Android的 - 如何从片段访问getter方法​​在父活动 [英] Android - How to access a getter method in parent Activity from Fragment

问题描述

我有了我需要在一个片段中使用。的值的FragmentActivity

I have a FragmentActivity that has the values I needed to be used in a Fragment.

这是我做的方式，但我对如何访问吸气的FragmentActivity不知道。

This is the way I do it, but I have no idea on how to access the getter in the FragmentActivity.

ItemDetailActivity

ItemDetailActivity

public class ItemDetailActivity extends FragmentActivity implements ActionBar.TabListener {

    public String getItem_id() {
        return item_id;
    }

    public String getUser_id() {
        return user_id;
    }
    ...
}

ItemPhotosFragment

ItemPhotosFragment

public class ItemPhotosFragment extends Fragment {
    public ItemPhotosFragment() {
        user_id = getActivity().getUser_id();
    }
}

正如你可以在FragmentActivity看，我实现TabListener。所以我想的价值观传递给所有标签（片段）。

As you can see in the FragmentActivity, I'm implementing TabListener. So I'm want to pass the values to all tabs (fragments).

我如何做到这一点？从getActivity访问最佳实践，因为我看到了一些解决方案在这里暗示吧。

How do I do this? Is accessing from getActivity a best practice because I saw some of the solutions here suggesting it.

推荐答案

类型转换为母公司活动：

type cast into parent activity:

写 onActivityCreated 这code的片段里面没有构造函数：

write this code in onActivityCreated inside your fragment not in constructor:

user_id =((ItemDetailActivity )getActivity()).getUser_id();

这是关于片段的生命周期。 onActivityCreated 当片段成为活动的一部分，这是从哪儿getActivity（）不返回第一个回调称为空

It's about fragment's life-cycle. onActivityCreated is called when fragment becomes part of the activity and this is the first callback from where getActivity() doesn't return null

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