I have one button in mainactivity when i click on button formactivty opened then after saved the data and i killed the app it display from main activity, it doesn't show welcome activity by using shared preference. any one can solve this one
Main Activity
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void open(View v) {
Intent i = new Intent(MainActivity.this,Form.class);
startActivity(i);
}
}
FormActivty
public class Form extends Activity {
SharedPreferences sp;
public static String Filename= "LoginFile";
public static String key = "status";
EditText namee,emaill;
String Name,Email;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
sp = getSharedPreferences(Filename,MODE_PRIVATE);
boolean res = sp.getBoolean(key,false);
if (res) {
setContentView(R.layout.welcom);
} else {
setContentView(R.layout.form);
}
}
public void save(View v) {
namee = (EditText)findViewById(R.id.name);
emaill = (EditText)findViewById(R.id.email);
Name = namee.getText().toString();
Email = emaill.getText().toString();
SharedPreferences.Editor ed = sp.edit();
ed.putBoolean(key,true);
ed.putString("k1",Name);
ed.putString("k2",Email);
ed.commit();
Intent i = new Intent(this,Welcome.class);
startActivity(i);
}
}
Welcome Activity
public class Welcome extends Activity {
SharedPreferences sp;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.welcom);
sp = getSharedPreferences(Form.Filename,MODE_PRIVATE);
TextView tv= (TextView)findViewById(R.id.text);
TextView tv1= (TextView)findViewById(R.id.text1);
String username,email;
Intent i = getIntent();
Bundle b = new Bundle();
b= i.getExtras();
username = sp.getString("k1","");
email = sp.getString("k2","");
tv.setText(username);
tv1.setText(email);
}
public void logout(View v) {
SharedPreferences.Editor ed = sp.edit();
ed.putBoolean(Form.key,false);
ed.commit();
Intent i = new Intent(this,MainActivity.class);
startActivity(i);
}
}
On your MainActivity, under onCreate(), there should be a code that checks if your SharedPreference is empty. If it's empty, it should go to Form.class or it should not do anything since you have a button there in MainActivity. If not, then go to Welcome.class. You're almost there, just do some minor tweaks on your code and you'll get it.
public class MainActivity extends AppCompatActivity {
SharedPreferences sp;
public static String Filename= "LoginFile";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
sp = getSharedPreferences(Filename,MODE_PRIVATE);
String name = sp.getString("k1", "");
if(!name.isEmpty()){
Intent intent = new Intent(MainActivity.this, Welcome.class);
startActivity(intent);
}
}
public void open(View v) {
Intent i = new Intent(MainActivity.this,Form.class);
startActivity(i);
}
}
If you'll notice on this code, every time the app is killed and you start it again, it'll check if sharedpreference is empty. If not, it will go directly to Welcome.class.
Related
I am tryting to simply check to load the correct starting activity i do:
public class MainActivity extends AppCompatActivity {
public static final String TAG = "MainActivity";
public SharedPreferences sharedPreferences = MyApplication.getAppContext().getSharedPreferences("sharedPrefs", MODE_PRIVATE);
public SharedPreferences.Editor editor = sharedPreferences.edit();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
boolean onBoardingComplete = sharedPreferences.getBoolean("firstRun", true);
if(onBoardingComplete){
Intent navIntent = new Intent(this, NavigationStartActivity.class);
startActivity(navIntent);
}else{
Intent onBoardIntent = new Intent(this, OnBoardingActivity.class);
startActivity(onBoardIntent);
}
}
I get a null pointer exception on the initialisation of sharedPreferences effectively line 5 here. My sharedPrefs file exists in the storage data/data/com.myap/shared_prefs/sharedPrefs.xml
I have no idea why this would return null.
move it inside onCreate because outside context is null
public class MainActivity extends AppCompatActivity {
public static final String TAG = "MainActivity";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
SharedPreferences sharedPreferences = getSharedPreferences("sharedPrefs", MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPreferences.edit();
boolean onBoardingComplete = sharedPreferences.getBoolean("firstRun", true);
if (onBoardingComplete) {
Intent navIntent = new Intent(this, NavigationStartActivity.class);
startActivity(navIntent);
} else {
Intent onBoardIntent = new Intent(this, OnBoardingActivity.class);
startActivity(onBoardIntent);
}
}
}
I'm making an Android app and in my app, I add the feature of storing the login state.
