警报对话框简化

Question

我试图写一个简化的AlertDialog，这样我就可以更多的在家与科特林，如果我不能使自己的语言做机器人，然后使科特林的行为，就像PureBasic将是理论。

我遇到的问题是这个错误：

4027-4027/com.example.cardgamexxx E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.cardgamexxx, PID: 4027
android.view.WindowManager$BadTokenException: Unable to add window -- token null is not valid; is your activity running?
    at android.view.ViewRootImpl.setView(ViewRootImpl.java:1444)
    at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:469)
    at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:114)
    at android.app.Dialog.show(Dialog.java:505)
    at android.app.AlertDialog$Builder.show(AlertDialog.java:1157)
    at com.example.cardgamexxx.Requester.messageRequester(Requester.kt:33)
    at com.example.cardgamexxx.MainActivity.onCreate$lambda-3(MainActivity.kt:695)
    at com.example.cardgamexxx.MainActivity.lambda$Zt8ODWx7LLRfq4535q7hQg5xQfw(Unknown Source:0)
    at com.example.cardgamexxx.-$$Lambda$MainActivity$Zt8ODWx7LLRfq4535q7hQg5xQfw.onClick(Unknown Source:2)
    at android.view.View.performClick(View.java:8160)
    at android.widget.TextView.performClick(TextView.java:16222)
    at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:1119)
    at android.view.View.performClickInternal(View.java:8137)
    at android.view.View.access$3700(View.java:888)
    at android.view.View$PerformClick.run(View.java:30236)
    at android.os.Handler.handleCallback(Handler.java:938)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:246)
    at android.app.ActivityThread.main(ActivityThread.java:8512)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:602)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1130)

使用此代码：

package com.example.cardgamexxx

import android.app.AlertDialog
import android.content.Context
import com.example.cardgamexxx.RequesterType.MessageRequester_Ok
import com.example.cardgamexxx.RequesterType.MessageRequester_YesNo
import com.example.cardgamexxx.RequesterType.MessageRequester_YesNoCancel

//------------------------------------------------------------------------------
//  Very PureBasic'ish 'Requester' dialogs.
//------------------------------------------------------------------------------

object RequesterType {
    const val MessageRequester_Ok = 1            // to have the 'ok' only button (default)
    const val MessageRequester_YesNo = 2         // to have 'yes' or 'no' buttons
    const val MessageRequester_YesNoCancel = 3   // to have 'yes', 'no' and 'cancel' buttons
}

class Requester {

    fun inputRequester() {

    }

    fun messageRequester(appContext: Context,title: String,message: String,flags: Int) : Int {

        var result: Int = 0

        if( flags == MessageRequester_Ok ) {
            AlertDialog.Builder(appContext)
                .setTitle(title) // R.string.question_title
                .setMessage(message) // R.string.question_message
                .setPositiveButton("Ok") { _, _ -> result = 0 }
                .show()
        }

        if( flags == MessageRequester_YesNo ) {
            AlertDialog.Builder(appContext)
                .setTitle(title) // R.string.question_title
                .setMessage(message) // R.string.question_message
                .setPositiveButton("Yes") { _, _ -> result = 0 }
                .setNegativeButton("No") { _, _ -> result = 1 }
                .show()
        }

        if( flags == MessageRequester_YesNoCancel ) {
            AlertDialog.Builder(appContext)
                .setTitle(title) // R.string.question_title
                .setMessage(message) // R.string.question_message
                .setPositiveButton("Yes") { _, _ -> result = 0 }
                .setNegativeButton("No") { _, _ -> result = 1 }
                .setNegativeButton("Cancel") { _, _ -> result = 2 }
                .show()
        }

        return result

    }

    fun openFileRequester() {

    }

    fun pathRequester() {

    }

    fun saveFileRequester() {

    }

}

另一个问题是，在打开时请求者应该是‘代码’阻塞的意思，而不是这一切都很重要，但是如果"messageRequester()“返回一个结果，那么调用"messageRequester()”的代码就可以根据所给出的答案更改流。

