Develop Reference

Android toasts sometimes not showing when the app was started for the first time

I understand that the title might sound a little bit misleading, but it will make sense in a second.
When does the problem occur?
The toasts are shown always, but not at the first time when the user launches the app. When the app is fired for the first time an App Intro is being displayed, In my MainActivity i check my SharedPreferencesand start an Intent which holds the AppIntro when the user visits the app the first time.
I show a quick Intro and also ask the User for the Storage Permission Then my SearchFragment in the corresponding ViewPager is shown.
When and where are the Toasts being fired?
When the user clicks on a Button, I call the method showInfoToast() where I pass the Context and the String as Argument and then my Toasts are being shown. I use the Library Toasty from GrenderG but it doesn't make any difference with the default Toast.
public static void showInfoToast(String infoMessage, Context context) {
Toasty.info(context, infoMessage, Toast.LENGTH_SHORT, true).show();
}
What have I tried / what do I think the problem is?
The Context passed to the method. As said I call the method showInfoToast in my onClickListener in the SearchFragment I pass getContext() But it seems not to be the problem, as I have seen when I stepped over it with the Debugger, Context is from the MainActivity.
The Library Toasty but the same error occures in the default Toasts
That's why in my opinion somehow the App Intro Intent messes up the Context/The SearchFragment the problem has to be there as it only happens on the first launch of the app.
Code snippet onClickListener in Search Fragment:
goViralButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
synchronized (this) {
showInfoToast("Please add users", getContext());
}
}
});
Code snippet App Intro launched by the MainActivity:
// Initialize SharedPreferences
SharedPreferences getPrefs = PreferenceManager
.getDefaultSharedPreferences(getBaseContext());
// Create a new boolean and preference and set it to true
boolean isFirstStart = getPrefs.getBoolean("firstStart", true);
// If the activity has never started before...
if (isFirstStart) {
// Launch app intro
final Intent i = new Intent(MainActivity.this, IntroActivity.class);
runOnUiThread(new Runnable() {
#Override
public void run() {
startActivity(i);
}
});
// Make a new preferences editor
SharedPreferences.Editor e = getPrefs.edit();
// Edit preference to make it false because we don't want this to run again
e.putBoolean("firstStart", false);
// Apply changes
e.apply();
}
Logcat output when I press the goViral Button:
Unable to start animation, surface is null or no children.
Toast already killed
...

How to finish the main activity from other Activity

Hello how do you finish Main activity
Assume that there are 3 Activities and 1 Fragment
LoginActivity , MainActivity, infoFrgMent, ChangePwdActivity.
The scenario is when I loggedin in LoginActivitythen MainActivity will show up LoginActivity will finish() then i will go to my info which is 'infoFrgMent' then i want to change my password after i changed my password.
LoginActivity will shows up Again to relogin but whenever i try to press back MainActivity shows up and didn't finished.

You need to remove previous activities form stack
setFlags to intent from MainActivity to LoginActivity
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
refer : https://developer.android.com/guide/components/activities/tasks-and-back-stack.html

What you need is to add the Intent.FLAG_CLEAR_TOP. This flag makes sure that all activities above the targeted activity in the stack are finished and that one is shown.
Another thing that you need is the SINGLE_TOP flag. With this one you prevent Android from creating a new activity if there is one already created in the stack.
Just be wary that if the activity was already created, the intent with these flags will be delivered in the method called onNewIntent(intent) (you need to overload it to handle it) in the target activity.
Then in onNewIntent you have a method called restart or something that will call finish() and launch a new intent toward itself, or have a repopulate() method that will set the new data. I prefer the second approach, it is less expensive and you can always extract the onCreate logic into a separate method that you can call for populate.

To finish another Activity you have to create a static method to finish this Like here:
MainActivity.java
private static MainActivity activity;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_activity);
activity = this;
}
public static void finishThis()
{
try
{
if (activity != null)
{
activity.finish();
}
}
catch (Exception ex)
{
ex.printStackTrace();
}
}
And call it like this:
AnotherActivity.java
MainActivity.finishThis();
That's it

Add data to recyclerView from Sqlite in realtime?

I've made an app that is receiving some data from a TCP Client to my TCP Server that store the data in SQlite DB, and actually i've made a recyclerView where to visualize all that data but now my issue is what i'm trying like 2 weeks to refresh the recyclerView in real Time, i mean if a TCP Client will send a new package to my TCP Server and if i'm in the activity with the recyclerView the data have to be added dynamically.
I will also accept any type of tips and suggestions on how to improve my app.
Actually it's my 1st app i've ever created in Android.
HERE you can find my Server(TCPServer),RecyclerViewAdapter,Adapter(constructor),allert.java(class where i invoke the RecyclerViewAdapter.
Hope someone will be able to help me and ill be very grateful.

Try sending broadcast method. Here are the steps :
Make a inner class that extends BroadcastReceiver in your activity.
private class ExampleBroadcastReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
//do stuffs here, e.g. getting extras from intent
}
Declare a instance of the class outside any methods.
public class MainActivity extends AppCompatActivity {
private ExampleBroadcastReceiver exampleBroadcastReceiver;
#Override
protected void onCreate(Bundle savedInstanceState) {
//stuffs
}
}
Override onResume method. Initialize the instance you just made in this method. Then, register it with a intent-filter. This will make sure that your broadcast receiver ready when user open the activity.
#Override
protected void onResume() {
super.onResume();
IntentFilter filter = new IntentFilter();
filter.addAction("com.example.MainActivity");
exampleBroadcastReceiver = new ExampleBroadcastReceiver();
LocalBroadcastManager.getInstance(this).registerReceiver(exampleBroadcastReceiver, filter);
}
Override onPause method and unregister your receiver.
#Override
protected void onPause() {
super.onPause();
try {
LocalBroadcastManager.getInstance(this).unregisterReceiver(exampleBroadcastReceiver);
} catch (IllegalArgumentException e) {
if (!e.getMessage().contains("Receiver not registered")) {
// unexpected, re-throw
throw e;
}
Make sure you use ArrayList for dynamic data.
Whenever you receive data from server, after you store them in your database, send a broadcast with extras contains data you want to display in your activity.
EDITED
I registered the receiver using an instance of LocalBroadcastManager.

