Question

在switch语句中，我使用了一些在另一个类中定义的常量。 IDE告诉我constant expression required。

我正在编写一个Android应用程序，在MainActivity中我这样写：

private static final int HOMEFRAGMENTINDEX = 0;
private static final int MESSAGEFRAGMENTINDEX = 1;
private static final int SNSFRAGMENTINDEX = 2;
private static final int DISCOVERYFRAGMENTINDEX = 3;
private static final int MINEFRAGMENTINDEX = 4;

public static int getHomefragmentindex() {
    return HOMEFRAGMENTINDEX;
}

public static int getMessagefragmentindex() {
    return MESSAGEFRAGMENTINDEX;
}

public static int getSnsfragmentindex() {
    return SNSFRAGMENTINDEX;
}

public static int getDiscoveryfragmentindex() {
    return DISCOVERYFRAGMENTINDEX;
}

public static int getMinefragmentindex() {
    return MINEFRAGMENTINDEX;
}

在另一个类中我使用switch语句：

final int homeFragmentIndex = MainActivity.getHomefragmentindex();
final int messageFramentIndex = MainActivity.getMessagefragmentindex();
final int snsFragmentIndex = MainActivity.getSnsfragmentindex();
final int discoveryFragmentIndex = MainActivity.getDiscoveryfragmentindex();
final int mineFragentIndex = MainActivity.getMinefragmentindex();

switch (mCurIndicator) {
case homeFragmentIndex:
    // do something
    break;
case messageFramentIndex:
    // do something
    break;
case snsFragmentIndex:
    // do something
    break;
case discoveryFragmentIndex:
    // do something
    break;
case mineFragentIndex:
    // do something
    break;
default:
    break;
}

Android Studio告诉我constant expression required，但我确实使用了static fianl int。也许你可以帮忙解决这个问题，谢谢。

Answer 1

class Some{
    public static final int HOMEFRAGMENTINDEX = 0;
    public static final int MESSAGEFRAGMENTINDEX = 1;
    public static final int SNSFRAGMENTINDEX = 2;
    public static final int DISCOVERYFRAGMENTINDEX = 3;
    public static final int MINEFRAGMENTINDEX = 4;

}

class AnotherClass{
    void yourMethod(int mCurIndicator){ 
        switch (mCurIndicator) {
            case Some.HOMEFRAGMENTINDEX:
                // do something
                break;
            case Some.MESSAGEFRAGMENTINDEX:
                // do something
                break;
            case Some.SNSFRAGMENTINDEX:
                // do something
                break;
            case Some.DISCOVERYFRAGMENTINDEX:
                // do something
                break;
            case Some.MINEFRAGMENTINDEX:
                // do something
                break;
            default:
                break;
            }

    }
}

java：需要常量表达式。 switch satement使用一些在另一个calss中定义的常量

1 个答案: