Consider there is one activity, named Activity S.
Then there will be many activities, say 10 activities, named A, B, C, ..., J.
How can I achieve this:
From those A--J activities, when the back button is pressed, always go back to activity S.
Regardless of the ordering or how the activities are created.
For example:
Starting from S, go to B, then D, then G.
In activity G, press back button, and will go back to S.
== EDIT ==
Should I use Activity.finish() method when leaving all A--J activities ?
You could accomplish this in different ways depending on the exact result you desire. You could add the following line to your <activity> tags in your manifest.xml for those Activities
android:noHistory="true"
or use an Intent flag when overrdiing onBackPressed() in each
#Override
public void onBackPressed()
{
Intent i = new Intent(CurrentActivity.this, S.class);
i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);`
startActivity(i);
super.onBackPressed();
}
this will clear the other Activities from the stack and return you to S.
If you want to keep the Activities on the stack while returning to S then you can change the flag used
#Override
public void onBackPressed()
{
Intent i = new Intent(CurrentActivity.this, S.class);
i.setFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);`
startActivity(i);
super.onBackPressed();
}
The last way will bring S to the front and keep the other Activities on the stack which I don't think is what you want but just another option. You will probably want one of the first two ways.
You have to do like this to achieve, Set a flag that will Clear every activity from stack and pass intent to S.class, like this
#Override
public void onBackPressed() {
// TODO Auto-generated method stub
super.onBackPressed();
Intent intent=new Intent(this,S.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
}
Related
Suppose I have activities named A, B, C, D. Now, consider A has been launched as the root activity and B has been launched from A and C has been launched from B and D has been launched from C.
Now I have a button named "Success" in the activity D. If suppose, I press the button "Success" in the activity D, then the activity C should be removed from the history stack and go to activity B, but on Pressing back key from the activity D should display activity C instead of B and Clear D from stack. Please can anyone help me to resolve this problem?
Add this Code in your Activity_D for Button click
btnSuccess.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
startActivity(new Intent(Activity_D.this, Activity_B.class));
finishAffinity();
}
});
Also add this in your Activity_D to Handle Back Button Pressed.
#Override
public void onBackPressed() {
finish();
super.onBackPressed();
}
From Activity_C to Activity_D
startActivity(new Intent(Activity_C.this, Activity_D.class));
Don't call finish() here.
When you click on Success button, you can use the following line of code to open your B activity:
Intent d_intent = new Intent(D.this, B.class);
d_intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
d_intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(d_intent);
finish();
Here Activity B will be started from the back stack rather than a new instance because of Intent.FLAG_ACTIVITY_CLEAR_TOP and Intent.FLAG_ACTIVITY_NEW_TASK clears the stack and makes it the top one. So when we press the back button the whole application will be terminated. And on Back press you need to simply call
finish();
Hope it will help you out.
I have created two activity i.e Activity A & Activity B ,if i clicked Next Button i.e in Activity A going to Activity B properly But when i click on back button i want to go from Activity B to Activity A and page swipe from left side to right side and on click next page swipe right to left,
here is my code
public void onBackPressed() {
Intent intent = new Intent(ActivityB.this, Activity.class);
startActivity(intent);
finish();
Just Remove finish() from Activity.
Because when you go to second activity and finish first activity, there is no any activity and stack.
So If you click back button from second activity, application will be finish if there is no Activity in stack.
You should use this Approach.
Ex.
In Activity.java
Intent first = new Intent(Activity.this,ActivityB.class);
startAcivity(first);
// Don't use finish() here.
In ActivityB.Java
Just click on built in back button.
or If you want to use your own back button.
Use finish(); in button click event.
You can use only onBackPressed();
public void onBackPressed() {
super.onBackPressed();
}
Android Overriding onBackPressed()
How to go previous Activity by using back button
No need to put an intent and start a new activity that would take you to previous activity.
Just call 'finish()'
It would go back to previous activity as Android activities are stored in the activity stack
If you have other activities that are present in between the activites say if android stack is filled with Activity A>Activity C>Activity B,If you want to go to Activity A on finish of Activityy B then you have to set an intent flag like FLAG_ACTIVITY_REORDER_TO_FRONT or FLAG_ACTIVITY_PREVIOUS_IS_TOP
Just use finish() no need for intent as A is already in stack and when you finish B, A will come to surface
public void onBackPressed() {
finish();
}
Read this to learn more about android activity stack.
public void onBackPressed() {
// TODO Auto-generated method stub
finish();
super.onBackPressed();
}
I have four activities
ListActivity
Itemdetail_Activity
record1_Act
record2_act.
I can go from ListActivity -> record1_Act and from ListActivity <-record1_Act properly but when I want to go from Itemdetail_Activity -> record2_act and return back from Itemdetail_Activity <- record2_act it always goes record2_act to ListActivity.
