Java 字典<字符串，列表<对象>>
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Java dictionary<String, List<Object>>
提问by Julius
I was making a game with XNA game studio and now I want to rewrite it in Java. It's something like a 2D Minecraft clone. For collision detection, I have to loop through all blocks in the game to check on whether the player is colliding with a block. With a huge number of blocks, it is impossible to do so, so I made a grid system. I divided the world into grids which contain blocks, and put them into a dictionary.
我正在使用 XNA 游戏工作室制作游戏，现在我想用 Java 重写它。这有点像 2D Minecraft 克隆版。对于碰撞检测，我必须遍历游戏中的所有块以检查玩家是否与块发生碰撞。有大量的块，这是不可能的，所以我做了一个网格系统。我将世界划分为包含块的网格，并将它们放入字典中。
Dictionary<string, List<Block>> gameBlocks;
Now I have only to loop through the blocks in the current grid.
现在我只需要遍历当前网格中的块。
This is the method to register a block:
这是注册块的方法：
public void RegisterBlock(Block block)
{
idX = (int)(block.blockPosition.X / width);
idY = (int)(block.blockPosition.Y / height);
string id = idX.ToString() + "_" + idY.ToString();
if (gameBlocks.ContainsKey(id))
{
gameBlocks[id].Add(block);
}
else
{
gameBlocks.Add(id, new List<Block>());
gameBlocks[id].Add(block);
}
}
Now I am trying to rewrite it in Java but I don't know how to put something into a Dictionary.
现在我正在尝试用 Java 重写它，但我不知道如何将某些内容放入字典中。
回答by Brian
Use Java's Mapinterface and HashMapclass. Your method would look like this in Java:
使用 Java 的Map接口和HashMap类。您的方法在 Java 中如下所示：
private Map<String, List<Block>> gameBlocks = new HashMap<String, List<Block>>(); // Java 6
// OR:
private Map<String, List<Block>> gameBlocks = new HashMap<>(); // Java 7
public void registerBlock(Block block) {
idX = (int)(block.blockPosition.X / width);
idY = (int)(block.blockPosition.Y / height);
String id = idX + "_" + idY;
if (gameBlocks.containsKey(id)) {
gameBlocks.get(id).add(block);
} else {
gameBlocks.put(id, new ArrayList<Block>());
gameBlocks.get(id).add(block);
}
}
Notice some of the corrections I've made for Java's recommended formatting/naming styles.
请注意我对 Java 推荐的格式/命名样式所做的一些更正。
