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Vaadin 8.5.1-行更新后刷新网格

vaadin8 vaadin refresh grid java

SDS · 技术社区 · 6 年前

当一行的it属性发生更改时,我使用 grid.getDataProvider().refreshItem(selectedRow) 或 grid.getDataProvider().refreshAll()

我得说清楚 grid.setItems()

我正在使用下面的代码片段创建网格

    msgGrid = new ABSMsgGrid();

    List<ConsoleEntry> messageEntryList = new ArrayList<>();
    if (inputConsole != null) {
        messageEntryList.addAll(inputConsole.getMessageEntryList());
    }

    msgGridDataProvider = new ListDataProvider<ConsoleEntry>(messageEntryList) {

        @Override
        public Object getId(ConsoleEntry item) {
            return item.getId();
        }
    };

    msgGrid.setDataProvider(msgGridDataProvider);



//on changing property of the grid row, i use the below snippet
private void handleHideRowMenuItem(GridContextMenu<ConsoleEntry> contextMenu, ConsoleEntry selectedConsoleItem) {
        if (!selectedConsoleItem.isHidden()) {
            hideRowMenuItem = contextMenu.addItem("Hide Row", VaadinIcons.EYE_SLASH, selectedMenuItem -> {
                    selectedConsoleItem.hide();
                    **msgGridDataProvider.refreshItem(selectedConsoleItem);**
                }
            });
        }
}

public class ConsoleEntry {

        @Override
        public boolean equals(Object obj) {
            // TODO Auto-generated method stub
            if (obj instanceof ConsoleEntry) {
                ConsoleEntry temp = (ConsoleEntry) obj;
                String msgRef2 = temp.getMsgRef();
                return this.getMsgRef().equalsIgnoreCase(msgRef2);
            }
            return false;
        }

        @Override
        public int hashCode() {
            // TODO Auto-generated method stub
            return super.hashCode();
        }

        public String getId(){
            return this.getMsgRef();
        }
}

我也看到过类似的问题,但没有一个解决方案奏效。

How to refresh the vaadin Grid after you change something?

Vaadin - Refresh grid after row modification

如果有人能分享如何解决这个问题的建议,我将不胜感激

短暂性脑缺血发作

2 回复 | 直到 6 年前

André Schild 6 年前

要使一个项被视为同一个项(以及刷新工作),您需要正确地实现 equals() 和 hashCode() 对象上的方法。

从文件中

公共无效刷新项(T项)

从接口复制的说明:数据提供程序

DataProviderListeners,该项已被更新或替换为新实例。

equals(Object)和#hashCode()将新旧项实例视为相等,或者

应该实现DataProvider.getId(对象)以返回适当的标识符。

除此之外,您还应该创建 ListDataProvider 列表数据提供程序

Basil Bourque 6 年前

作为 correct Answer by Schild 说,你必须 override your equals and hashCode

对于数据驱动的业务对象,这通常意味着只需查看对象上的标识符,该标识符是您在数据库中的主键(如果您使用数据库,则会是主键)。

如下例所示,我们的 Status 类有一个 UUID universally unique identifier (UUID) (128位值,规范地显示为36个字符的十六进制字符串,带有连字符)。我们的 等于 和 哈希码 只考虑对象的一个成员。

@Override
public boolean equals ( Object obj ) {  // Compare the UUID member named `uuid`.
    if ( obj == this ) { return true; }
    if ( obj instanceof Status ) { return this.getUuid().equals( ( ( Status ) obj ).getUuid() ); }
    return false;
}

@Override
public int hashCode () {
    return Objects.hashCode( this.uuid );
}  // Compare the UUID member named `uuid`.

示例应用程序

在本例中,我们跟踪三个设备。一个 地位 对象表示每个对象。

NativeSelect 在Vaadin中),并单击某个按钮。在这里选择行是不相关的。

为了您的启发,我在 Grid . 这两种方法在Vaadin业务应用程序中都很常见:

修改现有对象支持 网格
替换目标对象,但在其id字段中使用相同的标识符值。

例如,在某些情况下,可以编写数据存储库服务代码以始终返回新实例。在其他情况下,我们可能有意地用改变来更新现有对象。

    private void updateByModifying ( Status s , Integer integer ) {
        s.setCurrentStatus( integer );
        grid.getDataProvider().refreshItem( s );
    }

    private void updateByInstantiating ( Status s , Integer integer ) {
        boolean removed = statuses.remove( s );
        Status replacement = new Status( s.getUuid() , s.getName() , integer );
        boolean added = statuses.add( replacement );
        grid.getDataProvider().refreshItem( replacement );
    }

