Android 获取联系人的游标返回null

在我的应用程序中，我想从电话簿中获取所有联系人。我编写的代码总是给我空的

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代码

//在后台获取联系人

static class GetContacts extends AsyncTask<Void, Void, List<ContactsModel>> {
    private Context context;
    private ContentResolver contactResolver;
    private ContactsModel contactsModel;
    private List<String> listPhones = Collections.emptyList();
    private List<String> listEmails = Collections.emptyList();
    private List<ContactsModel> listContacts = Collections.emptyList();
    private String phone;
    private String email;
    private String id;
    private Cursor phoneCursor;
    private Cursor emailCursor;

    public GetContacts(Context context) {
        this.context = context;

    }

    @Override
    protected List<ContactsModel> doInBackground(Void... params) {

        contactResolver = context.getContentResolver();
        Cursor cur = contactResolver.query(ContactsContract.Contacts.CONTENT_URI,
                null, null, null, null);
        if (cur.getCount() > 0) {
            while (cur.moveToNext()) {
                contactsModel = new ContactsModel();

                id = cur.getString(cur.getColumnIndex(ContactsContract.Contacts._ID));
                contactsModel.name = cur.getString(cur.getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME));

                if (Integer.parseInt(cur.getString(cur.getColumnIndex(ContactsContract.Contacts.HAS_PHONE_NUMBER))) > 0) {

                    phoneCursor = contactResolver.query(
                            ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
                            null,
                            ContactsContract.CommonDataKinds.Phone.CONTACT_ID + " = ?",
                            new String[]{id}, null);

                    while (phoneCursor.moveToNext()) {
                        // Do something with phones
                        int phoneType = phoneCursor.getInt(phoneCursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.TYPE));
                        String phoneNo = phoneCursor.getString(phoneCursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
                        //you will get all phone numbers according to it's type as below switch case.
                        switch (phoneType) {
                            case ContactsContract.CommonDataKinds.Phone.TYPE_MOBILE:
                                phone = phoneNo;
                                break;
                            case ContactsContract.CommonDataKinds.Phone.TYPE_HOME:
                                phone = phoneNo;
                                break;
                            case ContactsContract.CommonDataKinds.Phone.TYPE_WORK:
                                phone = phoneNo;
                                break;
                            case ContactsContract.CommonDataKinds.Phone.TYPE_WORK_MOBILE:
                                phone = phoneNo;
                                break;
                            case ContactsContract.CommonDataKinds.Phone.TYPE_OTHER:
                                phone = phoneNo;
                                break;
                            default:
                                break;
                        }

                        listPhones.add(phone);
                    }


                    emailCursor = contactResolver.query(ContactsContract.CommonDataKinds.Email.CONTENT_URI,
                            null,
                            ContactsContract.CommonDataKinds.Email.CONTACT_ID + " = ?", new String[]{id}, null);

                    while (emailCursor.moveToNext()) {
                        //String emai = emailCursor.getString(emailCursor.getColumnIndex(ContactsContract.CommonDataKinds.Email.DATA));
                        int type = emailCursor.getInt(emailCursor.getColumnIndex(ContactsContract.CommonDataKinds.Email.TYPE));
                        String s = (String) ContactsContract.CommonDataKinds.Email.getTypeLabel(context.getResources(), type, "");
                        listEmails.add(emailCursor.getString(emailCursor.getColumnIndex(ContactsContract.CommonDataKinds.Email.DATA)));

                    }

                    listContacts.add(contactsModel);
                    emailCursor.close();
                    phoneCursor.close();


                }


            }


        }

        cur.close();


        return listContacts;
    }

    @Override
    protected void onPostExecute(List<ContactsModel> contactsModels) {


    }
}

我的通讯录中有1000多个联系人

P.S - I also have requested permission to read contact in manifest

---

在我看到的代码中，on

onPostExecute

方法是空的。我认为在这个方法中，必须设置已经填充的

列表

@Override
    protected void onPostExecute(List<ContactsModel> contactsModels) {
       listContacts = contactsModels;
    }

@覆盖
PostExecute上受保护的void（列出联系人模型）{
listContacts=contactsModels；
}

---

因为您在

doInBackground

中从手机中检索数据，但您在哪里传递数据？希望对大家有所帮助

您需要在查询时向内容提供商提供投影

String[] mProjection =
{
    UserDictionary.Words._ID,    // Contract class constant for the _ID column name
    UserDictionary.Words.WORD,   // Contract class constant for the word column name
    UserDictionary.Words.LOCALE  // Contract class constant for the locale column name
};


contactResolver = context.getContentResolver();
        Cursor cur = contactResolver.query(ContactsContract.Contacts.CONTENT_URI,
                mProjection, null, null, null);

以上只是查询内容提供者时的投影示例

String[] mProjection =
{
    UserDictionary.Words._ID,    // Contract class constant for the _ID column name
    UserDictionary.Words.WORD,   // Contract class constant for the word column name
    UserDictionary.Words.LOCALE  // Contract class constant for the locale column name
};


contactResolver = context.getContentResolver();
        Cursor cur = contactResolver.query(ContactsContract.Contacts.CONTENT_URI,
                mProjection, null, null, null);

你可以参考这个链接，

---

但是我没有收到任何联系。我没有很好地与你解除联系。对不起。。你的返回列表在你的工作背景的末尾联系，但是这个列表不是一个符号，我认为错误来自它，但是我可能是错的。。在你的doInBackground方法中，如果你记录你的列表，它是空的吗？在doInBackground中，如果我运行调试器，它不会进入内部，如果（cur.getCount>0）你尝试过log吗？是的，仍然是相同的东西，映射要返回的列的列表。传递null将返回所有列，这是低效的。