I have a scenario where, after logging in through a login page, there will be a sign-out button on each activity.
On clicking sign-out, I will be passing the session id of the signed in user to sign-out. Can anyone guide me on how to keep session id available to all activities?
Any alternative to this case
In your current Activity, create a new Intent:
String value="Hello world";
Intent i = new Intent(CurrentActivity.this, NewActivity.class);
i.putExtra("key",value);
startActivity(i);
Then in the new Activity, retrieve those values:
Bundle extras = getIntent().getExtras();
if (extras != null) {
String value = extras.getString("key");
//The key argument here must match that used in the other activity
}
Use this technique to pass variables from one Activity to the other.
The easiest way to do this would be to pass the session id to the signout activity in the Intent you're using to start the activity:
Intent intent = new Intent(getBaseContext(), SignoutActivity.class);
intent.putExtra("EXTRA_SESSION_ID", sessionId);
startActivity(intent);
Access that intent on the next activity:
String sessionId = getIntent().getStringExtra("EXTRA_SESSION_ID");
The docs for Intents has more information (look at the section titled "Extras").
Passing Intent extras is a good approach as Erich noted.
The Application object is another way though, and it is sometimes easier when dealing with the same state across multiple activities (as opposed to having to get/put it everywhere), or objects more complex than primitives and Strings.
You can extend Application, and then set/get whatever you want there and access it from any Activity (in the same application) with getApplication().
Also keep in mind that other approaches you might see, like statics, can be problematic because they can lead to memory leaks. Application helps solve this too.
Source class:
Intent myIntent = new Intent(this, NewActivity.class);
myIntent.putExtra("firstName", "Your First Name Here");
myIntent.putExtra("lastName", "Your Last Name Here");
startActivity(myIntent)
Destination Class (NewActivity class):
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.view);
Intent intent = getIntent();
String fName = intent.getStringExtra("firstName");
String lName = intent.getStringExtra("lastName");
}
You just have to send extras while calling your intent.
Like this:
Intent intent = new Intent(getApplicationContext(), SecondActivity.class);
intent.putExtra("Variable name", "Value you want to pass");
startActivity(intent);
Now on the OnCreate method of your SecondActivity you can fetch the extras like this.
If the value you sent was in long:
long value = getIntent().getLongExtra("Variable name which you sent as an extra", defaultValue(you can give it anything));
If the value you sent was a String:
String value = getIntent().getStringExtra("Variable name which you sent as an extra");
If the value you sent was a Boolean:
Boolean value = getIntent().getBooleanExtra("Variable name which you sent as an extra", defaultValue);
It helps me to see things in context. Here are two examples.
Passing Data Forward
Main Activity
Put the data you want to send in an Intent with a key-value pair. See this answer for naming conventions for the key.
Start the Second Activity with startActivity.
MainActivity.java
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
// "Go to Second Activity" button click
public void onButtonClick(View view) {
// get the text to pass
EditText editText = (EditText) findViewById(R.id.editText);
String textToPass = editText.getText().toString();
// start the SecondActivity
Intent intent = new Intent(this, SecondActivity.class);
intent.putExtra(Intent.EXTRA_TEXT, textToPass);
startActivity(intent);
}
}
Second Activity
You use getIntent() to get the Intent that started the second activity. Then you can extract the data with getExtras() and the key you defined in the first activity. Since our data is a String we will just use getStringExtra here.
SecondActivity.java
public class SecondActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
// get the text from MainActivity
Intent intent = getIntent();
String text = intent.getStringExtra(Intent.EXTRA_TEXT);
// use the text in a TextView
TextView textView = (TextView) findViewById(R.id.textView);
textView.setText(text);
}
}
Passing Data Back
Main Activity
Start the Second Activity with startActivityForResult, providing it an arbitrary result code.
Override onActivityResult. This is called when the Second Activity finishes. You can make sure that it is actually the Second Activity by checking the result code. (This is useful when you are starting multiple different activities from the same main activity.)
Extract the data you got from the return Intent. The data is extracted using a key-value pair. I could use any string for the key but I'll use the predefined Intent.EXTRA_TEXT since I'm sending text.
MainActivity.java
public class MainActivity extends AppCompatActivity {
private static final int SECOND_ACTIVITY_REQUEST_CODE = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
// "Go to Second Activity" button click
public void onButtonClick(View view) {
// Start the SecondActivity
Intent intent = new Intent(this, SecondActivity.class);
startActivityForResult(intent, SECOND_ACTIVITY_REQUEST_CODE);
}
// This method is called when the second activity finishes
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
// check that it is the SecondActivity with an OK result
if (requestCode == SECOND_ACTIVITY_REQUEST_CODE) {
if (resultCode == RESULT_OK) {
// get String data from Intent
String returnString = data.getStringExtra(Intent.EXTRA_TEXT);
// set text view with string
TextView textView = (TextView) findViewById(R.id.textView);
textView.setText(returnString);
}
}
}
}
Second Activity
Put the data that you want to send back to the previous activity into an Intent. The data is stored in the Intent using a key-value pair. I chose to use Intent.EXTRA_TEXT for my key.
Set the result to RESULT_OK and add the intent holding your data.
Call finish() to close the Second Activity.
SecondActivity.java
public class SecondActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
}
// "Send text back" button click
public void onButtonClick(View view) {
// get the text from the EditText
EditText editText = (EditText) findViewById(R.id.editText);
String stringToPassBack = editText.getText().toString();
// put the String to pass back into an Intent and close this activity
Intent intent = new Intent();
intent.putExtra(Intent.EXTRA_TEXT, stringToPassBack);
setResult(RESULT_OK, intent);
finish();
}
}
Updated Note that I had mentioned the use of SharedPreference. It has a simple API and is accessible across an application's activities. But this is a clumsy solution, and is a security risk if you pass around sensitive data. It's best to use intents. It has an extensive list of overloaded methods that can be used to better transfer many different data types between activities. Have a look at intent.putExtra. This link presents the use of putExtra quite well.
In passing data between activities, my preferred approach is to create a static method for the relevant activity that includes the required parameters launch the intent. Which then provides easily setup and retrieve parameters. So it can look like this
public class MyActivity extends Activity {
public static final String ARG_PARAM1 = "arg_param1";
...
public static getIntent(Activity from, String param1, Long param2...) {
Intent intent = new Intent(from, MyActivity.class);
intent.putExtra(ARG_PARAM1, param1);
intent.putExtra(ARG_PARAM2, param2);
return intent;
}
....
// Use it like this.
startActivity(MyActvitiy.getIntent(FromActivity.this, varA, varB, ...));
...
Then you can create an intent for the intended activity and ensure you have all the parameters. You can adapt for fragments to. A simple example above, but you get the idea.
Try to do the following:
Create a simple "helper" class (factory for your Intents), like this:
import android.content.Intent;
public class IntentHelper {
public static final Intent createYourSpecialIntent(Intent src) {
return new Intent("YourSpecialIntent").addCategory("YourSpecialCategory").putExtras(src);
}
}
This will be the factory for all your Intents. Everytime you need a new Intent, create a static factory method in IntentHelper. To create a new Intent you should just say it like this:
IntentHelper.createYourSpecialIntent(getIntent());
In your activity. When you want to "save" some data in a "session" just use the following:
IntentHelper.createYourSpecialIntent(getIntent()).putExtra("YOUR_FIELD_NAME", fieldValueToSave);
And send this Intent. In the target Activity your field will be available as:
getIntent().getStringExtra("YOUR_FIELD_NAME");
So now we can use Intent like same old session (like in servlets or JSP).
You can also pass custom class objects by making a parcelable class. Best way to make it parcelable is to write your class and then simply paste it to a site like http://www.parcelabler.com/. Click on build and you will get new code. Copy all of this and replace the original class contents.
Then-
Intent intent = new Intent(getBaseContext(), NextActivity.class);
Foo foo = new Foo();
intent.putExtra("foo", foo);
startActivity(intent);
and get the result in NextActivity like-
Foo foo = getIntent().getExtras().getParcelable("foo");
Now you can simply use the foo object like you would have used.
Another way is to use a public static field in which you store data, i.e.:
public class MyActivity extends Activity {
public static String SharedString;
public static SomeObject SharedObject;
//...
The most convenient way to pass data between activities is by passing intents. In the first activity from where you want to send data, you should add code,
String str = "My Data"; //Data you want to send
Intent intent = new Intent(FirstActivity.this, SecondActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.putExtra("name",str); //Here you will add the data into intent to pass bw activites
v.getContext().startActivity(intent);
You should also import
import android.content.Intent;
Then in the next Acitvity(SecondActivity), you should retrieve the data from the intent using the following code.
String name = this.getIntent().getStringExtra("name");
You can use SharedPreferences...
Logging. Time store session id in SharedPreferences
SharedPreferences preferences = getSharedPreferences("session",getApplicationContext().MODE_PRIVATE);
Editor editor = preferences.edit();
editor.putString("sessionId", sessionId);
editor.commit();
Signout. Time fetch session id in sharedpreferences
SharedPreferences preferences = getSharedPreferences("session", getApplicationContext().MODE_PRIVATE);
String sessionId = preferences.getString("sessionId", null);
If you don't have the required session id, then remove sharedpreferences:
SharedPreferences settings = context.getSharedPreferences("session", Context.MODE_PRIVATE);
settings.edit().clear().commit();
That is very useful, because one time you save the value and then retrieve anywhere of activity.
From Activity
int n= 10;
Intent in = new Intent(From_Activity.this,To_Activity.class);
Bundle b1 = new Bundle();
b1.putInt("integerNumber",n);
in.putExtras(b1);
startActivity(in);
To Activity
Bundle b2 = getIntent().getExtras();
int m = 0;
if(b2 != null){
m = b2.getInt("integerNumber");
}
The standard approach.
Intent i = new Intent(this, ActivityTwo.class);
AutoCompleteTextView textView = (AutoCompleteTextView) findViewById(R.id.autocomplete);
String getrec=textView.getText().toString();
Bundle bundle = new Bundle();
bundle.putString(“stuff”, getrec);
i.putExtras(bundle);
startActivity(i);
Now in your second activity retrieve your data from the bundle:
Get the bundle
Bundle bundle = getIntent().getExtras();
Extract the data…
String stuff = bundle.getString(“stuff”);
Kotlin
Pass from First Activity
val intent = Intent(this, SecondActivity::class.java)
intent.putExtra("key", "value")
startActivity(intent)
Get in Second Activity
val value = intent.getStringExtra("key")
Suggestion
Always put keys in constant file for more managed way.
companion object {
val KEY = "key"
}
You can send data between activities using intent object.
Consider you have two activities namely FirstActivity and SecondActivity.
Inside FirstActivity:
Using Intent:
i = new Intent(FirstActivity.this,SecondActivity.class);
i.putExtra("key", value);
startActivity(i)
Inside SecondActivity
Bundle bundle= getIntent().getExtras();
Now you can use different bundle class methods to get values passed from FirstActivity by Key.
E.g.
bundle.getString("key"),bundle.getDouble("key") ,bundle.getInt("key") etc.
If you want to tranfer bitmap between Activites/Fragments
Activity
To pass a bitmap between Activites
Intent intent = new Intent(this, Activity.class);
intent.putExtra("bitmap", bitmap);
And in the Activity class
Bitmap bitmap = getIntent().getParcelableExtra("bitmap");
Fragment
To pass a bitmap between Fragments
SecondFragment fragment = new SecondFragment();
Bundle bundle = new Bundle();
bundle.putParcelable("bitmap", bitmap);
fragment.setArguments(bundle);
To receive inside the SecondFragment
Bitmap bitmap = getArguments().getParcelable("bitmap");
Transfering Large Bitmaps
If you are getting failed binder transaction, this means you are exceeding the binder transaction buffer by transferring large element from one activity to another activity.
So in that case you have to compress the bitmap as an byte's array and then uncompress it in another activity, like this
In the FirstActivity
Intent intent = new Intent(this, SecondActivity.class);
ByteArrayOutputStream stream = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPG, 100, stream);
byte[] bytes = stream.toByteArray();
intent.putExtra("bitmapbytes",bytes);
And in the SecondActivity
byte[] bytes = getIntent().getByteArrayExtra("bitmapbytes");
Bitmap bmp = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
Intent intent = new Intent(YourCurrentActivity.this, YourActivityName.class);
intent.putExtra("NAme","John");
intent.putExtra("Id",1);
startActivity(intent);
You can retrieve it in another activity. Two ways:
int id = getIntent.getIntExtra("id", /* defaltvalue */ 2);
The second way is:
Intent i = getIntent();
String name = i.getStringExtra("name");
Supplemental Answer: Naming Conventions for the Key String
The actual process of passing data has already been answered, however most of the answers use hard coded strings for the key name in the Intent. This is usually fine when used only within your app. However, the documentation recommends using the EXTRA_* constants for standardized data types.
Example 1: Using Intent.EXTRA_* keys
First activity
Intent intent = new Intent(getActivity(), SecondActivity.class);
intent.putExtra(Intent.EXTRA_TEXT, "my text");
startActivity(intent);
Second activity:
Intent intent = getIntent();
String myText = intent.getExtras().getString(Intent.EXTRA_TEXT);
Example 2: Defining your own static final key
If one of the Intent.EXTRA_* Strings does not suit your needs, you can define your own at the beginning of the first activity.
static final String EXTRA_STUFF = "com.myPackageName.EXTRA_STUFF";
Including the package name is just a convention if you are only using the key in your own app. But it is a necessity to avoid naming conflicts if you are creating some sort of service that other apps can call with an Intent.
First activity:
Intent intent = new Intent(getActivity(), SecondActivity.class);
intent.putExtra(EXTRA_STUFF, "my text");
startActivity(intent);
Second activity:
Intent intent = getIntent();
String myText = intent.getExtras().getString(FirstActivity.EXTRA_STUFF);
Example 3: Using a String resource key
Although not mentioned in the documentation, this answer recommends using a String resource to avoid dependencies between activities.
strings.xml
<string name="EXTRA_STUFF">com.myPackageName.MY_NAME</string>
First activity
Intent intent = new Intent(getActivity(), SecondActivity.class);
intent.putExtra(getString(R.string.EXTRA_STUFF), "my text");
startActivity(intent);
Second activity
Intent intent = getIntent();
String myText = intent.getExtras().getString(getString(R.string.EXTRA_STUFF));
Here is my best practice and it helps a lot when the project is huge and complex.
Suppose that I have 2 activities, LoginActivity and HomeActivity.
I want to pass 2 parameters (username & password) from LoginActivity to HomeActivity.
First, I create my HomeIntent
public class HomeIntent extends Intent {
private static final String ACTION_LOGIN = "action_login";
private static final String ACTION_LOGOUT = "action_logout";
private static final String ARG_USERNAME = "arg_username";
private static final String ARG_PASSWORD = "arg_password";
public HomeIntent(Context ctx, boolean isLogIn) {
this(ctx);
//set action type
setAction(isLogIn ? ACTION_LOGIN : ACTION_LOGOUT);
}
public HomeIntent(Context ctx) {
super(ctx, HomeActivity.class);
}
//This will be needed for receiving data
public HomeIntent(Intent intent) {
super(intent);
}
public void setData(String userName, String password) {
putExtra(ARG_USERNAME, userName);
putExtra(ARG_PASSWORD, password);
}
public String getUsername() {
return getStringExtra(ARG_USERNAME);
}
public String getPassword() {
return getStringExtra(ARG_PASSWORD);
}
//To separate the params is for which action, we should create action
public boolean isActionLogIn() {
return getAction().equals(ACTION_LOGIN);
}
public boolean isActionLogOut() {
return getAction().equals(ACTION_LOGOUT);
}
}
Here is how I pass the data in my LoginActivity
public class LoginActivity extends AppCompatActivity {
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
String username = "phearum";
String password = "pwd1133";
final boolean isActionLogin = true;
//Passing data to HomeActivity
final HomeIntent homeIntent = new HomeIntent(this, isActionLogin);
homeIntent.setData(username, password);
startActivity(homeIntent);
}
}
Final step, here is how I receive the data in HomeActivity
public class HomeActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
//This is how we receive the data from LoginActivity
//Make sure you pass getIntent() to the HomeIntent constructor
final HomeIntent homeIntent = new HomeIntent(getIntent());
Log.d("HomeActivity", "Is action login? " + homeIntent.isActionLogIn());
Log.d("HomeActivity", "username: " + homeIntent.getUsername());
Log.d("HomeActivity", "password: " + homeIntent.getPassword());
}
}
Done! Cool :) I just want to share my experience. If you working on small project this shouldn't be the big problem. But when your working on big project, it really pain when you want to do refactoring or fixing bugs.
The passing of data between activities is mainly by means of an intent object.
First you have to attach the data to the intent object with the use of the Bundle class. Then call the activity using either startActivity() or startActivityForResult() methods.
You can find more information about it, with an example from the blog post Passing data to an Activity.
You can try Shared Preference, it may be a good alternative for sharing data between the activities
To save session id -
SharedPreferences pref = myContexy.getSharedPreferences("Session
Data",MODE_PRIVATE);
SharedPreferences.Editor edit = pref.edit();
edit.putInt("Session ID", session_id);
edit.commit();
To get them -
SharedPreferences pref = myContexy.getSharedPreferences("Session Data", MODE_PRIVATE);
session_id = pref.getInt("Session ID", 0);
You can use Intent
Intent mIntent = new Intent(FirstActivity.this, SecondActivity.class);
mIntent.putExtra("data", data);
startActivity(mIntent);
Another way could be using singleton pattern also:
public class DataHolder {
private static DataHolder dataHolder;
private List<Model> dataList;
public void setDataList(List<Model>dataList) {
this.dataList = dataList;
}
public List<Model> getDataList() {
return dataList;
}
public synchronized static DataHolder getInstance() {
if (dataHolder == null) {
dataHolder = new DataHolder();
}
return dataHolder;
}
}
From your FirstActivity
private List<Model> dataList = new ArrayList<>();
DataHolder.getInstance().setDataList(dataList);
On SecondActivity
private List<Model> dataList = DataHolder.getInstance().getDataList();
Write following code in CurrentActivity.java
Intent i = new Intent(CurrentActivity.this, SignOutActivity.class);
i.putExtra("SESSION_ID",sessionId);
startActivity(i);
Access SessionId in SignOutActivity.java is following way
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sign_out);
Intent intent = getIntent();
// check intent is null or not
if(intent != null){
String sessionId = intent.getStringExtra("SESSION_ID");
Log.d("Session_id : " + sessionId);
}
else{
Toast.makeText(SignOutActivity.this, "Intent is null", Toast.LENGTH_SHORT).show();
}
}
Start another activity from this activity pass parameters via Bundle Object
Intent intent = new Intent(getBaseContext(), YourActivity.class);
intent.putExtra("USER_NAME", "xyz#gmail.com");
startActivity(intent);
Retrieve on another activity (YourActivity)
String s = getIntent().getStringExtra("USER_NAME");
This is ok for simple kind data type.
But if u want to pass complex data in between activity u need to serialize it first.
Here we have Employee Model
class Employee{
private String empId;
private int age;
print Double salary;
getters...
setters...
}
You can use Gson lib provided by google to serialize the complex data
like this
String strEmp = new Gson().toJson(emp);
Intent intent = new Intent(getBaseContext(), YourActivity.class);
intent.putExtra("EMP", strEmp);
startActivity(intent);
Bundle bundle = getIntent().getExtras();
String empStr = bundle.getString("EMP");
Gson gson = new Gson();
Type type = new TypeToken<Employee>() {
}.getType();
Employee selectedEmp = gson.fromJson(empStr, type);
1st way: In your current Activity, when you create an object of intent to open a new screen:
String value="xyz";
Intent intent = new Intent(CurrentActivity.this, NextActivity.class);
intent.putExtra("key", value);
startActivity(intent);
Then in the nextActivity in the onCreate method, retrieve those values which you pass from the previous activity:
if (getIntent().getExtras() != null) {
String value = getIntent().getStringExtra("key");
//The key argument must always match that used send and retrieve value from one activity to another.
}
2nd way: You can create a bundle object and put values in a bundle and then put the bundle object in intent from your current activity -
String value="xyz";
Intent intent = new Intent(CurrentActivity.this, NextActivity.class);
Bundle bundle = new Bundle();
bundle.putInt("key", value);
intent.putExtra("bundle_key", bundle);
startActivity(intent);
Then in the nextActivity in the onCreate method, retrieve those values which you pass from the previous activity:
if (getIntent().getExtras() != null) {
Bundle bundle = getIntent().getStringExtra("bundle_key");
String value = bundle.getString("key");
//The key argument must always match that used send and retrieve value from one activity to another.
}
You can also use the bean class to pass data between classes using serialization.
/*
* If you are from transferring data from one class that doesn't
* extend Activity, then you need to do something like this.
*/
public class abc {
Context context;
public abc(Context context) {
this.context = context;
}
public void something() {
context.startactivity(new Intent(context, anyone.class).putextra("key", value));
}
}
I recently released Vapor API, a jQuery flavored Android framework that makes all sorts of tasks like this simpler. As mentioned, SharedPreferences is one way you could do this.
VaporSharedPreferences is implemented as Singleton so that is one option, and in Vapor API it has a heavily overloaded .put(...) method so you don't have to explicitly worry about the datatype you are committing - providing it is supported. It is also fluent, so you can chain calls:
$.prefs(...).put("val1", 123).put("val2", "Hello World!").put("something", 3.34);
It also optionally autosaves changes, and unifies the reading and writing process under-the-hood so you don't need to explicitly retrieve an Editor like you do in standard Android.
Alternatively you could use an Intent. In Vapor API you can also use the chainable overloaded .put(...) method on a VaporIntent:
$.Intent().put("data", "myData").put("more", 568)...
And pass it as an extra, as mentioned in the other answers. You can retrieve extras from your Activity, and furthermore if you are using VaporActivity this is done for you automatically so you can use:
this.extras()
To retrieve them at the other end in the Activity you switch to.
Hope that is of interest to some :)
First Activity:
Intent intent = new Intent(getApplicationContext(), ClassName.class);
intent.putExtra("Variable name", "Value you want to pass");
startActivity(intent);
Second Activity:
String str= getIntent().getStringExtra("Variable name which you sent as an extra");
Use a global class:
public class GlobalClass extends Application
{
private float vitamin_a;
public float getVitaminA() {
return vitamin_a;
}
public void setVitaminA(float vitamin_a) {
this.vitamin_a = vitamin_a;
}
}
You can call the setters and the getters of this class from all other classes.
Do do that, you need to make a GlobalClass-Object in every Actitity:
GlobalClass gc = (GlobalClass) getApplication();
Then you can call for example:
gc.getVitaminA()
Related
I am trying to send the value stored in a variable my_var from one activity to the other in Android. There are probably already many similar questions here at SOV, but I have been trying things by my own, and so far, no success. I shall highly appreciate little help or hints on what I am doing wrong?
My (pseudo/example) code is like this:
public class MyActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {
public String my_var;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.my_layout);
My_method();
}
public void my_method() {
// This is a method that makes HTTP GET request and parse response to my_var
my_var = responseObject1.getX() + " " + responseObject1.getY()
}
// Then, at the bottom of MyActivity, I am creating an Intent to pass my_var to another activity to show it in TextView.
// I took this method from here[.][1]
public void rsa_key(String s){
Intent intent = new Intent(getBaseContext(), AnotherClass.class);
intent.putExtra("my_var", my_var);
startActivity(intent);
}
}
Then, in the other activity (in OnCreate), I am trying to get my_var like this:
// public String my_var in initialization
Intent intent = getIntent();
my_var = intent.getStringExtra("my_var");
The app compiles, and I get no errors, but I can't see my_var value (XML layout) when put it in TextView.setText(my_var); in the other activity. There were no useful hints in the log as well. Can somebody help me to understand what am I doing wrong? or missing something.
I also tried SharedPreferences like this but no luck!
In first acitvity:
SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(this);
SharedPreferences.Editor editor = sharedPref.edit();
editor.putString("varKey", my_var);
editor.commit();
Second actvity:
SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(this);
my_var = sharedPref.getString("varKey", my_var);
I shall highly appreciate help/suggestions to fix this. Many thanks!
try this code for putExtra and get data in the second activity.
Use this to "put" the file...
Intent i = new Intent(FirstScreen.this, SecondScreen.class);
i.putExtra("my_var", my_var);
startActivity(i);
Then, to retrieve the value try something like:
String newString;
if (savedInstanceState == null) {
Bundle extras = getIntent().getExtras();
if(extras == null) {
newString= null;
} else {
newString= extras.getString("my_var");
}
} else {
newString= (String) savedInstanceState.getSerializable("my_var");
}
This question already has answers here:
How do I pass data between Activities in Android application?
(53 answers)
Closed 3 years ago.
I'm writing an android app that tracks your weight and BMI. In order to update or set the two values for the first time, there is a second activity that allows me to input the values that should then pass to the first activity.
I've tried to achieve this in a few ways, the closest I got is the code below:
Second Activity: (UpdateProgressActivity.java)
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_body_progress);
Intent intentWeight = getIntent();
String WeightText = intentWeight.getStringExtra(EXTRA_MESSAGE);
TextView messageWeight = findViewById(R.id.weight);
messageWeight.setText(WeightText);
Intent intentBMI = getIntent();
String BMIText = intentBMI.getStringExtra(EXTRA_MESSAGE);
TextView messageBMI = findViewById(R.id.bmi);
messageBMI.setText(BMIText);
updateButton = findViewById(R.id.updateBodyProgress);
updateButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
openActivityUpdateProgress();
}
});
}
First Activity: (BodyProgressActivity.java)
public class UpdateProgressActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_update_progress);
Button confirmProgress;
confirmProgress = findViewById(R.id.confirmBodyStatus);
confirmProgress.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
returnToActivityProgress();
}
});
}
protected void returnToActivityProgress() {
Intent intent = new Intent(this, BodyProgressActivity.class);
startActivity(intent);
}
public void createStatus(View view) {
EditText messageWeight = findViewById(R.id.textNewWeight);
String textWeight = messageWeight.getText().toString();
Intent intentWeight = new Intent(Intent.ACTION_SEND); intentWeight.setType("text/plain");
intentWeight.putExtra(Intent.EXTRA_TEXT, textWeight);
String textWeigthTemp = getString(R.string.currentWeight);
Intent chosenIntentWeight = Intent.createChooser(intentWeight, textWeigthTemp);
startActivity(chosenIntentWeight);
EditText messageBMI = findViewById(R.id.textNewWeight);
String textBMI = messageBMI.getText().toString();
Intent intentBMI = new Intent(Intent.ACTION_SEND); intentBMI.setType("text/plain");
intentWeight.putExtra(Intent.EXTRA_TEXT, textBMI);
String textBMITemp = getString(R.string.currentBMI);
Intent chosenIntentBMI = Intent.createChooser(intentWeight, textBMITemp);
startActivity(chosenIntentBMI);
}
}
I'm getting the values from "textNewWeight" and "textNewBMI" from the second activity and must pass them to "weight" and "bmi" on the first activity.
What I'm getting in the first activity is just blank.
In the first activity. Use this code. We are using putExtra method to send the data to next activity through key and value. Key is the 1st parameter and value is the 2nd parameter. Key name can be your choice and it is used to retrieve the data in the 2nd activity. Value is the data which you want ti send to next activity.
Intent i=new Intent(firstactivity.this,secondactivity.class);
String weight=messageWeight.getText().toString();
i.putExtra(“weight”,weight);
startActivity(i);
In the second activity,use this to recieve the data.
Bundle b=getIntent().getExtras();
String recievedWeight=b.getString(“weight”);
the parameter name in the b.getString(“”) must be same as which you have declared in the 1st activity.
I'm a noobie making a quiz in Android Studio and i'm trying to pass an integer between activities to add to the amount of questions they got correct for the end but in the second activity it isn't changing when I answer the first question correct.
Question1 activity:
public class Question1 extends AppCompatActivity {
public int correctAnswers = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_question1);
Intent intent = new Intent(Question1.this, Question2.class);
Intent i = getIntent();
Intent answersCorrect = new Intent(Question1.this, Question2.class);
answersCorrect.putExtra("correctAnswers", correctAnswers);
}
public void submitQuestion1(View view) {
EditText question1TextInput = (EditText) findViewById(R.id.question1TextInput);
if (question1TextInput.getText().toString().length() >= 1) {
startActivity(new Intent(Question1.this, Question2.class));
if (question1TextInput.getText().toString().toUpperCase().contentEquals("FATHER")) {
correctAnswers += 1;
Intent answersCorrect = new Intent(Question1.this, Question2.class);
answersCorrect.putExtra("correctAnswers", correctAnswers);
}
}
}
}
Question2 Activity:
public class Question2 extends AppCompatActivity {
public int correctAnswers;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_question2);
Intent intent = getIntent();
int number = intent.getIntExtra("correctAnswers", 0);
TextView myAwesomeTextView = (TextView)findViewById(R.id.text);
myAwesomeTextView.setText(String.valueOf(number));
}
}
you duplicate your intent here:
Intent intent = new Intent(Question1.this, Question2.class);
Intent i = getIntent();
Intent answersCorrect = new Intent(Question1.this, Question2.class);
answersCorrect.putExtra("correctAnswers", correctAnswers);
replace it to:
Intent intent = new Intent(Question1.this, Question2.class);
intent.putExtra("correctAnswers", correctAnswers);
startActivity(intent);
in your second Activity:
int correctAnswers;
correctAnswers = (int) getIntent().getIntExtra("correctAnswers", 0);
So basically, when you have one activity and want to open a second activity, an Intent is the most important thing to have. It's responsible for communcation between your system and your application.
Intent is responsible for starting an activity, starting a service, and delivering a broadcast.
Note that there are two different types of intent: Explicit and Implicit.
Explicit Intent is used in this manner:
You have Activity_1 and you KNOW that you want to start Acticity_2 FROM Activity_1.
Implicit Intent is used when you DON'T know the name of the activity that you want to start.
Now, I know you probably understand what the StartActivity() method DOES, but StartActivity always requires an intent to go into the parenthesis. StartActivity(Activity_2); will not work.
So, when using Explicit Intent:
Intent i = new Intent(Activity_1.this, Activity_2.class);
StartActivity(i);
You start with making a reference - i - and, inside the parameters, the first being the activity from which you are calling the second activity, and the second being the activity which you want to call.
Here's a video on Intents as well: https://youtu.be/FH1Ym1KjJNc
Hope this helped.
Move the intent to a field. You only need it once.
Then, the issue is that you start the other activity too soon, without setting any value. You started the other activity with an empty, new Intent
public class Question1 extends AppCompatActivity {
public int correctAnswers = 0;
final Intent answersIntent = new Intent(Question1.this, Question2.class);
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_question1);
}
public void submitQuestion1(View view) {
EditText question1TextInput = (EditText) findViewById(R.id.question1TextInput);
String answer = question1TextInput.getText().toString();
// No need to check for length if directly checking another string
if (answer.toUpperCase().contentEquals("FATHER")) {
answersIntent.putExtra("correctAnswers", ++correctAnswers);
startActivity(answersIntent);
}
}
If you plan on sharing that value over many questions, try SharedPreferences.
FWIW, make a generic View for any question that has the question text and possible answer fields. Try not to make one activity per question.
I want to pass an ArrayList<String> and an ArrayList<Boolean> to my next activity, but whatever I try, it always seems to overwrite my first ArrayList with my second. Even if I use a boolean array in stead of an ArrayList, the same problem occurs. The KEY's are different and the values as well. I tried many things already (can't remember all of it), including Bundles, but the same keeps happening. What am I doing wrong?
In both cases (and many others), data comes back null.
EDIT: Cleaned up code after a night's sleep, as I noticed there were indeed some mistakes in it. Also, these are 2 ways that I tried to do it, but neither work.
In activity 1:
boolean [] checksDataOut;
private ArrayList<String> data = new ArrayList();
intent.putStringArrayListExtra(EXTRA_TODEVICES, data);
intent.putExtra(EXTRA_TO_DEVICES, checksDataOut);
startActivity(intent);
In Activity 2
public class DevicesInfo extends AppCompatActivity {
public ArrayList<String> data = new ArrayList();
public boolean [] checksDataIn;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_devices_info);
Intent intent = getIntent();
data = intent.getStringArrayListExtra(EXTRA_TODEVICES);
checksDataIn = intent.getBooleanArrayExtra(EXTRA_TO_DEVICES);
}
}
In activity 1:
private ArrayList<String> data = new ArrayList();
boolean [] checksDataOut;
Bundle extrasOut = new Bundle();
extrasOut.putStringArrayList(EXTRA_TODEVICES, data);
extrasOut.putBooleanArray(EXTRA_TO_DEVICES, checksDataOut);
intent.putExtras(extrasOut);
startActivity(intent);
In activity 2:
public class DevicesInfo extends AppCompatActivity {
public ArrayList<String> data = new ArrayList();
public ArrayList<Boolean> checksData = new ArrayList();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_devices_info);
Intent intent = getIntent();
Bundle bundle = intent.getExtras();
data = bundle.getStringArrayList(EXTRA_TODEVICES);
checksData = (ArrayList<Boolean>) bundle.get(EXTRA_TO_DEVICES);
}
}
Personally, I prefer placing that variable in the main activity, the activity which will only die when I close the program. I put it there as a public static variable. So when I launch a new activity, I just instruct it to retrieve data from the variable onCreate or onResume. I know some may say, it's poor programming. At least I can control the content effectively.
In base Activity: or Activity1 create these static fields:
public static ArrayList<String> data;
public static ArrayList<Boolean> checksData;
just before you call Activity2, update these 2 variables.
then call the Activity2 normally.
as Activity2 is created or resumed, where you need data, call data in Activity1, like this Activity1.data; where you want to use checksData, call Activity1.checksData.
First, If you plan on using getBooleanArray, you need to pass a boolean[] using putExtra not a list.
Second, it's null if it cannot be found. It's not clear where your constants are defined but they must be the same, so try using a regular string while debugging.
Putting
boolean[] checksDataOut;
...
Bundle extrasOut = new Bundle();
extrasOut.putBooleanArray("boolArray", checksDataOut);
intent.putExtras(extrasOut);
// or intent.putExtra("boolArray", checksDataOut);
startActivity(intent);
Getting
public boolean[] checksDataIn;
...
Intent intent = getIntent();
checksDataIn = intent.getBooleanArrayExtra("boolArray");
If it's still null, put a break point or log the entire contents of the Bundle to the logcat.
I want to make an app which plays sounds with different amount of times between sounds but I don't know how to do it.
The amount of times are defined by the user in EditText in a setting activity and then the songs are played in another activity so I need to link the EditText value in the other activity.
Here is my code to transform the content of my EditText into a variable but I don't know how to use it in my other interface :
EditText myEdit = (EditText) findViewById(R.id.editText1);
String myEditValue = myEdit.getText().toString();
time = Integer.parseInt(myEditValue);
It would be even better if someone can tell me how to transfer my EditText value in an enum but if you only know how to transfer between activities and not from an activity to an enum it will be ok.
Here is my enum code :
public enum phaseTimer {
WAITING("APPUYEZ", valueInEditText1),
LOADING("ATTENTE", valueInEditText2),
ON_YOUR_MARK("A VOS MARQUES", valueInEditText3),
READY("PRET", valueInEditText4),
GO("PARTEZ", valueInEditText5);
public String message;
public int time;
phaseTimer(String message, int time) {
this.message = message;
this.temps = temps;
}
public String getMessage() {
return message;
}
}
Intent i = new Intent(this, theotheractivityname.class);
i.putExtra("myEditValue",myEditValue );
startActivity(i);
from the other activity, you can get your string with
String newString;
Bundle extras = getIntent().getExtras();
newString= extras.getString("myEditValue");
This is a simple way here:
Intent intent = new Intent(getBaseContext(), YourClass.class);
intent.putExtra("EXTRA_SESSION_ID", yourVariable);
startActivity(intent);
Access that intent on next activity
String s = getIntent().getStringExtra("EXTRA_SESSION_ID");
Credit to this answer: How do I pass data.....