Android-检测何时可以看到RecyclerView中的最后一个项目 [英] Android - Detect when the last item in a RecyclerView is visible

问题描述

我有一个方法可以检查用户是否完全可见RecyclerView中的最后一个元素，到目前为止，我已经有了这段代码 问题是如何检查RecyclerView是否到达底部?

I have a method that will check if the last element in a RecyclerView is completely visible by the user, so far I have this code The problem is how to check if the RecyclerView has reached it's bottom ?

PS 我有项目分隔符

public void scroll_btn_visibility_controller(){
    if(/**last item is visible to user*/){
        //This is the Bottom of the RecyclerView
        Scroll_Top_Btn.setVisibility(View.VISIBLE);
    }
    else(/**last item is not visible to user*/){
        Scroll_Top_Btn.setVisibility(View.INVISIBLE);
    }
}

更新: 这是我尝试过的尝试之一

boolean isLastVisible() {
    LinearLayoutManager layoutManager = ((LinearLayoutManager)rv.getLayoutManager());
    int pos = layoutManager.findLastCompletelyVisibleItemPosition();
    int numItems =  disp_adapter.getItemCount();
    return (pos >= numItems);
}
public void scroll_btn_visibility_controller(){

    if(isLastVisible()){
        Scroll_Top.setVisibility(View.VISIBLE);
    }
    else{
        Scroll_Top.setVisibility(View.INVISIBLE);
    }
} 

到目前为止，没有成功，我认为这些行中有问题:

so far no success I think there is something wrong within these lines :

int pos = layoutManager.findLastCompletelyVisibleItemPosition();
int numItems =  disp_adapter.getItemCount();

推荐答案

尝试与onScrollStateChanged一起使用将解决您的问题

try working with onScrollStateChanged it will solve your issue

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