I have made an app with many activities and I have included a bottom navigation bar to all of them. I used finish(); after any intent not to get any memory leak problem but when I press the back button of my phone the app closes. What should I do?
//an intent of my app
Button btnsuita = (Button) findViewById(R.id.souita_btn);
btnsuita.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(HotelRooms.this, HotelRoomsSouita.class);
startActivity(intent);
finish();
}
});
//An Example of Bottom Navigation Bar
BottomNavigationView bottomNavigationView = (BottomNavigationView) findViewById(R.id.BottomNavView_bar);
BottomNavigationViewHelper.disableShiftMode(bottomNavigationView);
Menu menu = bottomNavigationView.getMenu();
android.view.MenuItem menuItem = menu.getItem(0);
menuItem.setChecked(true);
bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.ic_home:
Intent intent1 = new Intent(HotelRoomsSouita.this, MainMenu.class);
startActivity(intent1);
finish();
break;
case R.id.ic_back:
Intent intent2 = new Intent(HotelRoomsSouita.this, HotelRooms.class);
startActivity(intent2);
finish();
break;
case R.id.ic_contact_us:
Intent intent3 = new Intent(HotelRoomsSouita.this, Mail.class);
startActivity(intent3);
finish();
break;
}
return false;
}
});
Remove finish() in the switch every case.
If you want to ignore back button clicks, then you can add this code in the activity.
#Override
public void onBackPressed() {
//Do anything if you wish
}
Since you are finishing every activity ,there is o activity remain in the backstack or background . so the application closes.
You can use view pager to inflate fragment for bottom navigation view . This is the correct approach by google material design guid lines.
Never use activity for bottom navigation view .
And still if you continue with your activity , then override the onBackpress method of the activtiy .
If I understand your problem correctly you want the user to be able to go back in previous activities while your application does not cause any memory leaks(by starting same activity again and again)
Solution:
Remove finish() from each case in onNavigationItemSelected
Go to your manifest file and add android:launchMode="singleInstance" to each Activity
Ovveride onBackPressed so that it does nothing in your first-started activity as dcanh121 said.
If you do that then if user tries to open the same Activity which was already opened before, it will cause the app to open the previous activity instead of creating a new one.. (read more about this)
Therefore you won't have any memory leak problems :)
Im able to send data to parent activity when back button is pressed.
However, for up button i cannot implement similar logic and data is not getting returned to parent activity why is that ?
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
// Respond to the action bar's Up/Home button
case android.R.id.home:
NavUtils.navigateUpFromSameTask(this);
.....
Intent resultIntent = new Intent();
resultIntent.putExtra("noteJSON", noteJSON.toString());
setResult(Activity.RESULT_OK, resultIntent);
this.finish();
return true;
}
return super.onOptionsItemSelected(item);
}
Im using startActivityForResult to start childactivity. On onactivityresult basically handling the intent info. When back, button is pressed its working. When UP is pressed onactivityresult never gets executed. Thats the problem
When you call navigateUpFromSameTask method, it finishes the current activity and starts (or resumes) the appropriate parent activity. If the target parent activity is in the task's back stack, it is brought forward. As a result onActivityResult won't be called.
If you want to ensure result is returned via onActivityResult then remove call to navigateUpFromSameTask as follows:
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
// Respond to the action bar's Up/Home button
case android.R.id.home:
....
Intent resultIntent = new Intent();
resultIntent.putExtra("noteJSON", noteJSON.toString());
setResult(Activity.RESULT_OK, resultIntent);
this.finish();
return true;
}
return super.onOptionsItemSelected(item);
}
try below
case android.R.id.home:
NavUtils.navigateUpFromSameTask(this);
.....
startActivity(new Intent(YourActivity.this,ParentActivity.class).putExtra("noteJSON", noteJSON.toString()));
return true;
I want to do something simple on android app.
How is it possible to go back to a previous activity.
What code do I need to go back to previous activity
Android activities are stored in the activity stack. Going back to a previous activity could mean two things.
You opened the new activity from another activity with startActivityForResult. In that case you can just call the finishActivity() function from your code and it'll take you back to the previous activity.
