如何从碎片和活动中传递价值并获得价值 [英] How to pass and get value from fragment and activity

问题描述

如何通过片段和活动获得价值?

How to pass and get value from fragment and activity?

推荐答案

这是Android Studio建议的解决方案(=当您使用文件创建Blank-Fragment-> New-> Fragment-> Fragment(Blank)并检查包括片段工厂方法").

Here is the Android Studio proposed solution (= when you create a Blank-Fragment with File -> New -> Fragment -> Fragment(Blank) and you check "include fragment factory methods").

将其放入片段中

class MyFragment: Fragment {

...

    companion object {

            @JvmStatic
            fun newInstance(isMyBoolean: Boolean) = MyFragment().apply {
                arguments = Bundle().apply {
                    putBoolean("REPLACE WITH A STRING CONSTANT", isMyBoolean)
                }
            }
     }
}

.apply是创建对象或设置为

.apply is a nice trick to set data when an object is created, or as they state here:

以this值作为接收者调用指定的函数[block] 并返回this值.

Calls the specified function [block] with this value as its receiver and returns this value.

然后在活动"或片段"中执行以下操作:

Then in your Activity or Fragment do:

val fragment = MyFragment.newInstance(false)
... // transaction stuff happening here

并读取片段中的参数，例如:

and read the Arguments in your Fragment such as:

private var isMyBoolean = false

override fun onAttach(context: Context?) {
    super.onAttach(context)
    arguments?.getBoolean("REPLACE WITH A STRING CONSTANT")?.let {
        isMyBoolean = it
    }
}

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