iOS开发-调用系统相机和相册获取照片示例

前言：相信大家都知道大部分的app都是有我的模块的，而在我的模块基本都有用户的头像等信息，并且是可以更改头像的。那么今天小编给大家简单介绍一下iOS开发中如何调用系统相机拍照或者相册获取照片。要获取系统相机或者相册，我们需要使用到 UIImagePickerController 这个类。下面我们来看一下如何实现：

首先，需要遵循 UIImagePickerController 代理的两个协议： <UIImagePickerControllerDelegate, UINavigationControllerDelegate>。为什么是两个协议呢？你按着 command 键，点击 UIImagePickerController 的 delegate 就会发现其实这个代理遵循了两个协议。

#import "HeaderPhotoViewController.h"

@interface HeaderPhotoViewController () <UIImagePickerControllerDelegate, UINavigationControllerDelegate>

@property (nonatomic, strong) UIImageView * imageView;
@end

@implementation HeaderPhotoViewController

- (void)viewDidLoad {
  [super viewDidLoad];
  self.navigationItem.title = @"设置头像";
  self.view.backgroundColor = [UIColor whiteColor];

  [self setNavigation];
  [self addSubviews];
  [self makeConstraintsForUI];
}

#pragma mark - set navigation

- (void)setNavigation {

  self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCamera target:self action:@selector(selectPhoto:)];
}

#pragma mark - navitation item action

- (void)selectPhoto:(UIBarButtonItem *)itemCamera {

  //创建UIImagePickerController对象，并设置代理和可编辑
  UIImagePickerController * imagePicker = [[UIImagePickerController alloc] init];
  imagePicker.editing = YES;
  imagePicker.delegate = self;
  imagePicker.allowsEditing = YES;

  //创建sheet提示框，提示选择相机还是相册
  UIAlertController * alert = [UIAlertController alertControllerWithTitle:@"请选择打开方式" message:nil preferredStyle:UIAlertControllerStyleActionSheet];

  //相机选项
  UIAlertAction * camera = [UIAlertAction actionWithTitle:@"相机" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {

    //选择相机时，设置UIImagePickerController对象相关属性
    imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;
    imagePicker.modalPresentationStyle = UIModalPresentationFullScreen;
    imagePicker.mediaTypes = @[(NSString *)kUTTypeImage];
    imagePicker.cameraCaptureMode = UIImagePickerControllerCameraCaptureModePhoto;
    //跳转到UIImagePickerController控制器弹出相机
    [self presentViewController:imagePicker animated:YES completion:nil];
  }];

  //相册选项
  UIAlertAction * photo = [UIAlertAction actionWithTitle:@"相册" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {

    //选择相册时，设置UIImagePickerController对象相关属性
    imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    //跳转到UIImagePickerController控制器弹出相册
    [self presentViewController:imagePicker animated:YES completion:nil];
  }];

  //取消按钮
  UIAlertAction * cancel = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {

    [self dismissViewControllerAnimated:YES completion:nil];
  }];

  //添加各个按钮事件
  [alert addAction:camera];
  [alert addAction:photo];
  [alert addAction:cancel];

  //弹出sheet提示框
  [self presentViewController:alert animated:YES completion:nil];
}

#pragma mark - add subviews

- (void)addSubviews {

  [self.view addSubview:self.imageView];
}

#pragma mark - make constraints

- (void)makeConstraintsForUI {

  __weak typeof(self)weakSelf = self;

  [_imageView mas_makeConstraints:^(MASConstraintMaker *make) {

    make.size.mas_equalTo(CGSizeMake(Screen_Width, Screen_Width));
    make.centerX.mas_equalTo(weakSelf.view.mas_centerX);
    make.centerY.mas_equalTo(weakSelf.view.mas_centerY);
  }];
}

#pragma mark - imagePickerController delegate

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info {

  [picker dismissViewControllerAnimated:YES completion:nil];
  //获取到的图片
  UIImage * image = [info valueForKey:UIImagePickerControllerEditedImage];
  _imageView.image = image;
}

#pragma mark - setter and getter

- (UIImageView *)imageView {

  if (!_imageView) {

    _imageView = [[UIImageView alloc] init];
    _imageView.backgroundColor = [UIColor greenColor];
    _imageView.contentMode = UIViewContentModeScaleAspectFill;
  }
  return _imageView;
}

@end

OK！demo的所有代码都已经给大家呈现出来了，最后一步就是配置plist文件，千万不要忘了这个，要不会崩的。plist文件里边添加调用相机的字段Privacy - Camera Usage Description 和调用相册的字段：Privacy - Photo Library Usage Description。万事俱备，就差一个测试的苹果手机了，相机的测试需要使用真机测试。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持呐喊教程。

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