文章目錄
前言
- 爲了寫圖像識別，需要能通過相冊和照相機獲取照片，因此學習一下UIImagePickerController
關於UINavigationControllerDelegate
-
在使用UIImagePickerController時需要遵守<UIImagePickerControllerDelegate, UINavigationControllerDelegate>
-
原因要看一下UIImagePickerController的定義
@interface UIImagePickerController : UINavigationController <NSCoding>
@property(nullable,nonatomic,weak) id <UINavigationControllerDelegate, UIImagePickerControllerDelegate> delegate;
- UIImagePickerController本身就是繼承於UINavigationController的
- 同時delegate的申明裏也寫清楚了要遵守這兩個協議
- 猜測可能是因爲 UIImagePickerController本身就設計了工具欄的變化
初始化UIImagePickerController卡頓
- 執行self.imagePickerController = [[UIImagePickerController alloc] init];初始化時，模擬機直接出現了3，4秒的卡頓
- 在stack overflow上同樣有人遇到這個問題UIImagePickerController really slow when calling alloc init
- 高贊回答說只要demo不是debug model也就是不是通過Xcode運行就沒事，經過測試，這是真的
- 剩下的就很直接的異步就完事了
- 所以最後覺得這一塊改不改無所謂
檢驗相冊是否可用
+ (BOOL)isSourceTypeAvailable:(UIImagePickerControllerSourceType)sourceType; // returns YES if source is available (i.e. camera present)
if (![UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]) {
return;
}
//判斷打開相冊是否可用
返回NO的幾種可能性
- 模擬機上沒有照相機可以開啓，需要使用真機
- 在Info.plist裏沒有增加key
- 沒有鎖定豎屏
UIImagePickerControllerDelegate
#pragma mark - UIImagePickerControllerDelegate
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<UIImagePickerControllerInfoKey,id> *)info {
//銷燬控制器
[picker dismissViewControllerAnimated:YES completion:nil];
//設置圖片
self.testImageView = [[UIImageView alloc] init];
_testImageView.image = info[UIImagePickerControllerOriginalImage];
NSLog(@"%@FAILQSTZZ", _testImageView.image);
}
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker {
NSLog(@"FAILQSTSD");
[self dismissViewControllerAnimated:YES completion:nil];
}