UIImagePickerController概述：
UIImagePickerController 類是獲取選擇圖片和視頻的用戶接口戏阅。我們可以用這個controller選擇我們所需要的圖片和視頻。對于這個類來說比較特殊蕾殴，我們不能夠任意定制笑撞，也不可以繼承生成子類。
我們在用UIImagePickerController類的時候钓觉，只需要調用用代碼實現(xiàn)其在什么位置顯示和開始茴肥，當然我們之后可以選擇所需的圖片和影片，或者也可以不選擇點擊取消即可荡灾。
但是在我們調用接口之前瓤狐，我們需要確認：
一：當前設備是否支持使用UIImagePickerController，這個時候我們需要調用isSourceTypeAvailable:方法判斷批幌。
二：查看符合的媒體類型（圖片或者視頻）础锐，這個時候我們調用availableMediaTypesForSourceType: 方法判斷。
同時使用UIImagePickerController時逼裆，我們需要UIImagePickerControllerDelegate協(xié)議代理實現(xiàn)一些特定時間特定的動作郁稍。在調用攝像頭的時候我們可以選擇使用閃光燈，但是默認條件下對視頻有10分鐘的限制胜宇，需要用videoMaximumDuration屬性更改默認時間耀怜，三：之后我們設定界面媒體的屬性
1：sourceType //從哪選取媒體
enum {
UIImagePickerControllerSourceTypePhotoLibrary,
UIImagePickerControllerSourceTypeCamera,
UIImagePickerControllerSourceTypeSavedPhotosAlbum
};
typedef NSUInteger UIImagePickerControllerSourceType;
2: mediaTypes
mediaTypes用來確定再picker里顯示那些類型的多媒體文件，圖片桐愉？視頻财破？
+ (NSArray *)availableMediaTypesForSourceType:(UIImagePickerControllerSourceType)sourceType
一共有三個可選的代理方法UIImagePickerControllerDelegate
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info;
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker;
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)image editingInfo:(nullable NSDictionary<NSString *,id> *)editingInfo NS_DEPRECATED_IOS(2_0, 3_0);
-(void) pick{
[imagePicker takePicture];
}
- (IBAction)press:(id)sender {
imagePicker = ［UIImagePickerController alloc] init];
imagePicker.delegate = self;
imagePicker.mediaTypes = [UIImagePickerController availableMediaTypesForSourceType:UIImagePickerControllerSourceTypeCamera];
imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;
imagePicker.showsCameraControls = NO;
UIView* view = ［UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 44)];
view.backgroundColor = [UIColor redColor];
UIButton* button = ［UIButton alloc] initWithFrame:CGRectMake(0, 0, 40, 40)];
button.backgroundColor = [UIColor blueColor];
[button addTarget:self action:@selector(pick) forControlEvents:UIControlEventTouchUpInside];
[view addSubview:button];
CGRect newFrame = CGRectMake(0.0,436,320,44);
view.frame = newFrame;
imagePicker.cameraOverlayView = view;
[self presentModalViewController:imagePicker animated:YES];
}
-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
if (［info objectForKey:UIImagePickerControllerMediaType] isEqualToString:(NSString*)kUTTypeImage]) {
UIImage* image = [info objectForKey:UIImagePickerControllerOriginalImage];
UIImageWriteToSavedPhotosAlbum(image, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);
} else if (［info objectForKey:UIImagePickerControllerMediaType] isEqualToString:(NSString*)kUTTypeMovie]) {
NSString* path = ［info objectForKey:UIImagePickerControllerMediaURL] path];
UISaveVideoAtPathToSavedPhotosAlbum(path, self, @selector(video:didFinishSavingWithError:contextInfo:), nil);
}
[picker dismissModalViewControllerAnimated:YES];
}
-(void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
{
[picker dismissModalViewControllerAnimated:YES];
}
