Develop Reference

How to finish specific activities not all activities

In my android application suppose several activities are there
if using intent I go to other activities like this
[Activity A]->[activity B]->[Activity C]->[Activity-D]->[Activity N]
and now when am on activity N when I pressed button then I want to go to Activity B and want to destroy Activity C And Activity D but Activity A should not destroy. I also searched in various posts but I didn't get exactly the same solution.
Any help will be appriciated

In ActivityN, to return to ActivityB use this:
Intent intent = new Intent(this, ActivityB.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);
startActivity(intent);
Using the flag CLEAR_TOP will finish all activities in the stack that are on top of ActivityB. In the example you gave, this will finish ActivityN, ActivityD and ActivityC. Using the flag SINGLE_TOP will make sure that this will return control to the existing instance of ActivityB (ie: it won't create a new instance of ActivityB).

In Your Activity C do like this
public static ActivityC instance = null;
public class ActivityC extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
instance = this;
}
}
And in your Activity D do like this
public static ActivityD instance = null;
public class ActivityD extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
instance = this;
}
}
Finally in your Activity N. Do Something like this
public class ActivityN extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Button yourButton= (Button) findViewById(R.id.yourButton);
yourButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
ActivityC.instance.finish();
Activityd.instance.finish();
finish();
}
});
}
}

Here's my approach.
From Activity A, don't just start the Activity B, call startActivityForResult() method. Do this for all subsequent calls.
Now, when you press the button from Activity N, set the result for a custom value and call the finish() method for Activity N. Now you should hit the onActivityResult method on your Activity D. Now you can check whether the result was you pressing the button. Depending on your result, keep on setting the result and subsequently calling finish() on each Activity.
This should technically work.

Try this code:
//Activity A
Intent i = new Intent(getApplicationContext,ActvityB.class);
startActivity(i);
//Activity B
Intent i = new Intent(getApplicationContext,ActvityC.class);
startActivity(i);
//Activity C
Intent i = new Intent(getApplicationContext,ActvityC.class);
startActivity(i);
finish();
// finish here actvity which you want to finish
//Try this second way:
In your first activity, declare one Activity object like this,
public static Activity fa;
onCreate()
{
fa = this;
}
now use that object in another Activity to finish first-activity like this,
onCreate()
{
FirstActivity.fa.finish();
}

EDIT : Use startActivityForResult() instead of startActivity()
So depending on the result you can change the behavour.
Say for example When you wanted to go to ActivityB just return some flag in the INTENT. When it will be caught in Activity D and C in onActivityResult(), finish them and you will be finally on B.

Flag Intent.FLAG_ACTIVITY_CLEAR_TOP may solve your problem:
http://developer.android.com/reference/android/content/Intent.html#FLAG_ACTIVITY_CLEAR_TOP

You can start ActivityC, ActivityD, ActivityN with the same request code passed to startForResult(requestCode)
And then at ActivityN, use finishActivity(int requestCode).
Documentation for finishActivity(int requestCode)
Force finish another activity that you had previously started with startActivityForResult.
Params:
requestCode – The request code of the activity that you had given to startActivityForResult().
If there are multiple activities started with this request code, they will all be finished.

get activity().finish() not killing activity

I have a launcher Activity A which calls to an Activity B. B has multiple fragments. Now what I want is to be able to kill B from one of those fragments. I used getActivity().finish() but it would just kill the fragment.
How do I kill the activity/exit app from a fragment?

There is a way discussed in docs: http://developer.android.com/training/basics/fragments/communicating.html
Make Fragment define an interface which the Activity implements. Then make call to the Activity and then let the Activity to finish(or something else).
public class MyActivity extends Activity
implements MyFragment.MyListener {
public void onMyCancel() {
finish();
}
}
public class MyFragment extends Fragment {
private MyListener callback;
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
callback= (MyListener) activity;
}
public interface MyListener {
public void onMyCancel();
}
public void btnCancel(View v) {
callback.onMyCancel();
}
}

you can only call finish() in your activity B , this would close your current activity.

if you want to close your app you can simply use:
System.exit(0);
this will kill whole application process.

