我有一个描述 #ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN
#endif
#include <sdkddkver.h>
#include <Windows.h>
#include <stdio.h>
#include <stdlib.h>
#include <tchar.h>
#include <strsafe.h>
typedef struct DataTransfer {
BOOL Updated;
int Counter;
} TRANSFER, *PTRANSFER;
TRANSFER Payload;
PTRANSFER pPayload;
DWORD dwThreadId;
HANDLE hThread;
LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
void DisplayData(HDC hDC);
void ErrorHandler(LPTSTR lpszFunction);
DWORD WINAPI Counter(LPVOID lpParam);
int
APIENTRY
wWinMain(
HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPWSTR lpCmdLine,
int nShowCmd)
{
MSG msg;
WNDCLASSEX wcex;
ZeroMemory(&wcex, sizeof(wcex));
wcex.cbSize = sizeof(wcex);
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpszClassName = TEXT("MYFIRSTWINDOWCLASS");
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
wcex.hCursor = LoadCursor(hInstance, IDC_ARROW);
wcex.lpfnWndProc = WndProc;
wcex.hInstance = hInstance;
if (!RegisterClassEx(&wcex))
return 1;
CREATESTRUCT cs;
ZeroMemory(&cs, sizeof(cs));
cs.x = 0;
cs.y = 0;
cs.cx = 200;
cs.cy = 300;
cs.hInstance = hInstance;
cs.lpszClass = wcex.lpszClassName;
cs.lpszName = TEXT("Test");
cs.style = WS_OVERLAPPEDWINDOW;
HWND hWnd = ::CreateWindowEx(
cs.dwExStyle,
cs.lpszClass,
cs.lpszName,
cs.style,
cs.x,
cs.y,
cs.cx,
cs.cy,
cs.hwndParent,
cs.hMenu,
cs.hInstance,
cs.lpCreateParams);
if (!hWnd)
return 1;
DWORD dwThreadId;
HANDLE hThread;
pPayload = (PTRANSFER)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(TRANSFER));
if (pPayload == NULL)
ExitProcess(2);
pPayload->Updated = FALSE;
pPayload->Counter = 0;
// Display the window.
ShowWindow(hWnd, SW_SHOWDEFAULT);
UpdateWindow(hWnd);
hThread = CreateThread(
NULL,
0,
Counter,
pPayload,
0,
&dwThreadId);
if (hThread == NULL)
ExitProcess(2);
while (1)
{
if (pPayload->Updated == TRUE)
{
// InvalidateRect(hWnd, NULL, FALSE);
// RedrawWindow(hWnd, NULL, NULL, RDW_INVALIDATE | RDW_UPDATENOW);
UpdateWindow(hWnd);
}
if (GetMessage(&msg, NULL, 0, 0) > 0)
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
::UnregisterClass(wcex.lpszClassName, hInstance);
return (int)msg.wParam;
}
LRESULT
CALLBACK
WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
PAINTSTRUCT paintStruct;
HDC hDC;
switch (uMsg)
{
case WM_DESTROY:
::PostQuitMessage(0);
break;
case WM_PAINT:
hDC = BeginPaint(hWnd, &paintStruct);
DisplayData(hDC);
EndPaint(hWnd, &paintStruct);
return 0;
break;
default:
return ::DefWindowProc(hWnd, uMsg, wParam, lParam);
}
return 0;
}
void DisplayData(HDC hDC)
{
char OutputStr[32];
sprintf_s(OutputStr, sizeof(OutputStr) - 1, "%d", pPayload->Counter);
TextOut(hDC, 100, 100, OutputStr, strlen(OutputStr));
}
DWORD WINAPI Counter(LPVOID lpParam)
{
PTRANSFER pTransfer;
pTransfer = (PTRANSFER)lpParam;
while (1)
{
pTransfer->Counter++;
pTransfer->Updated = TRUE;
Sleep(1000);
}
}
void ErrorHandler(LPTSTR lpszFunction)
{
LPVOID lpMsgBuf;
LPVOID lpDisplayBuf;
DWORD dw = GetLastError();
FormatMessage(
FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL,
dw,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
(LPTSTR)&lpMsgBuf,
0, NULL);
lpDisplayBuf = (LPVOID)LocalAlloc(LMEM_ZEROINIT,
(lstrlen((LPCTSTR)lpMsgBuf) + lstrlen((LPCTSTR)lpszFunction) + 40) * sizeof(TCHAR));
StringCchPrintf((LPTSTR)lpDisplayBuf,
LocalSize(lpDisplayBuf) / sizeof(TCHAR),
TEXT("%s failed with error %d: %s"),
lpszFunction, dw, lpMsgBuf);
MessageBox(NULL, (LPCTSTR)lpDisplayBuf, TEXT("Error"), MB_OK);
LocalFree(lpMsgBuf);
LocalFree(lpDisplayBuf);
}
的片段类。创建元素需要RecyclerView。 array正在通过解析array来形成。当我使用良好的互联网连接时，一切都很好，我可以看到理想的项目列表。但是使用低速连接我的JSON是空的。
我意识到UI存在一些问题，但我没有足够的知识来解决我的问题。
这是一段代码：
