My iphone keeps turning off. Its like its not charged but it was on a charger all night and is hooked to a charger now and it will just show the apple sign as if it were turning on and then shuts off again

if the charger is working and connected properly , it will charge with out the phone being switched on
check the charger with another phone or it could be a bad battery not accepting a charge

1) First of all, check your charging cable. It won't supply a sufficient amount of energy to start the IPhone if it is bent or punctured. If it is try buying or using an alternative charger 2). If it still won't turn on, press and hold the home button for 30-60 seconds. If it still won't work, contact your local phone or apple store to get the problem sorted.

If you're attempting to charge your iPhone using a USB cable on your computer, check that your computer is not in a power-saving mode. Computer states, like Sleep or Hibernate, do not supply enough power to the iPhone to charge it. Keep the computer turned on and in an alert state to ensure that power is flowing through the USB charger to the iPhone.

If your iPhone's battery runs very far down, the iPhone won't turn on. That's because it's using its remaining battery life to preserve your data and settings.So, your iPhone could be refusing to turn on because its battery doesn't have enough juice. In that case, plug your iPhone into a wall charger or into your computer (plug it directly into the computer; some USB ports on keyboards don't have enough power to charge iPhones). Let it sit for 10-20 minutes. If it was low on battery and needed a charge, when it's got enough juice to power the screen, it will turn on and show you its charging status, starting with the red battery icon.During this process, you may also want to make sure there's no lint packed into your cable or the iPhone's dock connector. This isn't a hugely common problem, but a lot of pocket lint could interfere with the iPhone getting a charge.

Maybe you can change a new battery, or check your charger firstly. dont be worry, your phone is ok.

Once you purchase the iphone,dont use it yet.Instead of using it right away,kindly charge your IPhone with the wall charger for 3 hrs.Please dont use the Iphone while charging.Kindly check always if the battery is full.Once its fully charged then that's the time that you can use the iPhone. Once fully charged, let the iPhone's battery fully drain.Please keep the iPhone off for 2 hours.Fully charge your iPhone and allow the battery to rest in the fully charged state for two hours. (You may use your iPhone during this time as long as the iPhone is plugged in).Repeat the third and fourth step a maximum of three times if you feel your battery indicator is inaccurate.

Here are some tips for your everyday charging for your IPhone:
#1 - Charge your iPhone throughout the day when available. Charge EVERY night, regardless of charge level. This will keep your battery active, which is healthy for the iPhone's battery.
#2 - Use a wall charger or car charger w/ rated output 5V 1A. Computer chargers might not charge when the computer is in standby mode.
#3 - You cannot overcharge your iPhone. You don't need to disconnect the iPhone from the charger after it's done charging. Once fully charged, the iPhone will run strictly off of AC power and will not damage the battery.
#4 - Every two months, make sure you fully charge and fully drain the battery, in one cycle. This calibrates your battery indicator. If you fail to do this, your indicator will become inaccurate. Calibrating your battery does not improve battery life.
#5 - If you ever need to store your iPhone for any reason, make sure your battery is stored @ roughly 50% and in a cool environment.
#6 - Always charge your iPhone out of its case (assuming you can easily remove the case). Charging your iPhone inside your case will make the iPhone hotter, which is bad for the battery.
#7 - Charge your iPhone in a cool location. Charging your iPhone in a cool environment has a tremendous impact on your battery's lifespan. The colder the location you use to charge, the more charging cycles you can complete without your battery deteriorating. Avoid charging in direct sunlight.
#8 - Use properly rated chargers. Using chargers that are not properly rated will have a huge impact on your battery's lifespan. Make sure your car charger has the same rating as the official Apple charger.
The official Apple wall charger is rated as follows:
Input: 100 240V ~ 50/60 Hz 1.0A
Output: 5V 1A
Thanks!

Keep the home and power button pressed for 10 seconds, then, leave power and keep the home button pressed...shud be able to see the charging cable logo...then restore it...

ypu might have not allowed all the waterto dry,send it to apple for service