Android studio 报错Constant expression required

这个错误通常是因为在声明常量时没有使用正确的语法。在Java中，常量必须使用关键字“final”进行声明，并且必须在声明时进行初始化。例如：

final int MY_CONSTANT = 42;

如果您已经使用了“final”关键字并且仍然遇到此错误，请确保您正在使用的值是一个编译时常量，而不是运行时常量。运行时常量是在程序运行时计算的值，而编译时常量是在编译时计算的值。

相关问题

androidstudio case r.id报错 Constant expression required

在Android Studio中，switch语句的case中必须是常量，而R.id.xxx为非常量，所以会报错。解决这个问题的方法有两种：

1.使用if-else语句代替switch语句，例如：

if (view.getId() == R.id.button1) {
    // do something
} else if (view.getId() == R.id.button2) {
    // do something
} else if (view.getId() == R.id.button3) {
    // do something
}

2.将R.id.xxx转换为常量，例如：

final int BUTTON1_ID = R.id.button1;
final int BUTTON2_ID = R.id.button2;
final int BUTTON3_ID = R.id.button3;

switch (view.getId()) {
    case BUTTON1_ID:
        // do something
        break;
    case BUTTON2_ID:
        // do something
        break;
    case BUTTON3_ID:
        // do something
        break;
}

Android Studio Constant expression required

"Constant expression required" error in Android Studio usually occurs when you try to use a non-constant value in a place where a constant value is required.

To fix this error, you need to make sure that all the values that you use in the code are constants. For example, if you are defining an array size, you need to use a constant value instead of a variable.

Here is an example:

int size = 10;
int[] arr = new int[size]; // This will cause "Constant expression required" error

// To fix this error, you can define the array size as a constant value:
final int SIZE = 10;
int[] arr = new int[SIZE];

By defining the array size as a constant value, you can avoid the "Constant expression required" error in Android Studio.