素数面selectManyCheckbox

Question

我有selectManyCheckbox，但是在change事件发生后，我无法从它获得选中的值(所选值的列表保持为空)。会触发更改事件，但在调试模式下，listSelectedSignalCauses中没有值。我试图设置一些转换器，但也没有帮助(可能是错误的转换器)。

<p:selectManyCheckbox value="#{SignalAnalysisBean.listSelectedSignalCauses}" layout="pageDirection" styleClass="lstSignal">  
  <f:selectItems value="#{SignalAnalysisBean.listSignalCauses}" var="causes" itemValue="#{causes}" itemLabel="#{causes.name}"  />
  <p:ajax process="@this" update="test" event="change" listener="#{SignalAnalysisBean.checkCausesList}" />  
                    </p:selectManyCheckbox>
<h:outputText value="#{SignalAnalysisBean.arrSize}" id="test" />

public class SignalAnalysisBean extends AbstractBean {
    private List<GeneralCollDTO> listSignalCauses;
    private List<GeneralCollDTO> listSelectedSignalCauses;
    //...

    public void checkCausesList(){
        arrSize = 4 + listSelectedSignalCauses.size();
    }
    //...
}

public class GeneralCollDTO {
    private String name;
    private String value;

    public GeneralCollDTO() { }

    public GeneralCollDTO(String n, String v) {
        this.name = n;
        this.value = v;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }
}

Answer 1

最后，我最终得到了对我来说工作良好的通用转换器。

@FacesConverter(value = "generalCollDTOConverter", forClass = GeneralCollDTOConverter.class)
public class GeneralCollDTOConverter  implements Converter {

  private static Map<Object, String> entities = new HashMap<Object, String>();

  @Override
  public String getAsString(FacesContext context, UIComponent component, Object value) {
    synchronized (entities) {
        if (!entities.containsKey(value)) {
            String uuid = UUID.randomUUID().toString();
            entities.put(value, uuid);
            return uuid;
        } else {
            return entities.get(value);
        }
    }
  }

  @Override
  public Object getAsObject(FacesContext context, UIComponent component, String value) {
    for (Entry<Object, String> entry : entities.entrySet()) {
        if (entry.getValue().equals(value)) {
            System.out.println("getKey:" + entry.getKey());
            return entry.getKey();
        }
    }
    return value;
  }
}

Answer 2

为了向您的托管bean发送自定义对象，您需要实现一个转换器，否则您将无法这样做。下面的代码基于您的代码实现了它，它可能是解决问题的方法。

@FacesConverter(value = "generalCollDTOConverter", forClass = GeneralCollDTOConverter.class)
public class GeneralCollDTOConverter implements Converter {

    @Override
    public Object getAsObject(FacesContext ctx, UIComponent component, String value) {
        if (value != null) {
            return component.getAttributes().get(value);
        }
        return null;
    }

    @Override
    public String getAsString(FacesContext ctx, UIComponent component, Object value) {
        if (value != null && value instanceof GeneralCollDTO) {
            GeneralCollDTO generalCollDTO = (GeneralCollDTO) value;

            if (generalCollDTO.getName() != null) {
                component.getAttributes().put(generalCollDTO.getName(), value);
                return generalCollDTO.getName();
            }
        }
        return null;
    }
}



<p:selectManyCheckbox converter="generalCollDTOConverter" value="#{SignalAnalysisBean.listSelectedSignalCauses}" layout="pageDirection" styleClass="lstSignal">