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我正在尝试制作一个仅在输入 2 个字符后才显示建议的 SuggestBox。我的想法是在文本长度为 1 时隐藏建议，使用类 DefaultSuggestionDisplay。我试图在 SuggestionBox 本身及其 TextBox 上附加不同的处理程序，如 KeyPressHandler 和 KeyUpHandler，但它们似乎都不起作用。你有什么建议吗”？:D

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2 回答 2

1

您可以扩展DefaultSuggestionDisplay和覆盖showSuggestions方法：

public class MySuggestionDisplay extends DefaultSuggestionDisplay {
    @Override
    protected void showSuggestions(SuggestBox suggestBox, Collection<? extends Suggestion> suggestions, boolean isDisplayStringHTML, boolean isAutoSelectEnabled, SuggestionCallback callback) {
        if(suggestBox.getText().length() > 1)
            super.showSuggestions(suggestBox, suggestions, isDisplayStringHTML, isAutoSelectEnabled, callback);
    }
}

您必须将新显示传递给SuggestBox构造函数：

public class MySuggestBox extends SuggestBox {
    public MySuggestBox() {
        super(
            new MySuggestOracle(),
            new TextBox(), 
            new MySuggestionDisplay());
    }
}

在此构造函数中，您应该提供：

  • 你自己的SuggestOracle班级（这里命名MySuggestOracle） - 我想你有一个
  • TextBox- 它是输入文本的默认小部件（您可以提供自己的，只需要实现HasText）
  • SuggestionDisplay- 使用showSuggestions方法被覆盖的那个。

这是完整的工作示例代码，显示至少输入 2 个字符的建议：

import java.util.ArrayList;
import java.util.Collection;

import com.google.gwt.user.client.ui.SuggestBox;
import com.google.gwt.user.client.ui.SuggestOracle;
import com.google.gwt.user.client.ui.SuggestOracle.Suggestion;
import com.google.gwt.user.client.ui.TextBox;

public class MySuggestBox extends SuggestBox {

    public MySuggestBox() {
        super(
            new SuggestOracle() {
                @Override
                public void requestSuggestions(Request request, Callback callback) {
                    ArrayList<Suggestion> suggestions = new ArrayList<Suggestion>();
                    suggestions.add(new MySuggestion("aaa"));
                    suggestions.add(new MySuggestion("bbb"));
                    suggestions.add(new MySuggestion("ccc"));
                    suggestions.add(new MySuggestion("ddd"));

                    Response response = new Response();
                    response.setSuggestions(suggestions);
                    callback.onSuggestionsReady(request, response);
                }
            }, 
            new TextBox(), 
            new MySuggestionDisplay());
    }

    public static class MySuggestionDisplay extends DefaultSuggestionDisplay {
        @Override
        protected void showSuggestions(SuggestBox suggestBox, Collection<? extends Suggestion> suggestions, boolean isDisplayStringHTML, boolean isAutoSelectEnabled, SuggestionCallback callback) {
            if(suggestBox.getText().length() > 1)
                super.showSuggestions(suggestBox, suggestions, isDisplayStringHTML, isAutoSelectEnabled, callback);
        }
    }

    public static class MySuggestion implements Suggestion {

        private String text;

        public MySuggestion(String text) {
            this.text = text;
        }

        @Override
        public String getDisplayString() {
            return text;
        }

        @Override
        public String getReplacementString() {
            return text;
        }
    }
}
于 2016-06-05T22:32:47.620 回答
0

您可以扩展 SuggestBox 并覆盖showSuggestionList()方法。

添加 KeyUpHandler 不起作用，因为您添加了另一个 KeyUpHandler，而不是替换 SuggestBox 添加到其自己的 TextBox 中的那个。

编辑：

@Override
showSuggestionList() {
    if (getTextBox().getValue().length() > 1) {
        super.showSuggestionList();
    }
}
于 2016-06-03T17:39:14.590 回答