OnTextChangedListener 中的 MutableLIst 错误

Question

我的应用程序的一项功能允许用户通过键入 Edittext 来更新他们练习的元素。在后台，我使用 TextWatcher 来侦听更改并将每个更改保存到 UI 打开时弹出的 mutableList。它适用于超过 1 个元素的 mutableList。但是当只有一个元素时 returns 会出错。

我使用 MutableList 的方式有问题吗？

我这里把数据输入arraylist

dialogViewModel.clickedExercise(this, exerciseID) {repList = it.numberOfReps.split(", ") as MutableList<String> ...}

然后我为每个元素创建一个 Edittext。

                editTextReps.apply {
                    setText(reps)
                    //textAlignment = View.TEXT_ALIGNMENT_CENTER
                    textSize = 20f
                    id = repInt
                    setBackgroundColor(WHITE)
                    setPadding(0, 0, 16, 0)
                    layoutParams = ViewGroup.LayoutParams(
                        ViewGroup.LayoutParams.WRAP_CONTENT,
                        ViewGroup.LayoutParams.WRAP_CONTENT
                    )...}

我然后监听每个 EditText 中的变化

editTextReps.addTextChangedListener(object : TextWatcher {
                    override fun afterTextChanged(p0: Editable?) {
                        exercise.numberOfReps = repString.toString()
                        if (repTrial == repString.toString())
                            Log.d(TAG, "Nothing Change")
                        else
                            Log.d(TAG, "It changed")
                        dialogViewModel.update(exercise)
                        Log.d(TAG, repString.toString())
                        repString.clear()
                    }

                    override fun beforeTextChanged(p0: CharSequence?, p1: Int, p2: Int, p3: Int) {
                    }

                    override fun onTextChanged(
                        exerciseString: CharSequence?,
                        p1: Int,
                        p2: Int,
                        p3: Int
                    ) {
                        //repList[listPosition]

                        //TODO: Position probably not right, error occurs when attempt is made to modify single set
                        Log.d(TAG, "${repList.size} , ${repList[listPosition]},\n$repTrial")
                        val testString = exerciseString.toString()
                        Log.d(TAG, "test: $testString")
                      
               this is the issue -> -> -> ->repList[listPosition] = testString
                      


  Log.d(TAG, "List Position: $listPosition, ${repList[listPosition]}")
                        for (rep in repList) {
                            repString.append("$rep, ")
                            Log.d(TAG, "${repList.size}")
                        }
                    }
                })

