提问人：thebitanpaul 提问时间：2/16/2023 最后编辑：thebitanpaul 更新时间：2/16/2023 访问量：16
当互联网关闭并且用户尝试发送邮件时，应用程序崩溃。需要防止崩溃
When internet turns off and user tries to send the mail, app crashes. Need to prevent the crash
问：
我已经在Asynctask中实现了邮件发送功能。当互联网可用并且用户尝试发送邮件时，邮件正在发送。但是，如果互联网关闭并且用户尝试发送邮件，则应用程序会崩溃。如何处理这个问题，使应用程序在任何情况下都不会崩溃？
WebView webView, webView1, webView2;
WebViewClient webViewClient;
EditText uid, concern, rno;
TextView contact, reel, raise, hostel;
ImageView AIML, BD, CC, IOT, CSE;
AsyncTask mytask;
public Session session;
public String username;
public String password;
public String subject;
public String messageToSend;
public String[] blocks = {"D1 ", "D2 ", "D3 ", "D4 ", "D5 "};
public String[] floors = {"1st floor ", "2nd floor ", "3rd floor ", "4th floor ", "5th floor "};
public String itemblock;
public String itemfloor;
AutoCompleteTextView autoCompleteTextViewblock, autoCompleteTextViewfloor;
ArrayAdapter<String> adapterItems;
public static int interval;
public static Timer timer;
public NotesFragment(){
}
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v= inflater.inflate(R.layout.fragment_notes, container, false);
AIML = v.findViewById(R.id.AIML);
BD = v.findViewById(R.id.BD);
CC = v.findViewById(R.id.CC);
IOT = v.findViewById(R.id.IOT);
CSE = v.findViewById(R.id.CSE);
contact = v.findViewById(R.id.contact);
reel = v.findViewById(R.id.reel);
uid = v.findViewById(R.id.uid);
rno = v.findViewById(R.id.roomno);
concern =v.findViewById(R.id.concern);
raise = v.findViewById(R.id.raise);
hostel = v.findViewById(R.id.hostel);
autoCompleteTextViewblock = v.findViewById(R.id.sblock);
autoCompleteTextViewfloor = v.findViewById(R.id.sfloor);
//selecting block
adapterItems = new ArrayAdapter<String>(getActivity(), R.layout.list_item,blocks);
autoCompleteTextViewblock.setAdapter(adapterItems);
autoCompleteTextViewblock.setOnItemClickListener(new AdapterView.OnItemClickListener(){
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
itemblock = adapterView.getItemAtPosition(i).toString();
// Toast.makeText(getActivity(), "Block: "+itemblock, Toast.LENGTH_SHORT).show();
}
});
//
// selecting floors
adapterItems = new ArrayAdapter<String>(getActivity(), R.layout.list_item,floors);
autoCompleteTextViewfloor.setAdapter(adapterItems);
autoCompleteTextViewfloor.setOnItemClickListener(new AdapterView.OnItemClickListener(){
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
itemfloor = adapterView.getItemAtPosition(i).toString();
// Toast.makeText(getActivity(), "Floor: "+itemfloor, Toast.LENGTH_SHORT).show();
}
});
//
//open cuims
contact.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
goLink("https://uims.cuchd.in/uims/");
}
});
//hosetel
hostel.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
startActivity(new Intent(getActivity(), hostel.class));
getActivity().finish();
}
});
//issue raiser
raise.setEnabled(isNetworkAvailable());
if(isNetworkAvailable()){
raise.setEnabled(true);
// raise.setText("Raise Issue");
}
else{
raise.setEnabled(false);
raise.getBackground().setColorFilter(Color.GRAY, PorterDuff.Mode.MULTIPLY);
raise.setTextColor(Color.BLACK);
raise.setText("Check Connection");
raise.setTextSize(18);
}
raise.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
username = "my_email";
password = "my_password";
String messageToSendone = itemblock;
String messageToSendtwo = itemfloor;
String messageToSendthree = rno.getText().toString();
String messageToSendfour = concern.getText().toString();
StringBuilder all = new StringBuilder();
all.append(messageToSendone);
all.append(messageToSendtwo);
all.append(messageToSendthree+" is facing issue of: ");
all.append(messageToSendfour);
messageToSend = all.toString();
subject = uid.getText().toString();
if (TextUtils.isEmpty(subject)){
uid.setError("Please enter your registered CU mail ID!");
return;
}