在本演示中,使用 Update row by 弹出式菜单(也称为下拉列表)。这两种方法都是通过调用 DataProvider::refreshItem . 注意,这两种方法都依赖于 等于 哈希码 正在正确实施。

Refresh all 显示使用的按钮 DataProvider::refreshAll 方法。

源代码

MyUI.java (进入瓦丁)
Status.java (我们的业务对象,POJO)
StatusLayout

MyUI.java

package com.basilbourque.example;

import javax.servlet.annotation.WebServlet;

import com.vaadin.annotations.Theme;
import com.vaadin.annotations.VaadinServletConfiguration;
import com.vaadin.server.VaadinRequest;
import com.vaadin.server.VaadinServlet;
import com.vaadin.ui.*;

import java.util.List;
import java.util.UUID;

/**
 * This UI is the application entry point. A UI may either represent a browser window
 * (or tab) or some part of an HTML page where a Vaadin application is embedded.
 * <p>
 * The UI is initialized using {@link #init(VaadinRequest)}. This method is intended to be
 * overridden to add component to the user interface and initialize non-component functionality.
 */
@Theme ( "mytheme" )
public class MyUI extends UI {

    @Override
    protected void init ( VaadinRequest vaadinRequest ) {
        Layout layout = new StatusLayout();
        this.setContent( layout );
    }

    @WebServlet ( urlPatterns = "/*", name = "MyUIServlet", asyncSupported = true )
    @VaadinServletConfiguration ( ui = MyUI.class, productionMode = false )
    public static class MyUIServlet extends VaadinServlet {
    }
}

Status.java状态

package com.basilbourque.example;

import java.util.Objects;
import java.util.UUID;

public class Status {
    // Members.
    private UUID uuid;
    private String name;
    private Integer currentStatus;  // 1 = Good, 0 = okay, -1 = Bad.

    // Constructor.
    public Status ( UUID uuid , String name , Integer currentStatus ) {
        this.uuid = uuid;
        this.name = name;
        this.currentStatus = currentStatus;
    }

    // -----------|  Object  |-------------------------

    @Override
    public boolean equals ( Object obj ) {  // Compare the UUID member named `uuid`.
        if ( obj == this ) { return true; }
        if ( obj instanceof Status ) { return this.getUuid().equals( ( ( Status ) obj ).getUuid() ); }
        return false;
    }

    @Override
    public int hashCode () {
        return Objects.hashCode( this.uuid );
    }  // Compare the UUID member named `uuid`.

    @Override
    public String toString () {
        return "Status{ " +
        "uuid=" + uuid +
        " | name='" + name + '\'' +
        " | currentStatus=" + currentStatus +
        " }";
    }

    // -----------|  Accessors  |-----------------------------

    public UUID getUuid () {
        return uuid;
    }

    public void setUuid ( UUID uuid ) {
        this.uuid = uuid;
    }

    public String getName () {
        return name;
    }

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

    public Integer getCurrentStatus () {
        return currentStatus;
    }

    public void setCurrentStatus ( Integer currentStatus ) {
        this.currentStatus = currentStatus;
    }
}

StatusLayout.java状态布局

package com.basilbourque.example;

import com.vaadin.data.provider.ListDataProvider;
import com.vaadin.ui.*;

import java.util.ArrayList;
import java.util.List;
import java.util.Optional;
import java.util.UUID;

public class StatusLayout extends VerticalLayout {
    // Members
    List< Status > statuses;
    Grid< Status > grid;

    final List< Integer > numbers = List.of( 1 , 0 , - 1 );
    NativeSelect< Integer > numberPopup;
    NativeSelect< Boolean > updatyByModifyingOrInstantiating;
    Button setPump, setCamera, setSensor, refreshAllButton;

    // Constructor
    public StatusLayout () {

        statuses = new ArrayList<>( 3 );
        statuses.add( new Status( UUID.fromString( "1c0d183e-c2ba-11e8-a355-529269fb1459" ) , "Pump" , numbers.get( 0 ) ) );
        statuses.add( new Status( UUID.fromString( "2490c74e-1aac-4d71-9a2c-880628dcfc28" ) , "Camera" , numbers.get( 1 ) ) );
        statuses.add( new Status( UUID.fromString( "6ae07414-f557-4a1e-a552-cb5ec5f48476" ) , "Sensor" , numbers.get( 2 ) ) );