How to display a toast message in only one activity?

In an application I am developing I have some code that attempts to submit information to the internet. If the connection can not be made, I pop up a toast message instructing the user to check the network connection.
Toast.makeText(getApplicationContext(), "Check network connection.", Toast.LENGTH_SHORT).show();
The problem I have is the toast message comes up no matter what the user is looking at! Even if the user is in a different app and my app is running in the background! This is not the desired behavior as I send a notification to the user if network activity fails. I only want the toast message to appear if the user is in the activity that is generating the network activity. Is there a way to do this?
If this is not possible my idea was to just put some kind of visual element in my activity - rather than display a toast message.
Thank You!

You can use a boolean class member in order to keep track of activity state changes.
public class YourClass extends Activity {
private boolean mIsResumed = false;
#Override
public void onResume() {
super.onResume();
mIsResumed = true;
}
#Override
public void onPause() {
super.onPause();
mIsResumed = false;
}
public boolean isResumed() {
return mIsResumed;
}
}
Then you can use something like this:
if (isResumed()) {
//show Toast
}

Use a dynamic BroadcastReceiver. Your background service will broadcast an Intent when something happens. All of your app's activities will register a dynamic BroadcastReceiver which will listen for these events. When such event occurs it will show a toast. When none of your activities are running nothing will happen.
Inside your service
public static final ACTION_SOMETHING = BuildConfig.APPLICATION_ID + ".ACTION_SOMETHING";
public void doSomething() {
// ...
// Show toast if app is running. Or let the app react however you please.
LocalBroadcastManager.getInstance(this).sendBroadcast(new Intent(ACTION_SOMETHING));
// ...
}
Of course you can put additional information in the Intent as extras and access them in the BroadcastReceiver.
Inside your activities
private final IntentFilter onSomethingIntentFilter = new IntentFilter(MyService.ACTION_SOMETHING);
private final BroadcastReceiver onSomething = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
// This check seems redundant but it's not. Google it.
if (MyService.ACTION_SOMETHING.equals(intent.getAction()) {
// Show toast here.
}
}
};
public void onResume() {
super.onResume();
// Start listening for events when activity is in foreground.
LocalBroadcastManager.getInstance(this).registerReceiver(onSomething, onSomethingIntentFilter);
}
public void onPause() {
super.onPause();
// Stop listening as soon as activity leaves foreground.
try {
LocalBroadcastManager.getInstance(this).unregisterReceiver(onSomething);
} catch (IllegalArgumentException ex) {}
}
You may want to pull this code to a common activity parent, a BaseActivity, so you don't repeat yourself.
This is a common case of Provider-Subscriber pattern. Another implementation would be an EventBus.

Keeping it simple, try adding a boolean flag in Activity and set its value as true in onResume & false in onPause. Then display the toast if the boolean flag is true.

Android popup style activity which sits on top of any other apps

What I want to create is a popup style application.
I have a service in the background - something arrives on the queue and i want an activity to start to inform the user - very very similar to the functionality of SMSPopup app.
So I have the code where something arrives on the queue and it calls my activity.
However for some reason the activity always shows on top of the originally started activity instead of just appearing on the main desktop of the android device.
As an example:
I have the main activity which is shown when the application is run
I have the service which checks queue
I have a popup activity.
When i start the main activity it starts the service - I can now close this.
I then have something on the queue and it creates the popup activity which launches the main activity with the popup on top of it :S How do I stop this and have it behave as i want...
The popup class is :
public class SMSPopup extends Activity implements OnClickListener{
public static String msg;
#Override
public void onCreate(Bundle bundle){
super.onCreate(bundle);
// Toast.makeText(getApplicationContext(), msg, Toast.LENGTH_LONG).show();
this.setContentView(R.layout.popup);
TextView tv = (TextView)findViewById(R.id.txtLbl);
Intent intent = getIntent();
if (intent != null){
Bundle bb = intent.getExtras();
if (bb != null){
msg = bb.getString("com.andy.tabletsms.message");
}
}
if(msg == null){
msg = "LOLOLOL";
}
tv.setText(msg);
Button b = (Button)findViewById(R.id.closeBtn);
b.setOnClickListener(this);
}
#Override
public void onClick(View v) {
this.finish();
}
}
and I call the activity from a broadcast receiver which checks the queue every 30 seconds or so :
if(main.msgs.size()>0){
Intent testActivityIntent = new Intent(context.getApplicationContext(), com.andy.tabletsms.work.SMSPopup.class);
testActivityIntent.putExtra("com.andy.tabletsms.message", main.msgs.get(0));
testActivityIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(testActivityIntent);
}
The layout is here : http://pastebin.com/F25u6wdM

This is against the design practice suggested by Android. See http://developer.android.com/guide/topics/ui/notifiers/notifications.html
A background Service should never launch an Activity on its own in order to receive user interaction.
You could show the message in a Toast and/or notification. From the notification, you could start a new intent.