嗨在此代码中Internet连接不检查是否没有互联网意味着我的应用程序崩溃了。在此代码中，如果我提供错误的用户名和密码而不是调用else condition.suppose我给了错误的用户名和密码我就是显示一条消息＆＃34;无效的用户名和密码＆＃34;但那条消息没有显示出来。
任何人都可以帮助我
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public class Login extends Activity {
ImageButton login;
private static final Pattern USERNAME_PATTERN = Pattern
.compile("[a-zA-Z0-9]{1,250}");
private static final Pattern PASSWORD_PATTERN = Pattern
.compile("[a-zA-Z0-9+_.]{4,16}");
EditText usname,pword,ustype;
TextView tv;
Boolean isInternetPresent = false;
String username1,password;
HttpPost httppost;
StringBuffer buffer;
String queryString;
String data="";
int i;
HttpResponse response;
HttpClient httpclient;
CheckBox mCbShowPwd;
String[] username,user_type;
ProgressDialog dialog = null;
ConnectionDetector cd;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.login);
login = (ImageButton)findViewById(R.id.login);
usname = (EditText)findViewById(R.id.username);
pword= (EditText)findViewById(R.id.password);
ustype= (EditText)findViewById(R.id.usertype);
tv = (TextView)findViewById(R.id.tv);
mCbShowPwd = (CheckBox) findViewById(R.id.cbShowPwd);
cd = new ConnectionDetector(getApplicationContext());
mCbShowPwd.setOnCheckedChangeListener(new OnCheckedChangeListener() {
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (!isChecked) {
pword.setTransformationMethod(PasswordTransformationMethod.getInstance());
} else {
pword.setTransformationMethod(HideReturnsTransformationMethod.getInstance());
}
}
});
login.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
new Thread(new Runnable() {
public void run() {
isInternetPresent = cd.isConnectingToInternet();
if (isInternetPresent) {
} else {
showAlertDialog(Login.this, "No Internet Connection",
"You don't have internet connection.", false);
}
}
}).start();
String username1 = usname.getText().toString();
String password = pword.getText().toString();
queryString = "username=" + username1 + "&password="
+ password ;
String user_type1 = DatabaseUtility.executeQueryPhp("usertype",queryString);
System.out.print(user_type1);
try
{
JSONArray JA = new JSONArray(user_type1);
username = new String[JA.length()];
user_type = new String[JA.length()];
for(int i=0;i<JA.length();i++)
{
username[i] = JA.getJSONObject(i).getString("username");
user_type[i] = JA.getJSONObject(i).getString("user_type");
}
}
catch(Exception e)
{
Log.e("Fail 3", e.toString());
e.printStackTrace();
}
if (username1.equals("") || password.equals("")) {
if (username1.equals("")) {
Toast.makeText(Login.this, "ENTER USERNAME",
Toast.LENGTH_LONG).show();
}
if (password.equals("")) {
Toast.makeText(Login.this, "ENTER PASSWORD",
Toast.LENGTH_LONG).show();
}
} else if (!CheckUsername(username1) && !CheckPassword(password)){
Toast.makeText(Login.this, "ENTER VALID USERNAME & PASSWORD",
Toast.LENGTH_LONG).show();
}
else{
final String usertype =user_type[i].toString();
try{
queryString = "username=" + username1 + "&password="
+ password +"&user_type="+usertype;
final String data = DatabaseUtility.executeQueryPhp("login",queryString);
System.out.println("data ::"+data.length());
runOnUiThread(new Runnable() {
public void run() {
}
});
if(data.equalsIgnoreCase("Admin user Found")){
runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(Login.this,"Login Success", Toast.LENGTH_SHORT).show();
}
});
startActivity(new Intent(Login.this, Home.class));
}
else if(data.equalsIgnoreCase("Student User Found")){
runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(Login.this,"Login Success", Toast.LENGTH_SHORT).show();
usname.setText("");
pword.setText("");
}
});
Intent i = new Intent(Login.this, Student_Attendance.class);
i.putExtra("username",username1);
startActivity(i);
}
else if(data.equalsIgnoreCase("Teacher user Found")){
runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(Login.this,"Login Success", Toast.LENGTH_SHORT).show();
}
});
startActivity(new Intent(Login.this, Home.class));
}
else {
tv.setText("InValid UserName and Password");
}
tv.setText("");
}catch(Exception e){
