Push Button signal not detected properly

Question

I have 6 different led connected to pin 2 to 7 and a push button connected to pin 8. I got two functions one turning led on and off with interval of one second and other one turning on and off led in color patterns. I am trying to switch between these two modes when i press push button. But its not working the way i want. I have to hold the push button till the all led are off to switch mode. I want my led to switch mode immediately after i press push button.

I have tried while loop to to switch mode when pin 8(push button) is high but i am getting same results i have to push and hold to make it work.

Heres my code:

//BUTTON STATE
int state = 0;
bool currentState = LOW;
bool lastState = LOW;

void setup() {
  // put your setup code here, to run once:
  for(int pin = 2;pin <8; pin++){//DECLARE PIN FOR OUTPUT FROM PIN 2 TO 7
    pinMode(pin,OUTPUT);
    pinMode(8,INPUT);
  }
}

bool buttonState(bool last){
  bool current = digitalRead(8);
  if(last != current){
    current = digitalRead(8);
  }
  return current;  
}

void led_dance(int mode){
 if(mode == 0 && digitalRead(8) != HIGH){
   mode_sequeal();
 }
 else{       
  mode_color(); 
 }
}

void mode_sequeal(){//TURN ON LED IN SERIES AND TURN IT OFF IN SERIES  
  for(int led = 2;led <8; led++){//FOR TURNING LED ON
    digitalWrite(led, HIGH);//TURNS LED ON    
    delay(1000);//DELAY FOR 1 SECONDS  
  }
  for(int led = 2;led <8; led++){//FOR TURNING LED OFF
    digitalWrite(led, LOW);
    delay(1000);//DELAY FOR 1 SECONDS
  }
}

void mode_color(){  
    digitalWrite(2,HIGH);
    digitalWrite(5,HIGH);
    delay(500);
    digitalWrite(2,LOW);
    digitalWrite(5,LOW);
    digitalWrite(3,HIGH);
    digitalWrite(7,HIGH);
    delay(500);
    digitalWrite(3,LOW);
    digitalWrite(7,LOW);
    digitalWrite(4,HIGH);
    digitalWrite(6,HIGH);
    delay(500);
    digitalWrite(4,LOW);
    digitalWrite(6,LOW);  
}

void loop() {
  // put your main code here, to run repeatedly:  
 currentState = buttonState(lastState);
 if(lastState == LOW && currentState == HIGH){
   state++;   
 }
 lastState = currentState;
 if(state == 2){
    state = 0; 
 }
 led_dance(state);
}  

Answer 1

Your problem is that you read your button only after led_dance is finished.

You have two choices:

Option one: You can make the code more cluttered and add reading state button before and after every delay like this:

   int buttonChanged()
   {
       // Put logic here to check button state and save it according to your wishes, for example:
       currentState = buttonState(lastState);
       if(lastState == LOW && currentState == HIGH)
       {
           state++;   
       }
       int stateChanged = lastState != currentState;
       lastState = currentState;
       if(state == 2)
       {
           state = 0; 
       }

       return stateChanged;
   }

   void mode_sequeal()
   {
       //TURN ON LED IN SERIES AND TURN IT OFF IN SERIES  
       for(int led = 2; led <8; led++)
       {
           //FOR TURNING LED ON
           digitalWrite(led, HIGH);//TURNS LED ON    
           if (buttonChanged())
           {
               return;
           }
           delay(1000);//DELAY FOR 1 SECONDS    
           if (buttonChanged())
           {
               return;
           }
       }

       for(int led = 2;led < 8; led++)
       {
           //FOR TURNING LED OFF  
           if (buttonChanged())
           {
               return;
           }
           digitalWrite(led, LOW);
           delay(1000);//DELAY FOR 1 SECONDS  
           if (buttonChanged())
           {
               return;
           }
       }
 }

Change other functions accordingly.

Option two: make your implementation event based thanks to Timer library:

http://playground.arduino.cc/Code/Timer

I will leave implementation of it to you, as my environment is not properly set up to test the code.

HINT: check out two-timers example, you need one timer for LEDs and other one for checking button.

EDIT:

Final note: event-based implementation is much harder to write and comprehend, but the final code is much cleaner, more readable, and does want you want much better. Checking for button every now and then slows down the application, and still have 1 second latency, but is much simpler to write and understand.

I recommend, that you try both and compare resulting files and board's behaviour for both implementations. I guarantee it will be most educating.