java - Intent 获取数据仅在一项 Activity 中出错

Question

我正在尝试从 adapter 传递一个intent 并在我的 Activity 中获取它。

每当我这样做时，它都会进入else 条件。

它没有得到值(value)而且我不知道为什么。当我在任何其他 Activity 中尝试相同的代码时，它运行得很好，但在这个 Activity 中，它总是给出一个 null Intent 值。

我知道关于如何获取和传递 Intent 有很多答案，但就我而言，它在一项 Activity 中不起作用，我不知道为什么。

My Adapter class:

holder.getSurvey.setOnClickListener(new View.OnClickListener() {
   @Override
        public void onClick(View v) {
            Intent intent = new Intent(context,AuthorMainScreen.class);
            intent.putExtra("work", "getting");
            context.startActivity(intent);
        }

My AuthorMainScreen Activity:

  public class AuthorMainScreen extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {

      Button newSurveyBtn, surveyWithRef, surveyResult;
      ArrayList<JSONObject> jsonObjects = new ArrayList<JSONObject>();

      public static TextView textView;
      DatabaseReference databaseReference, surveyReference;

      String referenceNo, loggedInUserId;
      AlertDialog dialog;
      ProgressDialog progressDialog;
      DrawerLayout drawerLayout;
      NavigationView navigationView;
      LinearLayout linearLayout;
      FirebaseAuth firebaseAuth;
      TextView headerEmailView, rateOk;
      Button headerLogout;
      EditText reference;


      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_author_navigation);

          progressDialog = new ProgressDialog(this);
          progressDialog.setMessage("Processing your request...");

          viewDeclaration();

          clickFunctionalities();

          ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                  this, drawerLayout, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
          drawerLayout.setDrawerListener(toggle);
          toggle.syncState();

          //drawerLayout.addDrawerListener(actionBarDrawerToggle);

          navigationView.setNavigationItemSelectedListener(this);
      }


      private void clickFunctionalities() {
          newSurveyBtn.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View view) {
                  surveyTitleDialog();
              }
          });

          surveyWithRef.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View v) {
                  referenceDialog();
                  rateOk.setOnClickListener(new View.OnClickListener() {
                      @Override
                      public void onClick(View view) {
                          referenceNo = reference.getText().toString().trim();

                          if (!referenceNo.isEmpty()) {
                              progressDialog.show();
                              getSurvey();
                              dialog.dismiss();
                          } else {
                              progressDialog.dismiss();
                              reference.setError("Reference # is required");
                          }
                      }
                  });
              }
          });

          surveyResult.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View view) {
                  referenceDialog();
                  rateOk.setOnClickListener(new View.OnClickListener() {
                      @Override
                      public void onClick(View view) {
                          referenceNo = reference.getText().toString().trim();

                          if (!referenceNo.isEmpty()) {
                              progressDialog.show();
                              getSurveyResultFile();
                              dialog.dismiss();
                          } else {
                              progressDialog.dismiss();
                              reference.setError("Reference # is required");
                          }
                      }
                  });

              }
          });


          linearLayout.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View v) {
                  if (drawerLayout.isDrawerOpen(GravityCompat.START)) {
                      drawerLayout.closeDrawer(GravityCompat.START);
                  } else {
                      drawerLayout.openDrawer(GravityCompat.START);
                  }
              }
          });

          headerLogout.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View v) {
                  FirebaseAuth.getInstance().signOut();
                  Intent intent = new Intent(AuthorMainScreen.this, LoginSignupActivity.class);
                  startActivity(intent);
                  finish();
              }
          });
      }

      private void surveyTitleDialog() {

          final AlertDialog.Builder textBuilder = new AlertDialog.Builder(this);

          LayoutInflater inflater = this.getLayoutInflater();
          View view = inflater.inflate(R.layout.survey_name_dialog, null);

          final EditText surveyName = view.findViewById(R.id.edt_set_survey_name);
          TextView ok = view.findViewById(R.id.survey_name_btn);

          ok.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View view) {
                  String surveyTitleName = surveyName.getText().toString().trim();
                  if (!surveyTitleName.equals("")) {
                      dialog.dismiss();
                      Intent intent = new Intent(AuthorMainScreen.this, MakeSurvey.class);
                      intent.putExtra("surveyname", surveyTitleName);
                      Toast.makeText(AuthorMainScreen.this, surveyTitleName, Toast.LENGTH_SHORT).show();
                      startActivity(intent);

                  } else {
                      surveyName.setError("Title is Required");
                  }

              }
          });

          TextView cancelBtn = view.findViewById(R.id.dismiss_dialog);
          cancelBtn.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View view) {
                  dialog.dismiss();

              }
          });

          textBuilder.setView(view);
          dialog = textBuilder.create();
          dialog.getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE);
          dialog.show();
          Window window = dialog.getWindow();
          window.setLayout(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
          dialog.setCancelable(false);
      }

      private void getSurvey() {

          surveyReference = FirebaseDatabase.getInstance().getReference().child(Constants.content).child(Constants.survey).child(referenceNo);
          surveyReference.addValueEventListener(new ValueEventListener() {
              @Override
              public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

