While the previous recipe illustrates how the static properties allow a game to remember values between different scenes, these values are forgotten once the game application has quit. Unity provides the PlayerPrefs feature to allow a game to store and retrieve data, between the different game playing sessions.
This recipe builds upon the previous recipe. In case you haven't completed the previous recipe, we have included a Unity package named game_scoreStaticVariables in the the 1362_10_05 folder. In order to follow this recipe using this package, you must do the following:
To save and load the player data using PlayerPrefs, follow these steps:
- Delete the C# script called
Player. - Edit the C# script called
UpdateScoreTextby replacing theStart()method with the following:void Start(){ Text scoreText = GetComponent<Text>(); int scoreCorrect = PlayerPrefs.GetInt("scoreCorrect"); int scoreIncorrect = PlayerPrefs.GetInt("scoreIncorrect"); int totalAttempts = scoreCorrect + scoreIncorrect; string scoreMessage = "Score = "; scoreMessage += scoreCorrect + " / " + totalAttempts; scoreText.text = scoreMessage; } - Now, edit the C# script called
IncrementCorrectScoreby replacing theStart()method with the following code:void Start () { int newScoreCorrect = 1 + PlayerPrefs.GetInt("scoreCorrect"); PlayerPrefs.SetInt("scoreCorrect", newScoreCorrect); } - Now, edit the C# script called
IncrementIncorrectScoreby replacing theStart()method with the following code:void Start () { int newScoreIncorrect = 1 + PlayerPrefs.GetInt("scoreIncorrect"); PlayerPrefs.SetInt("scoreIncorrect", newScoreIncorrect); } - Save your scripts and play the game. Quit from Unity and then restart the application. You will find that the player's name, level, and score are now kept between the game sessions.
We had no need for the Player class, since this recipe uses the built-in runtime class called PlayerPrefs, provided by Unity.
Unity's PlayerPrefs runtime class is capable of storing and accessing information (the string, int, and float variables) in the user's machine. Values are stored in a plist file (Mac) or the registry (Windows), in a similar way to web browser cookies, and therefore, remembered between game application sessions.
Values for the total correct and incorrect scores are stored by the Start() methods in the IncrementCorrectScore and IncrementIncorrectScore classes. These methods use the PlayerPrefs.GetInt("<variableName>") method to retrieve the old total, add 1 to it, and then store the incremented total using the PlayerPrefs.SetInt("<variableName>") method.
These correct and incorrect totals are then read each time the scene0_mainMenu scene is loaded, and the score totals displayed via the UI Text object on the screen.