navigation/runtime/src/main/java/androidx/navigation/NavController.java
public boolean popBackStack() {
        if (mBackStack.isEmpty()) {
            throw new IllegalArgumentException("NavController back stack is empty");
        }
        boolean popped = false;
        while (!mBackStack.isEmpty()) {
            popped = mBackStack.removeLast().getNavigator().popBackStack();
            if (popped) {
                break;
            }
        }
        return popped;
    }
/**
     * Attempts to pop the controller's back stack. Analogous to when the user presses
     * the system {@link android.view.KeyEvent#KEYCODE_BACK Back} button when the associated
     * navigation host has focus.
     *
     * @return true if the stack was popped, false otherwise
     */
Attempts to pop the controller's back stack. Analogous to when the user presses
the system  android.view.KeyEvent#KEYCODE_BACK Back button when the associated
navigation host has focus.

@return true if the stack was popped, false otherwise
Attempts to pop the controller ' s back stack . Analogous to when the user presses the system android . view . KeyEvent#KEYCODE_BACK Back button when the associated navigation host has focus . @return true if the stack was popped false otherwise
public boolean popBackStack() {
        if (mBackStack.isEmpty()) {
            throw new IllegalArgumentException("NavController back stack is empty");
        }
        boolean popped = false;
        while (!mBackStack.isEmpty()) {
            popped = mBackStack.removeLast().getNavigator().popBackStack();
            if (popped) {
                break;
            }
        }
        return popped;
    }
public boolean popBackStack ( ) { if ( mBackStack . isEmpty ( ) ) { throw new IllegalArgumentException ( "NavController back stack is empty" ) ; } boolean popped = false ; while ( ! mBackStack . isEmpty ( ) ) { popped = mBackStack . removeLast ( ) . getNavigator ( ) . popBackStack ( ) ; if ( popped ) { break ; } } return popped ; }
Attempts to pop the controller's back stack.
Attempts to pop the controller ' s back stack .