https://developer.android.com/training/basics/firstapp/starting-activity#kotlin
I am at this point on the training and have added the code as advised:
const val EXTRA_MESSAGE = "com.example.myfirstapp.MESSAGE"
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
}
/** Called when the user taps the Send button */
fun sendMessage(view: View) {
val editText = findViewById<EditText>(R.id.editText)
val message = editText.text.toString()
val intent = Intent(this, DisplayMessageActivity::class.java).apply {
putExtra(EXTRA_MESSAGE, message)
}
startActivity(intent)
}
}
However it doesn't like editText in (R.id.editText). It is showing in red and pressing alt + enter has not worked on this. I am only expecting to see an error on DisplayMessageActivity.
I have tried to find a fix to this error online but I can't seem to find anything to help.
Thank you all, this has now been resolved.
User Jems asked me to check the activity_main.xml to see if I had an id of editText. I did but it had additional wording. It was showing as editTextTextName, so I amended this to show only editText and now it is happy with the code.
Try With This:
val editText = findViewById<EditText>(R.id.editText) as EditText
Update
const val EXTRA_MESSAGE = "com.example.myfirstapp.MESSAGE"
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val editText = findViewById<EditText>(R.id.editText) as EditText
val message = editText.text.toString()
}
/** Called when the user taps the Send button */
fun sendMessage(view: View) {
val intent = Intent(this, DisplayMessageActivity::class.java).apply {
putExtra(EXTRA_MESSAGE, message)
}
startActivity(intent)
}
}
Related
I'm new at Kotlin, and I'm doing a simple app where the user writes something on EditText, presses a button then the app proceeds to show that text on SecondActivity, on that SecondActivity the user can do exactly the same thing, but on the FirstActivity (the one who shows up on the user starts the app) there are on EditText with "Welcome" text for default that shows empty when the application starts, this started to happen when I implement the text to be substituted by what the user writes on the SecondActivity
Here's the code for the FirtActivity
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val result = findViewById<TextView>(R.id.nomeUser)
val nameEntered = findViewById<EditText>(R.id.nameEntered)
val button = findViewById<Button>(R.id.button)
button.setOnClickListener{
val name = nameEntered.text.toString()
val intent = Intent(this#MainActivity, NomeEscrito::class.java)
intent.putExtra("Name", name)
startActivity(intent)
}
val intent = intent
val name = intent.getStringExtra("Name")
result.text = name
}
}
And here's the code for the SecondActivity
class NomeEscrito : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_nome_escrito)
val intent = intent
val name = intent.getStringExtra("Name")
val result = findViewById<TextView>(R.id.result)
result.text = name
val wordEntered = findViewById<EditText>(R.id.textPhrase)
val button2 = findViewById<Button>(R.id.button2)
button2.setOnClickListener{
val name2 = wordEntered.text.toString()
val intent2 = Intent(this#NomeEscrito, MainActivity::class.java)
intent2.putExtra("Name", name2)
startActivity(intent2)
}
}
}
The problem is in the following line of your FirstActivity:
val name = intent.getStringExtra("Name")
When you open up the app for the first time, there is no data in the intent. As a result, it returns an empty string.
You can do the a check for empty string before setting your EditText text to avoid this situation:
if (!name.isNullOrBlank()) {
result.text = name
}
Choose different keys in getStringExtra in both intent data passing
When I click the register button, it does not save the data and gives the following error;
com.google.firebase.auth.FirebaseAuthInvalidCredentialsException: The email address is badly formatted
Please help us find the error!