此代码适用于多个项目，但当 MutableList 仅包含一项时它会崩溃

错误读数

E/InputEventReceiver: Exception dispatching input event.
E/MessageQueue-JNI: Exception in MessageQueue callback: handleReceiveCallback
E/MessageQueue-JNI: java.lang.UnsupportedOperationException
        at java.util.AbstractList.add(AbstractList.java:148)
        at com.homeofficeprojects.countmyreps.DialogUpdateExercise$onCreate.onTextChanged(DialogUpdateExercise.kt:195)
        at android.widget.TextView.sendOnTextChanged(TextView.java:9754)
        at android.widget.TextView.handleTextChanged(TextView.java:9851)
        at android.widget.TextView$ChangeWatcher.onTextChanged(TextView.java:12509)
        at android.text.SpannableStringBuilder.sendTextChanged(SpannableStringBuilder.java:1263)
        at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:575)
        at android.text.SpannableStringBuilder.delete(SpannableStringBuilder.java:229)
        at android.text.SpannableStringBuilder.delete(SpannableStringBuilder.java:36)
        at android.text.method.BaseKeyListener.backspaceOrForwardDelete(BaseKeyListener.java:370)
        at android.text.method.BaseKeyListener.backspace(BaseKeyListener.java:71)
        at android.text.method.BaseKeyListener.onKeyDown(BaseKeyListener.java:479)
        at android.text.method.QwertyKeyListener.onKeyDown(QwertyKeyListener.java:362)
        at android.text.method.TextKeyListener.onKeyDown(TextKeyListener.java:141)
        at android.widget.TextView.doKeyDown(TextView.java:7665)
        at android.widget.TextView.onKeyDown(TextView.java:7442)
        at android.view.KeyEvent.dispatch(KeyEvent.java:2692)
        at android.view.View.dispatchKeyEvent(View.java:12450)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1896)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1896)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1896)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1896)
        at android.widget.ScrollView.dispatchKeyEvent(ScrollView.java:389)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1896)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1896)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1896)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1896)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1896)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1896)
        at com.android.internal.policy.DecorView.superDispatchKeyEvent(DecorView.java:428)
        at com.android.internal.policy.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1820)
        at android.app.Dialog.dispatchKeyEvent(Dialog.java:811)
        at com.android.internal.policy.DecorView.dispatchKeyEvent(DecorView.java:342)
        at android.view.ViewRootImpl$ViewPostImeInputStage.processKeyEvent(ViewRootImpl.java:5037)
        at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4905)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4426)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4479)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4445)
        at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4585)
        at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4453)
        at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4642)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4426)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4479)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4445)
        at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4453)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4426)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4479)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4445)
        at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4585)
        at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4453)
        at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4642)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4426)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4479)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4445)
        at android.view.ViewRootImpl$InputStage.
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.homeofficeprojects.countmyreps, PID: 10507
    java.lang.UnsupportedOperationException
        at java.util.AbstractList.add(AbstractList.java:148)
        at com.homeofficeprojects.countmyreps.DialogUpdateExercise$onCreate.onTextChanged(DialogUpdateExercise.kt:195)
        at android.widget.TextView.sendOnTextChanged(TextView.java:9754)
        at android.widget.TextView.handleTextChanged(TextView.java:9851)
        at android.widget.TextView$ChangeWatcher.onTextChanged(TextView.java:12509)
        at android.text.SpannableStringBuilder.sendTextChanged(SpannableStringBuilder.java:1263)
        at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:575)
        at android.text.SpannableStringBuilder.delete(SpannableStringBuilder.java:229)
        at android.text.SpannableStringBuilder.delete(SpannableStringBuilder.java:36)
        at android.text.method.BaseKeyListener.backspaceOrForwardDelete(BaseKeyListener.java:370)
        at android.text.method.BaseKeyListener.backspace(BaseKeyListener.java:71)
        at android.text.method.BaseKeyListener.onKeyDown(BaseKeyListener.java:479)
        at android.text.method.QwertyKeyListener.onKeyDown(QwertyKeyListener.java:362)
        at android.text.method.TextKeyListener.onKeyDown(TextKeyListener.java:141)
        at android.widget.TextView.doKeyDown(TextView.java:7665)
        at android.widget.TextView.onKeyDown(TextView.java:7442)
        at android.view.KeyEvent.dispatch(KeyEvent.java:2692)
        at android.view.View.dispatchKeyEvent(View.java:12450)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1896)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1896)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1896)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1896)
        at android.widget.ScrollView.dispatchKeyEvent(ScrollView.java:389)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1896)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1896)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1896)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1896)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1896)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1896)
        at com.android.internal.policy.DecorView.superDispatchKeyEvent(DecorView.java:428)
        at com.android.internal.policy.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1820)
        at android.app.Dialog.dispatchKeyEvent(Dialog.java:811)
        at com.android.internal.policy.DecorView.dispatchKeyEvent(DecorView.java:342)
        at android.view.ViewRootImpl$ViewPostImeInputStage.processKeyEvent(ViewRootImpl.java:5037)
        at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4905)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4426)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4479)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4445)
        at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4585)
        at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4453)
        at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4642)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4426)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4479)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4445)
        at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4453)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4426)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4479)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4445)
        at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4585)
        at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4453)
        at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4642)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4426)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4479)
E/AndroidRuntime:     at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4445)
        at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4453)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4426)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4479)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4445)
        at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4585)
        at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4453)
        at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4642)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4426)
        at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:7092)
        at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:7061)
        at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:7022)
        at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:7195)
        at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:186)
        at android.os.MessageQueue.nativePollOnce(Native Method)
        at android.os.MessageQueue.next(MessageQueue.java:326)
        at android.os.Looper.loop(Looper.java:160)
        at android.app.ActivityThread.main(ActivityThread.java:6669)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)

Answer 1

关于 split(delimiter) 方法 - 如果 delimiter 没有出现在输入的任何地方，则结果列表只有一个元素包含原始输入。因此，在这种情况下，输出列表是不可变的 (SingletonList) 并且不支持 add 操作（它会抛出 UnsupportedOperationException）。

要获取可变列表，可以使用toMutableList()方法：

repList = it.numberOfReps.split(", ").toMutableList()

OnTextChangedListener 中的 MutableLIst 错误

MutableLIst Error in OnTextChangedListener

android

kotlin

mutablelist