Remove an activity from the stack

I have three activities ActivityA, ActivityB, ActivityC.
Suppose in ActivityA, there is some code like...
if(someCondition()){
gotoActivityB();
}
else{
gotoActivityC();
}
Now, If user goes to ActivityB, ActivityA should not be finished.
If he goes to ActivityC, it should be finished.
Adding noHistory in manifest file doesn't work.
Also, finish()in if condition doesn't work, As there are many activities after ActivityC in which ActivityA should be in background.
I don't want to call startActivity(context,ActivityA.class)in those activities onBackPressed() because, it will again execute code of onCreate() in ActivityA.
So, is there a way, where i can remove ActivityA from the stack when user presses back button in ActivityB?
may be something like this:?
ActivityB.this.finish();
ActivityA.finish(); //some code to finish ActivityA

Okay, here is one way you can accomplish your goal. You will need to pass around the Activity context to wherever you need it in order to call finish() on it. I used the Application class to do this. I only used two classes to do it for the sake of time, but it should work just fine for your purposes. Here is how I did it:
This is the first class. It is the Activity that we want to close from another Activity.
public class MainActivity extends Activity implements OnClickListener {
private Button button;
// application instance
private MainApplication mainApplication;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mainApplication = (MainApplication) getApplicationContext();
// set the Activity's context for later usage. Doing this determines which
// Activity can be closed from another Activity.
mainApplication.setActivityContext(this);
button = (Button) findViewById(R.id.button1);
button.setOnClickListener(this);
}
public void onClick(View v) {
switch (v.getId()) {
case R.id.button1:
Intent i = new Intent(this, SecondActivity.class);
startActivity(i);
break;
}
}
}
This is the Second Activity. Exiting out of it will also cause finish() to be called on the first class:
public class SecondActivity extends Activity {
private Activity activityContext;
private MainApplication mainApplication;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.second_activity_layout);
mainApplication = (MainApplication) getApplicationContext();
// get the Activity context you stored in the MainApplication class
// so you can call finish on it.
activityContext = mainApplication.getActivityContext();
}
#Override
protected void onPause() {
super.onPause();
// closes your defined Activity. If you press the back button you will find
// that you exit right out of the app as the other Activity gets popped off
// the stack.
activityContext.finish();
}
}
And the Application class:
public class MainApplication extends Application {
private Activity activityContext;
public Activity getActivityContext() {
return activityContext;
}
public void setActivityContext(Activity activityContext) {
this.activityContext = activityContext;
}
}
And of course make sure to declare your MainApplication class in the AndroidManifest:
<application
android:name=".MainApplication"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
This is a sort of hacky way to do this. There may be better ways. But regardless, you have to pass around the context of the Activity that you want to call finish() on. Then you can close it from anywhere.

Hi you can finish your activity in current activity itself based on the condition. or use StartActivityforResult based on the result you can finish your activity.
hope this will help you.

You can try this in another way, like i do.
Create a static instance variable of the activity in the beginning.
private static Activity1 thisAct = null; // Activity1 is name of class
Now initialize this variable in onCreate() method
thisAct = this;
Create a static method which will finish this activity
public static void finishActivity()
{
thisAct.finish();
}

While going to Activity C, clear the FLAG :
Intent cIntent = new Intent(view.getContext(), cActivity.class).setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(cIntent);

Call Public void

I have a public void in one class and I want to call it in another class when it creates but nothing seems to be working. here is the code of my first activity
public class activityone extends Activity {
public void actionC() {
//actions
}
Does anyone know how to call it in my second class?

In general, you need to have an instance of your activityone class in order to call an instance method.
To create an instance, you generally use a constructor like:
activityone a = new activityone();
a.actionC();
I'm not sure this is what you want though, because Activitys are generally created by the Android system itself and you should handle the onCreate method instead.

Here is what you can do:
public class activityone extends Activity {
/*public void actionC() {*/ //Instead on normal method, write your actions in onCreate()
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//actions
}
and in your second activity, do this:
Intent intent = new Intent(getApplicationContext(),activityone.class);
startActivity(intent);
Hope it helps !!!

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);