组合框跳转到键入的字符 [英] combobox jump to typed char

问题描述

我偶然发现了一个愚蠢的问题。但是，我没有找到一个解决方案（可能是因为没有使用正确的搜索关键字，或者使它太困难，当它可以很容易..）
场景：

I stumbled on (in my eyes) a silly problem. However I don't find a solution for this (maybe because of not using the right search keywords, or by making it too difficult when it can be easy..) Scenario:

我有一个包含500个客户的组合框。我必须选择一个单独的客户。

I have a combobox with 500 customers. I have to select a single costumer.

在Swing中，当列表关闭并开始输入时，它会自动跳转到输入的字母。例如：

In Swing, when the list was down and you started typing, it automatically jumps to the typed letter. E.g.:

项目：

• Adam




• 
  


• ...


• Steven


• Z人

• Adam
• Dirk
• Freddy
• ...
• Roger
• Steven
• Z person

当组合框列表打开时， 'R'，在摆动中，它跳到第一个以R开头的客户。在javafx 2它似乎没有那种行为...有一些选项，我必须启用或应该做一些类似使用可编辑组合框，并使一个

When the combobox list is open, I just type 'R' and, in swing, it jumped to the first customer starting with 'R'. In javafx 2 it seems it does not have that behaviour... Is there some option that I have to enable or should I do something like using an editable combobox instead and make a filter() method that is fired on every keypress?

编辑：基于Bhupendra答案的解决方案：

Edit: sollution based on Bhupendra's answer:

public class FilterComboBox<T> extends ComboBox<T> {
private final FilterComboBox<T> fcbo = this;

//private FilterComboBox fcbo = this;
private ObservableList<T> items;
private ObservableList<T> filter;
private String s;
private Object selection;

private class KeyHandler implements EventHandler< KeyEvent> {

    private SingleSelectionModel<T> sm;

    public KeyHandler() {
        sm = getSelectionModel();
        s = "";
    }

    @Override
    public void handle(KeyEvent event) {
        filter.clear();
        // handle non alphanumeric keys like backspace, delete etc
        if (event.getCode() == KeyCode.BACK_SPACE && s.length() > 0) {
            s = s.substring(0, s.length() - 1);
        } else {
            s += event.getText();
        }

        if (s.length() == 0) {
            fcbo.setItems(items);
            sm.selectFirst();
            return;
        }
        //System.out.println(s);
        if (event.getCode().isLetterKey()) {
            for (T item : items) {
                if (item.toString().toUpperCase().startsWith(s.toUpperCase())) {

                    filter.add(item);
                    //System.out.println(item);

                    fcbo.setItems(filter);

                    //sm.clearSelection();
                    //sm.select(item);

                }
            }
            sm.select(0);
        }

    }
}

public FilterComboBox(final ObservableList<T> items) {
    super(items);
    this.items = items;
    this.filter = FXCollections.observableArrayList();

    setOnKeyReleased(new KeyHandler());

    this.focusedProperty().addListener(new ChangeListener() {
        @Override
        public void changed(ObservableValue observable, Object oldValue, Object newValue) {
            if (newValue == false) {
                s = "";
                fcbo.setItems(items);
                fcbo.getSelectionModel().select((T)selection);
            }

        }
    });

    this.getSelectionModel().selectedItemProperty().addListener(new ChangeListener() {
        @Override
        public void changed(ObservableValue observable, Object oldValue, Object newValue) {
            if (newValue != null) {
                selection = (Object) newValue;
            }

        }
    });
}

}

解决方案

过滤器组合框最简单的形式是下面的代码。但是，需要更多的工作来完善它。
另外，如果列表是巨大的，在你的情况下，可能会有性能问题，因为我们循环通过每个按键的整个集合。

The simplest form of a filter combo box would be as the code below. But it would need more work to refine it. Also, if the list is huge, as in your case, there might be a performance issues as we are looping thru' the entire collection on each key press.

public class FilterComboBox extends ComboBox< String > {
    private ObservableList< String >    items;

    private class KeyHandler implements EventHandler< KeyEvent > {

        private SingleSelectionModel< String >  sm;
        private String                          s;

        public KeyHandler() {
            sm = getSelectionModel();
            s = "";
        }

        @Override
        public void handle( KeyEvent event ) {
            // handle non alphanumeric keys like backspace, delete etc
            if( event.getCode() == KeyCode.BACK_SPACE && s.length()>0)
                s = s.substring( 0, s.length() - 1 );
            else s += event.getText();

            if( s.length() == 0 ) {
                sm.selectFirst();
                return;
            }
            System.out.println( s );
            for( String item: items ) {
                if( item.startsWith( s ) ) sm.select( item );
            }
        }

    }

    public FilterComboBox( ObservableList< String > items ) {
        super( items );
        this.items = items;

        setOnKeyReleased( new KeyHandler() );
    }
}

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