简而言之，问题是我无法使用此功能来显示对话框。
public class Page_6Fragment extends android.support.v4.app.Fragment {
RecyclerView recyclerView;
List<Customer> customers;
CustomerAdapter adapter;
View rootView;
String TAG = "MainActivity - ";
Context context;
API api;
Activity a;
public static Page_6Fragment newInstance() {
Page_6Fragment fragment = new Page_6Fragment();
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
rootView = inflater.inflate(R.layout.activity_customer, container, false);
// View rootView = inflater.inflate(R.xml.pref, container, false);
// Intent intent = new Intent(PreferenceDemoActivity.this,PrefsActivity.class);
// startActivity(intent);
this.context = getActivity();
recyclerView = (RecyclerView) rootView.findViewById(R.id.recycler_view);
customers = new ArrayList<>();
adapter = new CustomerAdapter(context, customers);
adapter.setLoadMoreListener(new CustomerAdapter.OnLoadMoreListener(){
@Override
public void onLoadMore() {
recyclerView.post(new Runnable() {
@Override
public void run() {
int index = customers.size() - 1;
loadMore(index);
}
});
//Calling loadMore function in Runnable to fix the
// java.lang.IllegalStateException: Cannot call this method while RecyclerView is computing a layout or scrolling error
}
});
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(context));
//recyclerView.addItemDecoration(new VerticalLineDecorator(2));
recyclerView.setAdapter(adapter);
api = ServiceGenerator.createService(API.class);
load(0);
return rootView;
}
private void load(int index){
Call<List<Customer>> call = api.getCustomer(index);
call.enqueue(new Callback<List<Customer>>(){
@Override
public void onResponse(Call<List<Customer>> call, Response<List<Customer>> response){
// Toast.makeText(getActivity(), "tost "+response.body().get(0).post_writer, Toast.LENGTH_LONG).show();
// Log.i("TRUE_TRUE","Yes"+response.body().get(0).title);
if(response.isSuccessful()){
customers.addAll(response.body());
adapter.notifyDataChanged();
// Toast.makeText(MainActivity.this, "tost "+response.body().get(0).post_writer, Toast.LENGTH_LONG).show();
}else{
Log.e(TAG," Response Error "+String.valueOf(response.code()));
}
}
@Override
public void onFailure(Call<List<Customer>> call, Throwable t) {
Log.e(TAG," Response Error "+t.getMessage());
}
});
}
private void loadMore(int index){
//add loading progress view
customers.add(new Customer("load"));
adapter.notifyItemInserted(customers.size()-1);
Call<List<Customer>>call = api.getCustomer(index);
call.enqueue(new Callback<List<Customer>>(){
@Override
public void onResponse(Call<List<Customer>> call, Response<List<Customer>>response) {
if(response.isSuccessful()){
// remove loading view .......
customers.remove(customers.size()-1);
List<Customer>result=response.body();
if(result.size()>0){
// add loaded data
customers.addAll(result);
}else{//result size 0 means there is no more data available at server
adapter.setMoreDataAvailable(false);
//telling adapter to stop calling load more as no more server data available
Toast.makeText(context,"No More Data Available",Toast.LENGTH_LONG).show();
}
adapter.notifyDataChanged();
}else{
Log.e(TAG," Load More Response Error "+String.valueOf(response.code()));
}
}
@Override
public void onFailure(Call<List<Customer>>call,Throwable t) {
Log.e(TAG," Load More Response Error "+t.getMessage());
}
});
}
public void showDialog(){
Dialog dialog = new Dialog(context);
dialog.setCancelable(true);
View view = getActivity().getLayoutInflater().inflate(R.layout.layout, null);
dialog.setContentView(view);
dialog.show();
}
}
// class to call function
package com.example.android.wacher.adapters;
import android.app.Dialog;
import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import com.example.android.wacher.R;
import com.example.android.wacher.activities.HomeActivity;
import com.example.android.wacher.fragments.Page_6Fragment;
import com.example.android.wacher.models.Customer;
import java.util.List;
/**
* Created by cca on 23/12/2018.
