Develop Reference

How do I randomly start activities?

I'm looking to randomly start activities in android studio without repetition. I'd like to be able to start an activity randomly by clicking a button and in an 'if' statement. Whoever can help out that would be fantastic! Thank you.

ArrayList<Class> activities = new ArrayList<>();
#Override
public void onCreate(Bundle savedInstanceState) {
//your codes...
activities.add(History.class);
activities.add(Bookmark.class);
activities.add(Themes.class);
//your codes
}
public void openActivity(Class class_) {
Intent intent = new Intent(this, class_);
startActivity(intent);
}
public void openRandomActivity(){
Class that = activities.get(new Random().nextInt(activities.size()));
activities.remove(that); // after using, remove from list
openActivity(that);
}
Call openRandomActivity when a user click to button.

Has anyone successfully used setExitTransition on L?

I've been trying to use the new fancy animations that come with the L developer preview, but I'm having a lot of difficulties. In particular, I am not seeing any fancy animations. I'm trying to use the Explode exit transition. Here's the code:
public class ActivityA extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// inside your activity
getWindow().requestFeature(Window.FEATURE_CONTENT_TRANSITIONS);
// set an exit transition
getWindow().setExitTransition(new Explode());
setContentView(R.layout.activity_a);
// Find our button and add our click handler
Button button = (Button)findViewById(R.id.buttonA);
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Transition to activity B
Intent intent = new Intent(ActivityA.this, ActivityB.class);
startActivity(intent);
}
});
}
}

Instead of starting another activity using startActivity(intent); use the following statement.
startActivity(intent,ActivityOptions.makeSceneTransitionAnimation(this).toBundle());
I started another activity as said above and it worked for me.
It's said in google documentation Defining Custom Animations as follows.

Solved the problem - you need the
getWindow().requestFeature(Window.FEATURE_CONTENT_TRANSITIONS);
call on the activity you are transitioning too as well!

Try this.
public class MyActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// enable transitions
getWindow().requestFeature(Window.FEATURE_CONTENT_TRANSITIONS);
setContentView(R.layout.activity_my);
}
public void onSomeButtonClicked(View view) {
getWindow().setExitTransition(new Explode());
Intent intent = new Intent(this, MyOtherActivity.class);
startActivity(intent,
ActivityOptions
.makeSceneTransitionAnimation(this).toBundle());
}
}
requestFeature in onCreate an setExitTransition before startActivity

Android back button not going right activity And How to handle Activities in Android

Am creating small application using login, register and user details. After login am going to store login credential to shared preference and navigate to dashboard activity. In second time directly navigate to dashboard activity. This level of code is working fine.
Please consider I have three activity MainActivity, LoginActivity, RegisterActivity, DashboardActivity and ProfileActivity.
In my MainActivity If user value is sharedPreference directly moving to DashboardActivity
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if(new SessionManager(getApplicationContext()).isLoggedIn()){
startActivity(new Intent(getApplicationContext(), DashboardActivity.class));
}
}
In my DashboardActivity
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ImageButton imgBtn = (ImageButton) findViewById(R.id.imageButton1);
imgBtn.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
startActivity(new Intent(getApplicationContext(), ProfileActivity.class));
}
});
}
Now am simply press back button in device goes to MainActivity not DashboardActivity. I want to move activity to DashboardActivity only, not MainActivity. Please guide me how to do that. And how to handle session in Android.
Also I have bit confusion in using which flags and where to use. I tried in DashboardActivity but not working.
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ImageButton imgBtn = (ImageButton) findViewById(R.id.imageButton1);
imgBtn.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent newIntent = new Intent(getApplicationContext(), ProfileActivity.class);
newIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
newIntent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
newIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(newIntent);
}
});
}
Now I tried various possible ways but not getting solution.
Main problem occurs after navigating DashboardActivity to any Activity won't come back to DashbarodActivity instead of going MainActivity. I don't know why it happens. Any problem in MainActivity navigation

I'm not sure about that, but in DashboardActivity try to start your activity like this: startActivity(new Intent(DashboardActivity.this, ProfileActivity.class));

Just finish the current activity after starting the new one via Intent and you should achieve the desired functionality and this way you don't need any flags. Except for the MainActivity of course.