My Splash screen:
public class Splash extends AppCompatActivity {
private SharedPreferences preferences;
public int a = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_splash);
final ProgressBar progressBar = (ProgressBar) findViewById(R.id.progressbar);
new CountDownTimer(5000, 1000) {
#Override
public void onTick(long millisUntilFinished) {
a = a + 1;
progressBar.setProgress(a);
}
#Override
public void onFinish() {
SharedPreferences preferences = getSharedPreferences("login", MODE_PRIVATE);
String check = preferences.getString("login", "off");
if (check.equals("on")) {
startActivity(new Intent(Splash.this, Menu.class));
} else {
startActivity(new Intent(Splash.this, LoginPage.class));
}
}
}.start();
} }
My Login screen:
public class LoginPage extends AppCompatActivity {
private SharedPreferences preferences;
Context context;
Button login, register, database;
EditText username;
EditText password;
TextView msg;
MyDBManager db;
static final int REGISTRATION_REQUEST = 1; // The request code
#Override
protected void onCreate(final Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.loginpage);
db = new MyDBManager(this);
msg = (TextView) findViewById(R.id.msg);
login = (Button) findViewById(R.id.button);
register = (Button) findViewById(R.id.button2);
database = (Button) findViewById(R.id.button3);
username = (EditText) findViewById(R.id.user);
password = (EditText) findViewById(R.id.pass);
// Click and move to the next activity
login.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
db.open();
Cursor c = db.getUser(username.getText().toString(), password.getText().toString());
if (c.moveToFirst()) {
db.close();
context.startActivity(new Intent(context,Menu.class));
// Intent i=new Intent(getApplicationContext(),Menu.class); //
i.putExtra("Username", username.getText().toString()); //
startActivity(i); // call Login Activity
Store();
}
else
{
db.close();
// set error message when the username and/or password is not valid
msg.setText("Unable to login: wrong username or password!");
// Stay at the current activity.
}
}
private void Store() {
SharedPreferences preferences=context.getSharedPreferences("login",Context.MODE_PRIVATE);
SharedPreferences.Editor editor=preferences.edit();
editor.putString("login_status","on");
editor.commit();
}
});
// Click and move to the next activity
register.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(LoginPage.this, Registration.class);
startActivityForResult(intent, REGISTRATION_REQUEST);
}
});
// Click and move to the next activity
database.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(LoginPage.this, Database.class);
startActivity(intent);
}
});
}
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == REGISTRATION_REQUEST) {
//if(resultCode == Registration.RESULT_OK){
Log.d("Pikatchu", "User successfully registered!");
Bundle res = data.getExtras();
String result = res.getString("result");
System.out.println(result);
msg.setText(result);
}
}
}
My Menu screen:
public class Menu extends AppCompatActivity {
private SharedPreferences preferences;
Button startJourney, displayJourneys;
TextView msg; // where to display the name of the user
Button buttonLogout ;
/* the string is where to store data when we select something */
String db_username;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.menu);
buttonLogout = (Button) findViewById(R.id.btn_logout);
msg = (TextView) findViewById(R.id.msg);
startJourney = (Button) findViewById(R.id.recordingmode);
// Bundle bundle = getIntent().getExtras(); //
db_username = (bundle.getString("Username")); //// //// // Set
Welcome message to the user who logged in //
msg.setText("Welcome "+db_username);
// Click and move to the next activity // startJourney.setOnClickListener(new View.OnClickListener() { //
#Override // public void onClick(View v) { //
Intent intent = new Intent(Menu.this, Recordingmode.class); //
intent.putExtra("Username", db_username); //
startActivity(intent); // } // });
// Click and move to the next activity buttonLogout.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
SharedPreferences preferences=getSharedPreferences("login", Context.MODE_PRIVATE);
SharedPreferences.Editor editor=preferences.edit();
editor.putString("login_status","off");
editor.commit();
finish();
moveTaskToBack(true);
} });
}
}
But if I login in the app, the error is thrown:
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Context.getPackageName()' on a null
object reference
The code below is intended to pass the data, using bundle, collected on signing up in Signup.java to ViewProfile.java which displays the data. On checking for a key in the bundle, it returns true, however, the bundle is null when checked in ViewProfile.java. Help will b appreciated.
