Question

我真的不知道出了什么问题，因为total被初始化了，因为程序总是以案例1开始，因为最初的点击等于1。我该在哪里初始化它，还是出了什么问题？ >

    <android.support.constraint.ConstraintLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     xmlns:tools="http://schemas.android.com/tools"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      tools:context="com.tkmsoft.taahel.activities.MainActivity">

       <android.support.design.widget.AppBarLayout
         android:id="@+id/appBarLayout"
    android:layout_width="0dp"
    android:layout_height="?android:actionBarSize"
    android:theme="@style/AppTheme.AppBarOverlay"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.0"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent">

    <android.support.v7.widget.Toolbar
        android:id="@+id/main_toolbar"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/colorAccent"
        app:popupTheme="@style/AppTheme.PopupOverlay">

            <TextView
                android:id="@+id/toolbar_title"
                style="@style/TextAppearance.Widget.AppCompat.Toolbar.Title"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:layout_alignParentStart="true"
                android:layout_toStartOf="@+id/toolbar_filter_button"
                android:gravity="center|start"
                android:textColor="@android:color/white" />
     </android.support.v7.widget.Toolbar>

          </android.support.design.widget.AppBarLayout>
    <FrameLayout
        android:id="@+id/main_frameLayout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

                 </android.support.constraint.ConstraintLayout>
               </android.support.constraint.ConstraintLayout>

Answer 1

您需要输入外部总开关的定义，如下所示：

enterBut.addActionListener(new ActionListener()
    {
           public void actionPerformed(ActionEvent e)
           {
             double total = 0;
            switch(click)
                {

                  case 1:
                      double subtotal = Double.parseDouble(Atext.getText());
                      total = 0.05*Math.round(1.13*subtotal/0.05);
                      answer.setText("The total will be $" + total + " (tax included). Enter the amount of money the customer gave.");
                      int click = 2;

                  case 2:
                      double money = Double.parseDouble(Atext.getText());
                      click = 3;
                      if (money<total)
                      {
                          JOptionPane.showMessageDialog(window, "That is not enough money.");
                          click = 2;
                      }
                }

           }

    });

Answer 2

您应该在switch语句之前将“总计”初始化为0。

Answer 3

每个case中变量的范围对应于整个switch语句

switch(key) {
case 0:
    String str="zero";
    break;

case 1:
    str="One";
    break;

}

但是如果您创建带有括号的case，则需要在每个case或switch语句上方声明它

switch(key) {
case 0:{
    String str="zero";
    break;
    }
case 1:{
    String str="One";
    break;
}
}

OR

String str;
switch(key) {
case 0:{
     str="zero";
    break;
}
case 1:{
     str="One";
    break;
}
}

不断收到此错误：“变量总数可能尚未初始化”

3 个答案: