GridRowDragger (vaadin-server 8.15.1 API)

java.lang.Object
- com.vaadin.ui.components.grid.GridRowDragger<T>

Type Parameters:

T - The Grid bean type.

All Implemented Interfaces:

Serializable
```
public class GridRowDragger<T>
extends Object
implements Serializable
```
Allows dragging rows for reordering within a Grid and between two separate Grids when the item type is the same.
When dragging a selected row, all the visible selected rows are dragged. Note that ONLY currently visible rows are taken into account. The drop mode for the target grid is by default DropMode.BETWEEN.
To customize the settings for either the source or the target grid, use getGridDragSource() and getGridDropTarget().The drop target grid has been set to not allow drops for a target row when the grid has been sorted, since the visual drop target location would not match where the item would actually be dropped into. Additionally, a grid MUST NOT be the target of more than one GridRowDragger.
NOTE: this helper works only with ListDataProvider on both grids. If you have another data provider, you should customize data provider updating on drop with setSourceDataProviderUpdater(SourceDataProviderUpdater) & setTargetDataProviderUpdater(TargetDataProviderUpdater) and add a custom drop index calculator with setDropIndexCalculator(DropIndexCalculator).
In case you are not using a ListDataProvider and don't have custom handlers, UnsupportedOperationException is thrown on drop event.

Since:

8.2

Author:

Vaadin Ltd

See Also:

Serialized Form

Constructor Summary

Constructors
Constructor and Description
`GridRowDragger(Grid<T> grid)` Enables DnD reordering for the rows in the given grid.
`GridRowDragger(Grid<T> grid, DropMode dropMode)` Enables DnD reordering the rows in the given grid with the given drop mode.
`GridRowDragger(Grid<T> source, Grid<T> target)` Enables DnD moving of rows from the source grid to the target grid.
`GridRowDragger(Grid<T> source, Grid<T> target, DropMode dropMode)` Enables DnD moving of rows from the source grid to the target grid with the given drop mode.
`GridRowDragger(Grid<T> source, Grid<T> target, TargetDataProviderUpdater<T> targetDataProviderUpdater, SourceDataProviderUpdater<T> sourceDataProviderUpdater)` Enables DnD moving of rows from the source grid to the target grid with the custom data provider updaters.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`protected List<T>`	`getDraggedItems()` Returns the currently dragged items captured from the source grid no drag start event, or `null` if no drag active.
`DropIndexCalculator<T>`	`getDropIndexCalculator()` Gets the drop index calculator.
`GridDragSource<T>`	`getGridDragSource()` Returns the drag source grid, exposing it for customizations.
`GridDropTarget<T>`	`getGridDropTarget()` Returns the drop target grid to allow performing customizations such as altering `DropEffect`.
`SourceDataProviderUpdater<T>`	`getSourceDataProviderUpdater()` Returns the source grid data provider updater.
`TargetDataProviderUpdater<T>`	`getTargetDataProviderUpdater()` Returns the target grid data provider updater.
`protected void`	`handleDrop(GridDropEvent<T> event)` This method is triggered when there has been a drop on the target grid.
`void`	`setDropIndexCalculator(DropIndexCalculator<T> dropIndexCalculator)` Sets the drop index calculator for the target grid.
`void`	`setSourceDataProviderUpdater(SourceDataProviderUpdater<T> sourceDataProviderUpdater)` Sets the source data provider updater, which handles removing items from the drag source grid.
`void`	`setTargetDataProviderUpdater(TargetDataProviderUpdater<T> targetDataProviderUpdater)` Sets the target data provider updater, which handles adding the dropped items to the target grid.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - GridRowDragger
```
public GridRowDragger(Grid<T> grid)
```
    Enables DnD reordering for the rows in the given grid.
    DropMode.BETWEEN is used.
    NOTE: this only works when the grid has a ListDataProvider. Use the custom handlers setSourceDataProviderUpdater(SourceDataProviderUpdater) and setTargetDataProviderUpdater(TargetDataProviderUpdater) for other data providers.
    NOTE: When allowing the user to DnD reorder a grid's rows, you should not allow the user to sort the grid since when the grid is sorted, as the reordering doens't make any sense since the drop target cannot be shown for the correct place due to the sorting. Sorting columns is enabled by default for in-memory data provider grids. Sorting can be disabled for columns with Grid.getColumns() and Grid.Column.setSortable(boolean).
    
    Parameters:
    
    grid - Grid to be extended.
  - GridRowDragger
```
public GridRowDragger(Grid<T> grid,
                      DropMode dropMode)
```
    Enables DnD reordering the rows in the given grid with the given drop mode.
    NOTE: this only works when the grid has a ListDataProvider. Use the custom handlers setSourceDataProviderUpdater(SourceDataProviderUpdater) and setTargetDataProviderUpdater(TargetDataProviderUpdater) for other data providers.
    NOTE: When allowing the user to DnD reorder a grid's rows, you should not allow the user to sort the grid since when the grid is sorted, as the reordering doens't make any sense since the drop target cannot be shown for the correct place due to the sorting. Sorting columns is enabled by default for in-memory data provider grids. Sorting can be disabled for columns with Grid.getColumns() and Grid.Column.setSortable(boolean).
    
