I'm very new to iOS coding and I've been practicing with little app examples found online.
I'm reading examples in the "iOS Sensor Apps with Arduino" book and I've been following instructions for the serial communication example with the Adruino UNO board using the Redpark serial cable for the iPhone/iPad
I have the Redpark serial cable and their demo app, and a registered working developer profile. I've been able to communicate over serial with the demo app on the iPhone and the serial port on my computer.
In working with the example from the book and I've copied in this line to the iOS code:
bytesRead = [rscMgr read:rxBuffer length:numBytes];
However, when compiling this with the rest of the code it throws an error described as
Use of undeclared identifier "if"
I've looked everywhere for the word "if" and can't find it. I've also looked at the sample code from Redpark and the is similar if not identical, except for the buffer name.
Please let me know if I've provided enough detail and I'm forward to any advice this community may have, thanks again for offering your time.
Bellow is more of the code:
#import "ViewController.h"
#interface ViewController ()
#end
#implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
rscMgr = [[RscMgr alloc] init];
[rscMgr setDelegate:self];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (IBAction)sendString:(id)sender {
[self.textEntry resignFirstResponder];
//Add code here
}
#pragma mark - RscMgrDelegate methods
- (void)cableConnected:(NSString *)protocol {
[rscMgr setBaud:9600];
[rscMgr open];
}
- (void)cableDisconnected {
}
- (void)portStatusChanged {
- (void) readBytesAvailable:(UInt32)numBytes {
int bytesRead;
// Read the data out
**bytesRead = [rscMgr read:rxBuffer length:numBytes];**
NSLog( #"Read %d bytes from serial cable.", bytesRead);
for(int i = 0;i < numBytes;++i) {
lf.serialView.text =
[NSString stringWithFormat:#"%#%c",
self.textView.text,
((char *)rxBuffer)[i]];
}
}
- (BOOL) rscMessageReceived:(UInt8 *)msg TotalLength:(int)len {
return FALSE;
}
- (void) didReceivePortConfig {
}
#end
I want to write unit tests using Apple's default SenTestingKit for the below method:
- (NSDictionary*)getValueTags {
return _tags;
}
- (NSString*)getFlag {
NSString* jo = #"";
for (NSString* key in _tags) {
jo = [jo stringByAppendingFormat:#"%#=\"%#\"&", key, [_tags objectForKey:key]];
}
if ([jo length] > 0) {
jo = [jo substringToIndex:[jo length] - 1];
}
return jo;
}
I used default SenTesting
- (void)setUp
{
[super setUp];
// Set-up code here.
}
- (void)tearDown
{
// Tear-down code here.
[super tearDown];
}
-(void)testValueTags{
}
-(void)testGetFlag{
}
I am new to writing TestCases, I need some guideline for sample methods to write test cases
A test case has four distinct phases:
set up
exercise
verify
tear down
Some of these phases can be empty. For example, most tear down happens automatically if you use ARC.
When you're starting, don't put anything into the setUp or tearDown methods. Just write a single unit test. Here's a worked example. (I'm going to change the names, because Objective-C idiom is not to use the word "get". So instead of getFlag let's just call it flag.) I'm going to call the class `Example, and I'll use ARC. And I use the abbreviation "sut" for "system under test".
- (void)testFlagGivenOneEntry
{
// set up
Example *sut = [[Example alloc] init];
[sut setTags:#{ #"key1" : #"value1" }];
// execute & verify
STAssertEqualObjects([sut flag], #"key1=\"value1\"", nil);
}
That's one test. Let's add another.
