Implementing the Page Viewer

The first viewer component to be covered is the Page viewer, as illustrated in Listing 32.5. To use this viewer, you will create its CrystalReportViewer object. It, along with all the other viewers, exposes a method called setReportSource that accepts a valid report source object as obtained from the description in the previous section. Finally, again like the other viewers, it has a processHttpRequest method that accepts references to the current servlet context. This method does the actual rendering to HTML.

Listing 32.5. Viewing a Report over the Web

//To create a Java report viewer you need to instantiate a CrystalReportViewer

//object. To create a CrystalReportViewer object:

CrystalReportPartsViewer viewer = new CrystalReportViewer();



//Obtain a ReportSource object. Set the viewers report source by calling its

//setReportSource method.

viewer.setReportSource(reportSource);



//When you have created and initialized a Java report page viewer, you call

//its processHttpRequest method to launch it in a Web //browser.

viewer.processHttpRequest(request, response, getServletContext(), null);

Figure 32.1 shows the output of this code.

Figure 32.1. A report being displayed in an HTML page viewer.

All viewers including the Page viewer share a number of toolbar elements. These properties can be programmatically toggled and are displayed in Table 32.1. All the viewer properties must be set before calling the ProcessHTTPRequest method that displays the selected report. For example, to ensure the Crystal logo is displayed when the involved report is viewed, the code line

Viewer.HasLogo(true);

Table 32.1. Toolbar Elements (Page Viewer)

Property	Property Description
HasLogo	Includes or excludes the "Powered by Crystal" logo when rendering the report.
HasExportButton	Includes or excludes the export button when rendering the report.
HasGotoPageButton	Includes or excludes the Go to Page button when rendering the report.
HasPageNavigationButtons	Includes or excludes the page navigation buttons when rendering the report.
HasPrintButton	Includes or excludes the Print button when rendering the report.
HasRefreshButton	Includes or excludes the Refresh button when rendering the report.
HasSearchButton	Includes or excludes the Search button when rendering the report.
HasToggleGroupTreeButton	Includes or excludes the Group Tree toggle button when rendering the report.
HasViewList	Specifies whether the viewer should display a list of previous views of the report.
SetPrintMode	Set printing to use PDF or Active X printing (0=pdf, 1=actx).
HasZoomFactorList	Specifies zoom factor for displayed report.

needs to be included in the code before the processHTTPRequest method is called.

As the different viewers are introduced and discussed later in this chapter, some additional elements pertinent to the viewer being discussed will be displayed in that sections table.