我创建了一个主类，可以从中调用片段 在我要显示对话框的片段之一中 所以我把对话框显示功能 在Page_6Fragment里面，然后我从Customeradapter内部邀请它 我做了其他尝试，但没有成功。请帮助我，并为《准则》撰写适当的修正案
//Log cat:
Process: com.example.android.wacher, PID: 1542
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:147)
at com.example.android.wacher.adapters.CustomerAdapter$1.onClick(CustomerAdapter.java:65)
at android.view.View.performClick(View.java:5609)
at android.view.View$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)
// class Page_6Fragment
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;
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);
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(getActivity());
dialog.setCancelable(true);
View view = getActivity().getLayoutInflater().inflate(R.layout.layout, null);
dialog.setContentView(view);
dialog.show();
}
}
//CustomerAdapter
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) {
//Toast.makeText(context, ""+ position, Toast.LENGTH_LONG).show();
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;
}
}
//HomeActivity
public class HomeActivity extends AppCompatActivity {
TextView mToolBarTextView;
Toolbar toolbar;
private Context mContext;
//FragmentManager fm;
//Fragment selectedFragment = null;
Fragment selectedFragment;
private int count;
private int tootalPrice;
private int[] totalParts;
public int[] tP;
EditText et1;
EditText et2;
EditText et3;
EditText et4;
// butNext
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mContext = this;
getLayoutInflater().inflate(R.layout.toolbar, (ViewGroup) findViewById(android.R.id.content));
toolbar = (Toolbar) findViewById(R.id.toolbar);
mToolBarTextView = (TextView) findViewById(R.id.text_view_toolbar_title);
BottomNavigationView bottomNavigationView = (BottomNavigationView)
findViewById(R.id.navigation);
bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
selectedFragment = null;
LinearLayout root;
switch (item.getItemId()) {
case R.id.action_item1:
selectedFragment = Page_3Fragment.newInstance();
// selectedFragment = Page_2Fragment.newInstance();
break;
case R.id.action_item2:
// selectedFragment = Page_2Fragment.newInstance();
selectedFragment= null;
selectedFragment = Page_6Fragment.newInstance();
break;
case R.id.action_item3:
//Intent intent = new Intent(HomeActivity.this,PrefsActivity.class);
//startActivity(intent);
selectedFragment = new PreferenceFragmentCustom();
// addBar();
// initToolbar();
// selectedFragment=preferenceFragment;// Page_4Fragment.newInstance();
// selectedFragment = Page_4Fragment.newInstance();
break;
}
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.frame_layout, selectedFragment);
transaction.commit();
return true;
}
});
// Manually displaying the first fragment - one time only
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.frame_layout, Page_1Fragment.newInstance());
transaction.commit();
FunctionToolbar("الرئيسية");
// Used to select an item programmatically
// bottomNavigationView.getMenu().getItem(2).setChecked(true);
}
public void ShowDailoge(){
Dialog dialog = new Dialog(this);
dialog.setCancelable(true);
View view = selectedFragment.getActivity().getLayoutInflater().inflate(R.layout.layout, null);
dialog.setContentView(view);
dialog.show();
}
答案 0 :(得分：0)
您应从 selectedFragment.getActivity()
ShowDailoge()
尝试
public void ShowDailoge(){
Dialog dialog = new Dialog(this);
dialog.setCancelable(true);
dialog.setContentView(R.layout.layout_name);
dialog.show();
}
仅供参考
您应将 getActivity() 用于-> 片段 和 ActivityName.this 对于-> 活动 部分。