Keep track of the activity stack. Whenever you start a new activity with an intent you can specify an intent flag like FLAG_ACTIVITY_REORDER_TO_FRONT or FLAG_ACTIVITY_PREVIOUS_IS_TOP. You can use this to shuffle between the activities in your application. Haven't used them much though. Have a look at the flags here: http://developer.android.com/reference/android/content/Intent.html
As mentioned in the comments, if the activity is opened with startActivity() then one can close it with finish().
If you wish to use the Up button you can catch that in onOptionsSelected(MenuItem item) method with checking the item ID against android.R.id.home unlike R.id.home as mentioned in the comments.
Try Activity#finish(). This is more or less what the back button does by default.
Just write on click finish(). It will take you to the previous Activity.
Just this
super.onBackPressed();
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
This will get you to a previous activity keeping its stack and clearing all activities after it from the stack.
For example, if stack was A->B->C->D and you start B with this flag, stack will be A->B
Just call these method to finish current activity or to go back by onBackPressed
finish();
OR
onBackPressed();
Are you wanting to take control of the back button behavior? You can override the back button (to go to a specific activity) via one of two methods.
For Android 1.6 and below:
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK && event.getRepeatCount() == 0) {
// do something on back.
return true;
}
return super.onKeyDown(keyCode, event);
}
Or if you are only supporting Android 2.0 or greater:
#Override
public void onBackPressed() {
// do something on back.
return;
}
For more details: http://android-developers.blogspot.com/2009/12/back-and-other-hard-keys-three-stories.html
Try this is act as you have to press the back button
finish();
super.onBackPressed();
Add this in your onCLick() method, it will go back to your previous activity
finish();
or You can use this. It worked perfectly for me
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if ( id == android.R.id.home ) {
finish();
return true;
}
return super.onOptionsItemSelected(item);
}
if you want to go to just want to go to previous activity use
finish();
OR
onBackPressed();
if you want to go to second activity or below that use following:
intent = new Intent(MyFourthActivity.this , MySecondActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
//Bundle is optional
Bundle bundle = new Bundle();
bundle.putString("MyValue1", val1);
intent.putExtras(bundle);
//end Bundle
startActivity(intent);
If you have setup correctly the AndroidManifest.xml file with activity parent, you can use :
NavUtils.navigateUpFromSameTask(this);
Where this is your child activity.
Got the same problem and
finish(); OR super.onBackPressed();
worked fine for me, both worked same, but no luck with return
You can explicitly call onBackPressed is the easiest way
Refer Go back to previous activity for details
Start the second activity using intent (either use startActivity or startActivityForResult according to your requirements). Now when user press back button, the current activity on top will be closed and the previous will be shown.
Now Lets say you have two activities, one for selecting some settings for the user, like language, country etc, and after selecting it, the user clicks on Next button to go to the login form (for example) . Now if the login is unsuccessful, then the user will be on the login activity, what if login is successful ?
If login is successful, then you have to start another activity. It means a third activity will be started, and still there are two activities running. In this case, it will be good to use startActivityForResult. When login is successful, send OK data back to first activity and close login activity. Now when the data is received, then start the third activity and close the first activity by using finish.
You can try this:
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK && event.getRepeatCount() == 0) {
finish();
return true;
}
return super.onKeyDown(keyCode, event);
}
All new activities/intents by default have back/previous behavior, unless you have coded a finish() on the calling activity.
#Override
public void onBackPressed() {
super.onBackPressed();
}
and if you want on button click go back then simply put
bbsubmit.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
onBackPressed();
}
});
I suggest the NavUtils.navigateUpFromSameTask(), it's easy and very simple, you can learn it from the google developer.Wish I could help you!
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if ( id == android.R.id.home ) {
finish();
return true;
}
return super.onOptionsItemSelected(item);
}
Try this it works both on toolbar back button as hardware back button.
There are few cases to go back to your previous activity:
Case 1: if you want take result back to your previous activity then
ActivityA.java
Intent intent = new Intent(ActivityA.this, FBHelperActivity.class);
startActivityForResult(intent,2);
FBHelperActivity.java
Intent returnIntent = new Intent();
setResult(RESULT_OK, returnIntent);
finish();
Case 2: ActivityA --> FBHelperActivity---->ActivityA
ActivityA.java
Intent intent = new Intent(ActivityA.this, FBHelperActivity.class);
startActivity(intent);
FBHelperActivity.java
after getting of result call finish();
By this way your second activity will finish and because
you did not call finish() in your first activity then
automatic first activity is in back ground, will visible.
