按钮单击从url片段加载数据

Question

这是我试图修改的项目。该项目是片段式的。它是一个买卖的在线市场。下面的代码可以帮助在启动/打开应用程序时自动从服务器获取数据。但我不希望它自动加载数据，但当用户按下按钮时它会加载它将从服务器获取内容。下面的METHOD_STREAM_GET用于

public static final String METHOD_STREAM_GET = API_DOMAIN +“api /”+ API_VERSION +“/ method / stream.get”+ API_FILE_EXTENSION;。

package ml.shopnet.market;

public class StreamFragment extends Fragment implements Constants，SwipeRefreshLayout.OnRefreshListener {

private static final String STATE_LIST = "State Adapter Data";
private static final String STATE_LIST_2 = "State Adapter Data";

private static final int PROFILE_NEW_POST = 4;

RecyclerView mRecyclerView;
TextView mMessage;

SwipeRefreshLayout mItemsContainer;

FloatingActionButton mFabButton;

Button login;
GridView gridView;

private ArrayList<Item> itemsList;
private StreamListAdapter itemsAdapter;

private Parcelable mListState;

private int itemId = 0;
private int arrayLength = 0;
private Boolean loadingMore = false;
private Boolean viewMore = false;
private Boolean restore = false;

int pastVisiblesItems = 0, visibleItemCount = 0, totalItemCount = 0;

public StreamFragment() {
    // Required empty public constructor
}

@Override
public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    if (savedInstanceState != null) {

        itemsList = savedInstanceState.getParcelableArrayList(STATE_LIST_2);
        itemsAdapter = new StreamListAdapter(getActivity(), itemsList);

        restore = savedInstanceState.getBoolean("restore");
        itemId = savedInstanceState.getInt("itemId");

        viewMore = savedInstanceState.getBoolean("viewMore");

    } else {

        itemsList = new ArrayList<>();
        itemsAdapter = new StreamListAdapter(getActivity(), itemsList);

        restore = false;
        itemId = 0;
    }
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.fragment_latest, container, false);
    mItemsContainer = (SwipeRefreshLayout) rootView.findViewById(R.id.container_items);
    mItemsContainer.setOnRefreshListener(this);

    mMessage = (TextView) rootView.findViewById(R.id.message);

    mFabButton = (FloatingActionButton) rootView.findViewById(R.id.fabButton);
    mFabButton.setImageResource(R.drawable.ic_action_new);

    if (App.getInstance().getId() == 0) {

        mFabButton.setVisibility(View.GONE);
    }






    mRecyclerView = (RecyclerView) rootView.findViewById(R.id.recycler_view);

    final GridLayoutManager mLayoutManager = new GridLayoutManager(getActivity(), Helper.getGridSpanCount(getActivity()));
    mRecyclerView.setLayoutManager(mLayoutManager);
    mRecyclerView.addItemDecoration(new GridSpacingItemDecoration(Helper.getGridSpanCount(getActivity()), dpToPx(10), true));
    mRecyclerView.setItemAnimator(new DefaultItemAnimator());

    mRecyclerView.setAdapter(itemsAdapter);

    mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener()
    {
        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy)
        {
            if(dy > 0) //check for scroll down
            {
                visibleItemCount = mLayoutManager.getChildCount();
                totalItemCount = mLayoutManager.getItemCount();
                pastVisiblesItems = mLayoutManager.findFirstVisibleItemPosition();

                if (!loadingMore)
                {
                    if ((visibleItemCount + pastVisiblesItems) >= totalItemCount && (viewMore) && !(mItemsContainer.isRefreshing()))
                    {
                        loadingMore = true;
                        Log.e("...", "Last Item Wow !");

                        getItems();
                    }
                }
            }
        }
    });

    mRecyclerView.addOnItemTouchListener(new RecyclerItemClickListener(getActivity(), mRecyclerView, new RecyclerItemClickListener.OnItemClickListener() {
        @Override
        public void onItemClick(View view, int position) {

            Item i = (Item) itemsList.get(position);

            Intent intent = new Intent(getActivity(), ViewItemActivity.class);
            intent.putExtra("itemId", i.getId());
            startActivity(intent);
        }

        @Override
        public void onItemLongClick(View view, int position) {
            // ...
        }
    }));

    mFabButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            Intent intent = new Intent(getActivity(), NewItemActivity.class);
            startActivityForResult(intent, STREAM_NEW_POST);
        }
    });

    if (itemsAdapter.getItemCount() == 0) {

        showMessage(getText(R.string.label_empty_list).toString());

    } else {

        hideMessage();
    }

    if (!restore) {

        showMessage(getText(R.string.msg_loading_2).toString());

        getItems();
    }

    return rootView;
}

static class RecyclerItemClickListener implements RecyclerView.OnItemTouchListener {

    public interface OnItemClickListener {

        void onItemClick(View view, int position);

        void onItemLongClick(View view, int position);
    }

    private OnItemClickListener mListener;

    private GestureDetector mGestureDetector;

    public RecyclerItemClickListener(Context context, final RecyclerView recyclerView, OnItemClickListener listener) {

        mListener = listener;

        mGestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener() {
            @Override
            public boolean onSingleTapUp(MotionEvent e) {

                return true;
            }

            @Override
            public void onLongPress(MotionEvent e) {

                View childView = recyclerView.findChildViewUnder(e.getX(), e.getY());

                if (childView != null && mListener != null) {

                    mListener.onItemLongClick(childView, recyclerView.getChildAdapterPosition(childView));
                }
            }
        });
    }

    @Override
    public boolean onInterceptTouchEvent(RecyclerView view, MotionEvent e) {

        View childView = view.findChildViewUnder(e.getX(), e.getY());

        if (childView != null && mListener != null && mGestureDetector.onTouchEvent(e)) {

            mListener.onItemClick(childView, view.getChildAdapterPosition(childView));
        }

        return false;
    }

    @Override
    public void onTouchEvent(RecyclerView view, MotionEvent motionEvent) {

    }

    @Override
    public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {

    }
}

/**
 * RecyclerView item decoration - give equal margin around grid item
 */
public class GridSpacingItemDecoration extends RecyclerView.ItemDecoration {

    private int spanCount;
    private int spacing;
    private boolean includeEdge;

    public GridSpacingItemDecoration(int spanCount, int spacing, boolean includeEdge) {

        this.spanCount = spanCount;
        this.spacing = spacing;
        this.includeEdge = includeEdge;
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {

        int position = parent.getChildAdapterPosition(view); // item position
        int column = position % spanCount; // item column

        if (includeEdge) {

            outRect.left = spacing - column * spacing / spanCount; // spacing - column * ((1f / spanCount) * spacing)
            outRect.right = (column + 1) * spacing / spanCount; // (column + 1) * ((1f / spanCount) * spacing)

            if (position < spanCount) { // top edge

                outRect.top = spacing;
            }

            outRect.bottom = spacing; // item bottom

        } else {

            outRect.left = column * spacing / spanCount; // column * ((1f / spanCount) * spacing)
            outRect.right = spacing - (column + 1) * spacing / spanCount; // spacing - (column + 1) * ((1f /    spanCount) * spacing)

            if (position >= spanCount) {

                outRect.top = spacing; // item top
            }
        }
    }
}

/**
 * Converting dp to pixel
 */
private int dpToPx(int dp) {

    Resources r = getResources();

    return Math.round(TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp, r.getDisplayMetrics()));
}

@Override
public void onSaveInstanceState(Bundle outState) {

    super.onSaveInstanceState(outState);

    outState.putBoolean("viewMore", viewMore);

    outState.putBoolean("restore", true);
    outState.putInt("itemId", itemId);

    mListState = mRecyclerView.getLayoutManager().onSaveInstanceState();
    outState.putParcelable(STATE_LIST, mListState);

    outState.putParcelableArrayList(STATE_LIST_2, itemsList);
}

@Override
public void onRefresh() {

    if (App.getInstance().isConnected()) {

        itemId = 0;
        getItems();

    } else {

        mItemsContainer.setRefreshing(false);
    }
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {

    super.onActivityResult(requestCode, resultCode, data);

    if (requestCode == STREAM_NEW_POST && resultCode == getActivity().RESULT_OK && null != data) {

        itemId = 0;
        getItems();

    } else if (requestCode == ITEM_EDIT && resultCode == getActivity().RESULT_OK) {

        int position = data.getIntExtra("position", 0);

        Item item = itemsList.get(position);

        item.setContent(data.getStringExtra("post"));
        item.setImgUrl(data.getStringExtra("imgUrl"));

        itemsAdapter.notifyDataSetChanged();
    }
}

public void showToast(String msg) {
    Toast.makeText(getActivity(), msg, Toast.LENGTH_LONG).show();
}


    @Override
    public View getView(int position, View convertView, ViewGroup parent)
    {
        LayoutInflater inflater= (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        View row=inflater.inflate(R.layout.cell_categories, parent, false);

        ImageView myimage= (ImageView) row.findViewById(R.id.img);

        TextView mytitle= (TextView) row.findViewById(R.id.category);

        myimage.setImageResource(image[position]);

        mytitle.setText(title[position]);


        return row;
    }
}

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {

    super.onCreateOptionsMenu(menu, inflater);
}

public void getItems() {

    mItemsContainer.setRefreshing(true);

    CustomRequest jsonReq = new CustomRequest(Request.Method.POST, METHOD_STREAM_GET, null,
            new Response.Listener<JSONObject>() {
                @Override
                public void onResponse(JSONObject response) {

                    if (!isAdded() || getActivity() == null) {

                        Log.e("ERROR", "StreamFragment Not Added to Activity");

                        return;
                    }

                    if (!loadingMore) {

                        itemsList.clear();
                    }

                    try {

                        arrayLength = 0;

                        if (!response.getBoolean("error")) {

                            itemId = response.getInt("itemId");

                            if (response.has("items")) {

                                JSONArray itemsArray = response.getJSONArray("items");

                                arrayLength = itemsArray.length();

                                if (arrayLength > 0) {

                                    for (int i = 0; i < itemsArray.length(); i++) {

                                        JSONObject itemObj = (JSONObject) itemsArray.get(i);

                                        Item item = new Item(itemObj);

                                        itemsList.add(item);
                                    }
                                }
                            }
                        }

                    } catch (JSONException e) {

                        e.printStackTrace();

                    } finally {

                        loadingComplete();
                    }
                }
            }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {

            if (!isAdded() || getActivity() == null) {

                Log.e("ERROR", "StreamFragment Not Added to Activity");

                return;
            }

            loadingComplete();
        }
    }) {

        @Override
        protected Map<String, String> getParams() {
            Map<String, String> params = new HashMap<String, String>();
            params.put("accountId", Long.toString(App.getInstance().getId()));
            params.put("accessToken", App.getInstance().getAccessToken());
            params.put("itemId", Integer.toString(itemId));
            params.put("language", "en");

            return params;
        }
    };

    App.getInstance().addToRequestQueue(jsonReq);
}

public void loadingComplete() {

    if (arrayLength == LIST_ITEMS) {

        viewMore = true;

    } else {

        viewMore = false;
    }

    itemsAdapter.notifyDataSetChanged();

    if (itemsAdapter.getItemCount() == 0) {

        if (StreamFragment.this.isVisible()) {

            showMessage(getText(R.string.label_empty_list).toString());
        }

    } else {
        hideMessage();
    }
    loadingMore = false;
    mItemsContainer.setRefreshing(false);
}
public void showMessage(String message) {

    mMessage.setText(message);
    mMessage.setVisibility(View.VISIBLE);
}

public void hideMessage() {

    mMessage.setVisibility(View.GONE);
}

@Override
public void onAttach(Activity activity) {
    super.onAttach(activity);
}

@Override
public void onDetach() {
    super.onDetach();
}

}

您好，我还有另一个问题。感谢您解决第一个问题，下面的代码从categories.java接收数据，但我想修改它只打开一个类别ID，比如id 5，而不是从类别中接收类别ID我想让它从id“5中检索信息” “

package ml.shopnet.market;

public class CategoryFragment extends Fragment implements Constants，SwipeRefreshLayout.OnRefreshListener {

private static final String STATE_LIST = "State Adapter Data";

RecyclerView mRecyclerView;
TextView mMessage;

SwipeRefreshLayout mItemsContainer;

private ArrayList<Item> itemsList;
private StreamListAdapter itemsAdapter;

private int categoryId = 0;

private int itemId = 0;
private int arrayLength = 0;
private Boolean loadingMore = false;
private Boolean viewMore = false;
private Boolean restore = false;

private String title = "";

int pastVisiblesItems = 0, visibleItemCount = 0, totalItemCount = 0;

public CategoryFragment() {
    // Required empty public constructor
}

@Override
public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    if (savedInstanceState != null) {

        itemsList = savedInstanceState.getParcelableArrayList(STATE_LIST);
        itemsAdapter = new StreamListAdapter(getActivity(), itemsList);

        restore = savedInstanceState.getBoolean("restore");
        itemId = savedInstanceState.getInt("itemId");
        categoryId = savedInstanceState.getInt("categoryId");
        title = savedInstanceState.getString("title");

        viewMore = savedInstanceState.getBoolean("viewMore");

    } else {

        itemsList = new ArrayList<Item>();
        itemsAdapter = new StreamListAdapter(getActivity(), itemsList);

        restore = false;
        itemId = 0;
        categoryId = 0;

