Reorganizing code, moving controls, and FormAttachments

[mdonovan]

I am encountering a situation where Designer is generating code that has compile errors. I have a simple window with a label, text and button using FormLayout. The createContents() method looks like this -

protected void createContents() {
shell = new Shell();
shell.setLayout(new FormLayout());
shell.setSize(500, 375);
shell.setText("SWT Application");

final Label label = new Label(shell, SWT.NONE);
final FormData formData = new FormData();
formData.bottom = new FormAttachment(0, 144);
formData.top = new FormAttachment(0, 131);
formData.left = new FormAttachment(0, 200);
formData.right = new FormAttachment(0, 225);
label.setLayoutData(formData);
label.setText("Label");

final Button button = new Button(shell, SWT.NONE);
final FormData formData_2 = new FormData();
formData_2.top = new FormAttachment(0, 290);
formData_2.left = new FormAttachment(0, 240);
button.setLayoutData(formData_2);
button.setText("button");

text = new Text(shell, SWT.BORDER);
final FormData formData_1 = new FormData();
formData_1.top = new FormAttachment(label, 0, SWT.TOP);
formData_1.left = new FormAttachment(0, 265);
text.setLayoutData(formData_1);
//
}

I have moved some code around - all of the form data code to the end of the createContents() method -

protected void createContents() {
shell = new Shell();
shell.setLayout(new FormLayout());
shell.setSize(500, 375);
shell.setText("SWT Application");

final Label label = new Label(shell, SWT.NONE);

final Button button = new Button(shell, SWT.NONE);

text = new Text(shell, SWT.BORDER);

//
final FormData formData = new FormData();
formData.bottom = new FormAttachment(0, 144);
formData.top = new FormAttachment(0, 131);
formData.left = new FormAttachment(0, 200);
formData.right = new FormAttachment(0, 225);
label.setLayoutData(formData);
label.setText("Label");

final FormData formData_2 = new FormData();
formData_2.top = new FormAttachment(0, 290);
formData_2.left = new FormAttachment(0, 240);
button.setLayoutData(formData_2);
button.setText("button");

final FormData formData_1 = new FormData();
formData_1.top = new FormAttachment(label, 0, SWT.TOP);
formData_1.left = new FormAttachment(0, 265);
text.setLayoutData(formData_1); }

Then I move the button up closer to the text field, which causes it to become attached to that text field. The generated code now looks like -

protected void createContents() {
shell = new Shell();
shell.setLayout(new FormLayout());
shell.setSize(500, 375);
shell.setText("SWT Application");

final Label label = new Label(shell, SWT.NONE);

final Button button = new Button(shell, SWT.NONE);

text = new Text(shell, SWT.BORDER);
formData_2.left = new FormAttachment(text, -49, SWT.LEFT);
formData_2.right = new FormAttachment(text, -5, SWT.LEFT);
//
final FormData formData = new FormData();
formData.bottom = new FormAttachment(0, 144);
formData.top = new FormAttachment(0, 131);
formData.left = new FormAttachment(0, 200);
formData.right = new FormAttachment(0, 225);
label.setLayoutData(formData);
label.setText("Label");

FormData formData_2;
formData_2 = new FormData();
formData_2.top = new FormAttachment(0, 157);
formData_2.bottom = new FormAttachment(0, 180);
button.setLayoutData(formData_2);
button.setText("button");

final FormData formData_1 = new FormData();
formData_1.top = new FormAttachment(label, 0, SWT.TOP);
formData_1.left = new FormAttachment(0, 265);
text.setLayoutData(formData_1);
}

formData_2.left and formData_2.right are now being referenced before formData_2 is defined. Is this a problem with how Designer works or is it invalid to move the form data code after all of the widgets have been defined?

Thanks for any help or suggestions.
Mark

[Eric Clayberg]

I have moved some code around - all of the form data code to the end of the createContents() method

Moving those lines out of their expected sequence, definitely confused Designer. It expects the constraints to be near the widgets that use them.

[mdonovan]

Eric,

Would you say this is limitation of Designer or is this something that Designer should (and possibly will) be able to handle?

Thanks,
Mark

[Eric Clayberg]

Would you say this is limitation of Designer or is this something that Designer should (and possibly will) be able to handle?

This may be something we can add support for in the future.