Besides all the mentioned answers, their is still an alternative way of doing this, lets say you have two classes , class A and class B.
Class A you have made some activities like checkbox select, printed out some data and intent to class B.
Class B, you would like to pass multiple values to class A and maintain the previous state of class A, you can use, try this alternative method or download source code to demonstrate this
http://whats-online.info/science-and-tutorials/125/Android-maintain-the-previous-state-of-activity-on-intent/
or
http://developer.android.com/reference/android/content/Intent.html
Just try this in,
first activity
Intent mainIntent = new Intent(Activity1.this, Activity2.class);
this.startActivity(mainIntent);
In your second activity
#Override
public void onBackPressed() {
this.finish();
}
First, thing you need to keep in mind that, if you want to go back to a previous activity. Then don't call finish() method when goes to another activity using Intent.
After that you have two way to back from current activity to previous activity:
Simply call:
finish()
OR
super.onBackPressed();
To go back from one activity to another by clicking back button use the code given below use current activity name and then the target activity.
#Override
public void onBackPressed() {
// do something on back.
startActivity(new Intent(secondActivity.this, MainActivity.class));
return;
}
Please help me.
I use onOptionsItemSelected to get to settings layout. There I activate setDisplayHomeAsUpEnabled
public boolean onOptionsItemSelected(MenuItem settings){
setContentView(R.layout.settings);
getActionBar().setDisplayHomeAsUpEnabled(true);
return super.onOptionsItemSelected(settings);
}
How can I get back to main layout from settings layout?
In onOptionsItemSelected you need to find out whether the MenuItem that is clicked is your Home item.
I would use a switch like:
switch (settings.getItemId()) {
// If home icon is clicked return to main Activity
case android.R.id.home:
Intent intent = new Intent(this, MainActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
break;
}
Then I would either start the MainActivity again or just call finish() to end the current one. There is a very nice article with loads of samples which you might find useful here: http://www.vogella.com/articles/AndroidActionBar/article.html
I have an Android application with a MainActivity and I do this to create navigational tabs in onCreate:
ActionBar myActionBar = getActionBar();
myActionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
Tab tab = myActionBar.newTab().setText("FirstTab").setIcon(R.drawable.first_tab)
.setTabListener(new TabListener<FirstTabFragment>(this, "FirstTab",
FirstTabFragment.class));
... more tabs ...
The TabListener, I use this from developer.android.com:
http://developer.android.com/reference/android/app/ActionBar.html#newTab():
public static class TabListener<T extends Fragment> implements ActionBar.TabListener {
...
public TabListener(Activity activity, String tag, Class<T> clz) { ... }
}
So if a user clicks on the first tab, my fragment FirstTabFragment is called and executes onCreateView.
My problem is, if a user now clicks a button I do the following and I do not know how to switch to the next fragment:
private OnClickListener firstTabListener = new OnClickListener() {
#Override
public void onClick(View v) {
if (v == button1) {
Intent intent = new Intent(???, MyDetailsFragment.class);
startActivity(intent);
} else if (...) {
...
}
}
};
The MyDetailsFragmentshould show details to the selected item (button click), so I want to drill down to the details fragment and want to give some extra data to the new fragment, so the detail fragment knows which details of which selected item it should display.
The selected tab should not change and the back button should go back to the FirstTabFragment page.
I think I should start a new fragment, but it is not possible, the name of the method startActivity tells me that I start a new activity and not a fragment. So, I have to use the MainActivity and put into there the new fragment?
(I do not use the android-support-v4.jar library, because I only target Android 4 devices)
How can I solve this problem? Any ideas?
From the fragment, call a method on the hosting activity, telling it about the button click event. The activity can then do whatever is appropriate.
Personally, I think that totally replacing the contents of a tab is inappropriate in the vast majority of cases, but you are certainly welcome to do it.