README.md

Assignment 3: Fancy Twos

v1.01:

• minor edits

Goals

Learn to use:

• property animation
• custom views
• drawing
• gestures
• tab bars
• user defaults
• dynamic animations

This is the project where we end up with a real SwiftUI game we can give out to friends and family. We are not significantly changing core functionality, but we are adding many of the extras that make apps usable. See the demo video on ELMS.

Before you begin

This project is based on the last one, but copying Xcode projects is a dicy, multiple-step project, easy to mess up.

Instead, I suggest you create a new project assign3 in your repository, no need for any tests. Create new files with the same name in your last project ("model.swift" and any other files you created), and copy paste the files to this new project.

Run this version to ensure everything is working correctly, quit out of Xcode, git add your code, and then commit push to the server. Note that if you create more files, you need to manually add them as well. git status will tell you what has been modified or is new.

We realize that git is sometimes a challenging, non-intuitive tool, especially as we are not using Xcode's GUI interface, but understanding git will serve you well in almost any facet of the tech world going forward.

Task 1: Ensure Model is using Tile

Your model is conceptually unchanged. However, the view is now going to animate with tile movement, therefore needs to recognize specific tiles in order to identify tile movements.

Your data model should be based on Tiles, with a structure like this:

struct Tile {
    var val : Int
    var id : Int
    var lastRow: Int    // recommended
    var lastCol: Int    // recommended
}

val represents the value to be shown on the board, id is an unique id for this tile. You may also include lastRow and lastCol to represent the location of this Tile on the board (They could help you determine the frame of tiles in the view), and also include any other variables as you need. Then, the board in your model will change from Int to Tile?. With this change, you can explicitly manipulate each tile on the board by working on its corresponding "Tile" data structure.

Suppose we have a row of tiles as:

(val: 2, id: 13), (val:2, id:14), nil, nil

If we are collapsing left, we want Tile id = 13 to disapper, while moving id = 14 to its left, and change its value to 4. This will make the animation the view animation more straightforward and fluid. You might need to modify your model's shift() function to handle this task.

Task 2: TileViews

Your approach should be based custom views, called TileViews, that include the Tile structures you made previously. You might define the new views as follows:

struct TileView: View {
    var tile = Tile(val: 0, id: 0, lastRow: 0, lastCol: 0)
    ...
    
    init(tile: Tile) {
        self.tile = tile
        ...
    }   
    
    var body: some View {
        Text(tile.val.description)
        ...
    }
}

You can create a method func getFrame(t: TileView) -> CGRect to calculate the frame of each TileView, and use Offset to change the location of each tile shown on the screen. Your code should be able to perform as last assignment since each TileView has its unique id, value and frame on the screen.

You can make a list of TileView, and load the TileView with ForEach when the view gets updated. Each time a new tile is added to the list, or an old tile is removed from the list, or tile in the list changes, the view should get updated.

You may revise the spawn() method in Model or related method in View so that each time a new tile is spawned, its corresponding Tileview will be added to the list.

Task 3: Animation

You need to implement "tile moving animation" to show the movements of tiles while clicking the direction buttons.

Hint: You can implement the animation of tile movement by adding animation keywords at 2 locations of your implementation. You may also need to use .offset with variables to determine the start and end location of each tile. Example:

1. tileView:

ForEach (0..<tiles.count, id: \.self) { i in
    tileView[i].offset(x: x[i], y: y[i])
        .animation(.easeInOut(duration: 1))

2. Button:

Button (action: withAnimation
{movingUp}) {
    Text("Up")
}

There are plenty of ways to make animations in SwiftUI, you do not have to implement the same way as we did here. We will not inspect your code for this project, but only check your View.

Task 4: End of Game

In the last project, we never handled a situation when our game failed or ended. We should implement a Boolean variable isDone in model.swift, and a method func isGameDone() to check if the game is ended.

When will the game end?

1. When there is no any empty tile or possible moves of the tiles in the board. You should handle the situation where some of the directions are not executable where some other directions are executable. In this situation, clicking the un-executable direction button will do nothing. Only when ALL 4 directions are not executable, the game is ended.

2. When we click the New Game button. Every time we click the New Game button, the current game will end.

What will happen after the game ends?

A window should pop up to show the final score of current play. You can use ZStack to implement this view. By clicking the "Close" button should start a new game. Every time a game ends, the score should be recorded, this will be discussed in later task.

Task 5: Gestures

Add up, down, left, and right drag gestures to the board. Each direction gesture should work exactly the same as cliking the direction buttom. The gesture can be attached to your game board by adding .gesture(DragGesture ...) at the end of your board view.

Task 6: TabView

You should create a TabView in your ContentView.swift with three subviews. The first should be your board view, the second the high scores, and the third is your "About" screen.

Task 7: Implement the HighScores Page

For the Score Model:

1. Create a new data structure Score to record each game's result. You may want to add more variables and methods as needed. Hashable is not necessary but makes it much easier to sort the list. The following is an example of this data structure:

  struct Score: Hashable {
      var score: Int
      var time: Date
      
      func hash(into hasher: inout Hasher) {
          hasher.combine(time)
      }
      
      init(score: Int, time: Date) {
          self.score = score
          self.time = time
      }
  }

2. Create a high scores list. Add two initial entries (score = 300 and 400, while date time can be any time) to this list when the app gets initiated. This means that we should see two results in the score page even if we never played a game.

3. Sort the list. You can perform the sorting when the score page appears, or when new data points are added.

For The Score View: