Let's say I am on an Activity, user clicks a button, and I navigate to a web page.
Intent i = new Intent(Intent.ACTION_VIEW);
i.setData(Uri.parse("SOME_URL"));
startActivity(i);
it takes me to the web page, and then when I click back to goes to my activity, but it starts it all over again.
So is it possible to do this in a way so that after clicking the back button, it takes me to my activity, but instead of onCreate it call onRestart.
The goal is not going through onCreate again.
That is the normal life cycle of an Activity... you could save the state of the activity and restore it to get the "same" as before.
The main question should be: Why do you not want to go through onCreate? If it goes through it because it was destroyed before and need to be recreated. So not going through it will cause a lot of trouble.
You could set an intent in your activity (setIntent) before calling the web browser, then in your onCreate method, check for if this intent called you back (check the intent name or an extra) and if so, skip the rest of onCreate.
Before calling web browser :
Intent intentForThis = new Intent( "AfterWebBroswer" );
this.setIntent( intentForThis );
Intent i = new Intent(Intent.ACTION_VIEW);
i.setData(Uri.parse("SOME_URL"));
startActivity(i);
And then in your onCreateMethod
public void onCreate( Bundle b ) {
if( !getIntent().getAction().equals("AfterWebBrowser") ) {
//rest of onCreate
}//if
}//met
Regards,
Stéphane
Related
In my android activity B, I read values bundled in the intent like this
Bundle bundle = getIntent().getExtras();
Boolean mine = bundle.getString("mine").equals("1");
int pagenum = bundle.getInt("page");
When I start B from another activity A, I give in mine=0,pagenum=0.
And I can read that fine in B.
But then in B, I want to reload the activity, by finishing itself and opening another B. I also need to pass in the new data like this:
private void refresh(Boolean mine, int newpage) {
finish();
Intent myIntent = new Intent(this, AllThreadsScreen.class);
myIntent.putExtra("mine", mine ? "1" : "0");
myIntent.putExtra("page", Integer.toString(newpage, 10));
startActivity(myIntent);
}
When I call this, I make sure that newpage has a value of 1. However the problem is that, after starting the activity, when I read the page value from the bundle, it becomes 0 again...
Does anyone know whats wrong?
Thanks.
You are not "restarting" the Activity. If you call finish() and the lines after still work, then it ins't really finished, is it?
What is happening is the Activity may begin the process of finishing, but then receives a new Intent. Android doesn't actually destroy it.
Also, you don't need to finish the Activity anyway. just use onNewIntent (a little known, little used Activity method).
How to capture the new Intent in onNewIntent()?
I have a problem with my Login screen. When it's started, I check for network connection, and if it's disabled, I want to show NoNetworkActivity. And the same for every other screen: when Activity is launched, I check network connection and navigate to NoNetworkActivity is needed. When navigating, I want to save the Intent which launched this previous activity and finish it to disable the Back button redirection when on NoNetworkActivity. So, when connection is restored, I want to launch that intent and get actual state of the app before this error:
LoginActivity
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
if (!App.getInstance().isNetworkConnected()) {
Intent noNetwork = new Intent(this, NoNetworkActivity.class);
noNetwork.putExtra(NoNetworkActivity.EXTRA_FAILED_INTENT, getIntent());
startActivity(noNetwork);
finish();
}
...
NoNetworkActivity
private void checkNetworkConnection() {
mCheckButton.setVisibility(View.INVISIBLE);
mProgressBar.setVisibility(View.VISIBLE);
if (App.getInstance().isNetworkConnected()) {
Intent failedIntent = getIntent().getParcelableExtra(EXTRA_FAILED_INTENT);
startActivity(failedIntent);
finish();
} else {
mCheckButton.setVisibility(View.VISIBLE);
mProgressBar.setVisibility(View.INVISIBLE);
App.toast("Connection failed");
}
}
And it's getting strange: startActivity(failedIntent) does NOTHING. I've tried to remove finish() from next line, and NoNetworkActivity just stays on top without anything happening.
And one more thing. You can suggest passing Activity actual class names instead of intents, but I realy need Intent. That's because I'm using a lot of starting actions for every activity and a bunch of extras.
Thanks in advance for any help. Cheers!
Very bad approach. Don't use it.
First, you don't need to finish previous activity just to disable Back action. You can override onBackPressed().
Second, you don't need to start parent activity again. Just call a new activity with startActivityForResult(); and override onActivityResult() callback.