*/
public class CustomerAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
public final int TYPE_MOVIE = 0;
public final int TYPE_LOAD = 1;
static Context context;
List<Customer> customers;
OnLoadMoreListener loadMoreListener;
boolean isLoading = false, isMoreDataAvailable = true;
public CustomerAdapter(Context context, List<Customer> customers) {
this.context = context;
this.customers = customers;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater inflater = LayoutInflater.from(context);
if(viewType==TYPE_MOVIE){
return new CustomerHolder(inflater.inflate(R.layout.row_movie,parent,false));
}else{
return new LoadHolder(inflater.inflate(R.layout.row_load,parent,false));
}
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, final int position) {
if(position>=getItemCount()-1 && isMoreDataAvailable && !isLoading && loadMoreListener!=null){
isLoading = true;
loadMoreListener.onLoadMore();
}
if(getItemViewType(position)==TYPE_MOVIE){
((CustomerHolder)holder).bindData(customers.get(position));
if(((CustomerHolder)holder).buttonViewOption != null)((CustomerHolder)holder).buttonViewOption.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// call function
Page_6Fragment.newInstance().showDialog();
}
});
}
}
@Override
public int getItemViewType(int position) {
if(customers.get(position).type.equals("movie")){
return TYPE_MOVIE;
}else{
return TYPE_LOAD;
}
}
@Override
public int getItemCount(){
return customers.size();
}
/* VIEW HOLDERS */
static class CustomerHolder extends RecyclerView.ViewHolder{
TextView tvTitle;
TextView tvRating;
Button buttonViewOption;
public CustomerHolder(View itemView) {
super(itemView);
tvTitle=(TextView)itemView.findViewById(R.id.title);
tvRating=(TextView)itemView.findViewById(R.id.rating);
buttonViewOption = (Button) itemView.findViewById(R.id.textViewOptions);
}
void bindData(Customer cust){
tvTitle.setText(cust.name);
tvRating.setText(cust.title);
}
}
static class LoadHolder extends RecyclerView.ViewHolder{
public LoadHolder(View itemView) {
super(itemView);
}
}
public void setMoreDataAvailable(boolean moreDataAvailable) {
isMoreDataAvailable = moreDataAvailable;
}
/* notifyDataSetChanged is final method so we can't override it
call adapter.notifyDataChanged(); after update the list
*/
public void notifyDataChanged(){
notifyDataSetChanged();
isLoading = false;
}
public interface OnLoadMoreListener{
void onLoadMore();
}
public void setLoadMoreListener(OnLoadMoreListener loadMoreListener) {
this.loadMoreListener = loadMoreListener;
}
}
当我调用 ShowDialog 函数时，发生错误（粘贴在下面。
我不知道为什么这个函数在Page_6Fragment类中不起作用。
Process: com.example.android.wacher, PID: 11335
java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.res.Resources$Theme android.content.Context.getTheme()' on a null object reference
at android.app.Dialog.<init>(Dialog.java:173)
at android.app.Dialog.<init>(Dialog.java:147)
at com.example.android.wacher.fragments.Page_6Fragment.showDialog(Page_6Fragment.java:153)
at com.example.android.wacher.adapters.CustomerAdapter$1.onClick(CustomerAdapter.java:70)
at android.view.View.performClick(View.java:5609)
at android.view.View$PerformClick.run(View.java:22259)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
你不能使用 Page_6Fragment.newInstance().showDialog(); .方法public void showDialog()应该private，因为它的句柄Context引用。显示应使用的其他位置的Dialog
public void showDialog(Context context){
Dialog dialog = new Dialog(context);
dialog.setCancelable(true);
dialog.setContentView(R.layout.layout);
dialog.show();
}
并且无需膨胀布局即可设置内容视图