dialog.dismiss();
System.out.println("Exception : " + e.getMessage());
}
}
usname.setText("");
pword.setText("");
}
});
}
private boolean CheckPassword(String password) {
return PASSWORD_PATTERN.matcher(password).matches();
}
private boolean CheckUsername(String username) {
return USERNAME_PATTERN.matcher(username).matches();
}
public void showAlertDialog(Context context, String title, String message, Boolean status) {
AlertDialog alertDialog = new AlertDialog.Builder(context).create();
// Setting Dialog Title
alertDialog.setTitle(title);
// Setting Dialog Message
alertDialog.setMessage(message);
// Setting alert dialog icon
alertDialog.setIcon((status) ? R.drawable.success : R.drawable.fail);
// Setting OK Button
alertDialog.setButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
}
});
// Showing Alert Message
alertDialog.show();
}
}
ConnectionDetector
public ConnectionDetector(Context context){
this._context = context;
}
public boolean isConnectingToInternet(){
ConnectivityManager connectivity = (ConnectivityManager)_context.getSystemService(Context.CONNECTIVITY_SERVICE);
if (connectivity != null)
{
NetworkInfo[] info = connectivity.getAllNetworkInfo();
if (info != null)
for (int i = 0; i < info.length; i++)
if (info[i].getState() == NetworkInfo.State.CONNECTED)
{
return true;
}
}
return false;
}
}
答案 0 :(得分：0)
尝试此操作以检查您的互联网连接
ConnectivityManager connectivityManager
= (ConnectivityManager) getApplicationContext().getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
isInternetPresent = activeNetworkInfo != null && activeNetworkInfo.isConnected();
答案 1 :(得分：0)
试试这个
public class ConnectionDetector {
private Context _context;
public ConnectionDetector(Context context){
this._context = context;
}
public boolean isConnectingToInternet(){
ConnectivityManager connectivity = (ConnectivityManager)
context.getSystemService(Context.CONNECTIVITY_SERVICE);
if (connectivity != null)
{
NetworkInfo[] info = connectivity.getAllNetworkInfo();
if (info != null)
for (int i = 0; i < info.length; i++)
if (info[i].getState() == NetworkInfo.State.CONNECTED)
{
return true;
}
}
return false;
}
}
这里是示例注册活动
public class RegisterActivity extends Activity {
AlertDialogManager alert = new AlertDialogManager();
ConnectionDetector cd;
EditText txtName;
EditText txtEmail;
Button btnRegister;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_register);
cd = new ConnectionDetector(getApplicationContext());
if (!cd.isConnectingToInternet())
{
alert.showAlertDialog(RegisterActivity.this,
"Internet Connection Error",
"Please connect to working Internet connection", false);
return;
}
if (SERVER_URL == null || SENDER_ID == null || SERVER_URL.length() == 0
|| SENDER_ID.length() == 0) {
alert.showAlertDialog(RegisterActivity.this, "Configuration Error!",
"Please set your Server URL and GCM Sender ID", false);
return;
}
txtName = (EditText) findViewById(R.id.txtName);
txtEmail = (EditText) findViewById(R.id.txtEmail);
btnRegister = (Button) findViewById(R.id.btnRegister);
btnRegister.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
String name = txtName.getText().toString();
String email = txtEmail.getText().toString();
if(name.trim().length() > 0 && email.trim().length() > 0){
// Launch Main Activity
Intent i = new Intent(getApplicationContext(), GCMMainActivity.class);
i.putExtra("name", name);
i.putExtra("email", email);
startActivity(i);
finish();
}else{
alert.showAlertDialog(RegisterActivity.this, "Registration Error!",
"Please enter your details", false);
}
}
});
}
}
答案 2 :(得分：0)
//USing This Class You can check InternetConnection
--------------------------------------------------------
public class IntennetConnection {
public static boolean CheckNetConnectivity(Context mContext) {
ConnectivityManager connec = (ConnectivityManager) mContext
.getSystemService(Context.CONNECTIVITY_SERVICE);
if (connec.getNetworkInfo(0).getState() == NetworkInfo.State.CONNECTED
|| connec.getNetworkInfo(1).getState() == NetworkInfo.State.CONNECTED)
return true;
return false;
}
}