        // Create a grid bound to the list
        grid = new Grid<>( Status.class );
        grid.setCaption( "Equipment Status" );
        grid.setItems( statuses );
//        grid.addColumn( Status :: getName ).setCaption( "Name" );
//        grid.addColumn( Status :: getCurrentStatus ).setCaption( "Status" );

        updatyByModifyingOrInstantiating = new NativeSelect<>( "Update row by: " , List.of( Boolean.TRUE , Boolean.FALSE ) );
        updatyByModifyingOrInstantiating.setValue( Boolean.TRUE );
        updatyByModifyingOrInstantiating.setItemCaptionGenerator( ( ItemCaptionGenerator< Boolean > ) item -> item ? "modifying" : "instantiating" );

        Label valueSetterLabel = new Label( "Set status:" );
        numberPopup = new NativeSelect<>();
        numberPopup.setItems( numbers );
        numberPopup.setValue( numbers.get( 1 ) );
//        numberPopup.setItemCaptionGenerator( item -> List.of( "Good" , "Okay" , "Bad" ).get( numbers.indexOf( item ) ) );  // Display words rather than the underlying number.

        // The `buttonClick` method below has logic depending on match between button name and `name` property on `Status` objects in grid.
        setPump = new Button( statuses.get( 0 ).getName() );  // Pump
        setPump.addClickListener( this :: buttonClick );
        setCamera = new Button( statuses.get( 1 ).getName() ); // Camera
        setCamera.addClickListener( this :: buttonClick );
        setSensor = new Button( statuses.get( 2 ).getName() );   // Sensor
        setSensor.addClickListener( this :: buttonClick );

        refreshAllButton = new Button( "Refresh all" );
        refreshAllButton.addClickListener( clickEvent -> grid.getDataProvider().refreshAll() );

        // Arrange
        grid.setWidth( 100 , Unit.PERCENTAGE );

        HorizontalLayout valueSetterBar = new HorizontalLayout();
        valueSetterBar.addComponents( valueSetterLabel , numberPopup , setPump , setCamera , setSensor );
        valueSetterBar.setComponentAlignment( valueSetterLabel , Alignment.MIDDLE_CENTER );
        valueSetterBar.setComponentAlignment( numberPopup , Alignment.MIDDLE_CENTER );
        valueSetterBar.setComponentAlignment( setPump , Alignment.MIDDLE_CENTER );
        valueSetterBar.setComponentAlignment( setCamera , Alignment.MIDDLE_CENTER );
        valueSetterBar.setComponentAlignment( setSensor , Alignment.MIDDLE_CENTER );

        addComponents( grid , updatyByModifyingOrInstantiating , valueSetterBar , refreshAllButton );
    }

    private void buttonClick ( Button.ClickEvent clickEvent ) {
        System.out.println( "TRACE - Setting " + clickEvent.getButton().getCaption() + " to " + this.numberPopup.getValue().toString() );
        // Find the `Status` object in the `List` whose name matches the name of the button clicked by user.
        Optional< Status > optionalStatus = statuses.stream().filter( status -> status.getName().equals( clickEvent.getButton().getCaption() ) ).findFirst();
        // We expect the matching `Status` to always be found. If not, throw exception.
        Status s = optionalStatus.orElseThrow( () -> new IllegalStateException( "Failed to find expected item in list of statuses: " + clickEvent.getButton().getCaption() ) );
        Integer valueToSet = this.numberPopup.getValue();
        // Set the `currentStatus` property on the `Status` object to the value of the selected popup menu item.
        // Try either updating by modifying existing row or by instantiating a new one.
        // Comment-out either of the next two lines.
        if(updatyByModifyingOrInstantiating.getValue().equals( Boolean.TRUE )) {
            this.updateByModifying( s , valueToSet );
        } else {
            this.updateByInstantiating( s , valueToSet );
        }
    }

    private void updateByModifying ( Status s , Integer integer ) {
        s.setCurrentStatus( integer );
        grid.getDataProvider().refreshItem( s );
    }

    private void updateByInstantiating ( Status s , Integer integer ) {
        boolean removed = statuses.remove( s );
        Status replacement = new Status( s.getUuid() , s.getName() , integer );
        boolean added = statuses.add( replacement );
        grid.getDataProvider().refreshItem( replacement );
    }
}