我有一个带有3个textviews的recyclerview适配器。我用模型类来设置文本。现在我想使用具有不同布局的相同适配器和不同的类，只有1个textview。当我尝试时，我得到NullPointerException（可能是因为其他2个textviews是空白的）。有没有办法使用不同布局和不同类别的相同适配器？
// second class - I used 1 textview
public class Customers extends AppCompatActivity{
private CShowProgress cShowProgress;
private RecyclerView mRecyclerView;
private TimeLineAdapter mTimeLineAdapter;
private List<TimeLineModel> mDataList = new ArrayList<>();
private static final String CUSTOMERS = "http://192.168.200.3/ubooktoday/android/showspacustomerlist";
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.customers);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
cShowProgress = CShowProgress.getInstance();
mRecyclerView = (RecyclerView) findViewById(R.id.recyclerView);
mRecyclerView.setLayoutManager(getLinearLayoutManager());
mRecyclerView.setHasFixedSize(true);
showCustomers();
}
private void showCustomers() {
if(mDataList!=null )mDataList.clear();
cShowProgress.showProgress(Customers.this);
StringRequest stringRequest = new StringRequest(Request.Method.POST, CUSTOMERS,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
cShowProgress.hideProgress();
try {
JSONArray jsonArray = new JSONArray(response);
for(int i=0; i<jsonArray.length(); i++){
JSONObject obj = jsonArray.getJSONObject(i);
TimeLineModel model = new TimeLineModel();
model.setCustname(obj.getString("customername"));
mDataList.add(model);
mTimeLineAdapter = new TimeLineAdapter(getApplicationContext(), R.layout.item_row_customer, mDataList);
mRecyclerView.setAdapter(mTimeLineAdapter);
}
mTimeLineAdapter.notifyDataSetChanged();
} catch (JSONException e) {
// JSON error
e.printStackTrace();
Toast.makeText(getApplicationContext(), "Json error: " + e.getMessage(), Toast.LENGTH_LONG).show();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(getApplicationContext(), "VolleyError" + error.toString(), Toast.LENGTH_LONG).show();
}
}) {
@Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
params.put("spaid", "145");
return params;
}
};
RequestQueue requestQueue = Volley.newRequestQueue(getApplicationContext());
requestQueue.add(stringRequest);
}
private LinearLayoutManager getLinearLayoutManager() {
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getApplicationContext());
return linearLayoutManager;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
onBackPressed();
break;
}
return true;
}
}
// first class - I used all 3 textviews
public class Walkin extends Fragment{
private RecyclerView mRecyclerView;
private TimeLineAdapter mTimeLineAdapter;
private List<TimeLineModel> mDataList = new ArrayList<>();
private static final String DASHBOARD = "My API";
@Nullable
@Override
@Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.walkin, container, false);
}
@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
mRecyclerView = (RecyclerView) view.findViewById(R.id.recyclerView);
mRecyclerView.setLayoutManager(getLinearLayoutManager());
mRecyclerView.setHasFixedSize(true);
showDashboard();
}
private void showDashboard() {
if(mDataList!=null )mDataList.clear();
cShowProgress.showProgress(getActivity());
StringRequest stringRequest = new StringRequest(Request.Method.POST, DASHBOARD,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
try {
JSONObject jsonObject = new JSONObject(response);
JSONArray jsonArray = jsonObject.getJSONArray("walkinlist");
for(int i=0; i<jsonArray.length(); i++){
JSONObject obj = jsonArray.getJSONObject(i);
TimeLineModel model = new TimeLineModel();
model.setCustname(obj.getString("customername"));
model.setTime(obj.getString("serviceDuration"));
model.setServname(obj.getString("service"));
mDataList.add(model);
mTimeLineAdapter = new TimeLineAdapter(getActivity(), R.layout.item_row_dashboard, mDataList);
mRecyclerView.setAdapter(mTimeLineAdapter);
}
mTimeLineAdapter.notifyDataSetChanged();
} catch (JSONException e) {
// JSON error
e.printStackTrace();
Toast.makeText(getActivity(), "Json error: " + e.getMessage(), Toast.LENGTH_LONG).show();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(getActivity(), "VolleyError" + error.toString(), Toast.LENGTH_LONG).show();
}
}) {
@Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
params.put("spaid", "145");
return params;
}
};
RequestQueue requestQueue = Volley.newRequestQueue(getActivity());
requestQueue.add(stringRequest);
}
private LinearLayoutManager getLinearLayoutManager() {
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity());
return linearLayoutManager;
}
}
// Adapter class
public class TimeLineAdapter extends RecyclerView.Adapter<TimeLineViewHolder> {
private List<TimeLineModel> mFeedList;
int resource;
private Context mContext;
public TimeLineAdapter(Context mContext, int resource, List<TimeLineModel> feedList) {
this.resource = resource;
this.mContext = mContext;
mFeedList = feedList;
}
@Override
public TimeLineViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = View.inflate(parent.getContext(), resource, null);
return new TimeLineViewHolder(view, viewType);
}
@Override
public void onBindViewHolder(TimeLineViewHolder holder, int position) {
TimeLineModel timeLineModel = mFeedList.get(position);
holder.servicename.setText(timeLineModel.getServname());
holder.custname.setText(timeLineModel.getCustname());
holder.time.setText(timeLineModel.getTime());
}
@Override
public int getItemCount() {
return (mFeedList!=null? mFeedList.size():0);
}
}
// ViewHolder class
public class TimeLineViewHolder extends RecyclerView.ViewHolder {
public TextView servicename, custname, time;
public TimeLineViewHolder(View itemView, int viewType) {
super(itemView);
servicename = (TextView) itemView.findViewById(R.id.tv_service);
custname = (TextView) itemView.findViewById(R.id.tv_cust);
time = (TextView) itemView.findViewById(R.id.tv_time);
}
}
答案 0 :(得分：6)
您可以使用getItemViewType()。
RecyclerView.Adapter。getItemViewType Override适配器中的int getItemViewType (int position)方法。 viewType参数来区分要扩展的布局。onBindViewHolder中使用instanceof检查创建了哪个ViewHolder并调用相关的绑定函数示例代码 -
// Adapter class
public class TimeLineAdapter extends RecyclerView.Adapter{
.....
int type;
public TimeLineAdapter(Context mContext, int resource, List<TimeLineModel> feedList,int layoutType) {
.....
.....
type=layoutType;
}
@Override
public int getItemViewType(int position) {
return type;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if(viewType==1){
View view = View.inflate(parent.getContext(), resource, null);
return new TimeLineViewHolder(view, viewType);
}else{
View view = View.inflate(parent.getContext(), resource, null);
return new TimeLineViewHolder2(view, viewType);
}
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if(holder instanceof TimeLineViewHolder){
TimeLineModel timeLineModel = mFeedList.get(position);
((TimeLineViewHolder) holder).servicename.setText(timeLineModel.getServname());
......
}
else if(holder instanceof TimeLineViewHolder2){
....
....
}
}
@Override
public int getItemCount() {
return (mFeedList!=null? mFeedList.size():0);
}
}