I'm fresh to iOS Programming, I'm trying my first test as a very simple game , so in this game I want to repeat a function every time the object reach y=80.
The problem in my code that the objects disappear and regenerate from the beginning ,so how can I repeat it?
-(void) TreeMoving{
Tree1.center=CGPointMake(Tree1.center.x, Tree1.center.y+1);
Tree2.center=CGPointMake(Tree2.center.x, Tree2.center.y+1);
Tree3.center=CGPointMake(Tree3.center.x, Tree3.center.y+1);
if (Tree1.center.y>590) {
[self PlaceTrees];
}
you can use the modulo ( % ) operator.
Try this :
if (Tree1.center.y % 80 == 0)
{
[self PlaceTrees];
}
Related
I've created a super simple count down application. You press a button, and the count down runs. The end result calculating looks like this:
10.0
9.999
9.998
...
And each whole number represents a second, so as you can imagine it runs fast.
While this loop runs, I have code in it to play a sound if it finds the current values to be 3.0 or 2.0 or 1.0 or 0.0.
Everything triggers and the sound plays, however it is glitchy as heck. About 80% of the time is triggers perfectly. The rest of the time it is either delayed by a fraction of a second or misses it completely. The sound effects are critical to the app.
I've used prepare to play properly and it did nothing to improve. My current implementation is using SKTAudio which I feel like is a bit overkill for my needs.
Any advice?
Please mind one moment - if you are using Double class to compare two values, you may find, that 2.0 value is not real 2.0, but 2.0000000001 for example. So, 2 and 2.0000001 are different values and your sound will no be played
Use may try smth. like
let checkValue: Double = 2 // your comparison value
let timerValue = 2.00000001 //for example
if (timerValue - Double(Int(timerValue))) == 0 && checkValue == timerValue {
print("Cool")
} else {
print("Not cool")
}
or almost the same
let checkValue: Double = 2 // your comparison value
let timerValue = 2.00000001 //for example
if timerValue == Double(Int(timerValue)) && timerValue == checkValue {
print("Cool")
} else {
print("Not cool")
}
Recently I've been writing a game that requires the Pitch of the device in order to move the character. However, to make it so the user doesn't have to play the game with the device fixed in one starting point every time, every time the user presses play I want the app to acquire the initial tilt. This does not work however, I've added a test button that is suppose to run the code:
func recordTilt() {
InitialTilt = MovementManager.deviceMotion?.attitude
print(InitialTilt)
}
The problem with this is that whenever the button is pressed, InitialTilt will return nil. However, if InitialTilt is run in a the Loop it will return a value every time.
Movement Manager Loop:
func setup() {
MovementManager = CMMotionManager()
MovementManager.deviceMotionUpdateInterval = 0.1
MovementManager.startDeviceMotionUpdates()
InintialTilt = Movementmanager.deviceMotion?.attitude
}
func movementManaging() {
//...
InintialTilt = Movementmanager.deviceMotion?.attitude // returns every
time
//...
}
func update() {
movementManaging()
}
Can someone please help explain to me why the (InintialTilt = Movementmanager.deviceMotion?.attitude) only returns a value while it is in a loop.
(Note: The movementManaging is basically a loop that controls the player's movements, if one were to expand the ...'s all they would get are a bunch of if methods that keep the player on screen. + InintialTilt = Movementmanager.deviceMotion?.attitude)
I am using a Bluno microcontroller to send / receive data from an iPhone, and everything is working as it should, but I would like to update the text of a UILabel with the real time data that is being printed from the Serial.print(numTicks); statement. If I stop the flowmeter the UILabel gets updated with the most current value, but I would like to update this label in realtime. I am not sure if this is a C / Arduino question or more of a iOS / Objective-C question. The sketch I'm loading on my Bluno looks like the following, https://github.com/ipatch/KegCop/blob/master/KegCop-Bluno-sketch.c
And the method in question inside that sketch looks like the following,
// flowmeter stuff
bool getFlow4() {
// call the countdown function for pouring beer
// Serial.println(flowmeterPin);
flowmeterPinState = digitalRead(flowmeterPin);
// Serial.println(flowmeterPinStatePinState);
volatile unsigned long currentMillis = millis();
// if the predefined interval has passed
if (millis() - lastmillis >= 250) { // Update every 1/4 second
// disconnect flow meter from interrupt
detachInterrupt(0); // Disable interrupt when calculating
// Serial.print("Ticks:");
Serial.print(numTicks);
// numTicks = 0; // Restart the counter.
lastmillis = millis(); // Update lastmillis
attachInterrupt(0, count, FALLING); // enable interrupt
}
if(numTicks >= 475 || valveClosed == 1) {
close_valve();
numTicks = 0; // Restart the counter.
valveClosed = 0;
return 0;
}
}
On the iOS / Objective-C side of things I'm doing the following,
- (void)didReceiveData:(NSData *)data Device:(DFBlunoDevice *)dev {
// setup label to update
_ticks = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
[_tickAmount setText:[NSString stringWithFormat:#"Ticks:%#",_ticks]];
[_tickAmount setNeedsDisplay];
NSLog(#"ticks = %#",_ticks);
}
Basically I would like to update the value of the UILabel while the flowmeter is working.
UPDATE
I just tested the functionality again with the serial monitor within the Arduino IDE, and I got the same if not similar results as to what I got via Xcode and the NSLog statements. So this leads me to believe something in the sketch is preventing the label from updating in real time. :/ Sorry for the confusion.
I use: MPMoviePlayerController to show video.
Below I put list of thumbs from the video.
When pressing a thumb I want to jump to a specific place in the video using: setCurrentPlaybackTime.
I also have a timer updating the selected thumb according to the location of the video using: currentPlaybackTime.
My problem: when calling: setCurrentPlaybackTime, the player keeps giving the seconds before seeking to the specific second. It take few seconds to the player to reflect the new seconds. In the mean time the experience of the user is bad: Pressing a thumb shows it selected for a show time, then the timer updates to the previous thumb, then it jumps back to the thumb I selected.
I tried using (in the timer):
if (moviePlayer.playbackState != MPMoviePlaybackStatePlaying && !(moviePlayer.loadState & MPMovieLoadStatePlaythroughOK)) return;
In order to prevent from the timer to update the selected thumb as long the player is in a transition phase between showing the previous thumb and the new thumb, but it doesn't seem to work. The "playbackState" and "loadState" seems to be totally inconstant and unpredictable.
For solving this issue, this how I have implemented this nasty state coverage in one of my projects. This is nasty and fragile but worked good enough for me.
I used two flags and two time intervals;
BOOL seekInProgress_;
BOOL seekRecoveryInProgress_;
NSTimeInterval seekingTowards_;
NSTimeInterval seekingRecoverySince_;
All of the above should be defaulted to NO and 0.0.
When initiating the seek:
//are we supposed to seek?
if (movieController_.currentPlaybackTime != seekToTime)
{ //yes->
movieController_.currentPlaybackTime = seekToTime;
seekingTowards_ = seekToTime;
seekInProgress_ = YES;
}
Within the timer callback:
//are we currently seeking?
if (seekInProgress_)
{ //yes->did the playback-time change since the seeking has been triggered?
if (seekingTowards_ != movieController_.currentPlaybackTime)
{ //yes->we are now in seek-recovery state
seekingRecoverySince_ = movieController_.currentPlaybackTime;
seekRecoveryInProgress_ = YES;
seekInProgress_ = NO;
seekingTowards_ = 0.0;
}
}
//are we currently recovering from seeking?
else if (seekRecoveryInProgress_)
{ //yes->did the playback-time change since the seeking-recovery has been triggered?
if (seekingRecoverySince_ != movieController_.currentPlaybackTime)
{ //yes->seek recovery done!
seekRecoveryInProgress_ = NO;
seekingRecoverySince_ = 0.0;
}
}
In the end, MPMoviePlayerController simply is not really meant for such "micro-management". I had to throw in at least half a dozen flags for state coverage in all kinds of situations and I would never recommend to repeat this within other projects. Once you reach this level, it might be a great idea to think about using AVPlayer instead.