Just simply override onBackPressed method in your ProfileActivity and call finish method.
#Override
public void onBackPressed() {
finish();
}

EDITED ANSWER:
on your ProfileActivity, try to override onBackPressed method then start the DashboardActivity again and don't forget to finish the current activity.
#Override
public void onBackPressed(){
startActivity( new Intent(this, DashboardActivity.class) );
finish();
}

Multiple activity instances problem

In my application I have an activity class A that has a listview with a cursor adapter.
From A I can go to the activity B, by pressing a button. From B I can go back to A by pressing a button (not by pressing the BACK button). This means that a new instance of the A activity is created.
From this point, if I press the BACK key, the current A activity is destroyed and B is popped. And if I press BACk again the initial A activity is popped. I hope it is clear.
My problem is that when the second A activity is destroyed, the database connection is reseted, in a static manner. So in the end, when the initial A activity is displayed, the listview will be empty.
My question is: should I try to have a single instance for the A activities, or shoud I change the database connection (to link it with the activity instance)?
Thanks a lot
Gratzi

First Of All In class A which is carrying your ListView . on clicking any Listview call the startActivity method for the Class B Activity without calling any finish().
I hope which is you are already doing.
Now in the Second Activity The button (Not the Back Button) you are using for calling Activity A . in its clickListener for calling Activity A dont call the startActivity(intentForA) instead call the finish(); for ending the Activity B. this will resume the A activity which is paused..
I hope this will help

You will need to create 3 Activities rather than 2.
Have a MAIN activity that does not really display anything.
So You have Activity A that is your main activity that can handle the connection to the DB etc.
Then Activity B and C can be the A and B that you have used.
Activity A (Main activity) can have a static instance of itself so you can refernce it's
Variables etc -OR- you can pass data from one activity to the other using Intent.put, etc.
I prefer the global static instance way as I'm a little old school on Java.
Edit:
Forgot to mention, to handle the 'closing' of the app, either Activity B or C must also close Activity.
public class ActivityA extends Activity {
ActivityA act_a_instance;
public int some_integer = 22;
#Override
public void onCreate(Bundle savedInstanceState) {
act_a_instance = this;//Now you can reference this Activity outside
//Your creation stuff etc
}
}
public class ActivityB extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
//Your creation stuff etc
//Reference stuff from ActivityA like so :
int temp_integer = ActivityA.act_a_instance.some_integer;
}
#Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.options_back:
startActivity(new Intent(this, ActivityC.class));
break;
}
}
#Override
protected void onStop() {
finish();
super.onStop();
}
}
public class ActivityB extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
//Your creation stuff etc
}
#Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.options_back:
startActivity(new Intent(this, ActivityB.class));
break;
}
}
#Override
protected void onStop() {
finish();
super.onStop();
}
}

Use below code hope this will solve your problem
Intent i = new Intent(B.this, A.class);
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);

Android: Button action not being called

I'm trying to make an app where you start at a menu, click a button and are brought to a list of items (which I later hope to make clickable). But I can't seem to make it call my next activity. Can anyone help?

Your main class / activity:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// Menu Button
Button startNewActivity = (Button)findViewById(R.id.startnew);
startNewActivity.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Intent newActivityIntent = new Intent(YOUR-CLASS-NAME.this,NewActivity.class);
startActivity(newActivityIntent);
}
});
Your NewActivity Class:
public class NewActivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.new);
}
}

Is the question "How do I call the next activity" ?
If so, it's pretty easy - Assuming the Activity you want to call is "SomeActivity", call this:
Intent someActivity = new Intent(getBaseContext(), SomeActivity.class);
startActivity(someActivity);
There's also a "startActivityForResult" method, if you want data back from the Activity you're calling. For reference, the Activity page of the API Documentation can be found here. Good luck!