从viewPager片段（Kotlin）中获取用户输入信息

Posted

tags:

篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了从viewPager片段（Kotlin）中获取用户输入信息相关的知识，希望对你有一定的参考价值。

我正在android Studio中工作，但遇到了从未遇到过的问题。

我正在制作一个接口，该接口引入JSON以创建自定义表单，并创建一系列由标签控制的片段，其中包含编辑文本和日期选择器等。这些表格是在网站上创建的；并且直到JSON将其插入之前，其内容是未知的。

我已经设置了SectionsPagerAdapter来处理创建节和占位符片段，以创建各种选择器和编辑文本。我正在使用ViewCompat.generateViewId（）自动生成视图ID。

目前，我正在使用模拟JSON数据进行测试，并且一切正常。用户能够输入信息并影响更改；并且无论用户有多少，更改都将随着用户在不同部分标签之间的导航而持久。

我遇到的问题是，在按下浮动操作按钮后试图从所有片段中获取输入数据。我只是还没有弄清楚如何从活动级别的片段中访问数据。

下面是代码：

CreateInspectionActivity

class CreateInspectionActivity : AppCompatActivity() {

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_create_inspection)

    //List of items to mock what I would receive as JSON
    val mockJSON = JSONArray()
    mockJSON.put(Pair("General", arrayListOf(
        Pair("General EditText", "editText"), Pair("General Date", "datePicker"),
        Pair("General Time", "timePicker"), Pair("General EditText 2", "editText"),
        Pair("General Rating", "rating"), Pair("General Rating 2", "rating"),
        Pair("General Rating 3", "rating"), Pair("General Rating 4", "rating"),
        Pair("General Rating 5", "rating"), Pair("General Rating 6", "rating"),
        Pair("General EditText 3", "editText"), Pair("General EditText 4", "editText"),
        Pair("General EditText 5", "editText"), Pair("General Date 2", "datePicker"),
        Pair("General Rating 7", "rating"), Pair("General Time 2", "timePicker"))))
    mockJSON.put(Pair("Secondary", arrayListOf(
        Pair("Secondary EditText", "editText"), Pair("Secondary EditText2", "editText"),
        Pair("Secondary EditText 3", "editText"), Pair("Secondary Date", "datePicker"),
        Pair("Secondary Time", "timePicker"),  Pair("Secondary Rating", "rating"),
        Pair("Secondary Rating 2", "rating"), Pair("Secondary Rating 3", "rating"),
        Pair("Secondary Rating 4", "rating"), Pair("Secondary Rating 5", "rating"))))
    mockJSON.put(Pair("Tertiary", arrayListOf(
        Pair("Tertiary Rating", "rating"), Pair("Tertiary Rating 2", "rating"),
        Pair("Tertiary Rating 3", "rating"), Pair("Tertiary Rating 4", "rating"),
        Pair("Tertiary Rating 5", "rating"), Pair("Tertiary Rating 6", "rating"),
        Pair("Tertiary Rating 7", "rating"), Pair("Tertiary Rating 8", "rating"),
        Pair("Tertiary Rating 9", "rating"), Pair("Tertiary Rating 10", "rating"))))
    mockJSON.put(Pair("Quaternary", arrayListOf(
        Pair("Quaternary Rating", "rating"), Pair("Quaternary Rating 2", "rating"),
        Pair("Quaternary Rating 3", "rating"), Pair("Quaternary Rating 4", "rating"),
        Pair("Quaternary Rating 5", "rating"), Pair("Quaternary Rating 6", "rating"),
        Pair("Quaternary Rating 7", "rating"), Pair("Quaternary Rating 8", "rating"),
        Pair("Quaternary Rating 9", "rating"), Pair("Quaternary Rating 10", "rating"),
        Pair("Quaternary Rating 11", "rating"), Pair("Quaternary Rating 12", "rating"),
        Pair("Quaternary Rating 13", "rating"), Pair("Quaternary Rating 14", "rating"),
        Pair("Quaternary Rating 15", "rating"), Pair("Quaternary Rating 16", "rating"),
        Pair("Quaternary Rating 17", "rating"), Pair("Quaternary Rating 18", "rating"),
        Pair("Quaternary Rating 19", "rating"), Pair("Quaternary Rating 20", "rating"))))
    mockJSON.put(Pair("Quinary", arrayListOf(
        Pair("Quinary Rating", "rating"), Pair("Quinary Rating 2", "rating"),
        Pair("Quinary Rating 3", "rating"), Pair("Quinary Rating 4", "rating"),
        Pair("Quinary Rating 5", "rating"), Pair("Quinary Rating 6", "rating"),
        Pair("Quinary Rating 7", "rating"), Pair("Quinary Rating 8", "rating"),
        Pair("Quinary Rating 9", "rating"), Pair("Quinary Rating 10", "rating"),
        Pair("Quinary Rating 11", "rating"), Pair("Quinary Rating 12", "rating"),
