Recently I started to try to switch to STM32cubeIDE. On the one hand, keil is really difficult to use, on the other hand, it is produced by ST itself and is free. My own point of view has always been that ST can't stand it anymore, and I made an IDE anew. Although based on eclips, there are still some problems, but personally think it is more comfortable than keil for the current use.

eclipse itself has the completion function, but it needs shortcut keys, which is not very convenient. What I want is automatic pop-up completion such as vs and idea.
Some netizens published their modified version before, but because of the version problem, it is not available, so I tried to modify it this time.

Because cubeIDE and eclipse are basically the same, I will explain from the perspective of eclipse below.

1. First install the CDT plug-in and plug-in (you can download it on the Marketplace)
Open the menu bar Help->Install New Software, enter the following address

https://download.eclipse.org/tools/cdt/releases/

Then continue to the next step until the installation is complete. After the window is closed, it will take a while to install, so be patient.
2. Same as above, use the following address to install the plug-in, and find it in the list: Eclipse Plug-in Develoment Environment under General Purpose Tools

http://download.eclipse.org/releases/photon

3. Open window->show view and select plugin-ins. Find org.eclipse.cdt.ui in plugin-ins. Right-click and select import as -> source project. After importing, you can see the plug-in project in your workspace.

4. Find
/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/contentassist/ContentAssistProcessor.java
modify public void setCompletionProposalAutoActivationCharacters(char[] activationSet)

public void setCompletionProposalAutoActivationCharacters(char[] activationSet) {
        //fCompletionAutoActivationCharacters= activationSet;
        String test = ".ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
        char[] triggers = test.toCharArray();
        fCompletionAutoActivationCharacters = triggers;
    }

5. Find
/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/contentassist/CContentAssistProcessor.java
Modify protected boolean verifyAutoActivation(ITextViewer viewer, int offset)

protected boolean verifyAutoActivation(ITextViewer viewer, int offset) {
    IDocument doc= viewer.getDocument();
    if (doc == null) {
        return false;
    }
    if (offset <= 0) {
        return false;
    }
    try {
        char activationChar= doc.getChar(--offset);
        switch (activationChar) {
        case ':':
            return offset > 0 && doc.getChar(--offset) == ':';
        case '>':
            return offset > 0 && doc.getChar(--offset) == '-';
        case '.':
            // Avoid completion of float literals
            CHeuristicScanner scanner= new CHeuristicScanner(doc);
            int token= scanner.previousToken(--offset, Math.max(0, offset - 200));
            // The scanner reports numbers as identifiers
            if (token == Symbols.TokenIDENT && !Character.isJavaIdentifierStart(doc.getChar(scanner.getPosition() + 1))) {
                // Not a valid identifier
                return false;
            }
            return true;
        default:
               return activationChar >= 97 && activationChar <= 122?true:activationChar >= 65 && activationChar <= 90;
        }
    } catch (BadLocationException e) {
    }
    return false;
}

6. The following can be exported, right click on the project -> Export, select JAR file.


The exported jar can be used, because the CDT is already installed, so just name the jar package with the original file name and overwrite it in the plugs under the installation directory, for example Mine is

org.eclipse.cdt.ui_6.6.0.201909091956.jar