Develop Reference

Why the EditText widget ends up being null?

I am trying to get the input from the EditText fields and store it into an SQLite database. But the Fields are null even after I enter text into it.
I did a similar thing earlier and it ended up just fine but I am confused what is causing the problem here.
package com.example.mridul.eventmanager;
import android.content.Intent;
import android.net.Uri;
import android.provider.MediaStore;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
public class CreateEvent extends AppCompatActivity {
EditText edit,edit2,edit3,edit4;
TextView t1;
ImageView img;
Button bpost;
public static final int PICK_IMAGE=1;
Uri imageuri;
Event in;
DatabaseHelper dc = new DatabaseHelper(this);
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_create_event);
edit = (EditText) findViewById(R.id.editText7);
edit2 = (EditText) findViewById(R.id.editText8);
edit3 = (EditText) findViewById(R.id.editText9);
edit4 = (EditText) findViewById(R.id.editText10);
t1 = (TextView) findViewById(R.id.textView6);
img = (ImageView) findViewById(R.id.imageView);
bpost = (Button) findViewById(R.id.button3);
t1.setOnClickListener(new View.OnClickListener(){
public void onClick(View vim){
operationGallery();
}
});
bpost.setOnClickListener(new View.OnClickListener(){
public void onClick(View vPost){
in.sEventName(edit.getText().toString()); //Problem here
in.sEventDesc(edit2.getText().toString());
in.sEventVenue(edit3.getText().toString());
in.sType(edit4.getText().toString());
in.sPic(imageuri.toString());
dc.addEvent(in);
Toast.makeText(getApplicationContext(), "Data Saved", Toast.LENGTH_SHORT).show();
Intent gBack = new Intent(CreateEvent.this, LoginActivity.class);
CreateEvent.this.startActivity(gBack);
}
});
} public void operationGallery(){
Intent im = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.INTERNAL_CONTENT_URI);
startActivityForResult(im , PICK_IMAGE);
}
public void onActivityResult(int requestcode, int resultcode, Intent data){
super.onActivityResult(requestcode, resultcode, data);
if((resultcode == RESULT_OK)&&(requestcode == PICK_IMAGE)){
imageuri = data.getData();
img.setImageURI(imageuri);
}
}
}
The following is the error which I am getting after executing the code

You have just forgot to initiate Event object "in"

Your Event object in is uninitialized.

Code doesn't work

I'm trying to make an APK that saves passwords with the site using two different ArrayLists. This way, I can get the right indexnumber of the site and get the password based on this indexnumber. In the beginning of MainActivity, I add two random Strings to the ArrayLists, so that I don't have to work with empty ArrayLists, but this is utterly useless I think.
The problem is I can only view the last site-password I have put in. Previous combinations are "lost."
code:
MainActivity.java
package com.example.prive.passwordsafe;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
public ArrayList<String> passwordList = new ArrayList<>();
public ArrayList<String> siteList = new ArrayList<>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
passwordList.add("ejifjejfijeifjeijfiejifjeijfiejfijefie");
siteList.add("iejfijeifjiejfiejidvjijijeijivjiejvijeivjejv");
Button addButton = (Button) findViewById(R.id.addButton);
Button showButton = (Button) findViewById(R.id.showButton);
addButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
firstIntent();
}
});
showButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
secondIntent();
}
});
}
#Override
public void onResume(){
super.onResume();
add();
}
private void firstIntent() {
Intent intent = new Intent(MainActivity.this, addActivity.class);
intent.putStringArrayListExtra("passwordList", passwordList);
intent.putStringArrayListExtra("siteList", siteList);
startActivity(intent);
}
private void secondIntent() {
Intent intent = new Intent(MainActivity.this, showActivity.class);
intent.putStringArrayListExtra("passwordList", passwordList);
intent.putStringArrayListExtra("siteList", siteList);
startActivity(intent);
}
public void add(){
Bundle pickupData = getIntent().getExtras();
if(pickupData == null){
return;
}
String receivedPassword = pickupData.getString("Password");
String receivedSite;
receivedSite = pickupData.getString("Site");
passwordList.add(receivedPassword);
siteList.add(receivedSite);
}
}
addActivity.java
package com.example.prive.passwordsafe;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class addActivity extends AppCompatActivity {
public EditText siteInsert, passwordInsert;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_toevoeg);
siteInsert = (EditText) findViewById(R.id.siteInsert);
passwordInsert = (EditText) findViewById(R.id.passwordInsert);
siteInsert.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Toast msg = Toast.makeText(getBaseContext(), "site", Toast.LENGTH_LONG);
msg.show();
}
});
passwordInsert.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Toast msg = Toast.makeText(getBaseContext(), "password", Toast.LENGTH_LONG);
msg.show();
}
});
Button button = (Button) findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String password = passwordInsert.getText().toString();
String site = siteInsert.getText().toString();
Intent intent = new Intent(addActivity.this, MainActivity.class);
intent.putExtra("Password", password);
intent.putExtra("Site", site);
startActivity(intent);
}
});
}
}
showActivity.java
package com.example.prive.passwordsafe;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
public class showActivity extends AppCompatActivity {
public EditText editText;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_toon);
Button showButton = (Button) findViewById(R.id.showButton);
Button backButton = (Button) findViewById(R.id.backButton);
editText = (EditText) findViewById(R.id.editText);
final TextView textView = (TextView) findViewById(R.id.textView);
Bundle pickupData = getIntent().getExtras();
final ArrayList<String> passwordList = pickupData.getStringArrayList("passwordList");
final ArrayList<String> siteList = pickupData.getStringArrayList("siteList");
editText.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Toast msg = Toast.makeText(getBaseContext(), "site", Toast.LENGTH_LONG);
msg.show();
}
});
if (passwordenList != null && siteList != null) {
showButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
int numberOfPasswords = passwordenList.size();
for (int i = 0; i <= numberOfPasswords; i++) {
String password;
String temporary = editText.getText().toString();
if (temporary.equals(siteList.get(i))) {
password = passwordList.get(i);
textView.setText(password);
}else{
password = "wrong input";
textView.setText(password);
}
}
}
});
}else{
return;
}
backButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
finish();
}
});
}
}

When you exit an Activity, all the data on it is lost. You have to persist your ArrayList in SQLite or use SharedPreferences instead.
SharedPreferences: https://developer.android.com/reference/android/content/SharedPreferences.html
SQLite: https://developer.android.com/training/basics/data-storage/databases.html