                  System.out.println(dataSnapshot);

                  if (dataSnapshot.hasChildren()) {
                      progressDialog.dismiss();
                      Intent intent = new Intent(getApplicationContext(), GetSurveys.class);
                      intent.putExtra(Constants.ref_no, referenceNo);
                      startActivity(intent);
                  } else {
                      progressDialog.dismiss();

                      Toast.makeText(getApplicationContext(), "Reference number is not valid !!!", Toast.LENGTH_LONG).show();
                  }
              }

              @Override
              public void onCancelled(@NonNull DatabaseError databaseError) {
                  progressDialog.dismiss();

                  Toast.makeText(getApplicationContext(), "Something went wrong!!!", Toast.LENGTH_SHORT).show();
              }
          });
      }

      public void getSurveyResultFile() {
          databaseReference = FirebaseDatabase.getInstance().getReference().child(Constants.content).child(Constants.Answers).child(loggedInUserId).child(referenceNo);

          databaseReference.addValueEventListener(new ValueEventListener() {
              @Override
              public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                  if (dataSnapshot.exists()) {
                      progressDialog.dismiss();

                      JSONArray dataSnapshotArray = new JSONArray();
                      JSONArray dataSnapshotChildrenArray;
                      JSONObject dataSnapshotChildrenAnswer;
                      JSONArray dataSnapshotChildrenAnswerValues;

                      for (DataSnapshot ds : dataSnapshot.getChildren()) {
                          System.out.println("sdsd" + ds);
                          dataSnapshotChildrenArray = new JSONArray();
                          ArrayList<Object> list = (ArrayList<Object>) ds.getValue();
                          for (int i = 0; i < list.size(); i++) {
                              HashMap<String, Object> map = (HashMap<String, Object>) list.get(i);
                              Iterator<Map.Entry<String, Object>> finalIterator = map.entrySet().iterator();

                              dataSnapshotChildrenAnswer = new JSONObject();
                              while (finalIterator.hasNext()) {
                                  Map.Entry<String, Object> entry = finalIterator.next();
                                  Object value = entry.getValue();
                                  String key = entry.getKey();
                                  try {
                                      dataSnapshotChildrenAnswer.put(key, value);
                                      if (value instanceof ArrayList) {
                                          dataSnapshotChildrenAnswerValues = new JSONArray();
                                          ArrayList<String> answers = (ArrayList<String>) value;
                                          for (int j = 0; j < answers.size(); j++) {
                                              dataSnapshotChildrenAnswerValues.put(answers.get(j));
                                          }
                                          dataSnapshotChildrenAnswer.put(key, dataSnapshotChildrenAnswerValues);
                                      }
                                  } catch (JSONException e) {
                                      e.printStackTrace();
                                  }
                              }
                              dataSnapshotChildrenArray.put(dataSnapshotChildrenAnswer);
                          }
                          dataSnapshotArray.put(dataSnapshotChildrenArray);
                          System.out.println("jso  " + dataSnapshotArray);
                      }
                      try {
                          saveCsv(dataSnapshotArray);
                      } catch (IOException e) {
                          e.printStackTrace();
                      } catch (JSONException e) {
                          e.printStackTrace();
                      }
                  } else {
                      Toast.makeText(AuthorMainScreen.this, "Sorry!!user or survey not found.", Toast.LENGTH_LONG).show();
                      progressDialog.dismiss();
                  }
              }

              @Override
              public void onCancelled(@NonNull DatabaseError databaseError) {
              }
          });

      }

      public void saveCsv(JSONArray outerArray) throws IOException, JSONException {
          if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
              if (checkSelfPermission(android.Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
                  ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
              }
          }

          String fileName = referenceNo + " Result";
          String rootPath = Environment.getExternalStorageDirectory().getAbsolutePath() + "/test/";
          File dir = new File(rootPath);
          if (!dir.exists()) {
              dir.mkdir();
          }
          File file = null;
          file = new File(rootPath, fileName);
          if (!file.exists()) {
              progressDialog.dismiss();
              file.createNewFile();
          }
          if (file.exists()) {
              progressDialog.dismiss();
              CSVWriter writer = new CSVWriter(new FileWriter(file), ',');
              for (int i = 0; i < outerArray.length(); i++) {
                  JSONArray innerJsonArray = (JSONArray) outerArray.getJSONArray(i);
                  for (int k = 0; k < innerJsonArray.length(); k++) {
                      String[][] arrayOfArrays = new String[innerJsonArray.length()][];
                      JSONObject innerJsonObject = (JSONObject) innerJsonArray.getJSONObject(k);
                      String[] stringArray1 = new String[innerJsonObject.length()];

