iOS資料存放區的幾種方式

iOS資料存放區的幾種方式

iOS的資料存放區是iOS應用開發的重要知識點：

關於這方面知識，網上有很多介紹，但對於代碼層次的使用方式並未有系統全面介紹。此文章針對iOS稍熟悉的童鞋，需要對CoreData的原理有一定的瞭解。目前儲存方式大概有以下幾種：

NSKeyedArchiver 適用簡單資料加密NSUserDefaults 適用配置參數Write 檔案操作，同NSKeyedArchiverSQLite3 操作較複雜，不建議使用。CoreData 取代SQLite3，但要遵循NSManagedObjectContext基本規則。

UT代碼確保使用方式正確。請閱讀以下內容：

#import #import #import "CoreDataHelper.h"@interface StudyUITests : XCTestCase@end@implementation StudyUITests- (void)setUp{    [super setUp];}- (void)tearDown{    [super tearDown];}-(void)testCoreData{    CoreDataHelper *coreHelper = [[CoreDataHelper alloc] init];    [coreHelper coreDataTest];}-(void)testSqlite3{    sqlite3 *db;        NSString *documentPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];    NSString *databasePath = [documentPath stringByAppendingPathComponent:@"test.sqlite"];        NSLog(@"db path: %@",databasePath);            if(sqlite3_open([databasePath UTF8String], &db) != SQLITE_OK){        sqlite3_close(db);        NSLog(@"open sqlite fail!");        NSAssert(FALSE, @"create sqlite error");    }        NSString *sqlCreateTable = @"CREATE TABLE IF NOT EXISTS ptable (ID INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, age INTEGER, address TEXT)";    char *error;    if(sqlite3_exec(db, [sqlCreateTable UTF8String], NULL, NULL, &error) != SQLITE_OK){        sqlite3_close(db);        NSLog(@"can not create table.");        NSAssert(FALSE, @"create table error");    }        NSString *deleteAllSql = @"delete from ptable";    if(sqlite3_exec(db, [deleteAllSql UTF8String], NULL, NULL, &error) != SQLITE_OK){        sqlite3_close(db);        NSLog(@"delete values from table");        NSAssert(FALSE, @"delete values from table");    }        NSString *sql1 = [NSString stringWithFormat:                      @"INSERT INTO '%@' ('%@', '%@', '%@') VALUES ('%@', '%@', '%@')",                      @"ptable", @"name", @"age", @"address", @"first name", @"23", @"pukou"];        NSString *sql2 = [NSString stringWithFormat:                      @"INSERT INTO '%@' ('%@', '%@', '%@') VALUES ('%@', '%@', '%@')",                      @"ptable", @"name", @"age", @"address",@"second name", @"20", @"qixia"];        if(sqlite3_exec(db, [sql1 UTF8String], NULL, NULL, &error) != SQLITE_OK){        sqlite3_close(db);        NSLog(@"can not insert sql1");        NSAssert(FALSE, @"create insert db (sql1) error");    }        if(sqlite3_exec(db, [sql2 UTF8String], NULL, NULL, &error) != SQLITE_OK){        sqlite3_close(db);        NSLog(@"can not insert sql2");        NSAssert(FALSE, @"create insert db (sql2) error");    }            //Read data and check result.        NSString *query = @"select * from ptable";        sqlite3_stmt *statement;            if(sqlite3_prepare_v2(db, [query UTF8String], -1, &statement, nil) == SQLITE_OK){        //start to traverse data                int size = 0;        while (sqlite3_step(statement) == SQLITE_ROW) {            size++;            char *name = (char*)sqlite3_column_text(statement, 1);            int age= (int)sqlite3_column_int(statement, 2);            char *address = (char*)sqlite3_column_text(statement, 3);                        NSString *nameStr = [[NSString alloc] initWithUTF8String:name];            NSString *addressStr = [[NSString alloc] initWithUTF8String:address];            NSLog(@"name: %@  age: %d address: %@",nameStr,age,addressStr);        }        NSAssert(size == 2, @"size should 2");    }else{        NSAssert(FALSE, @"query db error");    }    sqlite3_close(db);}-(void)testWriteToFile{    NSString *st1 = @"first";    NSString *st2 = @"second";        NSArray *array = [NSArray arrayWithObjects:st1,st2, nil];    NSString *path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];    NSAssert(path != nil, @"path is nil");    NSString *filename = [path stringByAppendingPathComponent:@"test.data"];    NSAssert([array writeToFile:filename atomically:YES],@"write successfully");        NSMutableArray *savearray = [NSMutableArray arrayWithContentsOfFile:filename];            NSAssert([[savearray objectAtIndex:0] isEqualToString:st1], @"not equal to str1");    NSAssert([[savearray objectAtIndex:1] isEqualToString:st2], @"not equal to str2");    }-(void)testUserDefault{    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];    NSString *name = @"test";    [defaults setObject:name forKey:@"name"];        UIImage *image = [UIImage imageNamed:@"photo"];        NSData *imageData = UIImagePNGRepresentation(image);    [defaults setObject:imageData forKey:@"image"];        //now read from data            NSString *name1=  [defaults objectForKey:@"name"];    NSData *imageData1 = [defaults objectForKey:@"image"];        NSAssert([name1 isEqualToString:name], @"name1 is equal to test");    NSAssert([imageData1 isEqualToData:imageData], @"image data is not equal");    }-(void)testKeyedArchiver{    NSString *save1 =@"test1";    NSString *save2 =@"test2";            NSArray *array = [NSArray arrayWithObjects:save1, save2, nil];    NSString *path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];            NSString *filename = [path stringByAppendingPathComponent:@"savedatatest"];    NSLog(@"filename : %@",filename);        //save data    NSAssert([NSKeyedArchiver archiveRootObject:array toFile:filename],@"archive successfully.");        array = [NSKeyedUnarchiver unarchiveObjectWithFile:filename];        save1 = [array objectAtIndex:0];        NSAssert([save1 isEqualToString:@"test1"], @"save1 must equals to test1");        save2 = [array objectAtIndex:1];    NSAssert([save2 isEqualToString:@"test2"], @"save1 must equals to test2");   }@end

