Android Studio's "expected resource of type" checks?

android, android-studio, lint, typechecking

Solution

(Thanks to @CommonsWare for the heads up).

There are Java annotations to support these checks in your own code. They can all be found in the `android.support.annotations` package:

- `IdRes`

- `DrawableRes`

- `LayoutRes`

- `StringRes`

- &c

In this case, for example, I could use:

private void mySetContentView(@LayoutRes int resourceId) {
    setContentView(resourceId);
}

and Android Studio will check that the provided resource id is indeed for a layout.

Moreover, these annotations are exported, so they can be especially useful when designing a library.

Sources:

- Video from Google I/O 2014: What's new in Android development tools

Problem

Android Studio Beta (0.8) has a nifty new feature where it checks that some `int` parameters are not arbitrary integers, but rather have some properties. For example, calling something like: ``` setContentView(R.id.textView1); ``` will correctly report that `R.id.textView1` is not a layout id (the message is "expected resource of type layout"). There are other cases of this peppered around. Understandably, this protection is lost as soon as you add your own methods into the mix, e.g. ``` private void mySetContentView(int resourceId) { setContentView(resourceId); } ``` I can then call `mySetContentView()` with any arbitrary integer and it will not complain. So, I have two (related) questions: - How is this achieved -- are the special checks "baked" into lint? - Is there any way to annotate the `mySetContentView()` method so that it will also report a resource type error when calling it with an invalid value?

Original source