        Pair("Quinary Rating 13", "rating"), Pair("Quinary Rating 14", "rating"),
        Pair("Quinary Rating 15", "rating"), Pair("Quinary Rating 16", "rating"),
        Pair("Quinary Rating 17", "rating"), Pair("Quinary Rating 18", "rating"),
        Pair("Quinary Rating 19", "rating"), Pair("Quinary Rating 20", "rating"))))
    mockJSON.put(Pair("Senary", arrayListOf(
        Pair("Senary Rating", "rating"), Pair("Senary Rating 2", "rating"),
        Pair("Senary Rating 3", "rating"), Pair("Senary Rating 4", "rating"),
        Pair("Senary Rating 5", "rating"), Pair("Senary Rating 6", "rating"),
        Pair("Senary Rating 7", "rating"), Pair("Senary Rating 8", "rating"),
        Pair("Senary Rating 9", "rating"), Pair("Senary Rating 10", "rating"),
        Pair("Senary Rating 11", "rating"), Pair("Senary Rating 12", "rating"),
        Pair("Senary Rating 13", "rating"), Pair("Senary Rating 14", "rating"),
        Pair("Senary Rating 15", "rating"), Pair("Senary Rating 16", "rating"),
        Pair("Senary Rating 17", "rating"), Pair("Senary Rating 18", "rating"),
        Pair("Senary Rating 19", "rating"), Pair("Senary Rating 20", "rating"))))
    mockJSON.put(Pair("Septenary", arrayListOf(
        Pair("Septenary Rating", "rating"), Pair("Septenary Rating 2", "rating"),
        Pair("Septenary Rating 3", "rating"), Pair("Septenary Rating 4", "rating"),
        Pair("Septenary Rating 5", "rating"), Pair("Septenary Rating 6", "rating"),
        Pair("Septenary Rating 7", "rating"), Pair("Septenary Rating 8", "rating"),
        Pair("Septenary Rating 9", "rating"), Pair("Septenary Rating 10", "rating"),
        Pair("Septenary Rating 11", "rating"), Pair("Septenary Rating 12", "rating"),
        Pair("Septenary Rating 13", "rating"), Pair("Septenary Rating 14", "rating"),
        Pair("Septenary Rating 15", "rating"), Pair("Septenary Rating 16", "rating"),
        Pair("Septenary Rating 17", "rating"), Pair("Septenary Rating 18", "rating"),
        Pair("Septenary Rating 19", "rating"), Pair("Septenary Rating 20", "rating"))))
    mockJSON.put(Pair("Octonary", arrayListOf(
        Pair("Octonary Rating", "rating"), Pair("Octonary Rating 2", "rating"),
        Pair("Octonary Rating 3", "rating"), Pair("Octonary Rating 4", "rating"),
        Pair("Octonary Rating 5", "rating"), Pair("Octonary Rating 6", "rating"),
        Pair("Octonary Rating 7", "rating"), Pair("Octonary Rating 8", "rating"),
        Pair("Octonary Rating 9", "rating"), Pair("Octonary Rating 10", "rating"),
        Pair("Octonary Rating 11", "rating"), Pair("Octonary Rating 12", "rating"),
        Pair("Octonary Rating 13", "rating"), Pair("Octonary Rating 14", "rating"),
        Pair("Octonary Rating 15", "rating"), Pair("Octonary Rating 16", "rating"),
        Pair("Octonary Rating 17", "rating"), Pair("Octonary Rating 18", "rating"),
        Pair("Octonary Rating 19", "rating"), Pair("Octonary Rating 20", "rating"))))
    mockJSON.put(Pair("Nonary", arrayListOf(
        Pair("Nonary Rating", "rating"), Pair("Nonary Rating 2", "rating"),
        Pair("Nonary Rating 3", "rating"), Pair("Nonary Rating 4", "rating"),
        Pair("Nonary Rating 5", "rating"), Pair("Nonary Rating 6", "rating"),
        Pair("Nonary Rating 7", "rating"), Pair("Nonary Rating 8", "rating"),
        Pair("Nonary Rating 9", "rating"), Pair("Nonary Rating 10", "rating"),
        Pair("Nonary Rating 11", "rating"), Pair("Nonary Rating 12", "rating"),
        Pair("Nonary Rating 13", "rating"), Pair("Nonary Rating 14", "rating"),
        Pair("Nonary Rating 15", "rating"), Pair("Nonary Rating 16", "rating"),
        Pair("Nonary Rating 17", "rating"), Pair("Nonary Rating 18", "rating"),
        Pair("Nonary Rating 19", "rating"), Pair("Nonary Rating 20", "rating"))))

    //Setup Adapter for different tabs
    //This creates the pager adapter with the mock JSON array to create a section tab for each,
    // and to send the associated information on to the Placeholder fragment
    //Setup adapter for view pager
    val sectionsPagerAdapter = SectionsPagerAdapter(this, supportFragmentManager, mockJSON)
    val viewPager: ViewPager = findViewById(R.id.view_pager)
    //Set this page limit to keep data across multiple tabs. This must be set to the number of tabs there'll be, minus 1
    viewPager.offscreenPageLimit = mockJSON.length()-1
    viewPager.adapter = sectionsPagerAdapter
    //Use view pager to populate tabs
    val tabs: TabLayout = findViewById(R.id.tabs)
    tabs.setupWithViewPager(viewPager)
    val fab: FloatingActionButton = findViewById(R.id.fab)

    fab.setOnClickListener { view ->
        //TODO: Get data from all the fragments
        for(item in 0 until viewPager.childCount) {
            Log.d("BEAU", "${viewPager.getChildAt(item)}")
            //val child: View = viewPager.getChildAt(item)
        }
    }
}
}

SectionsPagerAdapter

class SectionsPagerAdapter(private val context: Context, fm: FragmentManager, private val mockJSON: JSONArray) : FragmentPagerAdapter(fm, BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT) {

override fun getItem(position: Int): Fragment {
    val jsonList = arrayListOf<Pair<String, ArrayList<String>>>()
    for(i in 0 until mockJSON.length()){
        @Suppress("unchecked_cast")
        jsonList.add(mockJSON[i] as Pair<String, ArrayList<String>>)
    }
    // getItem is called to instantiate the fragment for the given page.
    // Return a PlaceholderFragment (defined as a static inner class below)
    return PlaceholderFragment.newInstance(position + 1, jsonList[position].second)
}

override fun getPageTitle(position: Int): CharSequence? {
    //Sort through the JSON and get a list of sections.
    // Then, create tabs based on those sections
    val jsonList = arrayListOf<Pair<String, ArrayList<String>>>()
    for(i in 0 until mockJSON.length()){
        @Suppress("unchecked_cast")
        jsonList.add(mockJSON[i] as Pair<String, ArrayList<String>>)
    }
    val sectionArray = arrayListOf<String>()
    //Get the various sections from mockJSONArray
    for (arrayItem in jsonList) {
        sectionArray.add(arrayItem.first)
    }

    return sectionArray[position]
}

override fun getCount(): Int {
    //Sort through the JSON and get a list of sections.
    // Then, create tabs based on those sections
    val jsonList = arrayListOf<Pair<String, ArrayList<String>>>()
    for(i in 0 until mockJSON.length()){
        @Suppress("unchecked_cast")
        jsonList.add(mockJSON[i] as Pair<String, ArrayList<String>>)
    }

    val sectionArray = arrayListOf<String>()
    //Get the various sections from mockJSONArray
    for (arrayItem in jsonList) {
        sectionArray.add(arrayItem.first)
    }

    // Show total pages in relation to size of tab titles array.
    return sectionArray.size
}
}

PlaceholderFragment

class PlaceholderFragment : Fragment() {

private lateinit var pageViewModel: PageViewModel
private val viewIDArrayList = arrayListOf<Int>()
private lateinit var fragmentActivity: FragmentActivity

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    fragmentActivity = activity!!
    pageViewModel = ViewModelProviders.of(this).get(PageViewModel::class.java).apply {
        setIndex(arguments?.getInt(ARG_SECTION_NUMBER) ?: 1)
    }
}

override fun onDestroyView() {
    super.onDestroyView()
    Log.d("BEAU", "View Destroyed!")
}

override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
    val root = inflater.inflate(R.layout.fragment_tab_test, container, false)
    val textView: TextView = root.findViewById(R.id.section_label)

    //Set page title with information gained from putInt in newInstance function below
    pageViewModel.text.observe(this, Observer<String> {
        textView.text = it
    })

