UI-senior(数据本地化-如何存储图片到本地)

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {

[super viewDidLoad];

#pragma mark ---图片--------

//根据ImageNamed获取图片(会在缓存中存储一份,下次再获取同名图片的话直接从缓存中取出)  优点:快 只有第一次时慢  缺点:会浪费内存,如果只用一次的话这块内存就会浪费掉了

//UIImage *image = [UIImage imageNamed:@"1"];

//根据ContentOfFile获取图片:每一次都会从路径中读取,不会占用内存.如果该图片只使用一次的话 推荐使用ContentOfFile

//UIImage *image1 = [[UIImage alloc] initWithContentsOfFile:@"1"];

//123.png

//[email protected]:两倍分辨率 5,5s,6,6s

//[email protected]:三倍分辨率 6plus ,6s plus

---

//第一步:创建一个图片对象
UIImage *image = [UIImage imageNamed:@"1"];

#pragma mark ---将UIImage类型对象转化成NSData类型---

    //第一个参数:表示转哪个UIImage类型的对象

    //第二个参数:压缩系数 越小压缩的越厉害

//第二步:将图片对象装换成NSData对象
NSData *data = UIImageJPEGRepresentation(image, 1);

//第三步:确定要存储文件夹的路径
NSString *documentPathStr = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES) objectAtIndex:0];
//第四步:确定要存储的文件
NSString *dataPath = [documentPathStr stringByAppendingPathComponent:@"data.png"];

//第五步:写入
[data writeToFile:dataPath atomically:YES];

UIImageView *imageView = [[UIImageView alloc] initWithImage:image];

[self.view addSubview:imageView];

#pragma mark ---将类型NSData对象转化成UIImage类型---

NSData *newData = [NSData dataWithContentsOfFile:dataPath];

UIImage *newImage = [[UIImage alloc] initWithData:newData];

NSLog(@"%@",newImage);

}

- (void)didReceiveMemoryWarning {

[super didReceiveMemoryWarning];

// Dispose of any resources that can be recreated.

}

@end