iOS-沙盒機制及數(shù)據(jù)存儲等操作

iOS的APP可以在自己的沙盒里讀寫文件，但是不可以訪問其他APP的沙盒。每一個APP都是一個信息孤立的房間，這些房間就相當(dāng)于一個沙盒，相互是不可以進行通信的，唯獨可以通過URL Scheme。沙盒里面的文件可以是照片、聲音文件、文件、屬性列表等。

沙盒的根目錄結(jié)構(gòu):Document、Library、temp。
1.Document：用于存儲用戶數(shù)據(jù)，iTunes備份和恢復(fù)的時候會包括此目錄。所以。蘋果建議將程序中建立的或在程序中瀏覽到的文件數(shù)據(jù)保存在該目錄下。
2.Library：包含兩個子目錄：Caches 和 Preferences。Caches用來存放用戶需要換成的文件。Preferences是APP的偏好設(shè)置，可以通過NSUserDefaults來讀取和設(shè)置。
3.tmp：用于存放臨時文件，這個可以存放一些當(dāng)APP退出后不需要再保存的文件。

獲取沙盒路徑
 //獲取路徑三種方法
 NSString *path = NSHomeDirectory();
 //拼接字符串
 NSString *documents = [path stringByAppendingString:@"/Documents"];
 //專業(yè)拼接路徑
 NSString *str = [path stringByAppendingPathComponent:@"Documents"];
系統(tǒng)提供的方法獲取Document路徑
NSArray *array = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *strD = [array objectAtIndex:0];
NSLog(@"%@",strD);
獲取library路徑
NSArray *arrayL = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES);
NSString *strL = [arrayL objectAtIndex:0];
NSLog(@"%@",strL);
獲取tmp路徑
NSString *path = NSTemporaryDirectory();
NSLog(@"%@",path);
獲取caches路徑
NSArray *arrayC = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
NSString *strC = [arrayC objectAtIndex:0];
NSLog(@"%@",strC);
用NSUserDefaults對Preferences進行讀取和設(shè)置
NSUserDefaults *user = [NSUserDefaults standardUserDefaults];
[user setObject:@"zhangsan" forKey:@"name"];
[user setObject:@"lisi" forKey:@"names"];
//將數(shù)據(jù)同步到沙盒的規(guī)定目錄下（library下的preferences目錄）
[user synchronize];

基本類型數(shù)據(jù)的存儲和讀取

  • 字符串存儲、讀取
- (void)saveString{
    //獲取Document目錄
    NSString *string = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    //在沙盒文件下創(chuàng)建文件
    NSString *newPath = [string stringByAppendingString:@"/text.txt"];
    //要存入的內(nèi)容
    NSString *name = @"UMR";
    //寫入文件
    [name writeToFile:newPath atomically:YES encoding:NSUTF8StringEncoding error:nil];
}
- (void)readingString{
    //獲取路徑
    NSString *str = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    NSString *newPath = [str stringByAppendingString:@"/text.txt"];
    //讀取數(shù)據(jù)
    NSString *string = [NSString stringWithContentsOfFile:newPath encoding:NSUTF8StringEncoding error:nil];
    NSLog(@"%@",string);
}
  • 數(shù)組存儲、讀取
- (void)saveArray{
    //1.獲取路徑
    //獲取目錄
    NSString *string = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    //在沙盒文件下創(chuàng)建文件
    NSString *newPath = [string stringByAppendingString:@"/array.plist"];
    //要存入的內(nèi)容
    NSArray *array = @[@"zhangsan",@"lisi",@"wangwu"];
    //寫入
    [array writeToFile:newPath atomically:YES];
    NSLog(@"%@",newPath);
}
- (void)readingArray{
    //獲取路徑
    NSString *str = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    NSString *newPath = [str stringByAppendingString:@"/array.plist"];
    //讀取數(shù)據(jù)
    NSArray *array = [NSArray arrayWithContentsOfFile:newPath];
    NSLog(@"%@",array);
}
  • 字典存儲、讀取
- (void)saveDictionary{
    //獲取路徑
    NSString *string = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    NSString *newPath = [string stringByAppendingString:@"/dictionary.plist"];
    //存儲內(nèi)容
    NSDictionary *dict = @{@"n1":@[@"1",@"2",@"3"],@"n2":@{@"a":@"d",@"s":@"g"},@"n3":@"uuummmrrr"};
    [dict writeToFile:newPath atomically:YES];
    NSLog(@"%@",newPath);
}
- (void)readingDictionary{
    //獲取路徑
    NSString *string = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    NSString *newPath = [string stringByAppendingString:@"/dictionary.plist"];
    //讀取內(nèi)容
    NSDictionary *dic = [NSDictionary dictionaryWithContentsOfFile:newPath];
    NSLog(@"%@",dic);
}
  • data存儲、讀取
- (void)saveData{
    //獲取路徑
    NSString *string = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    //存儲路徑
    NSString *newPath = [string stringByAppendingString:@"/data.plist"];
    //存儲內(nèi)容
    NSString *str = @"UMR";
    //將string轉(zhuǎn)換成data
    NSData *data = [str dataUsingEncoding:NSUTF8StringEncoding];
    //寫入文件夾
    [data writeToFile:newPath atomically:YES];
    NSLog(@"%@",newPath);
}
- (void)readingData{
    //獲取路徑
    NSString *string = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    //存儲路徑
    NSString *newPath = [string stringByAppendingString:@"/data.plist"];
    //從文件讀取data
    NSData *data = [NSData dataWithContentsOfFile:newPath];
    //將data轉(zhuǎn)換成為string
    NSString *str = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
    NSLog(@"%@",str);
}
  • image存儲 - 需轉(zhuǎn)換為data進行存儲和讀取
- (void)saveImage{
    //獲取路徑
    NSString *path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    //在文件路徑下面創(chuàng)建該文件夾
    NSString *newPath = [path stringByAppendingString:@"/image.png"];
    //將.png轉(zhuǎn)為data格式
    NSData *imageData = UIImagePNGRepresentation([UIImage imageNamed:@"name6.png"]);
//    NSData *imageD = UIImageJPEGRepresentation([UIImage imageNamed:@"name6.png"], 1); 如果是JPG格式的，后面的CGFloat為壓縮系數(shù);
    //將data文件寫入文件夾
    [imageData writeToFile:newPath atomically:YES];
    NSLog(@"%@",newPath);
}
- (void)readingImage{
    //獲取路徑，獲取文件
    NSString *path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    NSString *newPath = [path stringByAppendingString:@"/image.png"];
    NSData *imageData = [NSData dataWithContentsOfFile:newPath];
    //將data轉(zhuǎn)為圖片格式
    UIImage *image = [UIImage imageWithData:imageData];
    //獲取 - 賦值
    UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(120, 120, 120, 120)];
    imageView.image = image;
    [self.view addSubview:imageView];
    NSLog(@"%@",newPath);
}

