android - 无法解析符号 'NavigationView'

Question

我在 XML 文件的 DrawerLayout 中创建了一个 NavigationView - 但是当我尝试在 Java 中初始化它时出现此错误。

// DrawerLayout initialises fine
DrawerLayout drawerLayout = (DrawerLayout) findViewById(R.id.nav_drawer);
// Cannot resolve symbol 'NavigationView'
NavigationView navView = (NavigationView) findViewById(R.id.navigation_view);

我尝试添加导入行

import  android.support.design.widget.NavigationView

但这也给我错误。有任何想法吗？一直没能在网上找到解决办法。

编辑:添加 Tanis 的回答中给出的依赖项后，我得到了这些错误

Error:A problem occurred configuring project ':app'.
> Could not resolve all dependencies for configuration ':app:_debugCompile'.
   > Could not find com.android.support:design:22.2.1.
     Searched in the following locations:
         https://jcenter.bintray.com/com/android/support/design/22.2.1/design-22.2.1.pom
         https://jcenter.bintray.com/com/android/support/design/22.2.1/design-22.2.1.jar
         https://repo1.maven.org/maven2/com/android/support/design/22.2.1/design-22.2.1.pom
         https://repo1.maven.org/maven2/com/android/support/design/22.2.1/design-22.2.1.jar
         file:/C:/Users/SV_Laptop03/AppData/Local/Android/sdk/extras/android/m2repository/com/android/support/design/22.2.1/design-22.2.1.pom
         file:/C:/Users/SV_Laptop03/AppData/Local/Android/sdk/extras/android/m2repository/com/android/support/design/22.2.1/design-22.2.1.jar
         file:/C:/Users/SV_Laptop03/AppData/Local/Android/sdk/extras/google/m2repository/com/android/support/design/22.2.1/design-22.2.1.pom
         file:/C:/Users/SV_Laptop03/AppData/Local/Android/sdk/extras/google/m2repository/com/android/support/design/22.2.1/design-22.2.1.jar
     Required by:
         MyApp:app:unspecified  

Answer 1

听起来您没有将库作为 Gradle 依赖项包含在内。

将以下内容添加到您的 build.gradle 中:

dependencies {
    compile 'com.android.support:design:22.2.1'
}

错误消息“找不到 com.android.support:design:22.2.1”。意味着您可能没有安装最新版本的 Android 支持存储库。打开您的 SDK 管理器并确保“Extras”下的“Android Support Library”和“Android Support Repository”项目是最新的。