CoreData的使用稍微複雜一些，所以將其單獨放入Helper類中。Entity model包含name，age 和 address 三個屬性。可在測試工程建立，並產生Entity對象。

#import "CoreDataHelper.h"#import #import "Entity.h"@interface CoreDataHelper()@property (strong, nonatomic) NSManagedObjectModel *managedObjectModel;@property (strong, nonatomic) NSManagedObjectContext *managedObjectContext;@property (strong, nonatomic) NSPersistentStoreCoordinator *persistentStoreCoordinator;-(NSPersistentStoreCoordinator *)persistentStoreCoordinator;-(NSManagedObjectContext *)managedObjectContext;-(NSManagedObjectModel *)managedObjectModel;@end@implementation CoreDataHelper-(void)coreDataTest{    NSError *error = nil;    NSEntityDescription *entityDescription = [NSEntityDescription entityForName:@"Entity" inManagedObjectContext:self.managedObjectContext];    NSFetchRequest *request = [[NSFetchRequest alloc] init];    [request setEntity:entityDescription];        NSArray *oldResult = [[self.managedObjectContext executeFetchRequest:request error:&error] mutableCopy];    for (Entity *bb in oldResult) {        [self.managedObjectContext deleteObject:bb];    }    NSAssert([self.managedObjectContext save:&error], @"deleting.....");            /******insert *****/    Entity *entity = [[Entity alloc] initWithEntity:entityDescription insertIntoManagedObjectContext:nil];        entity.name = @"test";    entity.age = [NSNumber numberWithInt:20];    entity.address = @"beijing";    [self.managedObjectContext insertObject:entity];    NSAssert([self.managedObjectContext save:&error], @"inserting.....");            /*****query *****/    NSSortDescriptor *sortDescription = [[NSSortDescriptor alloc] initWithKey:@"age" ascending:NO];    NSArray *sortDescriptions = [[NSArray alloc] initWithObjects:sortDescription, nil];    [request setSortDescriptors:sortDescriptions];        NSMutableArray *array = [[self.managedObjectContext executeFetchRequest:request error:&error] mutableCopy];        for (Entity *bb in array) {        NSLog(@"name: %@ age:%@ address:%@",bb.name,bb.age,bb.address);    }    NSAssert([array count] == 1, @"count size is equal to 1");            /***** update and check****/    NSArray *updateResult = [[self.managedObjectContext executeFetchRequest:request error:&error] mutableCopy];    Entity *first = [updateResult objectAtIndex:0];    first.name = @"one";    NSAssert([self.managedObjectContext save:&error], @"updating.....");            updateResult = [[self.managedObjectContext executeFetchRequest:request error:&error] mutableCopy];    first = [updateResult objectAtIndex:0];    NSAssert([first.name isEqualToString:@"one"], @"need to equeal one");        /**** insert and check ****/    entity = [[Entity alloc] initWithEntity:entityDescription insertIntoManagedObjectContext:nil];        entity.name = @"test2";    entity.age = [NSNumber numberWithInt:23];    entity.address = @"nanjing";    [self.managedObjectContext insertObject:entity];    NSAssert([self.managedObjectContext save:&error], @"inserting.....");    array = [[self.managedObjectContext executeFetchRequest:request error:&error] mutableCopy];    for (Entity *bb in array) {        NSLog(@"name: %@ age:%@ address:%@",bb.name,bb.age,bb.address);    }    NSAssert([array count] == 2, @"now size is equal to 2");        }-(NSPersistentStoreCoordinator *)persistentStoreCoordinator{    if(_persistentStoreCoordinator)        return _persistentStoreCoordinator;            NSString *documentPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];        NSURL *storeURL = [NSURL fileURLWithPath:[documentPath stringByAppendingPathComponent:@"person.sqlite"]];        NSError *error = nil;        _persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];            if(![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error]){        NSLog(@"persistent error : %@",[error userInfo]);    }    return _persistentStoreCoordinator;}-(NSManagedObjectContext *)managedObjectContext{    if(_managedObjectContext)        return _managedObjectContext;        NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];        if(coordinator){        _managedObjectContext = [[NSManagedObjectContext alloc] init];        [_managedObjectContext setPersistentStoreCoordinator:coordinator];    }    return  _managedObjectContext;}-(NSManagedObjectModel *)managedObjectModel{    if(_managedObjectModel)        return _managedObjectModel;        NSURL *modeUrl = [[NSBundle mainBundle] URLForResource:@"Entity" withExtension:@"momd"];    _managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modeUrl];    return  _managedObjectModel;}@end