现从设备图片库和照相机获取图片
设备图片库和照相机是图像的两个重要来源,使用UIKit中提供的图像选择器UIImagePickerController可以轻易地实现从设备图片库和照相机获取图片。
目录
声明协议
UIViewController需声明实现如下两个协议
class viewController: UIViewController , UIImagePickerControllerDelegate , UINavigationControllerDelegate{
...
}
创建UIImagePickerController
定义一个UIImagePickerController
var imagePicker:UIImagePickerController!
创建一个UIButton,在其IBAction中添加代码
设备图片库:
if self.imagePicker == nil{
self.imagePicker = UIImagePickerController()
}
self.imagePicker.delegate = self
//设置图片来源为设备图片库
self.imagePicker.sourceType = .PhotoLibrary
self.presentViewController(self.imagePicker, animated: true, completion: nil)
照相机:
if UIImagePickerController.isSourceTypeAvailable(.Camera){
if self.imagePicker == nil{
self.imagePicker = UIImagePickerController()
}
self.imagePicker.delegate = self
//设置图片来源为相机
self.imagePicker.sourceType = .Camera
self.presentViewController(self.imagePicker, animated: true, completion: nil)
}
else{
//弹出警告框
let errorAlert = UIAlertController(title: "相机不可用", message: "", preferredStyle: UIAlertControllerStyle.Alert)
let cancelAction = UIAlertAction(title: "确定", style: UIAlertActionStyle.Cancel, handler: nil)
errorAlert.addAction(cancelAction)
self.presentViewController(errorAlert, animated: true, completion: nil)
}
UIImagePickerControllerDelegate委托
取消图片获取:
func imagePickerControllerDidCancel(picker: UIImagePickerController) {
self.imagePicker = nil
self.dismissViewControllerAnimated(true, completion: nil)
}
完成图片获取:
func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) {
//从info中取出获取的原始图片
let image = info[UIImagePickerControllerOriginalImage] as! UIImage
self.imageView.image = image
//设置图片显示模式
self.imageView.contentMode = .ScaleAspectFill
self.imagePicker.delegate = nil
self.dismissViewControllerAnimated(true, completion: nil)
}
UINavigationControllerDelegate协议
以下两个协议可以根据需求来选择是否实现
- navigationController:willShowViewController:animated
- navigationController:didShowViewController:animated
图片编辑
如果要将原始图片进行编辑如缩放,裁剪等后再使用
则在创建UIImagePickerController时添加:
self.imagePicker.allowsEditing = true
然后将实现UIImagePickerControllerDelegate中的
let image = info[UIImagePickerControllerOriginalImage] as! UIImage
改为
let image = info[UIImagePickerControllerEditedImage] as! UIImage
iOS 9 中的新错误
如果在iOS 9 Xcode 7.1 以上的版本运行可能会报以下错误
_BSMachError: (os/kern) invalid capability (20)
_BSMachError: (os/kern) invalid name (15)
解决方法:
打开Info.plist,将Localization native development region中的值由en改为United States