Develop Reference

Call startActivity(intent) Multiple times

Hello at the moment I have a problem with calling a new activity.
I want to call a new Activity Inside my SettingsActivity.
I call the SettingsActivity by pressing an Button :
Button button = findViewById(R.id.button_navSecond);
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, SettingsActivityModern.class);
startActivity(intent);
}
});
But at the next Button click to get to another Acitivty inside this Activity I get back to the Mainactivity
premiumBuy.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(SettingsActivityModern.this, BuyPremiumActivity.class);
startActivity(intent);
}
});
It seems like it is not possible to Call startActivity(intent); inside an activty which was called with this command. So how to prevent that?

Try adding the Activity in the AndroidManifest.xml like this:
<activity
android:name="com.example.foodgent.YOUR_ACTIVITY" />

How to put EditText info into a Intent variable

I'm trying to get the user information typed in the edit text. I want it saved into the Intent result variable. Trying to sending it back to the main activity afterwards. Keep getting the cannot resolve method. I'm thinking it must be that I'm missing a parameter in the putExtra() method
public class EnterDataActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_enterdata);
Button doneButton = (Button) findViewById(R.id.button_done);
final EditText getData = (EditText) findViewById(R.id.enter_data_here);
doneButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent result = new Intent();
result.putExtra(getData);
setResult(RESULT_OK, result);
finish(); // Ends sub-activity
}//ends onClick
});
}//ends onCreate void button
}

Well if you are trying to send the EditText that's not possible.
If you are trying to send the text that are on that EditText that's possible.
How to do it?
Declare a String to save the data (You can avoid this step, but that's more clear)
String mText = getData.getText().toString();
Then you'll use the getExtra() method to send the String to the new Activity
Intent i = new Intent(this, MyNewActivity.class);
i.putExtra("text_from_editText", mText);
startActivity(i);
Then the last step (You don't ask for it, but you'll need it), get the text.
//onCreate() of the second Activity
Intent i = getIntent();
String mText = i.getStringExtra("text_from_editText");

Replace result.putExtra(getData); with result.putExtra(getData.getText().toString()); to get the text from the EditText. Right now you're trying to put the entire EditText object into the intent as an extra instead of just the text from the EditText.

Crash when creating Activity

Good evening Stack !
I have started to learn Android development as a hobby and I am now trying to develop my first "real" application (I have made already only five simple applications from books).
In this application, I have two buttons that will "create" the same Activity but by using two different objects from the same base class, hence allowing me to customize the behavior of the application depending on the button that was clicked.
However, when I am trying to create the Intent instance, my application crashes.
Here is the code of the base Activity class
public class BaseDictionnaryActivity extends Activity
{
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.basedictionnary);
}
public void onDestroy()
{
super.onDestroy();
}
}
and here is the code that crashes. The line is the one creating the Intent object.
public class DictionnaryActivity extends Activity
{
private BaseDictionnaryActivity jlpt1;
private BaseDictionnaryActivity jlpt2;
private Button btjlpt1 = null;
private Button btjlpt2 = null;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.dictionnary);
jlpt2 = new BaseDictionnaryActivity();
jlpt1 = new BaseDictionnaryActivity();
btJLPT1 = (Button)findViewById(R.id.jlpt1);
btJLPT1.setOnClickListener(new View.OnClickListener()
{
public void onClick(View v)
{
Intent myIntent = new Intent(DictionnaryActivity.this,
jlpt1.getClass());
jlpt1.this.startActivity(myIntent);
}
});
btJLPT2 = (Button)findViewById(R.id.jlpt2);
btJLPT2.setOnClickListener(new View.OnClickListener()
{
public void onClick(View v)
{
Intent myIntent = new Intent(DictionnaryActivity.this,
jlpt2.getClass());
jlpt2.this.startActivity(myIntent);
}
});
}
public void onDestroy()
{
super.onDestroy();
}
}
Thank you for your help !

Just to make correction,
Intent myIntent = new Intent(DictionnaryActivity.this,
jlpt1.getClass());
In this the second argument must be, your target activity BaseDictionnaryActivity.class
So, it looks something like,
Intent myIntent = new Intent(DictionnaryActivity.this,
BaseDictionnaryActivity.class);
startActivity(myIntent);
Also please make sure there will be entry of BaseDictionnaryActivity in your Application's manifest file,
Which is look like,
<activity android:name=".BaseDictionnaryActivity"
....>
</activity>

Maybe:
Intent myIntent = new Intent(DictionnaryActivity.this,
BaseDictionnaryActivity.class);
startActivity(myIntent);

change this
Intent myIntent = new Intent(DictionnaryActivity.this,
NextActivity.class);

Intent myIntent = new Intent(DictionnaryActivity.this,
jlpt2.class);
^^^^^^^^^^^^
You need to provide next activity .class in second argument of Intent.

Replace jlpt1.getClass() with NameOfClassToBeLaunched.class
Also this is bad practice to create Activity instances in other activities.

Android inter-activity communication

Hi I am a total android newbie so my question might seem dumb.
I want to make a program that has two activities, one of them is TinyCalActivity1 and the other is TinyCalActivity2.
My intention was that I can make a button to switch between this activity,
package my.app.tinyCal;
public class TinyCalActivity1 extends Activity {
/** Called when the activity is first created. */
Button myButton;
EditText myEdit;
//Intent i = new Intent(TinyCalActivity1.this, TinyCalActivity2.class);
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
myButton = (Button)findViewById(R.id.Next);
myEdit = (EditText)findViewById(R.id.entry);
CharSequence thisNum = "1234565";
myEdit.setText(thisNum);
OnClickListener myListener = new OnClickListener(){
public void onClick(View v){
}
};
myButton.setOnClickListener(myListener);
}
}
and TinyCalActivity2.
However, when I write this line and run in my android AVD, it tells me that there's an error.
Intent i = new Intent(this, TinyCalActivity2.class);
There is no error hint in eclipse and I do not know why.
I create TinyCalActivity2.java as a separate file in the same folder as my TinyCalActivity1.java file. And I have registered TinyCalActivity2 in my AndroidManifest.xml.
I would really appreciate any help!

If you put your code
Intent i = new Intent(this, TinyCalActivity2.class);
in button click event, then this refers to button and not ACTIVITY. Thus, you need to mention it as
Intent i = new Intent(TinyCalActivity1.this, TinyCalActivity2.class);
This may resolve the issue

You can try this way.
myButton.setOnClickListener(new OnClickListener(){
public void onClick(View v){
Intent i = new Intent(this, TinyCalActivity2.class);
finish();
}
};

How to start new activity on button click

In an Android application, how do you start a new activity (GUI) when a button in another activity is clicked, and how do you pass data between these two activities?

Easy.
Intent myIntent = new Intent(CurrentActivity.this, NextActivity.class);
myIntent.putExtra("key", value); //Optional parameters
CurrentActivity.this.startActivity(myIntent);
Extras are retrieved on the other side via:
#Override
protected void onCreate(Bundle savedInstanceState) {
Intent intent = getIntent();
String value = intent.getStringExtra("key"); //if it's a string you stored.
}
Don't forget to add your new activity in the AndroidManifest.xml:
<activity android:label="#string/app_name" android:name="NextActivity"/>