我走错路了吗？我是否需要抛出这个想法，重新创造轮子，从根本上制造我自己的。

Answer 1

假设您使用应用程序上下文(因为您将其命名为appContext)来显示对话框，我相信这是异常的根本原因。

您应该传递当前的Activity上下文。

更改您的函数签名以确保传递一个活动：

fun messageRequester(activity: Activity, title: String, message: String, flags: Int) : Int {
...
}

关于代码阻塞，只有在后台线程上调用messageRequester函数才有可能，而这不是Android的原生方式。

您需要使用一些并发锁来锁定名为messageRequester的线程，并从AlertDialog的按钮侦听器中解锁它，通过将其保存到一个变量来转发它们的答案。

通常，我不建议使用锁，因为如果您不熟悉并发原则，那么使用锁是很危险的。

无论如何，我建议简单地在函数中传递一个lambda回调，然后用按钮侦听器的答案调用它。

使用回调

// enum to hold the answer (you're free to use whatever type you want for callback)
enum class Answer { YES, NO, CANCEL }

// Function signature
fun messageRequester(activity: Activity, title: String, message: String, flags: Int, callback: (answer: Answer) -> Unit) {
...

}

// How to pass result to callback from buttons listener
callback(Answer.YES)

// Passing callback to function
myRequester.messageRequester(activity, message, flags) { answer ->
  // Handle answer here
}

使用锁

// enum to hold the answer (you're free to use whatever type you want for callback)
enum class Answer { YES, NO, CANCEL }

// Function signature
fun messageRequester(activity: Activity, title: String, message: String, flags: Int) : Answer? {
  // Don't use main thread!!!!!!
  if (Looper.getMainLooper() == Looper.myLooper()) {
    throw IllegalStateException("Suspending main thread is forbidden!")
  }

  // Variable to hold the answer
  var answer: Answer? = null

  // The lock that holds the thread until an answer is given
  val countDownLatch = CountDownLatch(1)

  // How to pass answer from buttons listener (in AlertDialog creation)
  Listener {
    answer = Answer.YES
    countDownLatch.countDown()
  }
  
  // Wait for answer forever (not recommended since you can exit dialog without clicking buttons and block the thread forever)
  countDownLatch.await()

  // Wait for answer for 10 seconds (answer will be null in case of a timeout). returns false for timeouts.
  val handled = countDownLatch.await(10L, TimeOut.SECONDS)
  return answer 
}

Answer 2

虽然我会很好，并张贴的代码，以防别人发现它有用。

更新添加输入请求程序

像这样打电话；

myreq.messageRequester(this,
                  "Testing Ok!","with this message",
                       MessageRequester_Ok) { a ->

    Log.d("debug","$a")
}

添加了最后一个函数，openFileRequester / PathRequester

添加这个类文件。

package com.example.cardgamexxx

import android.app.Activity
import android.app.AlertDialog
import android.net.Uri
import android.text.InputType
import android.widget.EditText
import androidx.activity.result.contract.ActivityResultContracts
import androidx.appcompat.app.AppCompatActivity
import androidx.core.net.toUri
import com.example.cardgamexxx.RequesterType.InputRequester_Password
import com.example.cardgamexxx.RequesterType.MessageRequester_Ok
import com.example.cardgamexxx.RequesterType.MessageRequester_YesNo
import com.example.cardgamexxx.RequesterType.MessageRequester_YesNoCancel