I'm developing a BlackJack game for iOS. Keeping track of the current state and what needs to be done is becoming difficult. For example, I have a C++ class which keeps track of the current Game:
class Game {
queue<Player> playerQueue;
void hit();
void stand();
}
Currently I'm implementing it using events (Method A):
- (void)hitButtonPress:(id)sender {
game->hit();
}
void Game::hit() {
dealCard(playerQueue.top());
}
void Game::stand() {
playerQueue.pop();
goToNextPlayersTurn();
}
as more and more options are added to the game, creating events for each one is becoming tedious and hard to keep track of.
Another way I thought of implementing it is like so (Method B):
void Game::playersTurn(Player *player) {
dealCards(player);
while (true) {
string choice = waitForUserChoice();
if (choice == "stand") break;
if (choice == "hit")
dealCard(player);
// etc.
}
playerQueue.pop();
goToNextPlayersTurn();
}
Where waitForUserChoice is a special function that lets the user interact with the UIViewController and once the user presses a button, only then returns control back to the playersTurn function. In other words, it pauses the program until the user clicks on a button.
With method A, I need to split my functions up every time I need user interaction. Method B lets everything stay a bit more in control.
Essentially the difference between method A and B is the following:
A:
function A() {
initialize();
// now wait for user interaction by waiting for a call to CompleteA
}
function CompleteA() {
finalize();
}
B:
function B() {
initialize();
waitForUserInteraction();
finalize();
}
Notice how B keeps the code more organized. Is there even a way to do this with Objective-C? Or is there a different method which I haven't mentioned recommended instead?
A third option I can think of is using a finite state machine. I have heard a little about them, but I'm sure if that will help me in this case or not.
What is the recommended design pattern for my problem?
I understand the dilemma you are running into. When I first started iOS I had a very hard time wrapping my head around relinquishing control to and from the operating system.
In general iOS would encourage you to go with method A. Usually you have variables in your ViewController which are set in method A(), and then they are checked in CompleteA() to verify that A() ran first etc.
Regarding your question about Finite State Machines, I think that it may help you solve your problem. The very first thing I wrote in iOS was a FSM (there for this is pretty bad code) however you can take a look here (near the bottom of FlipsideViewController.m:
https://github.com/esromneb/ios-finite-state-machine
The general idea is that you put this in your .h file inside an #interface block
static int state = 0;
static int running = 0;
And in your .m you have this:
- (void) tick {
switch (state) {
case 0:
//this case only runs once for the fsm, so setup one time initializations
// next state
state = 1;
break;
case 1:
navBarStatus.topItem.title = #"Connecting...";
state = 2;
break;
case 2:
// if something happend we move on, if not we wait in the connecting stage
if( something )
state = 3;
else
state = 1;
break;
case 3:
// respond to something
// next state
state = 4;
break;
case 4:
// wait for user interaction
navBarStatus.topItem.title = #"Press a button!";
state = 4;
globalCommand = userInput;
// if user did something
if( globalCommand != 0 )
{
// go to state to consume user interaction
state = 5;
}
break;
case 5:
if( globalCommand == 6 )
{
// respond to command #6
}
if( globalCommand == 7 )
{
// respond to command #7
}
// go back and wait for user input
state = 4;
break;
default:
state = 0;
break;
}
if( running )
{
[self performSelector:#selector(tick) withObject:nil afterDelay:0.1];
}
}
In this example (modified from the one on github) globalCommand is an int representing the user's input. If globalCommand is 0, then the FSM just spins in state 4 until globalCommand is non zero.
To start the FSM, simply set running to 1 and call [self tick] from the viewController. The FSM will "tick" every 0.1 seconds until running is set to 0.
In my original FSM design I had to respond to user input AND network input from a windows computer running it's own software. In my design the windows PC was also running a similar but different FSM. For this design, I built two FIFO queue objects of commands using an NSMutuableArray. User interactions and network packet would enqueue commands into the queues, while the FSM would dequeue items and respond to them. I ended up using https://github.com/esromneb/ios-queue-object for the queues.
Please comment if you need any clarification.