Register code page;
class RegisterActivity : AppCompatActivity() {
private lateinit var binding : ActivityRegisterBinding
private lateinit var firebaseAuth: FirebaseAuth
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityRegisterBinding.inflate(layoutInflater)
setContentView(binding.root)
firebaseAuth = FirebaseAuth.getInstance()
binding.registerButton.setOnClickListener {
val email = binding.yourEmail.text.toString()
val pass = binding.editTextTextPassword2.text.toString()
val username = binding.editTextTextPersonName.text.toString()
if(email.isNotEmpty() && pass.isNotEmpty() && username.isNotEmpty()){
firebaseAuth.createUserWithEmailAndPassword(email , pass).addOnCompleteListener{
if (it.isSuccessful){
val intent = Intent(this, LoginActivity::class.java)
startActivity(intent)
}else{
Toast.makeText(this,it.exception.toString(), Toast.LENGTH_LONG).show()
}
}
}else{
Toast.makeText(this,"Empty Fields Are not Allowed !!", Toast.LENGTH_LONG).show()
}
}
val loginresetActivity = findViewById<TextView>(R.id.textView6)
textView6.setOnClickListener {
val Intent = Intent(this, LoginActivity::class.java)
startActivity(Intent)
}
}
}
I don't know if this will help but Make sure the string doesn't have white spaces im both sides (left and right)
val email = binding.yourEmail.text.toString().trim()
So I've been learning Mobile App Development from the Android Development Website but there seems to be an issue:
https://developer.android.com/training/basics/firstapp/starting-activity#kotlin
the code to build an intent when clicking on the button does not seem to work:
const val EXTRA_MESSAGE = "com.example.myfirstapp.MESSAGE"
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
}
/** Called when the user taps the Send button */
fun sendMessage(view: View) {
val editText = findViewById<EditText>(R.id.editTextTextPersonName)
val message = editText.text.toString()
val intent = Intent(this, DisplayMessageActivity::class.java).apply {
putExtra(EXTRA_MESSAGE, message)
}
startActivity(intent)
}
}
I modified it a bit and it seems to work this way
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
var btn = findViewById<Button>(R.id.button)
btn.setOnClickListener{
val editText = findViewById<EditText>(R.id.editTextTextPersonName)
val message = editText.text.toString()
val intent = Intent(this, DisplayMessageActivity::class.java).apply {
putExtra(EXTRA_MESSAGE, message)
}
startActivity(intent)
}
}
I'm not sure if I misunderstood something. If I did I'd like to be corrected. And if I didn't misunderstand and the code given doesn't work, how do I report the issue? I already unliked the page but the page didn't ask for more details.
I am having a ton of trouble passing the product of two EditTexts to a TextView in another activity. Here is my code for MainActivity.
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val button1: Button = findViewById(R.id.button1)
val editText1: EditText = findViewById(R.id.editText1)
val editText2: EditText = findViewById(R.id.editText2)
val firstNumber = editText1.toString().toInt()
val secondNumber = editText2.toString().toInt()
val product = firstNumber * secondNumber
button1.setOnClickListener{
val intent = Intent(this, Activity2::class.java)
intent.putExtra("RESULT_PRODUCT", product)
startActivity(intent)
}
}
}
Here is my code for Activity2:
class Activity2 : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_2)
val product = intent.getIntExtra("RESULT_SUM", 0)
textView1.text = product.toString()
}
}
I am relatively new to Kotlin and Android Studio but this has caused crashes left and right.
First of all, You have to calculate the product inside OnClickListener to get correct result.
button1.setOnClickListener{
val firstNumber = editText1.text.toString().trim()
val secondNumber = editText2.text.toString().trim()
if(!(firstNumber.isEmpty() or secondNumber.isEmpty())) {
val product = firstNumber.toInt() * secondNumber.toInt()
val intent = Intent(this, Activity2::class.java)
intent.putExtra("RESULT_PRODUCT", product)
startActivity(intent)
} else {
//Show messages
}
}
And then you have to use the exact key RESULT_PRODUCT that you use in your activity to pass data through intent
val product = intent.getIntExtra("RESULT_PRODUCT", 0)
You are passing "RESULT_PRODUCT" from MainActivity but getting "RESULT_SUM" in your Activity2. You should use intent.getIntExtra("RESULT_PRODUCT", 0) in you second activity.
This is the main activity
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
var userInput:EditText = findViewById(R.id.usr_input) as EditText
var button:Button = findViewById(R.id.ent_btn) as Button
button.setOnClickListener {
var name = userInput.text
val intent = Intent(this#MainActivity, screenTwo::class.java)
intent.putExtra("name", name)
startActivity(intent)
}
}
}
This is second screen
class screenTwo : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_screen_two)
var userName:TextView = findViewById(R.id.user_name) as TextView
var editText:EditText = findViewById(R.id.usr_text) as EditText
var outText:TextView = findViewById(R.id.output) as TextView
var showButton:Button = findViewById(R.id.btn_show) as Button
var back:Button = findViewById(R.id.btn_back) as Button
var name = intent.getStringExtra("name")
userName.text = name
showButton.setOnClickListener {
var text:String = editText.text.toString()
outText.text = text
}
back.setOnClickListener {
var goback = Intent(this#screenTwo, MainActivity::class.java)
startActivity(goback)
}
}
}
When I click on the button(variable_name) in the main activity, the app closes. Is it the intent or something is wrong in the second screen???
intent is not defind in SecondActivity
In SecondActivity : get intent by getIntent()
class screenTwo : AppCompatActivity() {
var name = getIntent().getStringExtra("name")
Most common error in this configuration is that you forgot to declare your screenTwo in your AndroidManifest.xml, inside the "application" node (your MainActivity should already be defined there) :
<activity
android:name=".screenTwo"
android:theme="yourTheme"/>
If this is not it, an error log might help us help you.
Sorry , it was a minor error from my side..
I didn't convert the variable 'name' to 'String'
var name = userInput.text.toString() //correction
It's working now,
Thanks anyway...