RoboGuice.getInjector抛出异常

Question

我尝试在我的安卓项目中使用RoboGuice 2，它工作正常，除非我尝试使用它在活动中注入视图。如果我试图从RoboActivity扩展我的活动，或者在onCreate方法中手动调用RoboGuice.getInjector(context)，我会得到以下异常：

FATAL EXCEPTION: main
    java.lang.RuntimeException: Unable to start activity}: com.google.inject.ConfigurationException: Guice configuration errors:
    1) Could not find a suitable constructor in roboguice.inject.ContextScope. Classes must have either one (and only one) constructor annotated with @Inject or a zero-argument constructor that is not private.
            at roboguice.inject.ContextScope.class(Unknown Source)
    while locating roboguice.inject.ContextScope
    1 error
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2295)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2349)
            at android.app.ActivityThread.access$700(ActivityThread.java:159)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1316)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:176)
            at android.app.ActivityThread.main(ActivityThread.java:5419)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:525)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1046)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:862)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: com.google.inject.ConfigurationException: Guice configuration errors:
    1) Could not find a suitable constructor in roboguice.inject.ContextScope. Classes must have either one (and only one) constructor annotated with @Inject or a zero-argument constructor that is not private.
            at roboguice.inject.ContextScope.class(Unknown Source)
    while locating roboguice.inject.ContextScope
    1 error
            at com.google.inject.internal.InjectorImpl.getProvider(InjectorImpl.java:1004)
            at com.google.inject.internal.InjectorImpl.getProvider(InjectorImpl.java:961)
            at com.google.inject.internal.InjectorImpl.getInstance(InjectorImpl.java:1013)
            at roboguice.inject.ContextScopedRoboInjector.<init>(ContextScopedRoboInjector.java:27)
            at roboguice.RoboGuice.getInjector(RoboGuice.java:149)
            ...

我使用maven通过以下依赖项将guice添加到我的项目中

<dependency>
  <groupId>org.roboguice</groupId>
  <artifactId>roboguice</artifactId>
  <version>2.0</version>
</dependency>

任何帮助都将不胜感激。

Answer 1

默认情况下，RoboGuice将尝试使用默认构造函数创建对象。你的对象似乎没有默认的构造函数。您可以通过以下方式解决此问题：

• 注释要与@Inject一起使用的构造函数(并确保该构造函数的所有参数也可由RoboGuice创建)
• 在尝试注入的对象中创建默认构造函数
• 如果您无法控制尝试注入的对象，则可以在注入阶段使用提供程序构造对象

Answer 2

我发现，如果我只是简单地扩展AbstractModule，正确配置它需要比简单地绑定上下文多得多的工作。

我按照javadoc中的解释扩展了DefaultRoboModule：

Injector injector =
    RoboGuice.setBaseApplicationInjector(
        this, Stage.PRODUCTION,
        Modules.override(RoboGuice.newDefaultRoboModule(this)).with(new MyModule())
    );

并且让一切都像预期的那样工作。

不管怎样，谢谢你。