vb.net print barcode labels An example using location and distance in Objective-C

Printer QR Code 2d barcode in Objective-C An example using location and distance

10.4.2 An example using location and distance
Draw QR-Code In Objective-C
Using Barcode printer for iPhone Control to generate, create Denso QR Bar Code image in iPhone applications.
www.OnBarcode.com
UCC - 12 Creator In Objective-C
Using Barcode encoder for iPhone Control to generate, create UCC - 12 image in iPhone applications.
www.OnBarcode.com
This section shows an example of using Core Location to record a starting location, monitor the current location, and calculate the distance between them. As usual, the foundation of this program is built in Interface Builder. Figure 10.4 displays the general setup. There are three labels: startLabel (at the top) and endLabel (at the bottom) each display information about a location; distanceLabel shows the distance between the two. There are two controls: a button control instantly updates the current location, and a segmented control chooses between miles and kilometers. They re each linked to an IBAction, which executes a method that you ll meet in the code.
Data Matrix ECC200 Creation In Objective-C
Using Barcode printer for iPhone Control to generate, create Data Matrix 2d barcode image in iPhone applications.
www.OnBarcode.com
GTIN - 13 Generator In Objective-C
Using Barcode generation for iPhone Control to generate, create EAN13 image in iPhone applications.
www.OnBarcode.com
Download from Wow! eBook <www.wowebook.com>
Code 128 Code Set C Generation In Objective-C
Using Barcode generation for iPhone Control to generate, create Code 128A image in iPhone applications.
www.OnBarcode.com
Painting Barcode In Objective-C
Using Barcode generation for iPhone Control to generate, create Barcode image in iPhone applications.
www.OnBarcode.com
Positioning: accelerometers, location, and the compass
Encoding Barcode In Objective-C
Using Barcode printer for iPhone Control to generate, create Barcode image in iPhone applications.
www.OnBarcode.com
GTIN - 8 Encoder In Objective-C
Using Barcode creator for iPhone Control to generate, create UPC - 8 image in iPhone applications.
www.OnBarcode.com
Figure 10.4 This simple utility shows off locations and distance.
Quick Response Code Decoder In .NET
Using Barcode decoder for VS .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Reading QR Code ISO/IEC18004 In C#.NET
Using Barcode recognizer for .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Listing 10.3 shows the code. This is the first of two longer examples in this chapter.
Making Data Matrix In Objective-C
Using Barcode creation for iPad Control to generate, create DataMatrix image in iPad applications.
www.OnBarcode.com
Printing Barcode In None
Using Barcode encoder for Microsoft Word Control to generate, create Barcode image in Microsoft Word applications.
www.OnBarcode.com
Listing 10.3 An application of Core Location for distances
Painting Barcode In Java
Using Barcode drawer for Android Control to generate, create Barcode image in Android applications.
www.OnBarcode.com
Paint Barcode In Java
Using Barcode creator for BIRT reports Control to generate, create Barcode image in BIRT reports applications.
www.OnBarcode.com
- (void)viewDidLoad { [super viewDidLoad]; myLM = [[CLLocationManager alloc] init]; myLM.delegate = self; myLM.desiredAccuracy = kCLLocationAccuracyNearestTenMeters; Starts location myLM.distanceFilter = 100; updates [myLM startUpdatingLocation]; } - (void)locationManager:(CLLocationManager *)manager Waits for didUpdateToLocation:(CLLocation *)newLocation updates fromLocation:(CLLocation *)oldLocation { if (startLoc == nil) { startLoc = newLocation; [self updateLocationFor:startLabel toLocation:newLocation]; [startLoc retain]; }
Barcode Maker In Java
Using Barcode generator for Eclipse BIRT Control to generate, create Barcode image in BIRT applications.
www.OnBarcode.com
Scan UCC - 12 In Visual Basic .NET
Using Barcode reader for .NET framework Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
[self updateLocationFor:endLabel toLocation:newLocation]; [self updateDistanceLabel:newLocation]; } - (IBAction)setEnd:(id)sender { [myLM stopUpdatingLocation];
Paint Code 3 Of 9 In VB.NET
Using Barcode maker for .NET Control to generate, create Code 3 of 9 image in .NET applications.