Signup.java
public class Signup extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_signup);
final EditText n=(EditText)findViewById(R.id.editText3);
final EditText u=(EditText)findViewById(R.id.editText4);
final EditText p=(EditText)findViewById(R.id.editText5);
final EditText c=(EditText)findViewById(R.id.editText6);
Button s=(Button)findViewById(R.id.button4);
final Userdatabase udb=new Userdatabase(this);
s.setOnClickListener(new View.OnClickListener()
{
public void onClick(View v)
{
String name=n.getText().toString();
String email=u.getText().toString();
String password=p.getText().toString();
String phone=c.getText().toString();
boolean b=udb.insertuser(name,email,password);
if(b==true) {
Intent i = new Intent(Signup.this, MainActivity.class);
Bundle bundle=new Bundle();
bundle.putString("NAME",name);
bundle.putString("ID",email);
bundle.putString("PHONE",phone);
i.putExtras(bundle);
startActivity(i);
}
else
Toast.makeText(getApplicationContext(),"Please try again",Toast.LENGTH_SHORT).show();
}
});
}
}
ViewProfile.java
public class ViewProfile extends AppCompatActivity {
String name,username,contact,profession;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_view_profile);
Intent intent=getIntent();
Bundle b=intent.getExtras();
if(b!=null) {
name = b.getString("NAME");
username = b.getString("ID");
contact = b.getString("PHONE");
TextView tv1=(TextView)findViewById(R.id.textView17);
TextView tv2=(TextView)findViewById(R.id.textView18);
TextView tv3=(TextView)findViewById(R.id.textView19);
tv1.setText(name);
tv2.setText(username);
tv3.setText(contact);
}
ImageView img=(ImageView)findViewById(R.id.imageView4);
img.setOnClickListener(new View.OnClickListener()
{
public void onClick(View v)
{
Intent i=new Intent(ViewProfile.this,Profile.class);
startActivity(i);
}
});
}
}
You are calling the wrong activity in the SignUp activity:
if(b==true) {
Intent i = new Intent(Signup.this, MainActivity.class);//problem here
You have set the intent as MainActivity.class and sending data to MainActivity and not to ViewProfile activity.
Change to this in SignUp activity:
if(b==true) {
Intent i = new Intent(Signup.this, ViewProfile.class);
I have two activities, MainActivity and SecondActivity. While passing int value from MainActivity to SecondActivity it becomes "0". I have tried with and without bundle, tried various solution already present on StackOverFlow, but no go.
Here is my code:
MainActivity
final Intent intent = new Intent(MainActivity.this, SecondActivity.class);
final TextView textView = findViewById(R.id.textView);
textView.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
Bundle bundle = new Bundle();
bundle.putInt("category",9);
intent.putExtras(bundle);
startActivity(intent);
}
});
SecondActivity:
package com.example.app;
import android.content.Intent;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
public class SecondActivity extends AppCompatActivity {
ViewPager viewPager;
TabsPagerAdapter pagerAdapter;
private int mMedCategory = 6;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
// String stringCategory = getIntent().getStringExtra("category_string");
int medCategory = getIntent().getIntExtra("category_int", -1);
setMedCategory(medCategory);
viewPager = findViewById(R.id.viewpager);
pagerAdapter = new TabsPagerAdapter(getSupportFragmentManager());
viewPager.setAdapter(pagerAdapter);
}
public int getMedCategory(){
return mMedCategory; //This value goes to TabsPagerAdapter
}
public void setMedCategory(int i){
mMedCategory = i;
}
}
You can try this:
MainActivity
TextView textView = findViewById(R.id.textView);
textView.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, SecondActivity.class);
intent.putExtra("category_int", 9);
intent.putExtra("category_string", "9");
startActivity(intent);
}
});
SecondActivity
private int medCategoryInt;
private String medCategoryString;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
medCategoryInt = getIntent().getIntExtra("category_int", 0);
medCategoryString = getIntent().getStringExtra("category_string");
}
You can have a look at How do I pass data between Activities in Android application?