Current responses are great but a more comprehensive answer is needed for beginners. There are 3 different ways to start a new activity in Android, and they all use the Intent class; Intent | Android Developers.
Using the onClick attribute of the Button. (Beginner)
Assigning an OnClickListener() via an anonymous class. (Intermediate)
Activity wide interface method using the switch statement. (not-"Pro")
Here's the link to my example if you want to follow along:
Using the onClick attribute of the Button. (Beginner)
Buttons have an onClick attribute that is found within the .xml file:
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="goToAnActivity"
android:text="to an activity" />
<Button
android:id="#+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="goToAnotherActivity"
android:text="to another activity" />
In Java class:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_activity);
}
public void goToAnActivity(View view) {
Intent intent = new Intent(this, AnActivity.class);
startActivity(intent);
}
public void goToAnotherActivity(View view) {
Intent intent = new Intent(this, AnotherActivity.class);
startActivity(intent);
}
Advantage: Easy to make on the fly, modular, and can easily set multiple onClicks to the same intent.
Disadvantage: Difficult readability when reviewing.
Assigning an OnClickListener() via an anonymous class. (Intermediate)
This is when you set a separate setOnClickListener() to each button and override each onClick() with its own intent.
In Java class:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_activity);
Button button1 = (Button) findViewById(R.id.button1);
button1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(view.getContext(), AnActivity.class);
view.getContext().startActivity(intent);}
});
Button button2 = (Button) findViewById(R.id.button2);
button2.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(view.getContext(), AnotherActivity.class);
view.getContext().startActivity(intent);}
});
Advantage: Easy to make on the fly.
Disadvantage: There will be a lot of anonymous classes which will make readability difficult when reviewing.
Activity wide interface method using the switch statement. (not-"Pro")
This is when you use a switch statement for your buttons within the onClick() method to manage all the Activity's buttons.
In Java class:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_activity);
Button button1 = (Button) findViewById(R.id.button1);
Button button2 = (Button) findViewById(R.id.button2);
button1.setOnClickListener(this);
button2.setOnClickListener(this);
}
#Override
public void onClick(View view) {
switch (view.getId()){
case R.id.button1:
Intent intent1 = new Intent(this, AnActivity.class);
startActivity(intent1);
break;
case R.id.button2:
Intent intent2 = new Intent(this, AnotherActivity.class);
startActivity(intent2);
break;
default:
break;
}
Advantage: Easy button management because all button intents are registered in a single onClick() method
For the second part of the question, passing data, please see How do I pass data between Activities in Android application?
Edit: not-"Pro"

Create an intent to a ViewPerson activity and pass the PersonID (for a database lookup, for example).
Intent i = new Intent(getBaseContext(), ViewPerson.class);
i.putExtra("PersonID", personID);
startActivity(i);
Then in ViewPerson Activity, you can get the bundle of extra data, make sure it isn't null (in case if you sometimes don't pass data), then get the data.
Bundle extras = getIntent().getExtras();
if(extras !=null)
{
personID = extras.getString("PersonID");
}
Now if you need to share data between two Activities, you can also have a Global Singleton.
public class YourApplication extends Application
{
public SomeDataClass data = new SomeDataClass();
}
Then call it in any activity by:
YourApplication appState = ((YourApplication)this.getApplication());
appState.data.CallSomeFunctionHere(); // Do whatever you need to with data here. Could be setter/getter or some other type of logic

When user clicks on the button, directly inside the XML like that:
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TextButton"
android:onClick="buttonClickFunction"/>
Using the attribute android:onClick we declare the method name that has to be present on the parent activity. So I have to create this method inside our activity like that:
public void buttonClickFunction(View v)
{
Intent intent = new Intent(getApplicationContext(), Your_Next_Activity.class);
startActivity(intent);
}

Intent iinent= new Intent(Homeactivity.this,secondactivity.class);
startActivity(iinent);

Intent in = new Intent(getApplicationContext(),SecondaryScreen.class);
startActivity(in);
This is an explicit intent to start secondscreen activity.

Emmanuel,
I think the extra info should be put before starting the activity otherwise the data won't be available yet if you're accessing it in the onCreate method of NextActivity.
Intent myIntent = new Intent(CurrentActivity.this, NextActivity.class);
myIntent.putExtra("key", value);
CurrentActivity.this.startActivity(myIntent);

Try this simple method.
startActivity(new Intent(MainActivity.this, SecondActivity.class));

From the sending Activity try the following code
//EXTRA_MESSAGE is our key and it's value is 'packagename.MESSAGE'
public static final String EXTRA_MESSAGE = "packageName.MESSAGE";
#Override
protected void onCreate(Bundle savedInstanceState) {
....
//Here we declare our send button
Button sendButton = (Button) findViewById(R.id.send_button);
sendButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//declare our intent object which takes two parameters, the context and the new activity name
// the name of the receiving activity is declared in the Intent Constructor
Intent intent = new Intent(getApplicationContext(), NameOfReceivingActivity.class);
String sendMessage = "hello world"
//put the text inside the intent and send it to another Activity
intent.putExtra(EXTRA_MESSAGE, sendMessage);
//start the activity
startActivity(intent);
}
From the receiving Activity try the following code:
protected void onCreate(Bundle savedInstanceState) {
//use the getIntent()method to receive the data from another activity
Intent intent = getIntent();
//extract the string, with the getStringExtra method
String message = intent.getStringExtra(NewActivityName.EXTRA_MESSAGE);
Then just add the following code to the AndroidManifest.xml file
android:name="packagename.NameOfTheReceivingActivity"
android:label="Title of the Activity"
android:parentActivityName="packagename.NameOfSendingActivity"

Intent i = new Intent(firstactivity.this, secondactivity.class);
startActivity(i);

Kotlin
First Activity
startActivity(Intent(this, SecondActivity::class.java)
.putExtra("key", "value"))
Second Activity
val value = getIntent().getStringExtra("key")
Suggestion
Always put keys in constant file for more managed way.
companion object {
val PUT_EXTRA_USER = "user"
}
startActivity(Intent(this, SecondActivity::class.java)
.putExtra(PUT_EXTRA_USER, "value"))

Starting an activity from another activity is very common scenario among android applications.
To start an activity you need an Intent object.
How to create Intent Objects?
An intent object takes two parameter in its constructor
Context
Name of the activity to be started. (or full package name)
Example:
So for example,if you have two activities, say HomeActivity and DetailActivity and you want to start DetailActivity from HomeActivity (HomeActivity-->DetailActivity).
Here is the code snippet which shows how to start DetailActivity from
HomeActivity.
Intent i = new Intent(HomeActivity.this,DetailActivity.class);
startActivity(i);
And you are done.
Coming back to button click part.
Button button = (Button) findViewById(R.id.someid);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent i = new Intent(HomeActivity.this,DetailActivity.class);
startActivity(i);
}
});

The way to start new activities is to broadcast an intent, and there is a specific kind of intent that you can use to pass data from one activity to another. My recommendation is that you check out the Android developer docs related to intents; it's a wealth of info on the subject, and has examples too.

You can try this code:
Intent myIntent = new Intent();
FirstActivity.this.SecondActivity(myIntent);

Start another activity from this activity and u can pass parameters via Bundle Object also.
Intent intent = new Intent(getBaseContext(), YourActivity.class);
intent.putExtra("USER_NAME", "xyz#gmail.com");
startActivity(intent);
Retrive data in another activity (YourActivity)
String s = getIntent().getStringExtra("USER_NAME");

// In Kotlin , you can do as
/* In First Activity, let in activity layout there is button which has id as button.
Suppose I have to pass data as String type from one activity to another */
val btn = findViewById<Button>(R.id.button)
btn.setOnClickListener {
val intent = Intent(baseContext, SecondActivity::class.java).apply {
putExtra("KEY", data)
}
startActivity(intent)
}
// In Second Activity, you can get data from another activity as
val name = intent.getStringExtra("KEY")
/* Suppose you have to pass a Custom Object then it should be Parcelable.
let there is class Collage type which I have to pass from one activity to another
*/
import android.os.Parcelable
import kotlinx.android.parcel.Parcelize
#Parcelize
class Collage(val name: String, val mobile: String, val email: String) : Parcelable
/* Activity First , let here data is Collage type. which I have to pass to another activity. */
val btn = findViewById<Button>(R.id.button)
btn.setOnClickListener {
val intent = Intent(baseContext, SecondActivity::class.java).apply {
putExtra("KEY", data)
}
startActivity(intent)
}
// then from second Activity we will get as
val item = intent.extras?.getParcelable<Collage>("KEY")

Button button = findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(SplashActivity.this,HomeActivity.class);
startActivity(intent);
}
});