//------------------------------------------------------------------------------
//  Very PureBasic'ish 'Requester' dialogs.
//
//  Alert Simplification
//  https://stackoverflow.com/questions/68554654/alert-dialog-simplification
//
//  Help From:
//
//  Shlomi Katriel
//  Ticherhaz FreePalestine
//------------------------------------------------------------------------------

object RequesterType {
    const val MessageRequester_Ok = 1            // to have the 'ok' only button (default)
    const val MessageRequester_YesNo = 2         // to have 'yes' or 'no' buttons
    const val MessageRequester_YesNoCancel = 3   // to have 'yes', 'no' and 'cancel' buttons
    const val InputRequester_Password = 4
}

enum class RequesterAnswer { YES, NO, CANCEL, OK }

class Requester {

    fun inputRequester(activity: Activity, title: String, message: String, flags: Int,callback: (answer: String) -> Unit) {

        val editText = EditText(activity)

        when (flags) {
            InputRequester_Password -> {
                editText.inputType = InputType.TYPE_CLASS_TEXT or InputType.TYPE_TEXT_VARIATION_PASSWORD
            }
        }

        val inputDialog = AlertDialog.Builder(activity)
            inputDialog.setTitle(title)
            .setView(editText)
            .setCancelable(false)
            .setNegativeButton("Cancel") { _, _ -> callback("CANCEL") }
            .setPositiveButton("OK") { _,_ -> callback (editText.text.toString()) }
            inputDialog.show()

    }

    fun messageRequester(activity: Activity, title: String, message: String, flags: Int,callback: (answer: RequesterAnswer) -> Unit) {

        if( flags == MessageRequester_Ok ) {
            AlertDialog.Builder(activity)
                .setTitle(title)
                .setMessage(message)
                .setPositiveButton("Ok") { _, _ -> callback(RequesterAnswer.OK) }
                .show()
        }

        if( flags == MessageRequester_YesNo ) {
            AlertDialog.Builder(activity)
                .setTitle(title)
                .setMessage(message)
                .setPositiveButton("Yes") { _, _ -> callback(RequesterAnswer.YES) }
                .setNegativeButton("No") { _, _ -> callback(RequesterAnswer.NO) }
                .show()
        }

        if( flags == MessageRequester_YesNoCancel ) {
            AlertDialog.Builder(activity)
                .setTitle(title)
                .setMessage(message)
                .setPositiveButton("Yes") { _, _ -> callback(RequesterAnswer.YES) }
                .setNegativeButton("No") { _, _ -> callback(RequesterAnswer.NO) }
                .setNegativeButton("Cancel") { _, _ -> callback(RequesterAnswer.CANCEL) } // doesn't work :(
                .show()
        }

    }

    fun openFileRequester(cActivity: AppCompatActivity,filter : String,callback: (answer: Uri) -> Unit) {
        val openFileRequester = cActivity.registerForActivityResult(ActivityResultContracts.GetContent()) { uri: Uri ->
            callback(uri)
        }
        openFileRequester.launch(filter)
    }

    fun pathRequester(cActivity: AppCompatActivity,filter : String,callback: (answer: Uri) -> Unit) {
        val getUserFolderData = cActivity.registerForActivityResult(ActivityResultContracts.OpenDocumentTree()) { uri: Uri ->
            callback(uri)
        }
        getUserFolderData.launch(filter.toUri())
    }

    fun saveFileRequester(cActivity: AppCompatActivity,filter : String,callback: (answer: Uri) -> Unit) {
        val getUserFolderData = cActivity.registerForActivityResult(ActivityResultContracts.OpenDocumentTree()) { uri: Uri ->
            callback(uri)
        }
        getUserFolderData.launch(filter.toUri())
    }

}

/*

    How to use.

myreq.messageRequester(this,
                       "Testing Ok!","with this message",
                       MessageRequester_Ok) { a ->

    Log.d("debug","$a")
}

myreq.messageRequester(this,
                       "Testing Yes / No","with this message",
                       MessageRequester_YesNo) { a ->

    Log.d("debug","$a")
}

myreq.messageRequester(this,
                       "Testing Yes/No Cancel!","with this message",
                       MessageRequester_YesNoCancel) { a ->

    Log.d("debug","$a")
}
*/