if (ContextCompat.checkSelfPermission(getApplicationContext(), Manifest.permission.READ_CONTACTS) != PackageManager.PERMISSION_GRANTED) {
    ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_CONTACTS}, REQUEST_CODE);
}

private void fetchAllContacts() {
    if (ContextCompat.checkSelfPermission(getApplicationContext(), Manifest.permission.READ_CONTACTS) != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_CONTACTS}, REQUEST_CODE);
    }
    ContentResolver resolver = getContentResolver();
    Uri uri = ContactsContract.CommonDataKinds.Phone.CONTENT_URI;
    Cursor cursor = resolver.query(uri, null, null, null, null);
    assert cursor != null;
    while (cursor.moveToNext()) {
        String cName = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
        String cNum = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
        Log.i("Contact", "姓名:" + cName);
        Log.i("Contact", "号码:" + cNum);
        Log.i("Contact", "======================");
    }
    cursor.close();
}

private void queryContact(String number){
    Uri uri = Uri.parse("content://com.android.contacts/data/phones/filter/" + number);
    ContentResolver resolver = getContentResolver();
    Cursor cursor = resolver.query(uri, new String[]{"display_name"}, null, null, null);
    assert cursor != null;
    if (cursor.moveToFirst()) {
        String name = cursor.getString(0);
        Log.i("Contact", number + "对应的联系人名称：" + name);
    }
    cursor.close();
}

if (ContextCompat.checkSelfPermission(getApplicationContext(), Manifest.permission.READ_CONTACTS) != PackageManager.PERMISSION_GRANTED) {
    ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_CONTACTS}, REQUEST_CODE);
    ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_PROFILE}, REQUEST_CODE);
}