I have read some code that people use something like this view.setOnLongClickListener(null); What does it means and for what can be useful ? why someone uses this ? is that the same as this view....

我愿利用梯度填充,利用信道提炼弧。 如何做到这一点?

我有线性布局和小观点(50px-50px),我想做的是把这种观点带给父母(我的情况是线性布局)。 但这不一定是线性布局,但如果可能,我想我......