www.OnBarcode.com
Scan USS Code 39 In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Forces location update
Barcode Creation In Java
Using Barcode printer for Android Control to generate, create Barcode image in Android applications.
www.OnBarcode.com
GTIN - 12 Printer In .NET Framework
Using Barcode printer for .NET framework Control to generate, create UPC-A image in .NET applications.
www.OnBarcode.com
Download from Wow! eBook <www.wowebook.com>
All about Core Location
[myLM startUpdatingLocation]; Forces } label - (IBAction)controlChange:(id)sender { update if (myLM.location) { [self updateDistanceLabel:myLM.location]; } Updates distance } label - (void)updateDistanceLabel:(CLLocation *)newLocation { if (startLoc != nil) { CLLocationDistance traveled = [startLoc getDistanceFrom:newLocation] / 1000; if (segmentControl.selectedSegmentIndex == 1) { traveled *= .62; } distanceLabel.text = [NSString stringWithFormat:@"%5.1f",traveled]; } } Updates - (void)updateLocationFor:(UILabel *)thisLabel location label toLocation:(CLLocation *)newLocation { CLLocationCoordinate2D curCoords = newLocation.coordinate; thisLabel.text = [NSString stringWithFormat: @"Lat: %2.4f; Long: %2.4f",curCoords.latitude,curCoords.longitude]; }
This program generally follows the broad outline of steps that we ve already discussed, but we ll go through each step in turn. Make sure to add the Core Location framework to your project and import CoreLocation/CoreLocation.h in all the files in which you intend to utilize location services. After that, you begin by initializing a CLLocationManager object and then set some standard properties here a delegate, the desiredAccuracy, and the distanceFilter. The desired accuracy of tens of meters and the update interval of every 100 meters may be more than this particular application requires, but you can tune these in your projects as seems appropriate. Remember that demanding more accuracy and updating more frequently will decrease the battery life of your user s iPhone or iPad. Finally, you start the CLLocationManager running B. The locationManager:didUpdateToLocation:fromLocation: method is the workhorse of this program C. It should be called shortly after the LocationManager starts updating and every time the user walks 100 meters or so. First, it saves the current location as the starting location the first time it s called, updating the startLabel at the same time. Then, every time it runs, it updates the endLabel and the distanceLabel. Note that you don t have to use the LocationManager s location property here (or at almost any other time in the program), because this method always provides the current location of the device; it seems to do so well before the location property is updated, based on our own tests. Caveat programmer. The next few methods have to do with I/O. The method setEnd: is run whenever the button control is pushed, to update the current location D. Unfortunately, there s no particularly clean way to ask for an update, so you must stop and start the location updates, as shown here. Letting the user force a location update is particularly important if you re using a high distanceFilter or if you re trying to measure altitude
Download from Wow! eBook <www.wowebook.com>
Positioning: accelerometers, location, and the compass
changes. In the altitude example, in the next section, you ll see an alternative way to do this, where the location manager usually isn t running at all. The controlChange: method is run whenever the segmented control is updated E. It updates the distanceLabel. Note that this is the one time when you depend on the location property, because there isn t a location event when you change the button. The last few methods are utilities. The updateDistanceLabel: method makes use of an interesting CLLocation method that we haven t discussed, getDistanceFrom: F. This measures the true distance between two locations, using complex calculations that correctly account for the curvature of the Earth. The method also converts meters to kilometers and alternatively converts them to miles, depending on the status of the segmented control. Finally, updateLocationFor:toLocation: updates either the startLabel or the endLabel by extracting the latitude and longitude coordinates from the CLLocation object it s passed G. The result is a program that can show a simple distance traveled in a single direction. If we were going to improve it, we d probably save the starting location to a file, and perhaps even make it possible to record multiple trips. But for the purposes of showing how Core Location works, this is sufficient. There s one thing that the example didn t show: how to measure altitude. It s another CLLocation property, but you ll write another short program to highlight this part of Core Location.
Copyright © OnBarcode.com . All rights reserved.