- (void) exportImpl
{
NSAutoreleasePool* pool =
[[NSAutoreleasePool alloc] init];
NSArray* documentPaths =
NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSSystemDomainMask,
YES);
NSString* documentsDir = [documentPaths
objectAtIndex:0];
NSString* csvPath = [documentsDir
stringByAppendingPathComponent: @"export.csv"];
// TODO:
mutex lock?
[sqliteDb exportCsv: csvPath];
[pool release];
// mail is graphical and must be run on UI
thread
[self performSelectorOnMainThread: @selector(mail:)
withObject: csvPath waitUntilDone: NO];
}
- (void) mail: (NSString*)
filePath
{
// here I stop animating the
UIActivityIndicator
//
http://howtomakeiphoneapps.com/home/2009/7/14/how-to-make-your-iphone-app-send-email-with-attachments.html
BOOL success = NO;
if ([MFMailComposeViewController
canSendMail]) {
// TODO: autorelease pool needed
?
NSData* database = [NSData
dataWithContentsOfFile: filePath];
if
(database != nil) {
MFMailComposeViewController* picker = [[MFMailComposeViewController alloc]
init];
picker.mailComposeDelegate =
self;
[picker setSubject:[NSString
stringWithFormat: @"%@ %@", [[UIDevice currentDevice] model], [filePath
lastPathComponent]]];
NSString*
filename = [filePath lastPathComponent];
[picker addAttachmentData: database mimeType:@"application/octet-stream"
fileName: filename];
NSString*
emailBody = @"Attached is the SQLite data from my iOS device.";
[picker setMessageBody:emailBody
isHTML:YES];
[self
presentModalViewController:picker animated:YES];
success = YES;
[picker release];
}
}
if (!success) {
UIAlertView* warning = [[UIAlertView alloc] initWithTitle: @"Error"
message: @"Unable to send
attachment!"
delegate: self
cancelButtonTitle: @"Ok"
otherButtonTitles:
nil];
[warning show];
[warning release];
}
}
//And then, I have a class that encapsulates all my SQLite data. This class
is the only one that makes sqlite calls. In this class, I have a method for
exporting data into a CSV file in my
app‘s caches directory. The
variable sqliteDb in the code above is an instance of this class.
Here‘s the method to export data:
-(void) exportCsv: (NSString*)
filename
{
// We record this filename, because the app
deletes it on exit
self.tempFile = filename;
NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];
// Setup the database object
sqlite3*
database;
// Open the database from the users
filessytem
if (sqlite3_open([self.databasePath UTF8String],
&database) == SQLITE_OK)
{
[self createTempFile: filename];
NSOutputStream*
output = [[NSOutputStream alloc] initToFileAtPath: filename append:
YES];
[output open];
if (![output hasSpaceAvailable]) {
NSLog(@"No space available in %@", filename);
// TODO: UIAlertView?
} else
{
NSString* header =
@"Source,Time,Latitude,Longitude,Accuracy\n";
NSInteger result = [output write: [header UTF8String] maxLength:
[header length]];
if (result <=
0) {
NSLog(@"exportCsv encountered error=%d from header write", result);
}
BOOL errorLogged = NO;
NSString* sqlStatement = @"select
timestamp,latitude,longitude,horizontalAccuracy from
my_sqlite_table";
// Setup the
SQL Statement and compile it for faster access
sqlite3_stmt* compiledStatement;
if (sqlite3_prepare_v2(database, [sqlStatement UTF8String], -1,
&compiledStatement, NULL) == SQLITE_OK)
{
//
Loop through the results and write them to the CSV file
while (sqlite3_step(compiledStatement) ==
SQLITE_ROW) {
// Read the data from the result row
NSInteger secondsSinceReferenceDate =
(NSInteger)sqlite3_column_double(compiledStatement, 0);
float lat =
(float)sqlite3_column_double(compiledStatement, 1);
float lon =
(float)sqlite3_column_double(compiledStatement, 2);
float accuracy =
(float)sqlite3_column_double(compiledStatement, 3);
if (lat != 0 && lon !=
0) {
NSDate* timestamp = [[NSDate alloc]
initWithTimeIntervalSinceReferenceDate: secondsSinceReferenceDate];
NSString* line = [[NSString alloc] initWithFormat:
@"%@,%@,%f,%f,%d\n",
table, [dateFormatter stringFromDate: timestamp], lat, lon,
(NSInteger)accuracy];
result = [output write: [line UTF8String] maxLength:
[line length]];
if (!errorLogged && (result <= 0))
{
NSLog(@"exportCsv write returned %d",
result);
errorLogged = YES;
}
[line release];
[timestamp release];
}
// Release the compiled statement from
memory
sqlite3_finalize(compiledStatement);
}
}
}
[output close];
[output release];
}
sqlite3_close(database);
[pool release];
}
-(void)
createTempFile: (NSString*) filename {
NSFileManager*
fileSystem = [NSFileManager defaultManager];
[fileSystem
removeItemAtPath: filename error: nil];
NSMutableDictionary* attributes = [[NSMutableDictionary alloc] init];
NSNumber* permission = [NSNumber numberWithLong: 0640];
[attributes setObject: permission forKey: NSFilePosixPermissions];
if (![fileSystem createFileAtPath: filename contents: nil attributes:
attributes]) {
NSLog(@"Unable to create temp file
for exporting CSV.");
// TODO:
UIAlertView?
}
[attributes
release];
}
My code is exporting a database of location information. Obviously,
inside exportCsv, you will need to replace my sqlite calls with ones that
are appropriate for your database content.
Also, the code stores the data in a temporary file. You‘ll probably want to
decide when to clean out those temp files.
Obviously, this code was written before ARC was available. Adjust as
needed.