    Parameters:
    
    grid - the grid to enable row DnD reordering on
    
    dropMode - DropMode to be used.
  - GridRowDragger
```
public GridRowDragger(Grid<T> source,
                      Grid<T> target)
```
    Enables DnD moving of rows from the source grid to the target grid.
    DropMode.BETWEEN is used.
    NOTE: this only works when the grids have a ListDataProvider. Use the custom handlers setSourceDataProviderUpdater(SourceDataProviderUpdater) and setTargetDataProviderUpdater(TargetDataProviderUpdater) for other data providers.
    
    Parameters:
    
    source - the source grid dragged from.
    
    target - the target grid dropped to.
  - GridRowDragger
```
public GridRowDragger(Grid<T> source,
                      Grid<T> target,
                      TargetDataProviderUpdater<T> targetDataProviderUpdater,
                      SourceDataProviderUpdater<T> sourceDataProviderUpdater)
```
    Enables DnD moving of rows from the source grid to the target grid with the custom data provider updaters.
    DropMode.BETWEEN is used.
    
    Parameters:
    
    source - grid dragged from
    
    target - grid dragged to
    
    targetDataProviderUpdater - handler for updating target grid data provider
    
    sourceDataProviderUpdater - handler for updating source grid data provider
  - GridRowDragger
```
public GridRowDragger(Grid<T> source,
                      Grid<T> target,
                      DropMode dropMode)
```
    Enables DnD moving of rows from the source grid to the target grid with the given drop mode.
    NOTE: this only works when the grids have a ListDataProvider. Use the other constructors or custom handlers setSourceDataProviderUpdater(SourceDataProviderUpdater) and setTargetDataProviderUpdater(TargetDataProviderUpdater) for other data providers.
    
    Parameters:
    
    source - the drag source grid
    
    target - the drop target grid
    
    dropMode - the drop mode to use
- Method Detail
  - setTargetDataProviderUpdater
```
public void setTargetDataProviderUpdater(TargetDataProviderUpdater<T> targetDataProviderUpdater)
```
    Sets the target data provider updater, which handles adding the dropped items to the target grid.
    By default, items are added to the index where they were dropped on for any ListDataProvider. If another type of data provider is used, this updater should be set to handle updating instead.
    
    Parameters:
    
    targetDataProviderUpdater - the target drop handler to set, or null to remove
  - getTargetDataProviderUpdater
```
public TargetDataProviderUpdater<T> getTargetDataProviderUpdater()
```
    Returns the target grid data provider updater.
    
    Returns:
    
    target grid drop handler
  - setSourceDataProviderUpdater
```
public void setSourceDataProviderUpdater(SourceDataProviderUpdater<T> sourceDataProviderUpdater)
```
    Sets the source data provider updater, which handles removing items from the drag source grid.
    By default the items are removed from any ListDataProvider. If another type of data provider is used, this updater should be set to handle updating instead.
    If you want to skip removing items from the source, you can use SourceDataProviderUpdater.NOOP.
    
    Parameters:
    
    sourceDataProviderUpdater - the drag source data provider updater to set, or null to remove
  - getSourceDataProviderUpdater
```
public SourceDataProviderUpdater<T> getSourceDataProviderUpdater()
```
    Returns the source grid data provider updater.
    Default is null and the items are just removed from the source grid, which only works for ListDataProvider.
    
    Returns:
    
    the source grid drop handler
  - setDropIndexCalculator
```
public void setDropIndexCalculator(DropIndexCalculator<T> dropIndexCalculator)
```
    Sets the drop index calculator for the target grid. With this callback you can have a custom drop location instead of the actual one.
    By default, items are placed on the index they are dropped into in the target grid.
    If you want to always drop items to the end of the target grid, you can use DropIndexCalculator#ALWAYS_DROP_TO_END.
    
    Parameters:
    
    dropIndexCalculator - the drop index calculator
  - getDropIndexCalculator
```
public DropIndexCalculator<T> getDropIndexCalculator()
```
    Gets the drop index calculator.
    Default is null and the dropped items are placed on the drop location.
    
    Returns:
    
    the drop index calculator
  - getGridDropTarget
```
public GridDropTarget<T> getGridDropTarget()
```
    Returns the drop target grid to allow performing customizations such as altering DropEffect.
    
    Returns:
    
    the drop target grid
  - getGridDragSource
```
public GridDragSource<T> getGridDragSource()
```
    Returns the drag source grid, exposing it for customizations.
    
    Returns:
    
    the drag source grid
  - getDraggedItems
```
protected List<T> getDraggedItems()
```
    Returns the currently dragged items captured from the source grid no drag start event, or null if no drag active.
    
    Returns:
    
    the currently dragged items or null
  - handleDrop
```
protected void handleDrop(GridDropEvent<T> event)
```
    This method is triggered when there has been a drop on the target grid.
    This method is protected only for testing reasons, you should not override this but instead use setSourceDataProviderUpdater(SourceDataProviderUpdater), setTargetDataProviderUpdater(TargetDataProviderUpdater) and setDropIndexCalculator(DropIndexCalculator) to customize how to handle the drops.
    
    Parameters:
    
    event - the drop event on the target grid

Class GridRowDragger<T>

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

GridRowDragger

GridRowDragger

GridRowDragger

GridRowDragger

GridRowDragger

Method Detail

setTargetDataProviderUpdater

getTargetDataProviderUpdater

setSourceDataProviderUpdater

getSourceDataProviderUpdater

setDropIndexCalculator

getDropIndexCalculator

getGridDropTarget

getGridDragSource

getDraggedItems

handleDrop