为什么我要避免片段非默认的构造函数？ [英] Why do I want to avoid non-default constructors in fragments?

问题描述

我创建一个应用程序与片段并在其中的一个，我创建了一个非默认的构造函数，得到了这样的警告：

I am creating an app with Fragments and in one of them, I created a non-default constructor and got this warning:

Avoid non-default constructors in fragments: use a default constructor plus Fragment#setArguments(Bundle) instead

谁能告诉我，为什么这不是一个好主意？

Can someone tell me why this is not a good idea?

您可以还建议我将如何做到这一点：

Can you also suggest how I would accomplish this:

public static class MenuFragment extends ListFragment {
    public ListView listView1;
    Categories category;

    //this is my "non-default" constructor
    public MenuFragment(Categories category){
        this.category = category;
    }....

在不使用非默认的构造函数？

Without using the non-default constructor?

推荐答案

请捆绑对象，并插入（在本例中您的类别对象）的数据。要小心，你不能直接传递这个对象进入包，除非它是序列化。 我觉得这是更好地建立自己的对象中的片段，并把唯一的ID或其他什么东西的线束。这是code创建和附加包：

Make a bundle object and insert your data (in this example your Category object). Be careful, you can't pass this object directly into the bundle, unless it's serializable. I think it's better to build your object in the fragment, and put only an id or something else into bundle. This is the code to create and attach a bundle:

Bundle args = new Bundle();
args.putLong("key", value);
yourFragment.setArguments(args);

此后，在您的片段的访问数据：

After that, in your fragment access data:

Type value = getArguments().getType("key");

这就是全部。

That's all.

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