- (void)testFlagGivenTwoEntries
{
// set up
Example *sut = [[Example alloc] init];
[sut setTags:#{ #"key1" : #"value1",
#"key2" : #"value2" }];
// execute & verify
STAssertEqualObjects([sut flag], #"key1=\"value1\"&key2=\"value2\"", nil);
}
At this point, we have duplicate code: the creation of the sut. Now we can promote the variable up to an instance variable of the class. Then we create it in setUp and destroy it in tearDown:
#interface ExampleTest : SenTestCase
#end
#implementation ExampleTest
{
Example *sut;
}
- (void)setUp
{
[super setUp];
sut = [[Example alloc] init];
}
- (void)tearDown
{
sut = nil;
[super tearDown];
}
- (void)testFlagGivenOneEntry
{
[sut setTags:#{ #"key1" : #"value1" }];
STAssertEqualObjects([sut flag], #"key1=\"value1\"", nil);
}
- (void)testFlagGivenTwoEntries
{
[sut setTags:#{ #"key1" : #"value1",
#"key2" : #"value2" }];
STAssertEqualObjects([sut flag], #"key1=\"value1\"&key2=\"value2\"", nil);
}
#end
For a more involved example, see Objective-C TDD: How to Get Started.
I am developing an Objective-C application, and what I want to do, is something like the following:
+-----------------+ +---------------+
| Some Object | <---------- | Synchronize |
|(Not Thread Safe)| | Proxy |
+-----------------+ / +---------------+
/
/ Intercepts [someobject getCount]
/ #synchronize (someObject)
/
[someObject getCount] /
+----------------------+
| Some Calling Object |
+----------------------+
What I've asking is, how can I create an object in objective-c, that intercepts messages sent to another object, in order to perform code before the message is sent to that object.
Some things that I think will not work:
Categories (I need this to only happen for certain instances of a class)
Rewriting the object (I don't have access to the source of the object)
Method swizzling (once again, this need to only happen for certain instances of a class)
You would implement an NSProxy that forwards messages to your non-thread-safe object.
Here is a nice writeup of message forwarding in Objective-C, and here is Apple's documentation.
To handle thread safety, it depends on what you need. If your non-thread-safe object must run on a specific thread then you can use a NSRunLoop on said thread to serialize messages to that object.
Here is an example of using NSInvocation in conjunction with NSRunLoop. In that example they're using performSelector:withObject:afterDelay: but to use it with performSelector:onThread:withObject:waitUntilDone: would be very similar.
Otherwise, just use a single NSRecursiveLock in your proxy.
If you know exactly what instances should have the behavior you are trying to achieve you can go with method swizzling and call the base implementation if the instance is not the one you are looking for.
You can have a global shared object that lists the "interesting" instances and use it in the swizzling implementation whether you have to call the base one or your custom one.
So, I bit the bullet, and decided to make my own proxy class. To subclass, you simply override the 'forwardInvocation:' message, and you call any code you need there, before calling [super forwardInvocation:]. Please not this will NOT work with vardic methods, as NSInvocation doesn't work with vardic methods.
#import <Foundation/Foundation.h>
#import <objc/runtime.h>
#import <objc/objc.h>
#import <objc/message.h>
#interface RJProxy : NSObject {
#private
NSObject *target;
}
#property(readwrite, retain) NSObject *target;
-(NSObject *) getTarget;
#end
#implementation RJProxy
#synthesize target;
-(NSMethodSignature *) methodSignatureForSelector:(SEL)aSelector
{
if (objc_getAssociatedObject(self, "isProxy"))
{
IMP NSObjectImp = [NSObject instanceMethodForSelector:#selector(methodSignatureForSelector:)];
NSMethodSignature *methodSignature = (NSMethodSignature *) NSObjectImp(self, #selector(methodSignatureForSelector:), aSelector);
if (methodSignature)
return methodSignature;
return [target methodSignatureForSelector:aSelector];
}
else
{
Class subClass = self->isa;
#try {
self->isa = objc_getAssociatedObject(self, "realSuperclass");
