B4A 中的错误：java.lang.RuntimeException：Object 应首先初始化（EditText）

Question

我最近开始学习 B4A (Basic For Android)，它是一个 IDE，可用于制作 Android 应用程序。

不幸的是，我在执行代码时遇到了一个错误，我不知道如何修复它。

错误是：java.lang.RuntimeException: Object 应该首先被初始化（EditText）。

我不知道为什么会收到此错误，请帮忙！

代码：

    #Region  Project Attributes 
    #ApplicationLabel: Chatbot
    #VersionCode: 1
    #VersionName: 
    'SupportedOrientations possible values: unspecified, landscape or portrait.
    #SupportedOrientations: portrait
    #CanInstallToExternalStorage: False
#End Region

#Region  Activity Attributes 
    #FullScreen: True
    #IncludeTitle: True
#End Region

Sub Process_Globals
    'These global variables will be declared once when the application starts.
    'These variables can be accessed from all modules.
    Private xui As XUI
End Sub

Sub Globals
    'These global variables will be redeclared each time the activity is created.
    Public Label1 As Label
    Public TBox As EditText
End Sub

Sub Activity_Create(FirstTime As Boolean)
    Activity.LoadLayout("Layout")
End Sub

Sub Activity_Resume
    Activity.LoadLayout("Layout")
End Sub

Sub Activity_Pause (UserClosed As Boolean)

End Sub

Sub Button1_Click
    Private Label1 As Label
    Private TBox As EditText
    If TBox.Text = "hello" Then 
        Label1.Text = "Hi!"
    Else 
        Label1.Text = "Invalid Command"
    End If
    End Sub

完整错误日志：

*** Service (starter) Create ***
** Service (starter) Start **
** Activity (main) Create, isFirst = true **
** Activity (main) Resume **
main_button1_click (java line: 372)
java.lang.RuntimeException: Object should first be initialized (EditText).
    at anywheresoftware.b4a.AbsObjectWrapper.getObject(AbsObjectWrapper.java:67)
    at anywheresoftware.b4a.objects.TextViewWrapper.getText(TextViewWrapper.java:36)
    at b4a.example.main._button1_click(main.java:372)
    at java.lang.reflect.Method.invoke(Native Method)
    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:213)
    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:197)
    at anywheresoftware.b4a.BA.raiseEvent(BA.java:193)
    at anywheresoftware.b4a.objects.ViewWrapper$1.onClick(ViewWrapper.java:80)
    at android.view.View.performClick(View.java:5638)
    at android.view.View$PerformClick.run(View.java:22430)
    at android.os.Handler.handleCallback(Handler.java:751)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:154)
    at android.app.ActivityThread.main(ActivityThread.java:6198)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:891)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:781)

请帮忙！！！！

Answer 1

问题是由于您两次加载布局而引起的。 Activity_Create 和 Activity_Resume 在应用启动时都会被调用。

您可以在此处找到有关应用程序生命周期的更多信息： https://www.b4x.com/android/forum/threads/android-activity-lifecycle.105551/#post-661112

我还建议你看看使用 B4xPages - https://www.b4x.com/android/forum/threads/b4x-b4xpages-cross-platform-and-simple-framework-for-managing-multiple-pages.118901/后 743752 。

即使对于单页应用程序，使用该框架的生命周期问题也不会成为问题。

ADDL：您在 Button1_Click 事件子中声明 Label1 和 TBox，请尝试删除它们。 它们已经在 Globals 中声明，不需要再次声明。

Answer 2

您必须首先初始化文本框，然后使用：

textbox.initialize("EventName")