I even used i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK); but it does not work. How to solve this issues?
Here is my code
Intent i = new Intent(record2_act.this, Itemdetail_Activity.class);
i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(i);
Intent i = new Intent(record1_Act.this, ListActivity.class);
i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(i);
finish();
After starting activity remove finish() call because it will clear that activity from stack and i see you have used finish in your code. also you do not need to set these flags.
In activity 4, implement onBackPressed() as,
#Override
public void onBackPressed()
{
Intent i = new Intent(4.this, 3.class);
startActivity(i);
}
call this method if you have any back button. And if you want to link the backpress for every activity you need to implement onBackPressed() method in every activity.
you can call onBackPressed() if previous activity not finished also you can use :
this.finish();
// Or
Activity currentActivity = this;
currentActivity.finish();
and if previous you finished activity you have to track user in activities and make list of activities, then move to :
activitiList.get(activityList.size() - 2);
// activityList.size() - 1 is last activity and activityList.size() - 2 is previous activity
Do check if ItemDetailsActivity is NOT calling finish()
Given:
6 activities. (A, B, C, D, E, F)
Each activity consists of several edittexts or a camera implementation and a next button to goto next activity (The activity which is going to be opened depends on the value entered by the user).
If edittexts are displayable or not comes from the server.
Incase there are no edittexts on the layout then only next button is shown.
Flow of the application: A->B->C(->D)->E->F
The Activity D opens only when a certain condition is met in activity C.
Todo:
Incase, The activity contains no edittext and only next button i should be able to skip this activity.
If the flow of my application is like: A->B->C->E->F Then when i press hard back the flow should be F->E->C->B->A
If the flow of my application is like: A->B->C->D->E->F Then when i press hard back the flow should be F->E->C->B->A
If the flow of my application is like: A->C->D->E->F Here we skipped B because there are no views in Activity B, When i press hard back the flow should be F->E->C->A
what i did:
To skip the activity when no fields are available inside onCreate(), I am checking if any field is displayable if no then i add the activity name in a stack if it is not present in it and then open the next activity.
// Block for skipping this screen
if (skipScreen) {
Intent i = new Intent(B.this, C.class);
startActivity(i);
finish();
} else {
if (!Constants.st.contains(B.class)) {
Constants.st.push(B.class);
}
}
And when i press back from an activity i pop() the name of that activity from the stack and peek() at the top of the stack and jump to that activity.
public void onBackPressed() {
super.onBackPressed();
Constants.st.pop();
Intent i = null;
if (Constants.st.isEmpty()) {
i = new Intent(B.this, A.class);
} else {
Class<Activity> jumpTo = Constants.st.peek();
i = new Intent(B.this, jumpTo);
}
startActivity(i);
finish();
}
I think the statePattern will be very helpfull. Here is a short tutorial.
There are some applications in which you can logout at any point within. e.g you login and then your browse around. you use the action bar or the menu button to logout. I can call finish() at that very point but then it will just pop the last activity. Even if i move the user forward to the Home Activity, still the stack remains in memory. Is there any way to destroy the remaining stack?
The easiest way to do this is to clear the stack back to your home or first activity, and pass an identifier saying to exit the app. For example:
public class ActivityOne extends Activity {
public static final String FINISH_THIS = "FINISH_THIS";
#Override
protected void onNewIntent(Intent intent) {
super.onNewIntent(intent);
if(intent.hasExtra(FINISH_THIS)) {
finish();
}
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if(getIntent().hasExtra(FINISH_THIS)) {
finish();
}
}
}
public class ActivityTwo extends Activity {
#Override
public boolean onOptionsItemSelected(MenuItem item) {
if(item.getItemId() == R.id.logout) {
Intent intent = new Intent(this, ActivityOne.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intent.putExtra(ActivityOne.FINISH_THIS, true);
startActivity(intent);
}
return true;
}
}
If ActivityOne is the root of your stack and ActivityTwo is where the user selected the option to logout, starting an intent that clears back to ActivityOne will get rid of the backstack. If you want the app to exit when logging out, you can pass an extra like I did with FINISH_THIS to signal the root/home activity to finish.
Another way to do this would be to call setResult(FINISH_THIS) where FINISH_THIS is an int identifier before calling finish(). Then in all other activities in the stack, you'd override onActivityResult and check the result to see if that activity needs to be finished. If it does, you set the result again and keep passing it down the line.
Using the intent method I outlined in the beginning is the preferred method for clearing the stack as it doesn't rely on daisy chaining results together but both options work well enough.
A quick and dirty way to do it would be onResume verify you are still logged in, if not then finish it. That way if they hit back, it will close each activity as it tries to open them. This would also prevent someone from using the app manager to re-enter your activity when you expect it to be closed.
Another idea would be read Android: Clear the back stack