Working with Database

Hi all,

Pretty sure that many of you have already worked on this.
An idea to frame things related to DB together.

Lets see how much this works!!!!


Ok Now lets proceed

1) Create Database

- (BOOL)createAppDatabase

{

    NSString *docsDir;

    NSArray *dirPaths;

    BOOL isSuccess = NO;

    

    dirPaths = NSSearchPathForDirectoriesInDomains

                                                 (NSDocumentDirectory, NSUserDomainMask, YES);

    

    docsDir = [dirPaths objectAtIndex:0];

    

    self.databasePath = [[NSString alloc] initWithString: 

           [docsDir stringByAppendingPathComponent: @"MyDatabase.db"]];

    

    NSFileManager *filemgr = [NSFileManager defaultManager];

    

    if ([filemgr fileExistsAtPath: databasePath ] == NO)

    {

              const char *dbpath = [databasePath UTF8String];

        

              if (sqlite3_open(dbpath, &database) == SQLITE_OK)

              {

                             isSuccess = YES;

                             sqlite3_close(database);

             }

             else

                             isSuccess = NO;

    }    

    return isSuccess;

}

2) Create Tables

- (BOOL)createTableWithSqlStatement:(NSString *)sqlStatement

{

    BOOL isSuccess = NO;

    NSFileManager *fileManager = [NSFileManager defaultManager];

    

    if ([fileManager fileExistsAtPath:self.databasePath ]  ==  YES)

    {

        const char *dbpath = [self.databasePath UTF8String];

        if (sqlite3_open(dbpath, &database) == SQLITE_OK)

        {

            char *errMsg;            

            const char *sql_stmt = [sqlStatement UTF8String];

            if (sqlite3_exec(database, sql_stmt, NULL, NULL, &errMsg) != SQLITE_OK)

            {

                isSuccess = NO;

                NSLog(@"Failed to create table");

            }

            sqlite3_close(database);

            return  isSuccess;

        }

        else

       {

            isSuccess = NO;

            NSLog(@"Failed to open/create database");

        }

    }

    return isSuccess;

}

3) Fetch Data from Table

NSString *sqlStatement = [NSString stringWithFormat:@"SELECT * FROM Info 

                                                                                             where userId=='%d'",@"21"];

- (LoginModel*)fetchDataFromInfoTable:(NSString*)sqlStatement

{

    sqlite3_stmt *sql_smt;

    LoginModel *loginModel;

    

    if (sqlite3_open([self.databasePath UTF8String], &database) == SQLITE_OK)

    {

        if (sqlite3_prepare_v2(database, [sqlStatement UTF8String], -1, &sql_smt, nil) 

                          == SQLITE_OK)

        {

            loginModel = [[LoginModel alloc] init];

            while(sqlite3_step(sql_smt)==SQLITE_ROW)

            {

                const char *s;

                

                s=(char *)sqlite3_column_text(sql_smt, 0); // Here 0 is the 1st column

                if(s==NULL)

                    loginModel.userID=@"";

                else

                    loginModel.userID =[NSString stringWithUTF8String:s];

                

                s=(char *)sqlite3_column_text(sql_smt, 1); // Here 1 is the 2nd column

                if(s==NULL)

                    loginModel.userName=@"";

                else

                    loginModel.userName =[NSString stringWithUTF8String:s];

            }

        }

        sqlite3_finalize(sql_smt);

        sqlite3_close(database);

    }

    else

    {

        loginModel = nil;

        NSLog(@"Failed to open/create database");

    }

    return loginModel;

}

4) Execute Statements

- (BOOL)executeSqlStatement:(NSString*)sqlStatement

{

    sqlite3_stmt *sql_smt;

    BOOL isSuccess = NO;

    

    if (sqlite3_open([self.databasePath UTF8String], &database) == SQLITE_OK)

    {

        if (sqlite3_prepare_v2(database, [sqlStatement UTF8String], -1, &sql_smt, nil) 

                     ==  SQLITE_OK)

        {

            if (SQLITE_DONE!=sqlite3_step(statement))

            {

                sqlite3_close(database);

                isSuccess = NO;

            }

            else {

                NSLog(@"Success");

                isSuccess = YES;

                NSLog(@"%@",sqlStatement);

            }

        }

        sqlite3_finalize(sql_smt);

        sqlite3_close(database);

    }

    else

    {

        isSuccess = NO;

        NSLog(@"Failed to open/create database");

    }    

    return isSuccess;

}

5) Call executeSqlStatement 

    NSString *sqlStatement = [NSString stringWithFormat:@"INSERT INTO Info

          (userId , userName) VALUES (%d,'%@')",[userID intValue],userName];

   [self executeSqlStatement:sqlStatement];

  sqlStatement = [NSString stringWithFormat:@"UPDATE Info 

            Set userName =  '%@' where userID =  '%d' ",@"Swati",@"21"];

    

  [self executeSqlStatement:sqlStatement];

sqlStatement = [NSString stringWithFormat: @"DELETE FROM Info

                                                                                    WHERE userID ='%d'",@"21"];

Hey where is my database ???