// if (!subject.contains("@cuchd.in") && !subject.contains("@cumail.in")
// && !subject.contains("@CUCHD.IN") && !subject.contains("@CUMAIL.IN")){
// uid.setError("Please enter correct CU mail ID!");
// return;
// }
if (TextUtils.isEmpty(messageToSendone)){
autoCompleteTextViewblock.setError("Please select the block no.");
return;
}
if (TextUtils.isEmpty(messageToSendtwo)){
autoCompleteTextViewfloor.setError("Please select the floor!");
return;
}
if (TextUtils.isEmpty(messageToSendthree)){
rno.setError("Please enter your room no.!");
return;
}
if (messageToSendthree.length() < 3) {
rno.setError("Please enter valid room no.!");
return;
}
if (messageToSendthree.length() > 4) {
rno.setError("Please enter valid room no.!");
return;
}
if (TextUtils.isEmpty(messageToSendfour)){
concern.setError("Please enter your issue!");
return;
}
//Caling the Asynctask class to execute and send mail
mytask = new Mytask().execute();
}
});
//stay nerd card
webView = v.findViewById(R.id.wb);
webView.loadUrl("https://sites.google.com/d/1r16RJHz0_2FwcYyP5V0pnrr_3pombkrA/p/1T5T_7ckEO9cSJK2TnV41PNBJXQlHzp3x/edit");
webView.setBackgroundColor(0);
webView.setWebViewClient(new WebViewClient(){
@Override
public boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request) {
return false;
}
});
//INTERNET ERROR MSG
webView.setWebViewClient(new WebViewClient() {
@Override
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
view.loadUrl("file:///android_asset/nerd.html");
}
});
WebSettings webSettings = webView.getSettings();
webSettings.setJavaScriptEnabled(true);
webView.getSettings().setPluginState(WebSettings.PluginState.ON);
webView.getSettings().setAllowFileAccess(true);
//shottbyparth
webView2 = v.findViewById(R.id.wb2);
webView2.loadUrl("https://sites.google.com/view/shottbyparth");
webView2.setBackgroundColor(0);
//keep in app
webView2.setWebViewClient(new WebViewClient(){
@Override
public boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request) {
return true;
}
});
//INTERNET ERROR MSG
webView2.setWebViewClient(new WebViewClient() {
@Override
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
view.loadUrl("file:///android_asset/partherror.html");
}
});
WebSettings webSettings2 = webView2.getSettings();
webSettings2.setJavaScriptEnabled(true);
webView2.getSettings().setPluginState(WebSettings.PluginState.ON);
webView2.getSettings().setAllowFileAccess(true);
//magic happens compiler
webView1 = v.findViewById(R.id.wb1);
webView1.loadUrl("https://www.tutorialspoint.com/online_cpp_compiler.php");
webView1.setBackgroundColor(0);
//keep in app
webView1.setWebViewClient(new WebViewClient(){
@Override
public boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request) {
return false;
}
});
//back button
webView1.setOnKeyListener(new View.OnKeyListener() {
@Override
public boolean onKey(View view, int keyCode, KeyEvent keyEvent) {
if(keyEvent.getAction() == keyEvent.ACTION_DOWN){
if(keyCode == KeyEvent.KEYCODE_BACK){
if(webView1 != null){
if(webView1.canGoBack()){
webView1.goBack();
}else {
getActivity().onBackPressed();
}
}
}
}
return true;
}
});
webView1.setWebViewClient(new WebViewClient() {
@Override
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
view.loadUrl("file:///android_asset/compiler.html");
}
});
//hiding web element with error message
webView1.setWebChromeClient(new WebChromeClient(){
@Override
public void onProgressChanged(WebView view, int newProgress) {
view.loadUrl("javascript:(function() { " +
"document.getElementById('north').style.display='none';})()");
}
});
WebSettings webSettings1 = webView1.getSettings();
webSettings1.setJavaScriptEnabled(true);
webView1.setVerticalScrollBarEnabled(true);
webView1.setHorizontalScrollBarEnabled(true);
webView1.setScrollbarFadingEnabled(false);
webView1.setScrollBarStyle(WebView.SCROLLBARS_OUTSIDE_OVERLAY);
// webView1.requestFocus();
//reel