                      //stringArray1[0]= (String) innerJsonObject.getString("type");

                      stringArray1[1] = "Questions";
                      stringArray1[2] = "Answers";
                      stringArray1[1] = (String) innerJsonObject.getString("title");
                      stringArray1[2] = "";
                      JSONArray jsonArray = (JSONArray) innerJsonObject.getJSONArray("answer");
                      for (int j = 0; j < jsonArray.length(); j++) {
                          stringArray1[2] += jsonArray.get(j).toString();
                          stringArray1[2] += ",";
                      }

                      arrayOfArrays[k] = stringArray1;
                      writer.writeNext(arrayOfArrays[k]);
                      System.out.println("aa " + Arrays.toString(arrayOfArrays[k]));
                  }
              }

              writer.close();
              Toast.makeText(this, fileName + " is been saved at " + rootPath, Toast.LENGTH_LONG).show();
          }
      }

      public void referenceDialog() {

          final AlertDialog.Builder rateBuilder = new AlertDialog.Builder(this);

          LayoutInflater inflater = this.getLayoutInflater();
          View view = inflater.inflate(R.layout.survey_refno_dialog, null);

          reference = view.findViewById(R.id.edt_survey_ref_no);
          rateOk = view.findViewById(R.id.ref_btnOk);
          TextView rateCancel = view.findViewById(R.id.ref_btnCancel);

          rateBuilder.setView(view);

          rateCancel.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View view) {
                  dialog.dismiss();
              }
          });
          dialog = rateBuilder.create();
          dialog.show();
          Window rateWindow = dialog.getWindow();
          rateWindow.setLayout(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
          dialog.setCancelable(false);
      }

      private void viewDeclaration() {
          newSurveyBtn = findViewById(R.id.new_surveys_button);
          surveyWithRef = findViewById(R.id.get_survey_button);
          surveyResult = findViewById(R.id.analyze_survey);
          linearLayout = findViewById(R.id.hamburg_icon_layout);
          drawerLayout = findViewById(R.id.drawer_layout);
          navigationView = findViewById(R.id.navigation_view);
          View view = navigationView.getHeaderView(0);
          headerEmailView = view.findViewById(R.id.header_email);
          headerLogout = findViewById(R.id.nav_logout);

          firebaseAuth = FirebaseAuth.getInstance();
          if (firebaseAuth.getCurrentUser() != null) {
              String userEmail = firebaseAuth.getCurrentUser().getEmail();
              headerEmailView.setText(userEmail);
          }

          if (firebaseAuth.getCurrentUser() != null && firebaseAuth.getCurrentUser().getUid() != null) {
              loggedInUserId = firebaseAuth.getCurrentUser().getUid();
          }
      }

      @Override
      public boolean onNavigationItemSelected(@NonNull MenuItem menuItem) {
          switch (menuItem.getItemId()) {
              case R.id.menu_share:
                  Intent intent = new Intent(Intent.ACTION_SEND);
                  intent.setType("text/plain");
                  intent.putExtra(Intent.EXTRA_SUBJECT, "DataPro");
                  intent.putExtra(Intent.EXTRA_TEXT, Constants.shareMessage);
                  startActivity(Intent.createChooser(intent, "Share Via"));
                  drawerLayout.closeDrawer(GravityCompat.START);
                  break;
              case R.id.menu_survey_count:
                  startActivity(new Intent(getApplicationContext(), UserAllSurveys.class));
                  drawerLayout.closeDrawer(GravityCompat.START);
                  break;
              case R.id.menu_new_instruments:
                  startActivity(new Intent(getApplicationContext(), CreateInstrument.class));
                  drawerLayout.closeDrawer(GravityCompat.START);
                  break;
              case R.id.menu_about_us:
                  Toast.makeText(getApplicationContext(), "About us", Toast.LENGTH_SHORT).show();
                  drawerLayout.closeDrawer(GravityCompat.START);
                  break;
          }
          return true;
      }

      @Override
      protected void onStart() {
          super.onStart();
          Intent intent = getIntent();
          /* if (intent.hasExtra("work") ) {
              String k = getIntent().getStringExtra("work");
              Toast.makeText(this, k, Toast.LENGTH_SHORT).show();
          } else {
              Toast.makeText(this, "eroor", Toast.LENGTH_SHORT).show();
          } */

          Bundle bundle = getIntent().getExtras();
          if (bundle != null ) {
              String k = bundle.getString("work");
              Toast.makeText(this, k, Toast.LENGTH_SHORT).show();
          } else {
              Toast.makeText(this, "error", Toast.LENGTH_SHORT).show();
          }
      }

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

Answer 1

这样试试

Bundle bundle = getIntent().getExtras();
if (bundle != null ) {
   String k = bundle.getString("work");
   Toast.makeText(this, k, Toast.LENGTH_SHORT).show();
} else {
   Toast.makeText(this, "error" , Toast.LENGTH_SHORT).show();
}