Here is the path >> Admin >> Library >> Application Support >> iPhone Simulator >> Your chosen Version >> Applications >> Here you will see a list of all apps on Simulator >> choose yours >> Documents >> MyDatabase.db

How to view the contents ???

You can install a plugin in /firefox named Sqlite Manager, click and provide the location and here is the DB view.....

JSON Utilization in iOS

Hi

The time since Apple has provided JSONSerialisation things have became far more easier.

For my ease i have created 2 methods for JSON Conversion to-fro.

Hope someone finds it suitable too.

+ (NSString*)convertDictionaryToJSONString:(NSDictionary*)dict

{

    NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dict

                                                                              options:NSJSONWritingPrettyPrinted

                                                                              error:nil];

    return [[NSString alloc] initWithData:jsonData 

                                                   encoding:NSUTF8StringEncoding];

}

+ (NSDictionary*)convertJSONDataToDictionary:(NSData*)data

{

    NSDictionary *parsedData = nil;

    parsedData = [NSJSONSerialization JSONObjectWithData:data

                                                                    options:NSJSONReadingMutableContainers

                                                                     error:nil];

    return parsedData; 

}

Save Image in Documents Directory

Hi all,

Yup i know its very basic for many but for some it may be useful ;)

//Get Array of paths :

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

//Get Documents Folder

NSString *documentsDirectory = [paths objectAtIndex:0]; 

//Create path of File, may be inside any directory

NSString *dataPath = [NSString stringWithFormat:@"%@/%@",documentsDirectory,currentElement.iD];

        

if (![[NSFileManager defaultManager] fileExistsAtPath:dataPath])

{

//For Creating directory

            [[NSFileManager defaultManager] createDirectoryAtPath:dataPath 

                                                                withIntermediateDirectories:NO 

                                                                                                 attributes:nil 

                                                                                                          error:nil];

}

        

[self saveImage:image withFileName:currentElement.iD ofType:@"png" inDirectory:dataPath];

//Here is the called method definition

- (void) saveImage:(UIImage *)image 

        withFileName:(NSString *)imageName

                    ofType:(NSString *)extension

            inDirectory:(NSString *)directoryPath

{

    if ([[extension lowercaseString] isEqualToString:@"png"])

    {

        [UIImagePNGRepresentation(image) writeToFile:[directoryPath stringByAppendingPathComponent:[NSString                                                                                                                       stringWithFormat:@"%@.%@", imageName, @"png"]] 

                                                                                 options:NSAtomicWrite 

                                                                                      error:nil];

    }

    else if ([[extension lowercaseString] isEqualToString:@"jpg"] ||

                 [[extension lowercaseString] isEqualToString:@"jpeg"]) 

   {

        [UIImageJPEGRepresentation(image, 1.0) writeToFile:[directoryPath stringByAppendingPathComponent:                                                                                                     [NSString stringWithFormat:@"%@.%@", imageName, @"jpg"]] 

                                                                                          options:NSAtomicWrite

                                                                                               error:nil];

    }

    else

   {

        NSLog(@"Image Save Failed\nExtension: (%@) is not recognized, use (PNG/JPG)", extension);

    }

}

Hope it helps

Enjoy :)

        

Working with UIPopOverControllers

Hi, I have been using them since popover feature was introduced.

I would like to show a small sample for those whom popover fascinates..

Hope you all find it simplest and helpful to..

Lets start.....

1) Create a Simple View based Application as a start project.

I created like this : 

2) Add files namely  : 

PopOverViewController.h

PopOverViewController.m

PopOverViewController.xib

DataViewController.h

DataViewController.m

DataViewController.xib

3) Lets start with file PopOverViewController.xib

Add a UIButton on iPad UI showing text "Show PopOver"

Link this button with an IBAction named - (IBAction)showPopOver:(id)sender

4) Moving towards PopOverViewController.m

 Firstly create a private property like this : 

Secondly Perform Action on the IBAction as : 

Explanation : 

• DataViewController is another controller with some UI components placed on its XIB.
• The IBActions are handled accordingly.

• We set the preferredContentSize property so that we can define the bounds of the popover being displayed.

• self.popOverController is the private property we created in the .m file. 
• This helps in presenting the DataController's view inside a popOver.

List of permitted Arrow Directions:

    UIPopoverArrowDirectionUp = 0,

    UIPopoverArrowDirectionDown = 1,

    UIPopoverArrowDirectionLeft =  2,

    UIPopoverArrowDirectionRight = 3,

    UIPopoverArrowDirectionAny = UIPopoverArrowDirectionUp | 

                                                          UIPopoverArrowDirectionDown | 

                                                          UIPopoverArrowDirectionLeft | 

                                                          UIPopoverArrowDirectionRight,

    UIPopoverArrowDirectionUnknown = NSUIntegerMax

5) Now moving towards DataViewController.h

6) UI Designing on DataViewController.xib

I added a label and 2 buttons which are associated with IBActions respectively.

7) Handling button clicks on DataViewController.m

Both the View Controllers are ready, now run the app and see the work..

One important thing for Orientation change : 

Whenever orientation change creates problem for popover presentation , remember to present popover again @ orientation did change selector.

      

        

Hope all are able to get help from this.

:)