Android studio use same integer in 2 activities

i was making an android app and i need to use one integer value in 2 activities. I tried using this code but it didn't work.
//Integer Sender
Intent myIntent = new Intent(A.this, B.class);
myIntent.putExtra("MyIntNameGoesHere", intValue);
startActivity(myIntent);
//Integer receiver
Intent mIntent = getIntent();
int intValue = mIntent.getIntExtra("intVariableName", 0);
It says Cannot resolve symbol intValue and Cannot resolve symbol A and the same for B.
Here's the whole code.
MainActivity:
import android.content.Intent;
import android.content.SharedPreferences;
import android.preference.PreferenceManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
int balance;
private SharedPreferences preferences;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Hide notification bar
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
//Click counter
final TextView text = (TextView) findViewById(R.id.balance_text);
assert text != null;
// to retreuve the values from the shared preference
preferences = PreferenceManager.getDefaultSharedPreferences(this);
balance = preferences.getInt("balance", 0);
text.setText(balance + " $");
final ImageButton button = (ImageButton) findViewById(R.id.click_button);
assert button != null;
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
balance++;
text.setText("" + balance + " $");
SharedPreferences.Editor editor = preferences.edit();
editor.putInt("balance", balance);
editor.apply();
}
});
final Button UpgradesButton = (Button) findViewById(R.id.upgrades_button);
assert UpgradesButton != null;
UpgradesButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
startActivity(new Intent(MainActivity.this, UpgradesActivity.class));
}
});
//Balance Integer Sender
}
}
UpgradesActivity:
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
public class UpgradesActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_upgrades);
//Hide notification bar
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
final Button e2u_button = (Button) findViewById(R.id.e2u_button);
assert e2u_button != null;
e2u_button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
}
});
final Button back_button = (Button) findViewById(R.id.back_button);
assert back_button != null;
back_button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
startActivity(new Intent(UpgradesActivity.this, MainActivity.class));
}
});
//TODO: Pass balance integer from MainActivity to here.
}
}
Error code:
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
public class UpgradesActivity extends AppCompatActivity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_upgrades);
//Receive balance from MainActivity
Intent mIntent = getIntent();
int intValue = mIntent.getIntExtra("key_int", 0);
//Hide notification bar
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
final Button e2u_button = (Button) findViewById(R.id.e2u_button);
assert e2u_button != null;
e2u_button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(balance >= 300){ //ERROR ON THIS LINE
}
}
});
final Button back_button = (Button) findViewById(R.id.back_button);
assert back_button != null;
back_button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
startActivity(new Intent(UpgradesActivity.this, MainActivity.class));
}
});
//TODO: Pass balance integer from MainActivity to here.
}
}
ALL ABOVE IS ANSWERED! ---------------------------------------------------------
Now i have problems with this part of the code:
#Override
public void onClick(View v) {
if(balance >= 300){
balance -= 300;
}
if(balance < 300){
final TextView text = (TextView) findViewById(R.id.not_enough_money_text);
assert text != null;
text.setText("You do not have enough money.");
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run() {
text.setText("");
}
}, 2000);
}
}
When i click the button it says i do not have enough money but i have over 300. Please help me.
I found out what the problem was but I'm not sure how to fix it. I need to send balance back to MainActivity. Can anyone help with that?

Send the data like this -
UpgradesButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, UpgradesActivity.class);
intent.putExtra("key_int", balance);
startActivity(intent);
}
});
And fetch it in onCreate() of UpgradesActivity -
Intent mIntent = getIntent();
int intValue = mIntent.getIntExtra("key_int", 0);

You're using different key when sending and receiving the Int.
Change this line:
int intValue = mIntent.getIntExtra("intVariableName", 0);
To this:
int intValue = mIntent.getIntExtra("MyIntNameGoesHere", 0);

SecondActivity is not receiving the value - Intent related

import android.content.Intent;
import android.content.SharedPreferences;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.animation.AnimationUtils;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.Random;
public class MainActivity extends AppCompatActivity {
TextView t1,t2;
Button generate1;
MediaPlayer pickupgold, pickupplatinum;
SharedPreferences mySharedPreferences;
private static Button button2;
#Override
protected void onCreate(Bundle savedInstanceState) {
mySharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
pickupgold = MediaPlayer.create(this, R.raw.pickup_gold);
pickupplatinum = MediaPlayer.create(this, R.raw.pickup_platinum);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
OnClickButtonListener();
final ImageView imageView = (ImageView) findViewById(R.id.imageView);
final ImageView imageView2 = (ImageView) findViewById(R.id.imageView2);
t1 = (TextView) findViewById(R.id.textView3);
t2 = (TextView) findViewById(R.id.textView8);
generate1 = (Button) findViewById(R.id.button);
generate1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
TextView userTextEntry = (TextView) findViewById(R.id.textView3);
String userData = userTextEntry.getText().toString();
int num2 = mySharedPreferences.getInt("INT_KEY1", Integer.parseInt(userData));
int num3 = mySharedPreferences.getInt("INT_KEY2", -1);
Intent intent = new Intent(MainActivity.this, SecondActivity.class);
intent.putExtra("parameter1", num2);
Random rand = new Random();
int num1 = rand.nextInt(100);
if (num1 % 2 == 0) {
pickupgold.start();
num2 += 1;
SharedPreferences.Editor editor = mySharedPreferences.edit();
editor.putInt("INT_KEY1", num2);
editor.apply();
t1.setText(String.format("%d", num2));
imageView.startAnimation(AnimationUtils.loadAnimation(MainActivity.this, android.R.anim.slide_in_left));
Toast.makeText(getApplicationContext(), R.string.foundgold2, Toast.LENGTH_LONG).show();
}else{
Toast.makeText(getApplicationContext(), R.string.notfoundgold, Toast.LENGTH_LONG).show();
} if (num1 == 1){
pickupplatinum.start();
num3 += 1;
SharedPreferences.Editor editor = mySharedPreferences.edit();
editor.putInt("INT_KEY2", num3);
editor.apply();
t2.setText(String.format("%d", num3));
imageView2.startAnimation(AnimationUtils.loadAnimation(MainActivity.this, android.R.anim.slide_in_left));
Toast.makeText(getApplicationContext(), R.string.foundplatinum1, Toast.LENGTH_LONG).show();
}
}
});
}
public void OnClickButtonListener() {
button2 = (Button)findViewById(R.id.button2);
button2.setOnClickListener(
new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent("com.example.tans.goldminer1.SecondActivity");
startActivity(intent);
}
}
);
}
This is MainActivity.java
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.widget.TextView;
public class SecondActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
Intent intent = getIntent();
int goldamountval = intent.getIntExtra("parameter1", 0);
TextView goldamount = (TextView) findViewById(R.id.goldamount);
goldamount.setText("" + goldamountval);
}
and This is SecondActivity.java
I think the int value should be loaded from MainActivity.java but
When I go to SecondActivity, It does not seem to appear, Just showing 0.
What's the reason and how can i solve it? and Sorry, My Code may look like confused. :<

Try this on SecondActivity
Intent intent = new Intent(MainActivity.this, SecondActivity.class);
intent.putExtra("parameter1", num2);
startActivity(intent );

You need to start the SecondActivity after the first two lines :
Intent intent = new Intent(MainActivity.this, SecondActivity.class);
intent.putExtra("parameter1", num2);
startActivity(intent);

Intent intent = new Intent(context, YourActivityClass.class);
intent.putExtra(KEY, );
startActivity(intent);
Seocnd Activity-
Intent intent = getIntent();
if (null != intent) {
String stringData= intent.getStringExtra(KEY);
int numberData = intent.getIntExtra(KEY, defaultValue);
boolean booleanData = intent.getBooleanExtra(KEY, defaultValue);
char charData = intent.getCharExtra(KEY, defaultValue);
}

Send a text from EditText to a second activity

I'm trying to take a text from the EditText widget and send it to a second activity, here is what I wrote until now:
package example.antonio.anexample;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.text.Editable;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.EditText;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EditText etxt = new EditText(this);
etxt.setHint("Write something");
Button btn = new Button(this);
btn.setText("Send");
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Editable input = etxt.getText();
Intent i = new Intent(MainActivity.this, SecondActivity.class);
i.putExtra("message", input.toString());
startActivity(i);
}
});
LinearLayout layout = new LinearLayout(this);
layout.setOrientation(LinearLayout.VERTICAL);
layout.addView(etxt);
layout.addView(btn);
setContentView(layout);
}
}
But as you can image it doesn't compile, how can I access the etxt variable from the inner class?

Make etxt final so you can access it on inner class
final EditText etxt = new EditText(this);
etxt.setHint("Write something");
Button btn = new Button(this);
btn.setText("Send");
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String input = etxt.getText();
Intent i = new Intent(MainActivity.this, SecondActivity.class);
i.putExtra("message", input.toString());
startActivity(i);
}
});