return [super methodSignatureForSelector:aSelector];
}
#finally {
self->isa = subClass;
}
}
}
-(void) forwardInvocation:(NSInvocation *)anInvocation
{
if (objc_getAssociatedObject(self, "isProxy"))
{
Class subClass = target->isa;
target->isa = objc_getAssociatedObject(self, "realSuperclass");
[anInvocation invokeWithTarget:target];
target->isa = subClass;
}
else
{
Class realSuperclass = objc_getAssociatedObject(self, "realSuperclass");
Class subclass = self->isa;
self->isa = realSuperclass;
if ([self respondsToSelector:[anInvocation selector]])
{
[anInvocation invokeWithTarget:self];
}
else
{
[self doesNotRecognizeSelector:[anInvocation selector]];
}
self->isa = subclass;
}
}
-(NSObject *) getTarget
{
if (objc_getAssociatedObject(self, "isProxy"))
{
return target;
}
return self;
}
#end
BOOL object_setProxy(NSObject *object, RJProxy *proxy);
BOOL object_setProxy(NSObject *object, RJProxy *proxy)
{
proxy.target = object;
Class objectClass = object_getClass(object);
Class objectSub = objc_allocateClassPair(objectClass, [[NSString stringWithFormat:#"%s_sub%i", class_getName(objectClass), objc_getAssociatedObject(objectClass, "subclassTimes")] UTF8String], 0);
objc_setAssociatedObject(objectClass, "subclassTimes", (id) ((int) objc_getAssociatedObject(objectClass, "subclassTimes") + 1), OBJC_ASSOCIATION_ASSIGN);
objc_registerClassPair(objectSub);
Class proxyClass = object_getClass(proxy);
Class proxySub = objc_allocateClassPair(proxyClass, [[NSString stringWithFormat:#"%s_sub%i", class_getName(proxyClass), objc_getAssociatedObject(proxyClass, "subclassTimes")] UTF8String], 0);
objc_setAssociatedObject(proxyClass, "subclassTimes", (id) ((int) objc_getAssociatedObject(proxyClass, "subclassTimes") + 1), OBJC_ASSOCIATION_ASSIGN);
objc_registerClassPair(proxySub);
object_setClass(object, proxySub);
object_setClass(proxy, proxySub);
objc_setAssociatedObject(object, "isProxy", (id) NO, OBJC_ASSOCIATION_ASSIGN);
objc_setAssociatedObject(proxy, "isProxy", (id) YES, OBJC_ASSOCIATION_ASSIGN);
objc_setAssociatedObject(object, "realSuperclass", objectClass, OBJC_ASSOCIATION_ASSIGN);
objc_setAssociatedObject(proxy, "realSuperclass", proxyClass, OBJC_ASSOCIATION_ASSIGN);
return NO;
}
#interface SynchronizeProxy : RJProxy
#end
#implementation SynchronizeProxy
-(void) forwardInvocation:(NSInvocation *)anInvocation {
#synchronized ([self getTarget])
{
[super forwardInvocation:anInvocation];
}
}
#end
int main (int argc, const char * argv[])
{
#autoreleasepool {
NSArray *arrayToSynchronize = [NSArray arrayWithObjects:#"This, is, a, test!", nil];
SynchronizeProxy *myProxy = [SynchronizeProxy new];
object_setProxy(arrayToSynchronize, myProxy);
// now all calls will be synchronized!
NSLog(#"Array at address 0x%X with count of %lu, and Objects %# ", (unsigned) arrayToSynchronize, [arrayToSynchronize count], arrayToSynchronize);
[myProxy release];
[arrayToSynchronize release];
}
return 0;
}
I'm having a problem with NSValueTransformer, instead of transforming the value (NSString) it's putting NULL into the database where the attributes are transformable. I'm using the apple example, which is the same are everyone else's example and I just can't get it to work on a simple level. I'm also putting breakpoints at transformedValue and reverseTransformedValue, but they never get hit.
My custom class
+ (void)registerValueTransformer {
[NSValueTransformer setValueTransformer:[[[self alloc] init] autorelease] forName:#"myTransformerTest"];
}
#pragma mark -
#pragma mark NSValueTransformer implementation
+ (BOOL)allowsReverseTransformation {
return YES;
}
+ (Class)transformedValueClass {
return [NSString class];
}
- (id)transformedValue:(id)value {
return #"Test in";
}
- (id)reverseTransformedValue:(id)value {
return #"Test Out";
}
And this in my app delegate
+(void) initialize
{
[super initialize];
[transformerTest registerValueTransformer];
}
And then in Core data I've made my attribute transformable with a name "myTransformerTest". And according to the apple documentation that should be it.
