/// <summary>
/// Check puzzle is finished.
/// </summary>
/// <returns>A Task to check finish of puzzle asynchrously</returns>
Task CheckFinished()
{
return(Task.Run(() =>
{
bool finish = true;
//check all puzzle square has original position
for (int row = 0; row < (int)_level; row++)
{
for (int col = 0; col < (int)_level; col++)
{
PuzzleSquare square = _puzzleSquares[row, col];
if (square != null)
{
if (square.OriginalX != square.PositionX || square.OriginalY != square.PositionY)
{
//Puzzle is not completed.
finish = false;
break;
}
}
}
if (!finish)
{
break;
}
}
//if all puzzle is match. create finish popup.
if (finish)
{
Device.BeginInvokeOnMainThread(() =>
{
DisplayFinishDialog();
});
_started = false;
}
}));
}
/// <summary>
/// Move one square to a specified direction.
/// If the direct == Direction.UNKNOW, it will choose an available direction automatically.
/// </summary>
/// <param name="square">Puzzle square object</param>
/// <param name="direct">The direction will move to</param>
private void MoveBlock(PuzzleSquare square, Direction direct)
{
//Get square's current position.
Position pos = new Position(square.PositionX, square.PositionY);
if (direct == Direction.UNKNOW)
{
if (pos.X + 1 == _blankPos.X && pos.Y == _blankPos.Y)
{
direct = Direction.RIGHT;
}
else if (pos.X - 1 == _blankPos.X && pos.Y == _blankPos.Y)
{
direct = Direction.LEFT;
}
else if (pos.X == _blankPos.X && pos.Y + 1 == _blankPos.Y)
{
direct = Direction.DOWN;
}
else if (pos.X == _blankPos.X && pos.Y - 1 == _blankPos.Y)
{
direct = Direction.UP;
}
else
{
return;
}
}
//Remove old image object from Grid.
_puzzleGrid.Children.Remove(square);
switch (direct)
{
case Direction.UP:
pos.Y--;
_blankPos.Y++;
break;
case Direction.DOWN:
pos.Y++;
_blankPos.Y--;
break;
case Direction.LEFT:
pos.X--;
_blankPos.X++;
break;
case Direction.RIGHT:
pos.X++;
_blankPos.X--;
break;
}
_puzzleGrid.Children.Add(square, pos.X, pos.X + 1, pos.Y, pos.Y + 1);
//replace blank to moved square.
_puzzleSquares[_blankPos.Y, _blankPos.X] = null;
_puzzleSquares[pos.Y, pos.X] = square;
square.PositionX = pos.X; //store current x position
square.PositionY = pos.Y; //store current y position
if (_started)
{
//after block is moved, checking if puzzle is completed.
//if puzzle is complete. display finish dialog.
if (_blankPos.X == ((int)_level - 1) && _blankPos.Y == ((int)_level - 1))
{
CheckFinished();
}
}
}
/// <summary>
/// Add image blocks in puzzle view
/// </summary>
/// <param name="grid">The container Grid layout</param>
/// <seealso cref="Grid">
private void CreatePuzzle(Grid grid)
{
int level = (int)_level;
int imageSize = 225;
int size = imageSize / level;
string folder = "";
//Clear _puzzleSquares firstly
int row = 0;
int col = 0;
//Clear puzzle grid
grid.Children.Clear();
//Initialize PuzzleSquare
for (row = 0; row < MAXNUM; row++)
{
for (col = 0; col < MAXNUM; col++)
{
_puzzleSquares[row, col] = null;
}
}
//The blank block's position at the right bottom corner.
_blankPos = new Position(level - 1, level - 1);
PuzzleSquare square = null;
if (level == 4)
{
folder = "4X4";
}
else
{
folder = "5X5";
}
for (row = 0; row < level; row++)
{
for (col = 0; col < level; col++)
{
//Does not add Image in blank block.
if (row == _blankPos.Y && col == _blankPos.X)
{
break;
}
//Create new square and then add puzzle grid.
square = new PuzzleSquare()
{
Source = folder + "/" + (row + 1).ToString() + "-" + (col + 1).ToString() + ".jpg",
MinimumWidthRequest = (720 - 2 * 2 * level) / level,
MinimumHeightRequest = (720 - 2 * 2 * level) / level,
PositionX = col,
PositionY = row,
OriginalX = col,
OriginalY = row,
};
//Add click event handler
square.Clicked += (s, e) =>
{
//Extract press square from sender.
PuzzleSquare clickedSquare = (PuzzleSquare)s;
MoveBlock(clickedSquare, Direction.UNKNOW);
};
//Add square to _puzzleSquares array
_puzzleSquares[row, col] = square;
//Add created Image object to Grid
grid.Children.Add(square, col, col + 1, row, row + 1);
}
}
}