Use Intent#getIntExtra() to retrieve an integer value from the intent:
From MainActivity:
Intent myIntent = new Intent(MainActivity.this, SecondActivity.class);
myIntent.putExtra("category", 9);
MainActivity.this.startActivity(myIntent);
From SecondActivity:
#Override
protected void onCreate(Bundle savedInstanceState) {
Intent intent = getIntent();
medCategory = intent.getIntExtra("category", -1);
}
Note that this would assign a default value of -1 to medCategory in the event that the key cannot be found.
I'm not sure but You may use this for second activity:
SecondActivity secondActivity = new SecondActivity();
if (secondActivity.getIntent.getExtras() != null)
{
int medCat = secondActivity.getIntent.getExtras().getInt("category");
}
Use this code. Remove final and try to initialize intent in onclick method not outside of it.
In your OnClick
Intent intent=new Intent(this,Main2Activity.class);
Bundle bundle = new Bundle();
bundle.putInt("category",9);
intent.putExtras(bundle);
startActivity(intent);
In your second activity
public class Main2Activity extends AppCompatActivity {
private int mMedCategory =0;
public int getmMedCategory() {
return mMedCategory;
}
public void setmMedCategory(int mMedCategory) {
this.mMedCategory = mMedCategory;
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
Bundle bundle=getIntent().getExtras();
if(bundle!=null){
int demoCategory =bundle.getInt("category");
setmMedCategory(demoCategory);
}else {
Toast.makeText(this, "null", Toast.LENGTH_SHORT).show();
}
}
public void Show(View view) {
Toast.makeText(this, String.valueOf(getmMedCategory()), Toast.LENGTH_SHORT).show();
}
}
EDIT
Created a demo project for you it is working. Show method is onclick method of a button.
I tried looking on other questions but nothing seems to work. Trying to pass the value stored in sUsername from activity Username.java to MainActivity.java (username).
This is Username.java:
public class Username extends ActionBarActivity implements View.OnClickListener {
EditText eUsername;
Button login;
String sUsername;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_username);
eUsername = (EditText) findViewById (R.id.username);
sUsername = eUsername.getText().toString();
login = (Button)findViewById(R.id.login);
login.setOnClickListener(this);
}
private void loginClick() {
Intent intent = new Intent(this, MainActivity.class );
intent.putExtra("containsUsername", sUsername); //first argument is the name of the string being passed
startActivity(intent);
}
public void onClick (View v) {
switch (v.getId()) {
case R.id.login:
loginClick();
break;
}
}
and this is MainActivity.java
public class MainActivity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Intent intent = getIntent();
Bundle bundle = intent.getExtras();
String username = bundle.getString("containsUsername");
WebView listOfSongs = (WebView) findViewById (R.id.webview);
String url = "http://ws.audioscrobbler.com/2.0/?method=user.gettoptracks&user="+username+"&api_key=68f82cd7b37e7b23800c2025066531c9&format=json";
listOfSongs.loadUrl(url);
}
your loginCheck Method should be like this:
private void loginClick() {
sUsername = eUsername.getText().toString();
Intent intent = new Intent(this, MainActivity.class );
intent.putExtra("containsUsername", sUsername); //first argument is the name of the string being
startActivity(intent);
}
As in on create your edittext might be empty.
Please check your edittext is empty or not. Chnage your method longClick.
private void loginClick(){
if(!sUsername.isEmpty()) {
Intent intent = new Intent(this, MainActivity.class );
intent.putExtra("containsUsername", sUsername);
startActivity(intent);
} else {
Toast.makeText(Username.this, "Please enter username.", Toast.LENGTH_LONG).show();
}
}