Not getting the output when trying the data from the sqlite database - iphone

Question

I am new to Objective - C and Sqlite database.So I don't understand what is the mistake in my code. I am doing a simple Todo List. In the first page, I want to display all the tasks and in the header, there is one add button.When we click on that button, it will move to the second storyboard.In that, we can enter the main task and subtask. I have created a new page named TodolistView1Controller and in that I have created the database and inserted the data into the db. But my problem is When we come back to the main page, it will not show the new task which we entered now. I will paste the code below :-
In TodolistView1Controller.m
-(void)viewDidLoad
{
NSString *docsDir;
NSArray *dirPaths;
// Get the documents directory
dirPaths = NSSearchPathForDirectoriesInDomains(
NSDocumentDirectory, NSUserDomainMask, YES);
docsDir = [dirPaths objectAtIndex:0];
// Build the path to the database file
databasePath = [[NSString alloc] initWithString: [docsDir stringByAppendingPathComponent: #"todo.db"]];
NSFileManager *filemgr = [NSFileManager defaultManager];
if ([filemgr fileExistsAtPath: databasePath ] == NO)
{
const char *dbpath = [databasePath UTF8String];
if (sqlite3_open(dbpath, &todoDB) == SQLITE_OK)
{
char *errMsg;
const char *sql_stmt = "CREATE TABLE IF NOT EXISTS TODO (ID INTEGER PRIMARY KEY AUTOINCREMENT, MYTASK TEXT, SUBTASK TEXT)";
if (sqlite3_exec(todoDB, sql_stmt, NULL, NULL, &errMsg) != SQLITE_OK)
{
status.text = #"Failed to create table";
}
status.text = #"Created the database";
sqlite3_close(todoDB);
} else {
status.text = #"Failed to open/create database";
}
} - (IBAction)save:(id)sender {
[myTask resignFirstResponder];
[subTask resignFirstResponder];
sqlite3_stmt *statement;
const char *dbpath = [databasePath UTF8String];
if (sqlite3_open(dbpath, &todoDB) == SQLITE_OK)
{
NSString *insertSQL = [NSString stringWithFormat: #"INSERT INTO TODO (MYTASK, SUBTASK) VALUES (\"%#\", \"%#\")", myTask.text, subTask.text];
const char *insert_stmt = [insertSQL UTF8String];
sqlite3_prepare_v2(todoDB, insert_stmt, -1, &statement, NULL);
if (sqlite3_step(statement) == SQLITE_DONE)
{
status.text = #"Contact added";
myTask.text = #"";
subTask.text = #"";
} else {
status.text = #"Failed to add contact";
}
NSLog(#"7");
sqlite3_finalize(statement);
sqlite3_close(todoDB);
}
And in Main ViewController.m
-(void)viewDidLoad
{
const char *dbpath = [databasePath UTF8String];
sqlite3_stmt *statement;
NSLog(#"Display1");
if (sqlite3_open(dbpath, &todoDB) == SQLITE_OK)
{
NSLog(#"Display2");
NSString *querySQL = [NSString stringWithFormat:
#"SELECT MYTASK, SUBTASK FROM TODO "];
NSLog(#"Display3");
const char *query_stmt = [querySQL UTF8String];
NSLog(#"Display4");
if (sqlite3_prepare_v2(todoDB, query_stmt, -1, &statement, NULL) == SQLITE_OK)
{
NSLog(#"Display5");
if (sqlite3_step(statement) == SQLITE_ROW)
{
NSLog(#"Display6");
NSLog(#"Data is displayed");
} else {
NSLog(#"Display7");
NSLog(#"Data cannot be displayed");
}
sqlite3_finalize(statement);
}
sqlite3_close(todoDB);
}
So whenever i run this, I am getting the output Display1, Display2, Display3 and Display4 in the console . Can anyone please tell me why i am not getting the output display5 and display6.
Thanks in advance.

Answer 1

When you first displayed your list of to-do task, they are rendered to screen.
Subsequent inserts into the database are stored into the database but you have not yet told the app to re-fetch the list of to-do task from the database when you returned to your main page.
In the "viewWillAppear" or "viewDidAppear" of your to-do list page, write a method to fetch all your to do list. Make sure when you fetch the records, you store them in your array which you will use to render them into the table view.
Then after you have fetched your list of to-do from the SQL database, execute this method
[myTableView reloadData];
That will essentially reload your table and display any new records which are contained in your array of to-do.