Android Studio XML上下文错误

<!-- 错误示例 -->
<TextView
    android:text="@string/non_existent_string" />

<!-- 正确示例 -->
<TextView
    android:text="@string/existing_string" />

<!-- 错误示例 -->
<TextView
    android:textColor="#GGGGGG" />

<!-- 正确示例 -->
<TextView
    android:textColor="#FFFFFF" />

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <!-- 其他视图 -->
</LinearLayout>

dependencies {
    implementation 'com.example:library:1.0.0'
}

<!-- res/layout/activity_main.xml -->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/non_existent_string" />
</LinearLayout>

<!-- res/values/strings.xml -->
<resources>
    <string name="non_existent_string">Hello, World!</string>
</resources>