在这里，我从移动设备上获取姓名，电子邮件，电话号码并尝试上传到服务器。如果联系人包含姓名，电子邮件和电话号码，则值将成功插入..但如果有任何字段是空的它正在抛出NULL指针异常。如何避免这一个..我的意思是如果联系人不包含电子邮件，它应该至少发送姓名和电话号码。
这是我的代码。
public class DisplayContact1 extends Activity {
private static String TAG = WorkDetails1.class.getSimpleName();
Button select;
private String vault;
List<AddressBookContact> list;
public static final String kvault = "vault_no";
public static final String kname = "name";
public static final String kphone = "phone";
public static final String kemail = "email";
public static final String kcontacts = "contacts";
public static final String SHARED_PREF_NAME = "myloginapp";
public static final String UPLOAD_URL = "http://oursite.com/contacts_1.php";
private static final int MY_PERMISSIONS_REQUEST_READ_CONTACTS = 1;
Cursor cursor;
LongSparseArray<AddressBookContact> array;
long start;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//getActionBar().setDisplayShowTitleEnabled(false);
setContentView(R.layout.display);
SharedPreferences sharedPreferences = getSharedPreferences(ProfileLogin.SHARED_PREF_NAME, MODE_PRIVATE);
vault = sharedPreferences.getString(ProfileLogin.EMAIL_SHARED_PREF,"Not Available");
getAllContacts(this.getContentResolver());
}
public void getAllContacts(ContentResolver cr) {
int result = ContextCompat.checkSelfPermission(DisplayContact1.this, Manifest.permission.READ_CONTACTS);
if (result == PackageManager.PERMISSION_GRANTED){
//fetches contacts from the phone contact list and displays in ascending order
list = new LinkedList<AddressBookContact>();
array = new LongSparseArray<AddressBookContact>();
start = System.currentTimeMillis();
String[] projection = {
ContactsContract.Data.MIMETYPE,
ContactsContract.Data.CONTACT_ID,
ContactsContract.Contacts.DISPLAY_NAME,
ContactsContract.CommonDataKinds.Contactables.DATA,
ContactsContract.CommonDataKinds.Contactables.TYPE,
};
String selection = ContactsContract.Data.MIMETYPE + " in (?, ?)";
String[] selectionArgs = {
ContactsContract.CommonDataKinds.Email.CONTENT_ITEM_TYPE,
ContactsContract.CommonDataKinds.Phone.CONTENT_ITEM_TYPE,
};
String sortOrder = ContactsContract.Contacts.SORT_KEY_ALTERNATIVE;
Uri uri = ContactsContract.Data.CONTENT_URI;
// we could also use Uri uri = ContactsContract.Data.CONTENT_URI;
cursor = getContentResolver().query(uri, projection, selection, selectionArgs, sortOrder);
contactsdisplay();
} else {
requestForLocationPermission();
}
}
private void requestForLocationPermission()
{
if (ActivityCompat.shouldShowRequestPermissionRationale(DisplayContact1.this, Manifest.permission.READ_CONTACTS))
{
}
else {
ActivityCompat.requestPermissions(DisplayContact1.this, new String[]{Manifest.permission.READ_CONTACTS}, MY_PERMISSIONS_REQUEST_READ_CONTACTS);
}
}
@Override
public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults)
{
switch (requestCode) {
case MY_PERMISSIONS_REQUEST_READ_CONTACTS:
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED)
{
getAllContacts(DisplayContact1.this.getContentResolver());
contactsdisplay();
}
break;
}
}
public void contactsdisplay() {
//Cursor phones = cr.query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null,null,null, null);
final int mimeTypeIdx = cursor.getColumnIndex(ContactsContract.Data.MIMETYPE);
final int idIdx = cursor.getColumnIndex(ContactsContract.Data.CONTACT_ID);
final int nameIdx = cursor.getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME);
final int dataIdx = cursor.getColumnIndex(ContactsContract.CommonDataKinds.Contactables.DATA);
final int typeIdx = cursor.getColumnIndex(ContactsContract.CommonDataKinds.Contactables.TYPE);
while (cursor.moveToNext()) {
long id = cursor.getLong(idIdx);
AddressBookContact addressBookContact = array.get(id);
if (addressBookContact == null) {
addressBookContact = new AddressBookContact(id, cursor.getString(nameIdx), getResources());
array.put(id, addressBookContact);
list.add(addressBookContact);
}
int type = cursor.getInt(typeIdx);
String data = cursor.getString(dataIdx);
String mimeType = cursor.getString(mimeTypeIdx);
if (mimeType.equals(ContactsContract.CommonDataKinds.Email.CONTENT_ITEM_TYPE)) {
// mimeType == ContactsContract.CommonDataKinds.Email.CONTENT_ITEM_TYPE
addressBookContact.addEmail(type, data);
} else {
// mimeType == ContactsContract.CommonDataKinds.Phone.CONTENT_ITEM_TYPE
addressBookContact.addPhone(type, data);
}
}
long ms = System.currentTimeMillis() - start;
cursor.close();
// done!!! show the results...
int i = 1;
for (AddressBookContact addressBookContact : list) {
Log.d(TAG, "AddressBookContact #" + i++ + ": " + addressBookContact.toString(true));
}
final String cOn = "<b><font color='#ff9900'>";
final String cOff = "</font></b>";
Spanned l1 = Html.fromHtml("got " + cOn + array.size() + cOff + " contacts<br/>");
Spanned l2 = Html.fromHtml("query took " + cOn + ms / 1000f + cOff + " s (" + cOn + ms + cOff + " ms)");
Log.d(TAG, "\n\n╔══════ query execution stats ═══════" );
Log.d(TAG, "║ " + l1);
Log.d(TAG, "║ " + l2);
Log.d(TAG, "╚════════════════════════════════════" );
SpannableStringBuilder msg = new SpannableStringBuilder().append(l1).append(l2);
ListView lv= (ListView) findViewById(R.id.lv);
lv.setAdapter(new ArrayAdapter<AddressBookContact>(this, android.R.layout.simple_list_item_1, list));
lv.setItemsCanFocus(false);
lv.setTextFilterEnabled(true);
select = (Button) findViewById(R.id.button1);
select.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View v){
uploadImage();
}
});
}
public void uploadImage(){
SharedPreferences sharedPreferences = getSharedPreferences(DisplayContact.SHARED_PREF_NAME, MODE_PRIVATE);
final String vault_no = vault;
class UploadImage extends AsyncTask<Void,Void,String> {
ProgressDialog loading;
@Override
protected void onPreExecute() {
super.onPreExecute();
loading = ProgressDialog.show(DisplayContact1.this,"Please wait...","uploading",false,false);
}
@Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
loading.dismiss();
if(s.equalsIgnoreCase("Successfully Saved")){
//Intent intent = new Intent(CollegeDetails.this,Work.class);
Toast.makeText(DisplayContact1.this, s, Toast.LENGTH_SHORT).show();
// startActivity(intent);
}else{
Toast.makeText(DisplayContact1.this,s,Toast.LENGTH_SHORT).show();
}
}
@Override
protected String doInBackground(Void... params) {
RequestHandler rh = new RequestHandler();
//RegisterUserClass rh = new RegisterUserClass();
HashMap<String,String> param = new HashMap<String,String>();
JSONArray contacts = new JSONArray();
int i = 1;
for (AddressBookContact addressBookContact : list) {
try {
Log.d(TAG, "AddressBookContact #" + i++ + ": " + addressBookContact.toString(true));
JSONObject contact = new JSONObject();
contact.put(kname, addressBookContact.name.toString());
contact.put(kvault, vault_no);
contact.put(kphone, addressBookContact.phone.toString());
if(addressBookContact.email.toString()!=null)
contact.put(kemail, addressBookContact.email.toString());
contacts.put(contact);
}
catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
param.put(kcontacts, contacts.toString());
System.out.println("param value.." + i++ +":"+ contacts.toString());
}
return rh.sendPostRequest(UPLOAD_URL, param);
}
}
UploadImage u = new UploadImage();
u.execute();
}
}
这里是 AddressBookContact.class
public class AddressBookContact {
private long id;
private Resources res;
String name;
LongSparseArray<String> email;
LongSparseArray<String> phone;
AddressBookContact(long id, String name, Resources res) {
this.id = id;
this.name = name;
this.res = res;
}
@Override
public String toString() {
return toString(false);
}
public String toString(boolean rich) {
SpannableStringBuilder builder = new SpannableStringBuilder();
if (rich) {
builder.append("id: ").append(Long.toString(id))
.append(", name: ").append(name);
} else {
builder.append("name: ").append(name);
}
if (phone != null) {
builder.append("\nphone: ");
for (int i = 0; i < phone.size(); i++) {
int type = (int) phone.keyAt(i);
builder.append(phone.valueAt(i));
if (i + 1 < phone.size()) {
builder.append(", ");
}
}
}
if (email != null) {
builder.append("\nemail: ");
for (int i = 0; i < email.size(); i++) {
int type = (int) email.keyAt(i);
builder.append(email.valueAt(i));
if (i + 1 < email.size()) {
builder.append(", ");
}
}
}
return builder.toString();
}
public void addEmail(int type, String address) {
if (email == null) {
email = new LongSparseArray<String>();
}
email.put(type, address);
}
public void addPhone(int type, String number) {
if (phone == null) {
phone = new LongSparseArray<String>();
}
phone.put(type, number);
}
}
如果电子邮件字段为空，我在此行收到空指针异常。
contact.put(kemail, addressBookContact.email.toString()); ..所以我添加了if循环来检查空状态..但是我也得到了异常。
答案 0 :(得分：1)
添加两个条件，如下所示，您的字符串可能不是null，但可以 空
""
if(addressBookContact.email.toString() != null && !addressBookContact.email.toString().equalsIgnoreCase(""))
contact.put(kemail, addressBookContact.email.toString());
答案 1 :(得分：1)
使用TextUtils。
if(!TextUtils.isEmpty(addressBookContact.email.toString())){
contact.put(kemail, addressBookContact.email.toString());
}
如果kemail是必填字段，那么在else条件下只需传递""空值。
答案 2 :(得分：1)
下面
if (addressBookContact.email.toString() != null)
您尝试从'email'变量获取String，该变量为null。 正确的比较是：
if (addressBookContact.email != null)