        Intent i = getActivity().getIntent();

        title = i.getStringExtra("title");
        categoryId = i.getIntExtra("categoryId", 0);
    }
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.fragment_category, container, false);

    mItemsContainer = (SwipeRefreshLayout) rootView.findViewById(R.id.container_items);
    mItemsContainer.setOnRefreshListener(this);

    mMessage = (TextView) rootView.findViewById(R.id.message);

    mRecyclerView = (RecyclerView) rootView.findViewById(R.id.recycler_view);

    final GridLayoutManager mLayoutManager = new GridLayoutManager(getActivity(), Helper.getGridSpanCount(getActivity()));
    mRecyclerView.setLayoutManager(mLayoutManager);
    mRecyclerView.addItemDecoration(new GridSpacingItemDecoration(Helper.getGridSpanCount(getActivity()), dpToPx(10), true));
    mRecyclerView.setItemAnimator(new DefaultItemAnimator());

    mRecyclerView.setAdapter(itemsAdapter);

    mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener()
    {
        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy)
        {
            if(dy > 0) //check for scroll down
            {
                visibleItemCount = mLayoutManager.getChildCount();
                totalItemCount = mLayoutManager.getItemCount();
                pastVisiblesItems = mLayoutManager.findFirstVisibleItemPosition();

                if (!loadingMore)
                {
                    if ((visibleItemCount + pastVisiblesItems) >= totalItemCount && (viewMore) && !(mItemsContainer.isRefreshing()))
                    {
                        loadingMore = true;
                        Log.e("...", "Last Item Wow !");

                        getItems();
                    }
                }
            }
        }
    });

    mRecyclerView.addOnItemTouchListener(new RecyclerItemClickListener(getActivity(), mRecyclerView, new RecyclerItemClickListener.OnItemClickListener() {
        @Override
        public void onItemClick(View view, int position) {

            Item i = (Item) itemsList.get(position);

            Intent intent = new Intent(getActivity(), ViewItemActivity.class);
            intent.putExtra("itemId", i.getId());
            startActivity(intent);
        }

        @Override
        public void onItemLongClick(View view, int position) {
            // ...
        }
    }));

    if (itemsAdapter.getItemCount() == 0) {

        showMessage(getText(R.string.label_empty_list).toString());

    } else {

        hideMessage();
    }

    if (title != null) {

        getActivity().setTitle(title);
    }

    if (!restore) {

        showMessage(getText(R.string.msg_loading_2).toString());

        getItems();
    }

    return rootView;
}

@Override
public void onSaveInstanceState(Bundle outState) {

    super.onSaveInstanceState(outState);

    outState.putBoolean("viewMore", viewMore);
    outState.putBoolean("restore", true);
    outState.putInt("itemId", itemId);
    outState.putInt("categoryId", categoryId);
    outState.putString("title", title);
    outState.putParcelableArrayList(STATE_LIST, itemsList);
}

@Override
public void onRefresh() {

    if (App.getInstance().isConnected()) {

        itemId = 0;
        getItems();

    } else {

        mItemsContainer.setRefreshing(false);
    }
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {

    super.onActivityResult(requestCode, resultCode, data);
}

public void getItems() {

    mItemsContainer.setRefreshing(true);

    CustomRequest jsonReq = new CustomRequest(Request.Method.POST, METHOD_CATEGORY_GET, null,
            new Response.Listener<JSONObject>() {
                @Override
                public void onResponse(JSONObject response) {

                    if (!isAdded() || getActivity() == null) {

                        Log.e("ERROR", "CategoryFragment Not Added to Activity");

                        return;
                    }

                    if (!loadingMore) {

                        itemsList.clear();
                    }

                    try {

                        arrayLength = 0;

                        if (!response.getBoolean("error")) {

                            itemId = response.getInt("itemId");
                            categoryId = response.getInt("categoryId");

                            if (response.has("items")) {

                                JSONArray itemsArray = response.getJSONArray("items");

                                arrayLength = itemsArray.length();

                                if (arrayLength > 0) {

                                    for (int i = 0; i < itemsArray.length(); i++) {

                                        JSONObject itemObj = (JSONObject) itemsArray.get(i);

                                        Item item = new Item(itemObj);

                                        itemsList.add(item);
                                    }
                                }
                            }
                        }

                    } catch (JSONException e) {

                        e.printStackTrace();

                    } finally {

                        loadingComplete();
                    }
                }
            }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {

            if (!isAdded() || getActivity() == null) {

                Log.e("ERROR", "CategoryFragment Not Added to Activity");

                return;
            }

            loadingComplete();
        }
    }) {

        @Override
        protected Map<String, String> getParams() {
            Map<String, String> params = new HashMap<String, String>();
            params.put("accountId", Long.toString(App.getInstance().getId()));
            params.put("accessToken", App.getInstance().getAccessToken());
            params.put("itemId", Long.toString(itemId));
            params.put("categoryId", Integer.toString(categoryId));
            params.put("language", "en");

            return params;
        }
    };

    App.getInstance().addToRequestQueue(jsonReq);
}

public void loadingComplete() {

    if (arrayLength == LIST_ITEMS) {

        viewMore = true;

    } else {

        viewMore = false;
    }

    itemsAdapter.notifyDataSetChanged();

    if (mRecyclerView.getAdapter().getItemCount() == 0) {

        if (isAdded()) {

            showMessage(getText(R.string.label_empty_list).toString());
        }

    } else {

        hideMessage();
    }

    loadingMore = false;
    mItemsContainer.setRefreshing(false);
}

static class RecyclerItemClickListener implements RecyclerView.OnItemTouchListener {

    public interface OnItemClickListener {

        void onItemClick(View view, int position);

        void onItemLongClick(View view, int position);
    }

    private OnItemClickListener mListener;

    private GestureDetector mGestureDetector;

    public RecyclerItemClickListener(Context context, final RecyclerView recyclerView, OnItemClickListener listener) {

        mListener = listener;

        mGestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener() {
            @Override
            public boolean onSingleTapUp(MotionEvent e) {

                return true;
            }

            @Override
            public void onLongPress(MotionEvent e) {

                View childView = recyclerView.findChildViewUnder(e.getX(), e.getY());

                if (childView != null && mListener != null) {

                    mListener.onItemLongClick(childView, recyclerView.getChildAdapterPosition(childView));
                }
            }
        });
    }

    @Override
    public boolean onInterceptTouchEvent(RecyclerView view, MotionEvent e) {

        View childView = view.findChildViewUnder(e.getX(), e.getY());

        if (childView != null && mListener != null && mGestureDetector.onTouchEvent(e)) {

            mListener.onItemClick(childView, view.getChildAdapterPosition(childView));
        }

        return false;
    }

    @Override
    public void onTouchEvent(RecyclerView view, MotionEvent motionEvent) {

    }

    @Override
    public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {

    }
}

/**
 * RecyclerView item decoration - give equal margin around grid item
 */
public class GridSpacingItemDecoration extends RecyclerView.ItemDecoration {

    private int spanCount;
    private int spacing;
    private boolean includeEdge;

    public GridSpacingItemDecoration(int spanCount, int spacing, boolean includeEdge) {

        this.spanCount = spanCount;
        this.spacing = spacing;
        this.includeEdge = includeEdge;
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {

        int position = parent.getChildAdapterPosition(view); // item position
        int column = position % spanCount; // item column

        if (includeEdge) {

            outRect.left = spacing - column * spacing / spanCount; // spacing - column * ((1f / spanCount) * spacing)
            outRect.right = (column + 1) * spacing / spanCount; // (column + 1) * ((1f / spanCount) * spacing)

            if (position < spanCount) { // top edge

                outRect.top = spacing;
            }

            outRect.bottom = spacing; // item bottom

        } else {

            outRect.left = column * spacing / spanCount; // column * ((1f / spanCount) * spacing)
            outRect.right = spacing - (column + 1) * spacing / spanCount; // spacing - (column + 1) * ((1f /    spanCount) * spacing)

            if (position >= spanCount) {

                outRect.top = spacing; // item top
            }
        }
    }
}

/**
 * Converting dp to pixel
 */
private int dpToPx(int dp) {

    Resources r = getResources();

    return Math.round(TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp, r.getDisplayMetrics()));
}

public void showMessage(String message) {

    mMessage.setText(message);
    mMessage.setVisibility(View.VISIBLE);
}

public void hideMessage() {

    mMessage.setVisibility(View.GONE);
}

@Override
public void onAttach(Activity activity) {
    super.onAttach(activity);
}

@Override
public void onDetach() {
    super.onDetach();
}

}

Answer 1

从

中删除getItems()

if (!restore) {

    showMessage(getText(R.string.msg_loading_2).toString());

    getItems();
}

将click listener设置为您的按钮，然后调用getItems()方法

    Button button = (Button) findViewById(R.id.button);
    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            showMessage(getText(R.string.msg_loading_2).toString());
            getItems();
        }
    });