    //get JSON data from bundle
    @Suppress("unchecked_cast")
    val jsonData = arguments!!.getStringArrayList("JSONData") as ArrayList<Pair<String, String>>

    fun createEditTextLine(titleString: String) {
        val verticalLayout = root.findViewById<LinearLayout>(R.id.createInspectionBodyLinearLayout)
        val layoutInflater = LayoutInflater.from(fragmentActivity)
        val linearLayout = layoutInflater.inflate(R.layout.template_edit_text, null) as LinearLayout
        verticalLayout.addView(linearLayout)
        val titleText = linearLayout.findViewById<TextView>(R.id.editTextTitle)
        titleText.id = ViewCompat.generateViewId()
        viewIDArrayList.add(titleText.id)
        titleText.text = titleString
        //if the number is even, color it differently to make the sections easier to differentiate
        if (titleText.id % 2 == 0) {
            linearLayout.setBackgroundColor(Color.parseColor("#F2F2F0"))
        }
    }

    fun createDatePickerLine(titleString: String) {
        val horizontalLayout = root.findViewById<LinearLayout>(R.id.createInspectionBodyLinearLayout)
        val layoutInflater = LayoutInflater.from(fragmentActivity)
        val linearLayout = layoutInflater.inflate(R.layout.template_date_picker, null) as LinearLayout
        horizontalLayout.addView(linearLayout)
        val dateTitle = linearLayout.findViewById<TextView>(R.id.dateTitle)
        dateTitle.id = ViewCompat.generateViewId()
        dateTitle.text = titleString
        viewIDArrayList.add(dateTitle.id)
        //if the number is even, color it differently to make the sections easier to differentiate
        if (dateTitle.id % 2 == 0) {
            linearLayout.setBackgroundColor(Color.parseColor("#F2F2F0"))
        }
    }

    fun createTimePickerLine(titleString: String) {
        val horizontalLayout = root.findViewById<LinearLayout>(R.id.createInspectionBodyLinearLayout)
        val layoutInflater = LayoutInflater.from(fragmentActivity)
        val linearLayout = layoutInflater.inflate(R.layout.template_time_picker, null) as LinearLayout
        horizontalLayout.addView(linearLayout)
        val timeTitle = linearLayout.findViewById<TextView>(R.id.timeTitle)
        timeTitle.id = ViewCompat.generateViewId()
        timeTitle.text = titleString
        viewIDArrayList.add(timeTitle.id)
        //if the number is even, color it differently to make the sections easier to differentiate
        if (timeTitle.id % 2 == 0) {
            linearLayout.setBackgroundColor(Color.parseColor("#F2F2F0"))
        }
    }

    fun createRatingBarLine(titleString: String) {
        val horizontalLayout = root.findViewById<LinearLayout>(R.id.createInspectionBodyLinearLayout)
        val layoutInflater = LayoutInflater.from(fragmentActivity)
        val linearLayout = layoutInflater.inflate(R.layout.template_rating_bar, null) as LinearLayout
        horizontalLayout.addView(linearLayout)
        val ratingTitle = linearLayout.findViewById<TextView>(R.id.ratingTitle)
        ratingTitle.id = ViewCompat.generateViewId()
        ratingTitle.text = titleString
        viewIDArrayList.add(ratingTitle.id)
        //if the number is even, color it differently to make the sections easier to differentiate
        if (ratingTitle.id % 2 == 0) {
            linearLayout.setBackgroundColor(Color.parseColor("#F2F2F0"))
        }
    }

    for (item in jsonData) {
        if (item.second == "editText") {
            createEditTextLine(item.first)
        }
        if (item.second == "datePicker") {
            createDatePickerLine(item.first)
        }
        if (item.second == "timePicker") {
            createTimePickerLine(item.first)
        }
        if (item.second == "rating") {
            createRatingBarLine(item.first)
        }
    }

    return root
}

companion object {
    /**
     * The fragment argument representing the section number for this
     * fragment.
     */
    private const val ARG_SECTION_NUMBER = "section_number"

    /**
     * Returns a new instance of this fragment for the given section
     * number.
     */
    @JvmStatic
    fun newInstance(sectionNumber: Int, jsonForThisSection: ArrayList<String>): PlaceholderFragment {
        return PlaceholderFragment().apply {
            arguments = Bundle().apply {
                putInt(ARG_SECTION_NUMBER, sectionNumber)
                putStringArrayList("JSONData", jsonForThisSection)
            }
        }
    }
}
}

PageViewModel

class PageViewModel : ViewModel() {

private val _index = MutableLiveData<Int>()
val text: LiveData<String> = Transformations.map(_index) {
    "Hello world from section: $it"
}

fun setIndex(index: Int) {
    _index.value = index
}
}

非常感谢您的帮助。

答案

您是否试图声明一个可以由您的Activity访问的全局变量（在类范围之外？）>

以上是关于从viewPager片段（Kotlin）中获取用户输入信息的主要内容，如果未能解决你的问题，请参考以下文章

从 ViewPager 中检索片段

onActivityResult 不会从 viewPager 片段调用

我在 viewpager 选项卡中的片段不刷新

从ViewPager android替换片段

如何将值从其他活动传递给 viewpager 片段？

如何使用 TabLayout 在 ViewPager 中的 Google 地图片段中获取当前位置