reel.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
goLink("https://sites.google.com/view/shottbyparth");
}
});
//notes
AIML.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
goLink("https://drive.google.com/drive/folders/1bolCGvvV9dKUFH8Uooe3DQGsP4gL1Vwu?usp=share_link");
}
});
BD.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Toast.makeText(getActivity(), "Content coming soon...", Toast.LENGTH_SHORT).show();
}
});
CC.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Toast.makeText(getActivity(), "Content coming soon...", Toast.LENGTH_SHORT).show();
}
});
IOT.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Toast.makeText(getActivity(), "Content coming soon...", Toast.LENGTH_SHORT).show();
}
});
CSE.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Toast.makeText(getActivity(), "Content coming soon...", Toast.LENGTH_SHORT).show();
}
});
contact.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
goLink("https://uims.cuchd.in/uims/");
}
});
return v;
}
//asynctask class
public class Mytask extends AsyncTask<Void, Void, Exception>
{
ProgressDialog dialogue;
@Override
protected void onPreExecute() {
super.onPreExecute();
dialogue = new ProgressDialog(getActivity());
dialogue.setTitle("Processing");
dialogue.setMessage("Calm down, your issue is being raised...");
dialogue.setIndeterminate(true);
dialogue.setCancelable(false);
dialogue.show();
}
@Override
protected Exception doInBackground(Void... params) {
ConnectivityManager connectivityManager = (ConnectivityManager) getActivity().getSystemService(Context.CONNECTIVITY_SERVICE);
Properties properties = new Properties();
properties.put("mail.smtp.auth", "true");
properties.put("mail.smtp.starttls.enable", "true");
properties.put("mail.smtp.host", "smtp.gmail.com");
properties.put("mail.smtp.port", "587");
properties.put("mail.smtp.socketFactory.port", "587");
properties.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
session = Session.getInstance(properties,
new javax.mail.Authenticator() {
@Override
protected PasswordAuthentication getPasswordAuthentication() {
return new PasswordAuthentication(username, password);
}
});
try {
NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
Message message = new MimeMessage(session);
message.setFrom(new InternetAddress(username));
message.setRecipients(Message.RecipientType.TO,
InternetAddress.parse("[email protected]"));
message.setSubject(subject);
message.setText(messageToSend);
Transport.send(message);;
} catch (MessagingException e) {
Log.e("EmailSendingError", e.getMessage());
throw new RuntimeException(e);
}
// StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
// StrictMode.setThreadPolicy(policy);
return null;
}
@Override
protected void onPostExecute(Exception e) {
// if (e != null) {
//
// Toast.makeText(getActivity(), "Error: " + e, Toast.LENGTH_LONG).show();
// } else {
// }
if (e == null) {
if(dialogue.isShowing()){
dialogue.dismiss();
}
rno.getText().clear();
concern.getText().clear();
uid.getText().clear();
autoCompleteTextViewblock.getText().clear();
autoCompleteTextViewfloor.getText().clear();
Toast.makeText(getActivity(), "Concern Raised Successfully", Toast.LENGTH_LONG).show();
} else {
// Handle failure...
Toast.makeText(getActivity(), "Error: " + e.getMessage(), Toast.LENGTH_LONG).show();
}
}
}
private boolean isNetworkAvailable() {
ConnectivityManager connectivityManager
= (ConnectivityManager) getActivity().getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
return activeNetworkInfo != null && activeNetworkInfo.isConnected();
}
private void goLink(String s) {
Uri uri = Uri.parse(s);
startActivity(new Intent(Intent.ACTION_VIEW, uri));
}
}```
I tried to check the internet before sending the mail, but it is not handling the problem when internet turns suddenly off while sending the mail. So I need the solution for this problem!
答： 暂无答案
评论