java - 将图像放入 tableColumn - updateItem 从未使用

Question

我正在尝试将图像添加到 tableView，并经历了几个问题和答案，但它仍然不起作用。

tableView 中的其他字段(如名称)已正确加载。

Intelij 告诉我 updateItem 从未使用过，这可能就是它不起作用的原因，但我不知道如何调试它......

这是我到目前为止得到的

    @FXML private TableColumn<PlayerManager, Image> tableColumnType;
    @FXML private void initialize(){

    tableColumnType.setCellFactory(param -> {
        //Set up the ImageView
        final ImageView imageview = new ImageView();
        imageview.setFitHeight(10);
        imageview.setFitWidth(10);
        ///imageview.setImage(imageComputer); //uncommenting this places the image on all cells, even empty ones
        //Set up the Table
        TableCell<PlayerManager, Image> cell = new TableCell<PlayerManager, Image>() {
            public void updateItem(PlayerManager item, boolean empty) {
                if (item != null) {  // choice of image is based on values from item, but it doesn't matter now
                    imageview.setImage(imageComputer);
                }
            }
        };

        // Attach the imageview to the cell
        cell.setGraphic(imageview);
        return cell;
    });
    }

我遇到的问题是:

How to add an Image into a JavaFx TableView column

Display image in table

Inserting images into TableView rows - JavaFX

Answer 1

updateItem的签名方法错误:应该是

public void updateItem(Image item, boolean empty) { /* ... */ }

如果编译器拒绝 @Override注释，那么您就知道您没有定义正确的方法。所以你应该使用@Override如果出现编译错误，则表明出现了问题。

所以你应该能够做到

@FXML private TableColumn<PlayerManager, Image> tableColumnType;
@FXML private void initialize(){

tableColumnType.setCellFactory(param -> {
        //Set up the ImageView
        final ImageView imageview = new ImageView();
        imageview.setFitHeight(10);
        imageview.setFitWidth(10);
        ///imageview.setImage(imageComputer); //uncommenting this places the image on all cells, even empty ones
        //Set up the Table
        TableCell<PlayerManager, Image> cell = new TableCell<PlayerManager, Image>() {
            @Override
            public void updateItem(Image item, boolean empty) {
                if (item != null) {  // choice of image is based on values from item, but it doesn't matter now
                    imageview.setImage(imageComputer);
                }
            }
        };

        // Attach the imageview to the cell
        cell.setGraphic(imageview);
        return cell;
    });
}

如果您的表格单元格需要访问实际的PlayerManager对象，那么您需要将表列设为 TableColumn<PlayerManager, PlayerManager>并更新cellValueFactory (你还没有显示)相应地。

最后，请注意您的 updateItem(...)方法需要处理所有情况，包括项目为空的空单元格。

所以你可能需要类似的东西

@FXML private TableColumn<PlayerManager, PlayerManager> tableColumnType;
@FXML private void initialize(){

    tableColumnType.setCellValueFactory(cellData -> new SimpleObjectProperty<PlayerManager>(cellData.getValue());

    tableColumnType.setCellFactory(param -> {
        //Set up the ImageView
        final ImageView imageview = new ImageView();
        imageview.setFitHeight(10);
        imageview.setFitWidth(10);
        ///imageview.setImage(imageComputer); //uncommenting this places the image on all cells, even empty ones
        //Set up the Table
        TableCell<PlayerManager, PlayerManager> cell = new TableCell<PlayerManager, PlayerManager>() {
            @Override
            public void updateItem(PlayerManager item, boolean empty) {
                if (item != null) {  // choice of image is based on values from item, but it doesn't matter now
                    imageview.setImage(imageComputer);
                } else {
                    imageView.setImage(null);
                }
            }
        };

        // Attach the imageview to the cell
        cell.setGraphic(imageview);
        return cell;
    });
}