object-c一些基础内容--简单整理版

#import <AVFoundation/AVFoundation.h>

@interface ViewController () <UIImagePickerControllerDelegate, UINavigationControllerDelegate>

@property (strong, nonatomic) UIImageView *imageView;
@property (strong, nonatomic) UIButton *cameraButton;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    self.imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, self.view.bounds.size.height)];
    self.imageView.contentMode = UIViewContentModeScaleAspectFit;
    [self.view addSubview:self.imageView];
    
    self.cameraButton = [UIButton buttonWithType:UIButtonTypeSystem];
    [self.cameraButton setTitle:@"拍照" forState:UIControlStateNormal];
    [self.cameraButton setFrame:CGRectMake(100, 100, 100, 40)];
    [self.view addSubview:self.cameraButton];
    
    [self.cameraButton addTarget:self action:@selector(takePhoto) forControlEvents:UIControlEventTouchUpInside];
}

- (IBAction)takePhoto:(id)sender {
    AVCaptureSession *captureSession = [[AVCaptureSession alloc] init];
    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    NSError *error;
    
    if ([device canCaptureVideo]) {
        AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];
        if (!input) {
            NSLog(@"%@", error);
            return;
        }
        
        if ([captureSession canAddInput:input]) {
            [captureSession addInput:input];
        } else {
            NSLog(@"无法添加输入设备");
            return;
        }
        
        AVCapturePhotoOutput *output = [[AVCapturePhotoOutput alloc] init];
        if ([captureSession canAddOutput:output]) {
            [captureSession addOutput:output];
        } else {
            NSLog(@"无法添加输出设备");
            return;
        }
        
        [output capturePhotoWithSettings:nil delegate:self completionHandler:^(CMSampleBufferRef sampleBuffer, NSError * _Nullable error) {
            if (!sampleBuffer) {
                NSLog(@"%@", error);
                return;
            }
            
            CIImage *image = [CIImage imageWithCVPixelBuffer:sampleBuffer];
            CGImageRef cgImage = [image JPEGRepresentation:1.0 quality:0.8];
            CGSize size = CGSizeMake([self.imageView frame].size);
            UIImage *uiImage = [UIImage imageWithCGImage:cgImage scaledToSize:size];
            [self.imageView setImage:uiImage];
        }];
    } else {
        NSLog(@"设备不支持视频捕获");
    }
}

@end

类

分组导航标记

self

NSObject

super

访问修饰限定符

property

synthesize

万能指针

instancetype

构造方法

自定义构造方法

引用计数器

僵尸对象

@class

自动释放池

ARC

mrc转arc

将一个类分为多个模块

非正式协议

延展

block

协议

NSString

NSURL

NSRange

NSMutableString

NSArray

NSDictionary

NSFileManager

CGPoint