英文:
Java: Method annotation to suppress NullPointerException warning
问题
我在我的代码中有以下的辅助方法，用于断言关于类中成员字段的某些属性。
private @Nullable Controller mController;
private boolean isControllerReady() {
return mController != null && mController.isReady();
}
在我的代码的其他地方，我调用类似这样的内容...
if (isControllerReady() && mController.canDoSomething()) {
mController.doSomething();
}
我的Android Studio在canDoSomething()上给了我一个警告：
Method invocation 'canDoSomething' may produce 'NullPointerException'
这应该是一个误报。有没有可能对isControllerReady进行注解，以便IDE在canDoSomething上抑制/忽略这个NPE警告？
英文:
I have the following helper method in my code that asserts some property about a member field in my class.
private @Nullable Controller mController;
private boolean isControllerReady() {
return mController != null && mController.isReady();
}
Elsewhere in my code, I invoke something like this...
if (isControllerReady() && mController.canDoSomething()) {
mController.doSomething();
}
My Android Studio gives me a warning on canDoSomething():
Method invocation 'canDoSomething' may produce 'NullPointerException'
This should be a false positive. Is it possible to annotate isControllerReady so that the IDE suppresses/ignores this NPE warning on canDoSomething?
答案1
得分: 1
我认为@SuppressWarnings注解是你在寻找的。然后，你可以对方法进行注解，并传入你想要抑制的编译器警告（或警告）。
@SuppressWarnings({"NullableProblems"})
private boolean isControllerReady() {
return mController != null && mController.isReady();
}
或者在Intellij中（这在Android Studio中也适用），你可以在突出显示的警告上按下Alt + Enter，然后从那里进行抑制。
参见https://www.jetbrains.com/help/idea/disabling-and-enabling-inspections.html?keymap=primary_xwin#suppress-inspections
编辑：格式化
英文:
I think the @SuppressWarnings annotation is what you're looking for. Then you'd annotate your method and pass in the compiler warning (or warnings) that you'd like to suppress.
@SuppressWarnings({"NullableProblems"})
private boolean isControllerReady() {
return mController != null && mController.isReady();
}
Alternatively on Intellij (this should also work in Android Studio), you can press Alt + Enter on the highlighted warning and suppress it from there.
Edit: formatting
答案2
得分: 1
由于您将mController标记为Nullable，编译器会尝试警告您在调用对象上的任何操作之前检查mController是否为非null。
您可以在条件语句中简单地添加空值检查。
if (isControllerReady() && mController != null && mController.canDoSomething()) {
mController.doSomething();
}
英文:
As you annotated mController as a Nullable, the compiler tries to warn you to check if mController is not null before you invoke any operation on the object.
You can simply add a null check in the condition.
if (isControllerReady() && mController != null && mController.canDoSomething()) {
mController.doSomething();
}
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