歸檔與反歸檔 - 復(fù)雜數(shù)據(jù)的沙盒存儲

  • eg：先創(chuàng)建一個Person對象，聲明相關(guān)屬性
//歸檔必須遵守NSCoding協(xié)議
@interface Person : NSObject<NSCoding>
@property (nonatomic,strong) NSString *name;
@property (nonatomic,strong) NSString *gender;
@property (nonatomic,assign) NSInteger age;
@end```
 - 在.m文件中實現(xiàn)這兩個NSCoding協(xié)議方法

@implementation Person
//對對象進行歸檔的時候調(diào)用

  • (void)encodeWithCoder:(NSCoder *)aCoder{
    [aCoder encodeObject:self.name forKey:@"name"];
    [aCoder encodeObject:self.gender forKey:@"gender"];
    [aCoder encodeInteger:self.age forKey:@"age"];
    }
    //對對象進行反歸檔的時候調(diào)用
  • (instancetype)initWithCoder:(NSCoder *)aDecoder{
    if (self = [super init]) {
    self.name = [aDecoder decodeObjectForKey:@"name"];
    self.gender = [aDecoder decodeObjectForKey:@"gender"];
    self.age = [aDecoder decodeIntegerForKey:@"age"];
    }
    return self;
    }
    @end```
  • 歸檔
- (void)saveData{
    Person *person = [[Person alloc] init];
    person.name = @"umr";
    person.gender = @"m";
    person.age = 18;
    //進行規(guī)檔操作
    //1.創(chuàng)建一個NSMutableData來存儲歸檔后的數(shù)據(jù)
    NSMutableData *Data = [[NSMutableData alloc] init];
    //2.創(chuàng)建歸檔器
    NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:Data];
    //3.進行歸檔
    [archiver encodeObject:person forKey:@"person"];
    //4.歸檔結(jié)束
    [archiver finishEncoding];
    //獲取沙盒路徑
    NSString *SDPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    NSString *newPath = [SDPath stringByAppendingString:@"/archiver.plist"];
    //寫入文件
    [Data writeToFile:newPath atomically:YES];
    NSLog(@"%@",newPath);
}```
 - 反歸檔
  • (void)readData{
    //獲取沙盒路徑
    NSString *path = [[self documentPath] stringByAppendingString:@"/archiver.plist"];
    //獲取數(shù)據(jù)
    NSData *data = [NSData dataWithContentsOfFile:path];
    NSKeyedUnarchiver *Unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];
    Person *person1 = [Unarchiver decodeObjectForKey:@"person"];
    [Unarchiver finishDecoding];
    NSLog(@"%@ %ld %@",person1.name,person1.age,person1.gender);
    }```
- (NSString *)documentPath{
    return [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
}```
### - 對象數(shù)組的歸檔與反歸檔
  • (void)codeArray{
    //創(chuàng)建兩個person對象
    Person *person1 = [[Person alloc] init];
    person1.name = @"huahua";
    Person *person2 = [[Person alloc] init];
    person2.name = @"UMR";

    存入數(shù)組 - 數(shù)組中的復(fù)雜對象必須遵守NSCoding協(xié)議，就可以直接對數(shù)組進行歸檔

    NSMutableArray *array = [[NSMutableArray alloc] initWithObjects:person1,person2, nil];
    //獲取路徑
    NSString *documentPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0];
    NSString *path = [documentPath stringByAppendingPathComponent:@"array.plist"];
    NSLog(@"%@",path);
    //歸檔
    [NSKeyedArchiver archiveRootObject:array toFile:path];
    //反歸檔
    NSArray *arr = [NSKeyedUnarchiver unarchiveObjectWithFile:path];
    // Person *per = arr[0];
    NSLog(@"%@",arr);
    }```
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