threads我明白，我会public class ListVideo extends Fragment {
private int loadLimit = 9;
private RecyclerView recyclerView;
private RecyclerAdapter adapter;
private LinearLayoutManager linearLayoutManager;
final OkHttpClient client = new OkHttpClient();
List<VideoData> videoList;
List<String> videoDataList;
JSONArray json_array_list_of_videos;
int counter = 0;
int offset;
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container,
@Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.listvideofragment, container, false);
}
@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
videoList = new ArrayList<>();
videoDataList = new ArrayList<>();
recyclerView = (RecyclerView) view.findViewById(R.id.list);
loadData(offset);
createRecycleView();
recyclerView.addOnScrollListener(new EndlessRecyclerOnScrollListener(
linearLayoutManager) {
@Override
public void onLoadMore(int offset) {
// do somthing...
loadMoreData(offset);
}
});
}
private void loadMoreData(int offset) {
loadLimit += 10;
loadData(offset);
adapter.notifyDataSetChanged();
}
private void loadData(final int offset) {
try {
Request request = new Request.Builder()
.url("http://video.motti.be/api/video.getVideoList?offset=" +
offset
+ "&limit=20")
.build();
client.newCall(request).enqueue(new Callback() {
@Override
public void onFailure(Request request, IOException throwable) {
throwable.printStackTrace();
}
@Override
public void onResponse(Response response) throws IOException {
try {
if (!response.isSuccessful())
throw new IOException("Unexpected code " + response);
Headers responseHeaders = response.headers();
for (int i = 0; i < responseHeaders.size(); i++) {
System.out.println(responseHeaders.name(i) + ": " + responseHeaders.value(i));
}
String json_string_obj = response.body().string();
JSONObject url = new JSONObject(json_string_obj);
json_array_list_of_videos = url.getJSONArray("data");
System.out.println(json_array_list_of_videos.toString());
for (int y = 0; y <= 9; y++) {
if (json_array_list_of_videos.get(y).toString().equals("A9knX0GXrg")) {
videoDataList.add("6kS9Tt1e47g");
} else {
videoDataList.add(json_array_list_of_videos.get(y).toString());
System.out.println("++++++" + json_array_list_of_videos.get(y).toString());
}
}
for (int i = counter; i <= loadLimit; i++) {
if (videoDataList == null) {
return;
} else {
VideoData next_queue_id = new VideoData(videoDataList.get(i));
videoList.add(next_queue_id);
counter++;
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
});
} catch (ArrayIndexOutOfBoundsException e) {
e.printStackTrace();
}
}
public void createRecycleView() {
adapter = new RecyclerAdapter(videoList, getContext());
linearLayoutManager = new LinearLayoutManager(getActivity());
linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(linearLayoutManager);
recyclerView.setAdapter(adapter);
}
}
之后再Response创建。由于缺乏知识，我很伤心，我不知道如何new adapter与thread等待的方法。
希望你不会发现这个问题是沉闷或愚蠢的，并会帮助我。
提前谢谢！
答案 0 :(得分：0)
修改其列表（videoList）后，需要通知适配器。
目前，loadMoreData(int offset)方法并不保证，因为loadData(offset);方法可以在修改列表之前返回（请求是异步处理的）。
你能做的是：
从adapter.notifyDataSetChanged();方法中删除loadMoreData(int offset)语句，并将其添加到onResponse(Response response)方法。
示例：
@Override
public void onResponse(Response response) throws IOException {
try {
...
for (int i = counter; i <= loadLimit; i++) {
if (videoDataList == null) {
return;
} else {
VideoData next_queue_id = new VideoData(videoDataList.get(i));
videoList.add(next_queue_id);
counter++;
}
}
ListVideo.this.runOnUiThread(new Runnable() {
@Override
public void run() {
adapter.notifyDataSetChanged();
}
});
} catch (Exception e) {
e.printStackTrace();
}
}
这种方法可能会产生其他问题，因为videoList可以同时被多个线程修改。您需要找到一种方法来同步对此列表的访问或使用线程安全列表。