android - 在 Fragment Kotlin 中调用 DialogFragment

Question

我正在尝试将我的 dialogfragment 调用到我的 loginfragment 中并显示一个警报对话框，该 show 方法说:

None of the following functions can be called with the arguments supplied. show(FragmentManager!, String!) defined in org.greenstand.android.TreeTracker.fragments.CustomDialogFragment show(FragmentTransaction!, String!) defined in org.greenstand.android.TreeTracker.fragments.CustomDialogFragment

val newFragment = CustomDialogFragment.newInstance("pass content here")

val fm = fragmentManager
newFragment.show(fm, "look")

这是我的 CustomDialogFragment 代码:

import android.app.Activity
import android.content.Intent
import android.content.pm.PackageManager
import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.Toast
import androidx.fragment.app.Fragment
import androidx.lifecycle.Observer
import kotlinx.android.synthetic.main.activity_main.*
import kotlinx.android.synthetic.main.fragment_login.*
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.GlobalScope
import kotlinx.coroutines.launch
import kotlinx.coroutines.withContext
import org.greenstand.android.TreeTracker.R
import org.greenstand.android.TreeTracker.application.Permissions
import org.greenstand.android.TreeTracker.utilities.*
import org.greenstand.android.TreeTracker.viewmodels.LoginViewModel
import org.koin.android.viewmodel.ext.android.viewModel
import timber.log.Timber
class CustomDialogFragment : DialogFragment()
{
    private var content: String? = null

    override fun onCreate(savedInstanceState: Bundle?)
    {
        super.onCreate(savedInstanceState)
        content = arguments!!.getString("content")

        val style = DialogFragment.STYLE_NO_FRAME
        val theme = R.style.DialogTheme
        setStyle(style, theme)
    }


    override fun onAttach(context: Context) {
        super.onAttach(context)
    }

    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup, savedInstanceState: Bundle): View
    {
        val view = inflater!!.inflate(R.layout.layout_dialog, container, false)

        val btnAccept = view.findViewById<View>(R.id.buttonAccept) as Button

        val textViewContent = view.findViewById<View>(R.id.textViewContent) as TextView
        textViewContent.text = content;

        btnAccept.setOnClickListener{
            dismiss();
        }

        return view;
    }

    companion object
    {
        fun newInstance(content: String) : CustomDialogFragment
        {
            val f = CustomDialogFragment()

            val args = Bundle()
            args.putString("content", content)
            f.arguments = args

            return f
        }
    }

}

有人可以指出我需要传递给 show 方法的确切内容吗？任何帮助表示赞赏，谢谢:)

Answer 1

[更新]
问题是该方法可以接收到 FragmentManager但它必须不为空，看看错误和不可为空的 Kotlin 符号FragmentManager!!所以你可以做

fm?.let {newFragment.show(fm, "your tag")}
//fm here can also be it

请参阅 Noushad Hasan 答案中的评论
您正在通过 FragmentManager对于该方法，它需要 FragmentTransaction和 String作为标签:

val transaction = supportFragmentManager.beginTransaction()
newFragment.show(transaction, "SOME_TAG")

几个建议:
你可以让你 DialogFragment使用 Kotlin 标准函数获得更多 kotliny

companion object {

        private const val KEY = "param1"

        @JvmStatic
        fun newInstance(param1: String) =
            ExampleDialogFragment().apply {
                arguments = bundleOf(KEY to param1)
            }
    }

您可以通过创建 Fragment 来获得一个很好的示例。使用 Android Studio 向导并检查工厂方法选项。
此外，由于标签将用于您的 DialogFragment您可以将其设为公共(public)常量:

 companion object {
        const val TAG = "TAG"
 }

也许您想仔细检查对话框 fragment 是否已经存在并将其删除，以实际作为新对话框工作

        val transaction = supportFragmentManager.beginTransaction()
        val previous = supportFragmentManager.findFragmentByTag(ExampleDialogFragment.TAG)
        if (previous != null) {
            transaction.remove(previous)
        }
        transaction.addToBackStack(null)

        val dialogFragment = ExampleDialogFragment.newInstance("parameter")
        dialogFragment.show(transaction, ExampleDialogFragment.TAG)