Question

我有一个RecyclerView，其中必须显示一组组。现在，进度条会显示很长时间，并且不会显示组。我正在使用改造来获取组。进度条加载很长时间，并且进度条的可见性消失了。没有显示任何数据。

这是Java文件

 private void getAllGroups(int offset, int limit) {
    if (offset == 0) {
        relativeLayout.setVisibility(View.VISIBLE);

        progressBar.setVisibility(View.VISIBLE);
    } else {
        loadLayout.setVisibility(View.VISIBLE);
    }

    Call<List<TrendingGroupsResponse>> allGroupsCall = retrofit.getAllMajorGroups(String.valueOf(offset), String.valueOf(limit));
    Callback<List<TrendingGroupsResponse>> allGroupsCallBack = new Callback<List<TrendingGroupsResponse>>() {
        @Override
        public void onResponse(Call<List<TrendingGroupsResponse>> call, Response<List<TrendingGroupsResponse>> response) {

            if (response.body() != null) {

                Gson gson = new Gson();
                Log.d(TAG, gson.toJson(response.body()));

                for (TrendingGroupsResponse response1 : response.body())
                    allGroupsList.add(new SelectionGroupItem(response1));

                if (response.body().size() < limit) {
                    reachedEnd = true;
                }
                loadmore = true;

                if (offset == 0) {
                    allGroupsAdapter = new GroupSelectionTrendingAdapter(getApplicationContext(),
                            allGroupsList, GroupSelectionActivity.this, ALL_GROUPS_MODE);

                    allGroups.setAdapter(allGroupsAdapter);

                } else if (allGroupsAdapter != null) 
                    allGroupsAdapter.notifyDataSetChanged();
                }

                groupSelectLayout.setVisibility(View.VISIBLE);
                mainlayout.setVisibility(View.VISIBLE);
                relativeLayout.setVisibility(View.GONE);
                progressBar.setVisibility(View.GONE);
                loadLayout.setVisibility(View.GONE);
            }
        }

        @Override
        public void onFailure(Call<List<TrendingGroupsResponse>> call, Throwable t) {


            View view = findViewById(R.id.root_view);
            Snackbar snackbar = Snackbar.make(view, "Network Error", Snackbar.LENGTH_INDEFINITE)
                    .setAction("RELOAD", new View.OnClickListener() {
                        @Override
                        public void onClick(View view) {
                            getTrendingGroups();
                            getAllGroups(offset, limit);
                        }
                    });
            snackbar.show();

        }
    };
    allGroupsCall.enqueue(allGroupsCallBack);
}

如何解决此问题，以便加载和显示数据？

Answer 1

也许您可以尝试在所有方法调用之前声明适配器（例如在onCreate()的{{1}}方法上）

GroupSelectionActivity

然后，在allGroupsAdapter = new GroupSelectionTrendingAdapter( getApplicationContext(), new ArrayList<SelectionGroupItem>(), GroupSelectionActivity.this, ALL_GROUPS_MODE ); // Considering allGroups is your RecyclerView allGroups.setAdapter(allGroupsAdapter);中公开方法GroupSelectionTrendingAdapter

updateData(List<SelectionGroupItem> items)

然后在您的回调中：

@UiThread
public void updateData(List<SelectionGroupItem> newItems) {
    /** 
     * this.selectionGroupItems is a property of GroupSelectionTrendingAdapter 
     * that is used to display the data. 
     *
     * It is init in the constructor, then it never changes 
     * and is never reset using the = operator
     */ 
    this.selectionGroupItems.clear()
    this.selectionGroupItems.addAll(newItems)
    // On the UI thread, as it is updating UI items.
    this.notifyDataSetChanged()
}

通过这种方式适配器永远不会改变，它是在屏幕寿命的一开始就设置的。唯一改变的是您在其中显示的数据。

runOnUiThread可以确保在显示线程上进行调用

另外，我不确定为什么将if (response.body() != null) { // ... for (TrendingGroupsResponse response1 : response.body()) allGroupsList.add(new SelectionGroupItem(response1)); // not needed anymore if (offset == 0) { // Call is wrapped to run on the UI thread runOnUiThread(new Runnable() { @Override public void run() { allGroupsAdapter.updateData(allGroupsList); } }); // ... }赋予适配器，因为getApplicationContext()也是上下文。请提醒不要将活动的引用保留在可以破坏的视图内，以免保留引用（内存泄漏）

数据加载时间很长，并且数据未在RecyclerView中显示

1 个答案: