Develop Reference

Close MainActivity(main) from another activity (ActivityPoliticas)

I'm looking for a solution to press the (non-personalized ads) button of the ActivityPolicies and close the MainActivity and then reopen the MainActivity with the correct ad.
MainActivity(principal)
public void politicas(View view) // button
{
Intent i = new Intent (this, ActivityPolicies.class);
i.putExtra("valor","politicas");
startActivity(i);
}
ActivityPolicies
public void NonPersonalizedAdvertising(View view) //button
{
SharedPreferences myPreferences = PreferenceManager.getDefaultSharedPreferences(MensajePoliticas.this);
SharedPreferences.Editor myEditor =myPreferences.edit();
myEditor.putString("POLITICAS","LEIDO_NOACEPTADO");
myEditor.commit();
//Missing some option to close the main activity
*
*
*
//Reopen the main activity
Intent entrar=new Intent(this,MainActivity.class);
startActivity(entrar);
finish(); // Close the current activity (ActivityPolicies)
}
The goal is to close the MainActivity to reload the correct personalized or non-personalized ad. I already have the code but I am missing this option to reload the MainActivity.
Another question:
Close the main activity to reload the ads, can I have problems with some Admob rule?
Thank you very much

If your MainActivity is in backstack, you can call same activity like this:
Intent entrar = new Intent(this,MainActivity.class);
entrar.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); // this will open the same MainActivity instance and also give you a new intent.
startActivity(entrar);
Now in your MainActivity you can override onNewIntent
#Override
protected void onNewIntent(Intent intent) {
super.onNewIntent(intent);
// here you will get the new Intent. You can reload only the ads programmatically or just call `this.recreate();`
}

Android setContentView on pretty short Activity life time

The first activity of my android app, the "launcher activity", finishes pretty quickly. It's goal is to redirect to the MainActivity or to the UserLoginActivity, depending on the value of a shared-preferences variable.
If this variable does not exist, it automatically perform a StartActivity to the MainActivity.
If this variable is set, then it will perform an HTTP request to my API, in order to Authenticate the user. Then it will start the MainActivity. The HTTP request usually takes less than one second.
The thing is that I would like to display a progress bar, in the center of the LauncherActivity, so the user can understand that something is loading.
The problem is that nothing is displayed on the screen. But if I comment the line that starts the activity, then it will be displayed... It seems that the activity duration is too fast to display anything !
I thought calling the setContentView() method will instantly load Views on the screen. Is my case a normal behavior ? How could I display a progress bar on the screen, knowing that the activity will last around one second ?
Here you can see my Launcher Activity
public class Launcher extends Activity {
private void goToUserLogin(){
Intent intent;
intent = new Intent(this, UserLoginActivity.class);
startActivity(intent);
finish();
}
private void goToMain(){
YokiAPI API = new YokiAPI(this);
Intent intent;
try {
if (API.authenticateSmart(YokiGlobals.preferences.getSavedUserId(this))) {
intent = new Intent(this, MainActivity.class);
startActivity(intent);
finish();
} else {
this.goToUserLogin();
}
} catch (Exception e){}
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_launcher);
// Launch Demo if First Run
if (YokiGlobals.preferences.getFirstLaunch(this)){
YokiGlobals.preferences.updateFirstLaunch(false, this);
this.launchDemo();
}
/*
** If userId saved, smart Auth and go to Main
** Else go to User Login for Full Auth or register
*/
if (YokiGlobals.preferences.getSavedUserId(this) == null){
this.goToUserLogin();
}
else {
this.goToMain();
}
}
}
And the .xml ressource file
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="THIS TEXT WONT APPEAR"
android:layout_marginTop="208dp"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true" />
</RelativeLayout>
Thanks,
Oscar

I thought calling the setContentView() method will instantly load Views on the screen
No it won't because you are still in onCreate(). If you want to see any UI you need to let the activity cycle to go further, so rework your code or move your authentication to separate activity, meybe?
PS: you use this. without any real reason.

