Question

您好我还是java上的新手希望学习这个不错的功能... 你好我有4个组合框，内部和内部相同是

-Select-
Item 1
Item 2
Item 3
Item 4

当我在Item 1上选择comboBox1时， comboBox2,comboBox3 and comboBox4只包含这些元素

-Select-
Item 2
Item 3
Item 4

然后当我在Item 3上选择comboBox2时，comboBox3 and comboBox4会有这个剩余的元素

-Select-
Item 2
Item 4

任何人都知道如何在Java上做到这一点？我在Netbeans上使用GUI Builder ......

编辑1

这是我的代码

private void jComboBox1ItemStateChanged(java.awt.event.ItemEvent evt) {
    jComboBox2.removeItem(jComboBox1.getSelectedItem());
    jComboBox3.removeItem(jComboBox1.getSelectedItem());
    jComboBox4.removeItem(jComboBox1.getSelectedItem());
}

然后我添加相同的代码jComboBox2, jComboBox3 and jComboBox4 ... 当我选择-Select-时-Select-也消失了......

另一个问题是，当我已经选择所有并且想要再次更换它时...所有项目都已消失，不再有更多选择..我只是想再次支持可用的项目......

编辑2

示例

jComboBox1
-Select-
Item 1
Item 2 <-- I select Item2, then the other combo box will remove Item 2**
Item 3
Item 4

jComboBox2
-Select-
Item 1
Item 3 <-- then I select Item 3
Item 4

jComboBox3
-Select-
Item 1
Item 4 <-- then Item 4

jComboBox4
-Select-
Item 1

但我正在改变主意......然后我需要回到jComboBox2选择Item3 所以我选择 jComboBox2并选择-Select-，以便我可以在item3上选择jComboBox4

但结果是 jComboBox4 null（没有项目）

Answer 1

不确定您的两个答案中的哪一个会被删除，但这里的答案又是一样的。请注意，您可以使用循环创建所有JComboBox和选项，以防止非常冗长的重复代码。然后你可以使用getSource（）方法来告诉事件来自哪个组合框。如果您将JComboBoxes创建为数组，则可以非常干净地遍历它们。为了重新添加内容，我只需跟踪已选择的内容以及使用String数组的组合框。然后，您可以检查此阵列并根据需要使用它来添加项目。请注意，他们不会以相同的顺序返回。如果你想要这个功能你可以使用insertItemAt，但这可能会有点混乱（因为索引不断变化，因为你要添加和删除项目）所以我已经把它留了出来。

//Declare and initialize the options that the comboboxes will have
String[] options = {"-Select-", "Item 1", "Item 2", "Item 3", "Item 4"};
//Declare and initialize an array that will hold the currently selected options in each combobox by index
//For example the currently selected value of comboBoxes[1] is selected[1]
String[] selected = {"-Select-", "-Select-", "-Select-", "-Select-"};

//Declare and initialize an array of comboBoxes. 
//Four comboboxes will be created all containing the options array
JComboBox[] comboBoxes = new JComboBox[4];
for(int i = 0; i < comboBox.length; i++) {
    comboBoxes[i] = new JComboBox(options);
}

private void jComboBox1ItemStateChanged(java.awt.event.ItemEvent evt) {
    //Loop through all of the comboboxes in comboBoxes
    for(int i = 0; i < comboBoxes.length; i++) {
        //Check to see if the current combobox in the array matches the source of your event
        if(evt.getSource() == comboBoxes[i]) {
            //Get the string value of the combobox that fired the event
            String currentSelection = (String)comboBoxes[i].getSelectedItem();
            //Make sure that the value actually changed
            if(!currentSelection.equals(selected[i]) {
                //If the previous value of the combobox was "-Select-" don't add it to all the other comboboxes
                if(!selected[i].equals(options[0])) {
                    //Add back the previous value to all comboboxes other than the one that fired the event
                    for(int j = 0; j < comboBoxes.length; j++) {
                        if(j != i) {
                            comboBoxes[j].addItem(selected[i]);
                        }
                    }
                }
                //If current value of the combobox is "-Select-" don't remove it from all other comboboxes
                if(!currentSelection.equals(options[0]) {
                    //Remove the current value from all comboboxes other than the one that fired the event
                    for(int j = 0; j < comboBoxes.length; j++) {
                        if(j != i) {
                            comboBoxes[j].removeItem(comboBoxes[i].getSelectedItem());
                        }
                    }
                }
            }
            //Set the selected item for the combobox that fired the event to the current value
            selected[i] = currentSelection;
        }
    }
}

Java - 如果在combox1中选择了一个值，那么它应该在所有其他组合框中禁用

1 个答案: