“这个”给了我一个片段错误

Why does this give me an error in the below fragment?

为什么这会在下面的片段中给我一个错误?

This is my code:

这是我的代码:

ArrayAdapter<String> adapter = new ArrayAdapter<String>(
                this, android.R.layout.simple_spinner_item, spinnerArray);

4 个解决方案

#1

Try this:

ArrayAdapter<String> adapter = new ArrayAdapter<String>(
            getActivity(), android.R.layout.simple_spinner_item, spinnerArray);

getContext() was added only on API 23 and should work only with few devices (since Android M still does not have a huge market share).

getContext()仅在API 23上添加,并且仅适用于少数设备(因为Android M仍然没有巨大的市场份额)。
getActivity() was added on API 11 and it is NOT deprecated.. So, you can use it.

在API 11上添加了getActivity()并且不推荐使用它。所以,你可以使用它。

#2

Replace this with this.getContext() or even simply just getContext()

用this.getContext()替换它,甚至只是getContext()

ArrayAdapter<String> adapter = new ArrayAdapter<String>(getContext(), 
                                   android.R.layout.simple_spinner_item, spinnerArray);

The reason being is that the constructor for an ArrayAdapter object looks like this,

原因是ArrayAdapter对象的构造函数如下所示,

From https://developer.android.com/reference/android/widget/ArrayAdapter.html,
ArrayAdapter(Context context, int resource, T[] objects)
or
ArrayAdapter(Context context, int resource, List<T> objects)

What was probably happening before is that the class that the line of code was in was most likely not of type Context; therefore, you can't use this alone as a parameter in the construction of an ArrayAdapter. If getContext() doesn't work, then I'd suggest trying getActivity() or getApplicationContext() as well.

以前可能发生的是代码行所在的类很可能不是Context类型;因此,您不能单独使用它作为构造ArrayAdapter的参数。如果getContext()不起作用,那么我建议尝试使用getActivity()或getApplicationContext()。

#3

Use getActivity() which return the context of the activity that the fragment is associated with.

使用getActivity()返回与片段关联的活动的上下文。

So your code becomes

所以你的代码变成了

ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_spinner_item, spinnerArray);`]

#4

-2

You can try getActivity().getApplicationContext() instead of using just this in fragment.

你可以尝试使用getActivity()。getApplicationContext()而不是在片段中使用它。

#1