Thank you for your help. I used AsyncTask in order to fetch data from the API.
The main UI thread can now load the view.
Here is some very simplified code that maybe could help others.
public class UserSmartAuthActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_user_smart_auth);
new SmartAuth().execute();
}
private class SmartAuth extends AsyncTask<Void, Void, Void> {
#Override
protected Void doInBackground(Void... params) {
Context context = getApplicationContext();
YokiAPI API = new YokiAPI(context);
Intent intent = null;
try {
if (API.authenticateSmart(YokiGlobals.preferences.getSavedUserId(context)))
intent = new Intent(context, MainActivity.class);
else
intent = new Intent(context, UserLoginActivity.class);
} catch (Exception e){}
startActivity(intent);
finish();
return null;
}
}
}

How to update Activity from thread started in another activity?

I have a Main activity and after click on button I start thread (but the thread is hidden in library and I have only callback in Main activity.
Now I want to start another activity (call A) where I want to put results from the thread.
Below is simplified code:
public class Main extends Activity {
XManager.ResultsCallback xResultsCallback = new XManager.ResultsCallback() {
// the method is called every 10 sec.
#Override
public void onResult(ArrayList<String> texts) {
}
};
XManager xManager = new xManager(xResultsCallback);
View.OnClickListener onClick = new View.OnClickListener() {
#Override
public void onClick(View arg0) {
XManager.start();
Intent i = new Intent(Main.this, A.class);
startActivity(i);
}
};
}
I want to update the content of A activity each time when onResult() method is called. How to do that?

Use LocalBroadcastManager,
In your Main Activity create function :
private void sendResult() {
Log.d("sender", "Broadcasting message");
Intent intent = new Intent("custom-event-name");
// You can also include some extra data.
intent.putExtra("message", "This is my result!");
LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
}
and add BroadcastReceiver in your A Activity
private BroadcastReceiver onResult= new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
Log.d("jazzy","onReceive called");
}
};
add on OnCreate
#Override
public void onCreate(Bundle savedInstanceState) {
// Register to receive messages.
LocalBroadcastManager.getInstance(this).registerReceiver(mMessageReceiver,
new IntentFilter("custom-event-name"));
}
add onDestroy
#Override
protected void onDestroy() {
LocalBroadcastManager.getInstance(this).unregisterReceiver(mMessageReceiver);
super.onDestroy();
}

I have a suggestion that you should do as follows:
Start Your Activity A on button click
Inside Activity A declare your XManager instance with a callback present in A itself
Then start your XManager as XManager.start(); that way you would be getting all the callbacks in your desired activity.
Have a great day!

I think if you want to decouple the logic, beside you can use the Android BroadcastReceiver, the another flexible choice is to use the Bus
And you can integrate it with gradle easily
dependencies {
compile 'com.squareup:otto:+'
}

onBackPressed() not working while coming from another activity

I have three activities: First, Second and Third. I used this method in Second activity:
public void onBackPressed() {
super.onBackPressed();
finish();
}
and this on Third activity:
public void onBackPressed() {
super.onBackPressed();
Intent i = new Intent(Third.this, Second.class);
startActivity(i);
finish();
}
The problem is when I press back button after coming from the Third activity, I am going into First activity instead of finish(). I am successfully exiting the application when I click back button right after coming from first activity but not after coming from Third activity.
How to solve this problem?
EDIT: Thanks for the answers guys,the answer of "Ved Prakash" solved the problem for me.But i have a weird problem now.When i press back button the app is successfully exiting but the app which i minimized to Recent Apps button is coming on to the screen and exiting.For example,if i have opened Setting app before opening my app,when i press back button,my app is exiting and immediately Settings app is also opening and exiting itself.What might be the problem?

Your problem is that you don't seem to understand how Activities work. The finish() function ends the current Activity, and then you receive the previous Activity from the backstack.
My recommendation is that you should use a single Activity, and hold Fragments inside it. If you want it so that pressing the Back button ends the application at any screen that is displayed, you could do the following:
Activity XML:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/initial_container"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
Activity that holds the Fragments:
public class InitialActivity extends FragmentActivity implements ReplaceWith
{
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_initial);
getSupportFragmentManager().addOnBackStackChangedListener(new OnBackStackChangedListener()
{
public void onBackStackChanged()
{
int backCount = getSupportFragmentManager().getBackStackEntryCount();
if (backCount == 0)
{
finish();
}
}
});
if (savedInstanceState == null)
{
getSupportFragmentManager().beginTransaction().add(R.id.initial_container, new FirstFragment()).commit();
}
}
#Override
public void replaceWith(Fragment fragment)
{
getSupportFragmentManager().beginTransaction().replace(R.id.initial_container, fragment).commit();
}
}
Example for a Fragment:
public class FirstFragment extends Fragment implements View.OnClickListener
{
private ReplaceWith activity_replaceWith;
private ImageView exampleImage;
public FirstFragment()
{
super();
}
#Override
public void onAttach(Activity activity)
{
super.onAttach(activity);
try
{
activity_replaceWith = (ReplaceWith) activity;
}
catch (ClassCastException e)
{
Log.e(getClass().getSimpleName(), "Activity of " + getClass().getSimpleName() + "must implement ReplaceWith interface!", e);
throw e;
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
View rootView = inflater.inflate(R.layout.fragment_first, container, false);
exampleImage = (ImageView) rootView.findViewById(R.id.fragment_first_example_image);
exampleImage.setOnClickListener(this);
return rootView;
}
#Override
public void onClick(View v)
{
if(v == exampleImage)
{
activity_replaceWith.replaceWith(new SecondFragment());
//please note that this should be done only if you are planning
//only on single-screen applications
//with no other layouts based on orientation or size
//otherwise, the Activity needs to be responsible for this, not the Fragment
}
}
}
This way, when you press the Back button, your application would end from any displayed screen.

Ok your code is wrong.
If you will look at activity source, you see that activity.onBackPressed() is calling finish(). So if call super.onBackPressed() you don't need to call finish.
Finish() is not stopping your application, it's stopping current activity.
Your code on third activity very strange. You are trying to stop activity and start another same activity.
What exactly you want to achieve?
If you want to exit application from your third activity, you need to clear your backstack. But I think you have problem with structure of your app.

Ok. then you should finish your first activity when you go to second activity like this(If you are using intent for that):
Intent it=new Intent(FirstActivity.this,SecondActivity.class);
finish();
startactivity(it);
and same for Second Activity:
Intent it=new Intent(SecondActivity.this,ThirdActivity.class);
finish();
startactivity(it);
this done your work...when you are in third activity the above activities are finished..
and when you press backButton you will be exit from application..
Good luck.

You can use -
public static final int FLAG_ACTIVITY_CLEAR_TOP
If set, and the activity being launched is already running in the
current task, then instead of launching a new instance of that
activity, all of the other activities on top of it will be closed and
this Intent will be delivered to the (now on top) old activity as a
new Intent.
And here is how -
When the user wishes to exit all open activities, they should press a button which loads the first Activity that runs when your app starts, in my case "MainActivity".
Intent intent = new Intent(getApplicationContext(), LoginActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intent.putExtra("EXIT", true);
startActivity(intent);
The above code clears all the activities except for LoginActivity. LoginActivity is the first activity that is brought up when the user runs the program. Then put this code inside the LoginActivity's onCreate, to signal when it should self destruct when the 'Exit' message is passed.
if (getIntent().getBooleanExtra("EXIT", false)) {
finish();
}
This explanation part is also introduced at exit-an-android-app.

Android - creating a "to next page" button

i have this code but every time i run the app and click on my button it crashes and i don't get why.. am i doing something wrong here any help would be great thanks
im trying to got to the "Sec.class" page/class
public class APPcalendarActivity extends Activity implements OnClickListener{
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
View continueButton = findViewById(R.id.continue_button);
continueButton.setOnClickListener( (OnClickListener) this);
}
//#Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch (v.getId()) {
case R.id.continue_button:
Intent i = new Intent(this, Sec.class);
startActivity(i);
break;
}
}
THIS IS WHAT I WAS MISSING IN THE MANISFEST.XML FILE
and i want to slap the person who downgraded my question
<activity android:name=".Sec"
android:label="#string/sec" >
</activity>

Check that you've declared an <activity> tag for the Sec activity in your AndroidManifest.xml.
But posting (or simply reading) the crash stacktrace from logcat would be more instructive.

Without knowing what the error is, it is really hard to guess what the problem is, but usually when this happens, the button (continueButton in your case) could not be found in the layout. So make sure that you have a View with id continue_button in main.xml.