如何通过Apache POI在Word文档中添加复选框？问题与解法

I'm working on generating Word documents using Apache POI, and I've been stuck trying to add checkboxes to the document. When I run this line of code:

run3.getCTR().getFldCharArray(0).addNewFfData().addNewCheckBox();

I hit this exception:

Exception in thread "main" java.lang.IndexOutOfBoundsException at org.openxmlformats.schemas.wordprocessingml.x2006.main.impl.CTRImpl.getFldCharArray(Unknown Source) at createSoluminaForm.main(createSoluminaForm.java:45)

Was wondering if any fellow devs have successfully implemented this feature and could share how?

After some trial and error, I got it working by properly setting up the field structure that Apache POI expects for form elements. Here's the helper method I created that handles both checkboxes and text input fields:

static void insertFormField(XWPFParagraph paragraph, String type, CTOnOff onOff) {
    XWPFRun run = paragraph.createRun();
    run.getCTR().addNewFldChar().setFldCharType(STFldCharType.BEGIN);
    if ("FORMTEXT".equals(type)) {
        run.getCTR().getFldCharArray(0).addNewFfData().addNewTextInput();
    } else if ("FORMCHECKBOX".equals(type)) {
        CTFFCheckBox checkbox = run.getCTR().getFldCharArray(0).addNewFfData().addNewCheckBox();
        checkbox.setChecked(onOff);
    }
    run = paragraph.createRun();
    run.getCTR().addNewInstrText().setStringValue(type);
    if ("FORMTEXT".equals(type)) {
        run = paragraph.createRun();
        run.getCTR().addNewFldChar().setFldCharType(STFldCharType.SEPARATE);
        for (int i = 0; i < 5; i++) {
            run = paragraph.createRun();
            //run.setText(" "); // Unicode Character 'EN SPACE' (U+2002)
            run.setText(" ");
        }
    }
    run = paragraph.createRun();
    run.getCTR().addNewFldChar().setFldCharType(STFldCharType.END);
}

How to use it: #

// Create a checked checkbox
CTOnOff checkedState = CTOnOff.Factory.newInstance();
checkedState.setVal(STOnOff.ON);
// Create an unchecked checkbox
CTOnOff uncheckedState = CTOnOff.Factory.newInstance();
uncheckedState.setVal(STOnOff.OFF);

// Insert the checkbox into your target paragraph
insertFormField(parag2, "FORMCHECKBOX", checkedState);
// insertFormField(parag2, "FORMCHECKBOX", uncheckedState); // For unchecked

The problem with my original code was that I was trying to access the field array before actually adding a field character to the run. By first adding the BEGIN field character, getFldCharArray(0) has a valid entry to work with, which fixes the IndexOutOfBoundsException.

内容的提问来源于stack exchange，提问作者demir5334