Java 局部变量隐藏字段是什么意思？
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What is the meaning of local variable hides a field?
提问by MikeV
So this is just a part of my code, and the entire program compiles and works, but I keep getting "local variable hides a field" next to lines three consecutive lines starting with "GameBoard myBoard = this.getGameBoard();. I'm just curious what that actually means and if it is doing anything to my program in the long run.
所以这只是我代码的一部分，整个程序都可以编译并运行，但是我一直在以“GameBoard myBoard = this.getGameBoard();”开头的三行连续行旁边出现“局部变量隐藏字段”。我'我只是好奇这实际上意味着什么，以及从长远来看它是否对我的程序有任何影响。
public void initialze(){
myBoard = getGameBoard();
obstacleLocations = myBoard.getObstaclePositions();
pastureLocations = myBoard.getPasturePositions();
GameBoard myBoard = this.getGameBoard();
ArrayList<GameLocation> obstacleLocations = myBoard.getObstaclePositions();
ArrayList<GameLocation> pastureLocations = myBoard.getPasturePositions();
GameLocation closestPasture = pastureLocations.get(0);
GameLocation closestObstacle = obstacleLocations.get(0);
采纳答案by Dawood ibn Kareem
It means you've got two different variables with the same name - myBoard. One of them is a field in your class. Another one is a local variable, that is, one that you've declared inside a method.
这意味着您有两个具有相同名称的不同变量 - myBoard。其中之一是您班级中的一个字段。另一个是局部变量，即您在方法中声明的变量。
It's a bad idea to have two variables with the same name. It can make your code very confusing and difficult to maintain.
有两个同名的变量是个坏主意。它会使您的代码非常混乱且难以维护。
回答by JFPicard
The local variable in a method is always the variable with the highest visibility. That's why in a class setter you always do something like:
方法中的局部变量始终是具有最高可见性的变量。这就是为什么在类二传手中你总是做这样的事情：
void setId(String id) {
this.id = id;
}
The this.idtells Java to assign the id(from the parameter) to the field variable. That's why this will not work:
该this.id通知Java来分配id（从参数）字段变量。这就是为什么这不起作用：
void setId(String id) {
id = id;
}
Since it'll assign idto itself.
因为它会分配id给自己。
You can read about scope, see: http://www.java-made-easy.com/variable-scope.htmlfor an example.
您可以阅读有关范围的信息，请参阅：http: //www.java-made-easy.com/variable-scope.html的示例。
