OC-UI阶段学习15-UIImagePickerController,照片选择器

一、UIImagePickerController

这个文章大部分摘别人的，自己总结下来更方便用一点

UIImagePickerController是系统提供的用来获取图片和视频的接口

获取的途径为相机，图库，相册

分为以下几个步骤：

1. 初始化UIImagePickerController 类；

2. 设置UIImagePickerController 实例的数据来源类型（下面解释）；

3. 设置代理；

4. 如果需要做图片修改的话设置allowsEditing =yes。

数据来源的类型有三种

enum {
   UIImagePickerControllerSourceTypePhotoLibrary ,//来自图库
   UIImagePickerControllerSourceTypeCamera ,//来自相机
   UIImagePickerControllerSourceTypeSavedPhotosAlbum //来自相册
};

用之前要检测设备是否支持

 if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
    {
        NSLog(@"支持相机");
    }
    if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary])
    {
        NSLog(@"支持图库");
    }
    if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeSavedPhotosAlbum])
    {
        NSLog(@"支持相片库");
    }

二、UIImagePickerController属性详解：

    //指定使用照相机模式,可以指定使用相册／照片库
    imagepicker.sourceType = UIImagePickerControllerSourceTypeCamera;

    //设置当拍照完或在相册选完照片后，是否跳到编辑模式进行图片剪裁。只有当showsCameraControls属性为true时才有效果
    imagepicker.allowsEditing = YES;

    //设置拍照时的下方的工具栏是否显示，如果需要自定义拍摄界面，则可把该工具栏隐藏
    imagepicker.showsCameraControls  = YES;

    //设置使用后置摄像头，可以使用前置摄像头
    imagepicker.cameraDevice = UIImagePickerControllerCameraDeviceRear;
    //设置闪光灯模式
    /*
     typedef NS_ENUM(NSInteger, UIImagePickerControllerCameraFlashMode) {
     UIImagePickerControllerCameraFlashModeOff  = -1,
     UIImagePickerControllerCameraFlashModeAuto = 0,
     UIImagePickerControllerCameraFlashModeOn   = 1
     };
     */
    imagepicker.cameraFlashMode = UIImagePickerControllerCameraFlashModeAuto;
    //设置相机支持的类型，拍照和录像
    imagepicker.mediaTypes = @[(NSString*)kUTTypeImage,(NSString*)kUTTypeMovie];

    //设置拍摄时屏幕的view的transform属性，可以实现旋转，缩放功能
   // imagepicker.cameraViewTransform = CGAffineTransformMakeRotation(M_PI*45/180);
   // imagepicker.cameraViewTransform = CGAffineTransformMakeScale(1.5, 1.5);
    //所有含有cameraXXX的属性都必须要sourceType是UIImagePickerControllerSourceTypeCamera时设置才有效果，否则会有异常

 //设置UIImagePickerController的代理
    imagepicker.delegate = self;

-(void)showCamera{
    //用模态方式呈现imagepicker，这个方法之后就会跳到对应的源位置，相机或者相册图库
    [self presentModalViewController:imagepicker animated:YES];

}

代理方法

当用户选取完成后调用；

- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker;

当用户取消选取时调用；

- (void)imagePickerController:(UIImagePickerController *)picker
 didFinishPickingMediaWithInfo:(NSDictionary *)info;

最后是我自己的实现，一般也就这么用了，点击相框进入相册，选一张图点choose，出来后相框就是选择的图了

//
#import "ThirdViewController.h"

//签订协议
@interface ThirdViewController ()<UINavigationControllerDelegate,UIImagePickerControllerDelegate>

@property (nonatomic,retain)UIImageView *myImageView;

@end

@implementation ThirdViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    //创建一块imageView
    _myImageView = [[UIImageView alloc]initWithFrame:CGRectMake((414-300)/2, 200, 300, 300)];
    _myImageView.backgroundColor = [UIColor whiteColor];
    //打开交互
    _myImageView.userInteractionEnabled = YES;
    [self.view addSubview:_myImageView];
    
    //添加一个手势
    UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(selectImage:)];
    [_myImageView addGestureRecognizer:tapGesture];
}

//实现手势的方法，进入相册
-(void)selectImage:(UIButton*)sender
{   //创建ImagePickController
    UIImagePickerController *myPicker = [[UIImagePickerController alloc]init];
    
    //创建源类型
    UIImagePickerControllerSourceType mySourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    
    myPicker.sourceType = mySourceType;
    
    //设置代理
    myPicker.delegate = self;
    //设置可编辑
    myPicker.allowsEditing = YES;
    //通过模态的方式推出系统相册
    [self presentViewController:myPicker animated:YES completion:^{
        NSLog(@"进入相册");
    }];
 
}

#pragma mark -- 实现imagePicker的代理方法

 -(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info
{
    //取得所选取的图片,原大小,可编辑等，info是选取的图片的信息字典
    UIImage *selectImage = [info objectForKey:UIImagePickerControllerEditedImage];
    
    //设置图片进相框
    self.myImageView.image = selectImage;
    [picker dismissViewControllerAnimated:YES completion:^{
        NSLog(@"模态返回") ;
    }];
}

@end

效果如下

中间有个相框，点一下进入相册，在相册中选择一张图片，点choose，出来相框的图片就变了