java - ArrayList仅存储最后读取的值

Question

我正在尝试从我的 Android 手机读取联系人信息并对其进行修改并将其写回到数据库中。 到目前为止，该项目共有三个类:

• MainActivity.java。这是我读取数据库、填充我创建的联系人对象并将它们放入列表中的地方。

  public class MainActivity extends Activity {
  private ArrayAdapter<String> adapter;
  
  // Store contacts values in these arraylist.
  // I t is not really needed for this implementation but I keep this just in case
  
  public static ArrayList<String> phoneValueArr = new ArrayList<>();
  public static ArrayList<String> nameValueArr = new ArrayList<>();
  
  // Store the values of names and associated phone numbers.
  public  ContactData contactsData= new ContactData(); 
  
  // List to store the contacts
  public  ContactsDataList contactsList= new ContactsDataList();
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  
  adapter = new ArrayAdapter<>
  (this, android.R.layout.simple_dropdown_item_1line, new ArrayList<String>());
  readContactsData();
  
  //Display the number of contacts
  Toast.makeText(getApplicationContext(),
          "read " + phoneValueArr.size() + " contacts. "  , Toast.LENGTH_LONG).show();
  
  
  pressButton();
  
      for(ContactData c:contactsList.getContacts()){
          Toast.makeText(getApplicationContext(),
                  c.getContact_name() + "Hopes   on God "  ,    Toast.LENGTH_LONG).show();
  
      }
  
  }
  }
  
  public  void readContactsData() {
  
  try {
  
      // Reading Contacts Name And Number
  
      String phoneNumber = "";
      ContentResolver cr = getBaseContext().getContentResolver();
  
      // Query to get contact name
  
      Cursor cur = cr.query(ContactsContract.Contacts.CONTENT_URI, null,
              null, null, null);
  
      // If data data found in contacts
      if (cur.getCount() > 0) {
  
       Log.i("AutocompleteContacts", "Reading   contacts........");
  
       int k = 0;
       String name = "";
  
       //Until there are no more contacts stored
        while (cur.moveToNext()) {
  
        String id = cur.getString(cur
        .getColumnIndex(ContactsContract.Contacts._ID));
        name = cur
        .getString(cur.getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME));
  
              // Check contact have phone number
              if (Integer
                      .parseInt(cur.getString(cur
                              .getColumnIndex(ContactsContract.Contacts.HAS_PHONE_NUMBER))) > 0) {
  
                  // Create query to get phone number by contact id
                  Cursor pCur = cr
                  .query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
                  null,
                  ContactsContract.CommonDataKinds.Phone.CONTACT_ID
                  + " = ?", new String[] { id },
                  null);
                  int j = 0;
  
                  //Until query is stopped
                  while (pCur.moveToNext()) {
                      // Sometimes get multiple data
                      if (j == 0) {
                          // Get Phone number
                          phoneNumber = ""
                                  + pCur.getString(pCur
                                          .getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
  
                          // Add contacts names to adapter
                          adapter.add(name);
  
                          // Add ArrayList names to adapter
                          phoneValueArr.add(phoneNumber.toString());
                          nameValueArr.add(name.toString());
  
                          // Set contact name and phone number
                          // i.e parse the SQLlite query to set the POJO's
                          contactsData.setPhone_number(phoneNumber.toString());
                          contactsData.setContact_name(name.toString());
  
  
                          // Add Contacts to list
                          contactsList.addContact(contactsData);
  
  
                        j++;
                          k++;
                      }
  
                  } // End while loop
  
                  pCur.close();
              } // End if
  
          }// End while loop
  
      } // End Cursor value check
      cur.close();
  
  } catch (Exception e) {
      Log.i("AutocompleteContacts", "Exception : " + e);
  }
  }
  

• ContactData 类，我在其中创建实例化对象的类。

  public class ContactData {
  
  public String contact_name;
  public String phone_number;
  
  public ContactData(){
  
  }
  
  public  ContactData(String contact_name, String phone_number) {
  
  this.contact_name=contact_name;
  this.phone_number=phone_number;
  }
  
  
  
  public String getContact_name() {
  return contact_name;
  }
  
  public void setContact_name(String contact_name) {
  this.contact_name = contact_name;
  }
  public String getPhone_number() {
  return phone_number;
  }
  public void setPhone_number(String phone_number) {
  this.phone_number = phone_number;
  }
  
   public String toString() {
      return contact_name + ", " + phone_number;
  }
  
  
  public boolean equals(Object obj) {
  if (obj instanceof ContactData) {
      ContactData contact = (ContactData) obj;
      return (contact_name.equals(contact.getContact_name()) && phone_number
              .equals(contact.getPhone_number()));
  }
  
  return false;
  }
  
  
  public int hashCode() {
      return (contact_name.length() + phone_number.length());
  }
   class ContactNameComparator implements Comparator<ContactData> {
      public int compare(ContactData contact1, ContactData contact2) {
          return   contact1.getContact_name().compareToIgnoreCase(contact2.getContact_name());
      }
   }
   }
  

• ContactsDataList 获取对象并存储它们。

   public class ContactsDataList  {
  
  
  
   public List<ContactData> contactList;
  
  public ContactsDataList() {
  
  this(new ArrayList<ContactData>());
  }
  
  public ContactsDataList(List<ContactData> contactList) {
  this.contactList = contactList;
  }
  
  public void addContact(ContactData contact) {
  if (contactList != null) {
          contactList.add(contact);
      }
  }
  
  public List<ContactData> getContacts() {
  return contactList;
  }
  
  public void setContacts(List<ContactData> contacts) {
  this.contactList = contacts;
  }
  
  
  }
  

列表中的联系人对象都是相同的，我看不出哪里出了问题，因为数组列表phoneValuerArr 和 nameValueArr 都具有正确的数据。

ContactsDataList，contactList，仅包含最后读取的联系人。

有人可以帮忙吗？

Answer 1

您在 while 循环的每次迭代中重用 ContactData 的相同实例，但只是更新其属性。您需要为每次迭代创建一个单独的实例

while (pCur.moveToNext()) {
    ...
    ContactData contactsData = new ContactData();
    contactsData.setPhoneNumber(...);
    ...
}