Google 跟踪代码管理器空容器

Question

我正在尝试遵循此处描述的内容：https://developers.google.com/tag-manager/android/v4/#init，这就是我所拥有的：

TagManager tagManager = TagManager.getInstance(this);
    tagManager.setVerboseLoggingEnabled(true);


    PendingResult<ContainerHolder> pending =
            tagManager.loadContainerPreferNonDefault("GTM-XXXXXX",
                    R.raw.gtm);


    pending.setResultCallback(new ResultCallback<ContainerHolder>() {
        @Override
        public void onResult(ContainerHolder containerHolder) {
            ContainerHolderSingleton.setContainerHolder(containerHolder);
            container = containerHolder.getContainer();
            Log.d("NICK","Inside onResult...") ;
            if (!containerHolder.getStatus().isSuccess()) {
                Log.e("CuteAnimals", "failure loading container");

                return;
            }

            ContainerLoadedCallback.registerCallbacksForContainer(container);
            containerHolder.setContainerAvailableListener(new ContainerLoadedCallback());

        }
    }, 3000, TimeUnit.MILLISECONDS);


    Log.d("NICK","Value: "+container.getString("test_value));

而发生的事情是上面Log 行的NullPointerException，因为container 为空：

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.nick.app/com.nick.app.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.google.android.gms.tagmanager.Container.getString(java.lang.String)' on a null object reference
                                                                     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
                                                                     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
                                                                     at android.app.ActivityThread.-wrap11(ActivityThread.java)
                                                                     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
                                                                     at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                     at android.os.Looper.loop(Looper.java:148)
                                                                     at android.app.ActivityThread.main(ActivityThread.java:5422)
                                                                     at java.lang.reflect.Method.invoke(Native Method)
                                                                     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                                                                     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
                                                                  Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.google.android.gms.tagmanager.Container.getString(java.lang.String)' on a null object reference

我为谷歌标签管理器启用了日志记录，我得到了在我看来是“正常”的行为：

05-16 11:53:04.865 22585-22662/com.nick.app V/GoogleTagManager: Deleted 0 expired items
05-16 11:53:04.867 22585-22585/com.nick.app V/GoogleTagManager: Attempting to load a container from the resource ID 2131034112 (com.nick.app:raw/gtm)
05-16 11:53:04.888 22585-22585/com.nick.app V/GoogleTagManager: The container was successfully loaded from the resource (using JSON file format)
05-16 11:53:04.903 22585-22664/com.nick.app V/GoogleTagManager: Attempting to load resource from disk
05-16 11:53:04.925 22585-22664/com.nick.app V/GoogleTagManager: loadAfterDelay: containerId=GTM-XXXXXXX delay=40721307
05-16 11:53:04.925 22585-22664/com.nick.app D/GoogleTagManager: Setting previous container version: NQ$0
05-16 11:53:04.929 22585-22664/com.nick.app V/GoogleTagManager: The Disk resource was successfully read.

而且我在onResult 中的日志语句也从未显示，这可以解释为什么container 为空，因为这是任何初始化都会发生的唯一位置。不应该达到onResult 并初始化container 吗？对于如何正确实施，我有点困惑。

Answer 1

加载ContainerHolder 是异步进行的，因此在您当前尝试从中记录值的点上尚未为其分配值。

您链接到的网站有以下关于onResult() 的文档。

onResult 方法将在以下情况之一被调用 发生：

1. 已加载保存的容器
2. 如果没有保存的容器，则加载网络容器
3. 发生指定的超时

这意味着在调用onResult(...) 之前，您无法访问container，因为这是为它分配值的地方。您可以将 log 语句移动到该方法中以测试检索值并在此时对容器执行任何其他操作。

public void onResult(ContainerHolder containerHolder) {
    ContainerHolderSingleton.setContainerHolder(containerHolder);
    container = containerHolder.getContainer();

    Log.d("NICK","Inside onResult...") ;
    if (!containerHolder.getStatus().isSuccess()) {
        Log.e("CuteAnimals", "failure loading container");
        return;
    }

    ContainerLoadedCallback.registerCallbacksForContainer(container);
    containerHolder.setContainerAvailableListener(new ContainerLoadedCallback());

    // do whatever you want with the container at this point
    Log.d("NICK","Value: " + container.getString("test_value));
}