I have an object that i intalize it's propertis with call to an init function, it works fine,
when i tried to add another object and intalize it the first object didn't get the properites, how do i initalize it to more then one object with diffrent or the same properties?
- (void)viewDidLoad {
pic1 = [[peopleAccel alloc] init];
}
Class peopleAccel:
- (id) init
{
self = [super init];
if (self != nil) {
position = CGPointMake(100.0, 100.0);
velocity = CGPointMake(4.0, 4.0);
radius = 40.0;
bounce = -0.1f;
gravity = 0.5f;
dragging = NO;
[[UIAccelerometer sharedAccelerometer] setDelegate:self];
acceleratedGravity = CGPointMake(0.0, gravity);
}
return self;
}
I see a problem with setting the delegate of sharedAccelerometer. Only one object can be a delegate of another object at a time. So you should create only one peopleAccel object.
EDIT:
If you need to send accelerometer events to more than one object, you can create a specific delegate object in charge of receiving accelerometer events and broadcasting them to your several peopleAccel objects via notifications. See this question for some hints: NSNotificationCenter vs delegation?
Create a proxy so multiple objects can receive accelerometer events.
Whether you should do this or use NSNotificationCenter is debatable and there are two camps, but personally I would use this approach. NSNotificationCenter has to check string names to recognise event type; this kind of approach could be ever so slightly faster especially with a bit more optimisation. A bit more typing but I would say also easier for someone else to follow.
Something like this...
/* PLUMBING */
/* in headers */
#protocol MyAccelSubDelegate
-(void)accelerometer:(UIAccelerometer*)accelerometer
didAccelerate:(UIAcceleration*)acceleration;
#end
#interface MyAccelSubDelegateProxy : NSObject <UIAccelerometerDelegate> {
NSMutableArray subDelegates;
}
-(id)init;
-dealloc;
-(void)addSubDelegate:(id<MyAccelSubDelegate>)subDelegate;
-(void)removeSubDelegate:(id<MyAccelSubDelegate>)subDelegate;
- (void)accelerometer:(UIAccelerometer *)accelerometer didAccelerate:
(UIAcceleration *)acceleration;
#end
/* in .m file */
#implementation MyAccelSubDelegateProxy
-(id)init { self = [super init];
if (self!=nil) subDelegates = [[NSMutableArray alloc] init]; return self; }
-dealloc { [subDelegates release]; }
-(void)addSubDelegate:(id<MyAccelSubDelegate>)subDelegate {
[subDelegates insertObject:subDelegate atIndex:subDelegates.count]; }
-(void)removeSubDelegate:(id<MyAccelSubDelegate>)subDelegate {
for (int c=0; c < subDelegates.count; c++) {
id<MyAccelSubDelegate> item = [subDelegates objectAtIndex:c];
if (item==subDelegate) { [subDelegates removeObjectAtIndex:c];
c--; continue; }
}
}
- (void)accelerometer:(UIAccelerometer *)accelerometer didAccelerate:
(UIAcceleration *)acceleration {
for (int c=0; c < subDelegates.count; c++)
[((id<MyAccelSubDelegate>)[subDelegates objectAtIndex:c])
accelerometer:accelerometer didAccelerate:acceleration];
}
#end
/* SOMEWHERE IN MAIN APPLICATION FLOW STARTUP */
accelProxy = [[MyAccelSubDelegateProxy alloc] init];
[UIAccelerometer sharedAcclerometer].delegate = accelProxy;
[UIAccelerometer sharedAcclerometer].updateInterval = 0.100; // for example
/* TO ADD A SUBDELEGATE */
[accelProxy addSubDelegate:obj];
/* TO REMOVE A SUBDELEGATE */
[accelProxy removeSubDelegate:obj];
/* SOMEWHERE IN MAIN APPLICATION SHUTDOWN */
[UIAccelerometer sharedAcclerometer].delegate = nil;
[accelProxy release];