我在 RCP 插件的视图中创建条形图。图表中要显示的数据来自 sqlite3 数据库文件。我编写的代码根据作为输入提供的日期将条形图显示到视图上，我们可以使用日历选择该日期。sqlite3 连接数据库文件并根据日期查询并获取条形图数据。Jfreechart 用于创建条形图，ChartComposite 将其显示在视图上。
问题是当我一个接一个地选择多个日期并要求显示时，所有图表都显示在同一个视图上，我不需要。输出必须如下，当我第二次选择日期时，必须删除当前图表并显示新图表。我试图在代码中添加 dispose() 但它不起作用。
以下是我的相同代码，
公共类 BarChartDisplay 扩展 ViewPart {
Text searchfield = null;
String path = SelectDataBase.path;
public static int error=0;
public static int info=0;
public static int critical=0;
public static int warning=0;
public BarChartDisplay() {
// TODO Auto-generated constructor stub
}
@Override
public void createPartControl(Composite parent) {
// TODO Auto-generated method stub
//Composite A:
final Composite mainComposite = new Composite(parent, SWT.NONE);
GridData mainLayoutData = new GridData(SWT.FILL, SWT.FILL, true, true);
mainLayoutData.horizontalSpan = 1;
mainComposite.setLayoutData(mainLayoutData);
GridLayout outerLayout = new GridLayout();
outerLayout.marginTop = 30;
outerLayout.marginLeft = 20;
outerLayout.marginRight = 20;
mainComposite.setLayout(outerLayout);
//Composite B:
final Composite selectComposite = new Composite(mainComposite, SWT.NONE);
GridData layoutData = new GridData(SWT.FILL, SWT.FILL, true, true);
layoutData.horizontalSpan = 1;
selectComposite.setLayoutData(layoutData);
GridLayout layout = new GridLayout(4, false);
selectComposite.setLayout(layout);
//Composite C:
final Composite barchartComposite = new Composite(mainComposite, SWT.NONE);
GridData layoutData2 = new GridData(SWT.FILL, SWT.FILL, true, true);
layoutData2.horizontalSpan = 1;
barchartComposite.setLayoutData(layoutData2);
GridLayout layout2 = new GridLayout(1, false);
barchartComposite.setLayout(layout2);
final CalendarCombo ccombo = new CalendarCombo(selectComposite, SWT.READ_ONLY | SWT.FLAT);
GridData layoutDataCal = new GridData(150, 40);
ccombo.computeSize(SWT.DEFAULT, SWT.DEFAULT);
ccombo.showCalendar();
ccombo.setLayoutData(layoutDataCal);
org.eclipse.swt.widgets.Button button = new org.eclipse.swt.widgets.Button(selectComposite, SWT.PUSH);
button.setText("Go");
button.addListener(SWT.Selection, new Listener() {
public void handleEvent(Event e) {
switch (e.type) {
case SWT.Selection:
error = 0;
info = 0;
warning = 0;
critical = 0;
DB db = new DB();
Connection conn = null;
conn = db.ConnTable(path);
Statement statement;
try {
statement = conn.createStatement();
String query = null;
String textfielddata = ccombo.getDateAsString();
System.out.println(textfielddata);
query = "select priority from log where creation_date = '"+ textfielddata +"'";
System.out.println(query);
ResultSet rs = statement.executeQuery(query);
while (rs.next()) {
int prioritydata = rs.getInt("priority");
if (prioritydata == 1)
error++;
else if (prioritydata == 2)
info++;
else if (prioritydata == 3)
warning++;
else if (prioritydata == 4)
critical++;
}
} catch (SQLException er) {
// TODO Auto-generated catch block
er.printStackTrace();
}
System.out.println("after query");
final CategoryDataset dataset = createDataset();
final JFreeChart chart = createChart(dataset);
ChartComposite frame = new ChartComposite(barchartComposite,SWT.NONE,chart,true);
frame.setLayoutData(new GridData(GridData.FILL_BOTH));
frame.pack();
frame.setVisible(true);
frame.setChart(chart);
frame.forceRedraw();
barchartComposite.getLayout();
break;
}
}
});
}
/**
* Returns a sample dataset.
*
* @return The dataset.
*/
private CategoryDataset createDataset() {
// row keys...
final String series1 = "First";
// column keys...
final String category1 = "error";
final String category2 = "info";
final String category3 = "warning";
final String category4 = "critical";
// create the dataset...
final DefaultCategoryDataset dataset = new DefaultCategoryDataset();
dataset.addValue(10, series1, category1);
dataset.addValue(5, series1, category2);
dataset.addValue(6, series1, category3);
dataset.addValue(9, series1, category4);
return dataset;
}
/**
* Creates a sample chart.
*
* @param dataset the dataset.
*
* @return The chart.
*/
private JFreeChart createChart(final CategoryDataset dataset) {
// create the chart...
final JFreeChart chart = ChartFactory.createBarChart(
"Priority BarChart", // chart title
"priority", // domain axis label
"Value", // range axis label
dataset, // data
PlotOrientation.VERTICAL, // orientation
true, // include legend
true, // tooltips?
false // URLs?
);
// NOW DO SOME OPTIONAL CUSTOMISATION OF THE CHART...
// set the background color for the chart...
chart.setBackgroundPaint(Color.white);
// get a reference to the plot for further customisation...
final CategoryPlot plot = chart.getCategoryPlot();
plot.setBackgroundPaint(Color.lightGray);
plot.setDomainGridlinePaint(Color.white);
plot.setRangeGridlinePaint(Color.white);
// set the range axis to display integers only...
final NumberAxis rangeAxis = (NumberAxis) plot.getRangeAxis();
rangeAxis.setStandardTickUnits(NumberAxis.createIntegerTickUnits());
// disable bar outlines...
final BarRenderer renderer = (BarRenderer) plot.getRenderer();
renderer.setDrawBarOutline(false);
// set up gradient paints for series...
final GradientPaint gp0 = new GradientPaint(
0.0f, 0.0f, Color.blue,
0.0f, 0.0f, Color.lightGray
);
renderer.setSeriesPaint(0, gp0);
final CategoryAxis domainAxis = plot.getDomainAxis();
domainAxis.setCategoryLabelPositions(
CategoryLabelPositions.createUpRotationLabelPositions(Math.PI / 6.0)
);
// OPTIONAL CUSTOMISATION COMPLETED.
return chart;
}
@Override
public void setFocus() {
// TODO Auto-generated method stub
}
}