Implement the View.OnClickListener interface and override the onClick method.
ImageView btnSearch;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_search1);
ImageView btnSearch = (ImageView) findViewById(R.id.btnSearch);
btnSearch.setOnClickListener(this);
}
#Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.btnSearch: {
Intent intent = new Intent(Search.this,SearchFeedActivity.class);
startActivity(intent);
break;
}

Although proper answers have been already provided but I am here for searching the answer in language Kotlin. This Question is not about language specific so I am adding the code to accomplish this task in Kotlin language.
Here is how you do this in Kotlin for andorid
testActivityBtn1.setOnClickListener{
val intent = Intent(applicationContext,MainActivity::class.java)
startActivity(intent)
}

The Most simple way to open activity on button click is:
Create two activities under the res folder, add a button to the first activity and give a name to onclick function.
There should be two java files for each activity.
Below is the code:
MainActivity.java
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import android.content.Intent;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void goToAnotherActivity(View view) {
Intent intent = new Intent(this, SecondActivity.class);
startActivity(intent);
}
}
SecondActivity.java
package com.example.myapplication;
import android.app.Activity;
import android.os.Bundle;
public class SecondActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity1);
}
}
AndroidManifest.xml(Just add this block of code to the existing)
</activity>
<activity android:name=".SecondActivity">
</activity>

Take Button in xml first.
<Button
android:id="#+id/pre"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#mipmap/ic_launcher"
android:text="Your Text"
/>
Make listner of button.
pre.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, SecondActivity.class);
startActivity(intent);
}
});

When button is clicked:
loginBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent= new Intent(getApplicationContext(), NextActivity.class);
intent.putExtra("data", value); //pass data
startActivity(intent);
}
});
To received the extra data from NextActivity.class :
Bundle extra = getIntent().getExtras();
if (extra != null){
String str = (String) extra.get("data"); // get a object
}

Write the code in your first activity .
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(MainActivity.this, SecondAcitvity.class);
//You can use String ,arraylist ,integer ,float and all data type.
intent.putExtra("Key","value");
startActivity(intent);
finish();
}
});
In secondActivity.class
String name = getIntent().getStringExtra("Key");

Place button widget in xml like below
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button"
/>
After that initialise and handle on click listener in Activity like below ..
In Activity On Create method :
Button button =(Button) findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new
Intent(CurrentActivity.this,DesiredActivity.class);
startActivity(intent);
}
});

An old question but if the goal is to switch displayed pages, I just have one activity and call setContentView() when I want to switch pages (usually in response to user clicking on a button). This allows me to simply call from one page's contents to another. No Intent insanity of extras parcels bundles and whatever trying to pass data back and forth.
I make a bunch of pages in res/layout as usual but don't make an activity for each. Just use setContentView() to switch them as needed.
So my one-and-only onCreate() has:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
LayoutInflater layoutInflater = getLayoutInflater();
final View mainPage = layoutInflater.inflate(R.layout.activity_main, null);
setContentView (mainPage);
Button openMenuButton = findViewById(R.id.openMenuButton);
final View menuPage = layoutInflatter.inflate(R.layout.menu_page, null);
Button someMenuButton = menuPage.findViewById(R.id.someMenuButton);
openMenuButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
setContentView(menuPage);
}
});
someMenuButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
do-something-interesting;
setContentView(mainPage);
}
}
}
If you want the Back button to go back through your internal pages before exiting the app, just wrap setContentView() to save pages in a little Stack of pages, and pop those pages in onBackPressed() handler.

your button xml:
<Button
android:id="#+id/btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="jump to activity b"
/>
Mainactivity.java:
Button btn=findViewVyId(R.id.btn);
btn.setOnClickListener(btnclick);
btnclick.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent=new Intent();
intent.setClass(Mainactivity.this,b.class);
startActivity(intent);
}
});

imageView.setOnClickListener(v -> {
// your code here
});

Kotlin 2022
The simplest way:
val a = Intent(this.context, BarcodeActivity::class.java)
a.putExtra("barcode", barcode)
startActivity(a)
and in the other side (BarcodeActivity in my case):
val intent: Intent = intent
var data = intent.getStringExtra("barcode")
Read more here