UIAlertController和UIImagePickerController的使用

UIAlertController 解释：下拉菜单
UIImagePickerController 解释：照片选取器

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1.UIAlertController

//1.声明UIAlertController *alert = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet];//2.增加一行按钮[alert addAction:[UIAlertAction actionWithTitle:@"拍照" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action)    {//点击按钮相应        NSLog(@"拍照"    );//3.显示[self presentViewController:alert  animated:YES completion:nil];

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2.UIImagePickerController

//1.包含代理< UIImagePickerControllerDelegate>//2.声明（可显示）UIImagePickerController *imagePick = [[UIImagePickerController alloc]init]; [self presentViewController:imagePick animated:YES completion:nil];  //3.设置 imagePick.allowsEditing = YES;    //图片可点击 imagePick.delegate = self;            // 委托代理//4.代理函数（选中相片后执行的操作）- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)image editingInfo:(NSDictionary *)editingInfo{//将UIImageView上的视图设为自己选择的图片    [self.mainImageView setImage:image];//隐藏此视图    [self dismissViewControllerAnimated:YES completion:nil];}