What's difference between removeAllViews() and removeAllViewsInLayout()

I am populating a linear layout dynamically. Depending upon response, I have to clear the past child views and create new views. I have read the document, but still be confused with the couple methods, they all look the same function. Which function I should use.

As Scott Biggs points out, the difference is not a big one. The only difference is that removeAllViews() calls requestLayout() and invalidate() afterwards. The key to why this difference is here is to understand the naming of removeAllViewInLayout(). Confusingly, its meaning isn't "remove all views within this view layout."

If we look at the similar method, removeViewInLayout(), we can understand what it's supposed to mean:

> Removes a view during layout. This is useful if in your onLayout() method, you need to remove more views.

So removeAllViewsInLayout() actually means "remove all views, and we're calling this method during a layout pass (i.e. onLayout())". That's why removeAllViewsInLayout() doesn't call through to requestLayout(), as it's assumed that you're already currently inside a layout pass, so requesting another layout pass is unneeded.

If you use removeAllViewsInLayout(), then it's your responsibility to ensure that you're calling this during a layout pass, or to properly call requestLayout() and invalidate() as needed.

removeAllViews() : Call this method to remove all child views from the ViewGroup. removeAllViewsInLayout() : Called by a ViewGroup subclass to remove child views from itself, when it must first know its size on screen before it can calculate how many child views it will render.

Well, looking at the source, there isn't much difference:

public void removeAllViews() {
    removeAllViewsInLayout();   // Details implemented here
    requestLayout();
    invalidate(true);
}

So unless you want to call invalidate() at a time of your choosing, you might as well use removeAllViews() and save yourself a bit of typing.

EDIT
For a more detailed explanation, see David Lui's answer. To sum it up, use removeAllViews() unless you're in the process of constructing a View--in which case you'd call removeAllViewsInLayout().