java如何将简单按钮锚定到snackbar

Question

我有一个按钮，而不是浮动动作按钮，我想用小吃店固定它，因为它用浮动动作栏固定，就像浮动动作按钮在显示小吃店时向上移动一样，用浮动动作栏我们这样做：

Snackbar.make(fab, s, Snackbar.LENGTH_SHORT);

我如何使用简单的按钮，比如snackbar和button，它们不知道snackbar的存在，反之亦然，并且可以独立移动

谢谢

Answer 1

您必须将Behavior附加到要随Snakebar移动的View上

在这里，我创建了一个自定义View，并将行为附加到它

@CoordinatorLayout.DefaultBehavior(CustomView.Behavior.class)
public class CustomView extends View {
    public CustomView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    public static class Behavior extends CoordinatorLayout.Behavior<CustomView> {

        public Behavior() {
            super();
        }

        public Behavior(Context context, AttributeSet attrs) {
            super(context, attrs);
        }

        @Override
        public void onAttachedToLayoutParams(@NonNull CoordinatorLayout.LayoutParams lp) {
            if (lp.dodgeInsetEdges == Gravity.NO_GRAVITY) {
                // This setting makes it works (learn from FloatingActionButton.Behavior)
                lp.dodgeInsetEdges = Gravity.BOTTOM;
            }
        }

        @Override
        public boolean onDependentViewChanged(CoordinatorLayout parent, CustomView child,
                                              View dependency) {
            return false;
        }
    }
}

在你的布局中使用这个CustomView，它应该可以工作

FloatingActionButton做同样的事情，它有一个内部的Behavior，它通过阴影填充、基于AppBarLayout运动的显示/隐藏来做更多的事情。在CoordinatorLayout中的每一个运动都基于它的Behavior机制

此处参考：http://saulmm.github.io/mastering-coordinator

p/S：关于Snakebar.make用法，将CoordinatorLayout传递到view参数，不传递任何其他组件，这将节省系统性能。如果查看Snakebar代码，它有一个循环，使用view参数查找根视图。根视图就是它想要的：

private static ViewGroup findSuitableParent(View view) {
    ViewGroup fallback = null;
    do {
        if (view instanceof CoordinatorLayout) {
            // We've found a CoordinatorLayout, use it
            return (ViewGroup) view;
        } else if (view instanceof FrameLayout) {
            if (view.getId() == android.R.id.content) {
                // If we've hit the decor content view, then we didn't find a CoL in the
                // hierarchy, so use it.
                return (ViewGroup) view;
            } else {
                // It's not the content view but we'll use it as our fallback
                fallback = (ViewGroup) view;
            }
        }

        if (view != null) {
            // Else, we will loop and crawl up the view hierarchy and try to find a parent
            final ViewParent parent = view.getParent();
            view = parent instanceof View ? (View) parent : null;
        }
    } while (view != null);

    // If we reach here then we didn't find a CoL or a suitable content view so we'll fallback
    return fallback;
}