Third, but most important. Why do you want to call a new activity just to show 'No Network' message? And what if network won't be re-established? Just create isNetworkEnabled() method and call it when user attempts to get data from the Internet, before sending actual request to server. If no network - notify a user with an alert or toast.
I suggest you use fragments instead of activities first of all.
Using fragments you can set retainInstance(true);
To disable coming back from an activity to the previous :
1)call finish() on that activity
2)
Intent i = new Intent();
i.setClass(this, MyActivity.class);
i.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
startActivity(i);`
It works with an explicit Intent.
In LoginActivity substitute:
noNetwork.putExtra(NoNetworkActivity.EXTRA_FAILED_INTENT, getIntent());
with:
noNetwork.putExtra(NoNetworkActivity.EXTRA_FAILED_INTENT, new Intent(this, LoginActivity.class));
Btw, Alexander Zhak has some good points in his answer
I am puzzled over this behavior I am experiencing in an application I am developing...
Short:
Intent data is not clearing out when the user presses the back button to leave the application and then presses the recent button to re-enter the application. (Every other case, the intent data is cleared out)
Long:
I have an application with a splash screen that is used to collect data that is passed in from a URI scheme. I then setup an intent to forward the data to the main activity. The main activity has fragments and is based off the master/detail template.
The intent data is cleared out in all cases, such as pressing the home button and then going back to the application, pressing the recent apps button and then going back to the application, etc. The only case where the intent data is not cleared out is when the user presses the back button and then the recent apps button to get back into the application.
Relevant snippets of code that involve the intents:
// Splash Screen Activity
#Override
protected void onPostExecute(Void result) {
// Data is done downloading, pass notice and app ids to next activity
Intent intent = new Intent(getBaseContext(), ListActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK);
intent.putExtra("id1", id1);
intent.putExtra("id2", id2);
intent.putExtra("id3", id3);
startActivity(intent);
finish();
}
// ListActivity retrieving intent data
Intent intent = getIntent();
if (intent != null) {
this.id1 = intent.getExtras().getString("id1");
this.id2 = intent.getExtras().getString("id2");
this.id3 = intent.getExtras().getString("id3");
}
// ListActivity clearing intent data
#Override
public void onPause() {
super.onPause();
// Clear intent data
Intent intent = getIntent();
intent.putExtra("id1", "");
intent.putExtra("id2", "");
intent.putExtra("id3", "");
}
I want to note that I have also tried using intent.removeExtra("id1") but that too did not work.
Any idea what is going on? It is as if Android is keeping the old intent even though onPause() is always called to clear the intent data.
actually this is due to Android starting the app from the history hence the intent extras are still in there
refer to this questions Android: Starting app from 'recent applications' starts it with the last set of extras used in an intent
so adding this conditional to handle this special case fixed it for me
int flags = getActivity().getIntent().getFlags();
if ((flags & Intent.FLAG_ACTIVITY_LAUNCHED_FROM_HISTORY) != 0) {
// The activity was launched from history
// remove extras here
}
I believe the difference here is that the Back key is actually causing your Activity to finish, where as pressing Home causes your activity to be paused, but not finished.So when your process is brought back to the front in the Home case, it is simply resuming an already existing Activity instance, whereas in the Back case, the system is instantiating a new copy of your Activity, calling onCreate(), and handing it a fresh copy of the last Intent recorded for that activity.
In onPause() you are clearing the extras in a "copy" of the Intent. You can try adding
setIntent(intent);
to onPause() after you've cleared the extras (although calling removeExtra() would probably also work instead of setting extras to empty strings).
NOTE:
However, I would suggest that this design is flawed. You shouldn't use the Intent to keep track of state in your application. You should save some state in shared preferences because this will survive your app being killed/restarted, a reboot of the phone, or whatever.
The problem is that the new Intent is not persisted, so that If the user presses the HOME button and your app goes to the background and then Android kills your app because it is not active, when the user returns to the app, Android will create a new process for your app and it will recreate the activity using the original Intent.
Also, if you read the documentation for getIntent() it says that it returns the Intent that started the activity.
To get around the issue I was facing, I opted to use SharedPreferences as a means to pass data between activities.
I know SharedPreferences isn't typically used for this purpose, but it solved my issue and works.
This is my first post, so please be nice :)
I have a question and no one gave the answer in the post I've seen.
My app has a list and a button to open an activity, this activity creates a new item to show in the list of the previous activity when pressing the button Create.
How can I do this?
This is the code I made for the first button:
intent = new Intent(this.getBaseContext(), NewTestActivity.class);
this.finish();
startActivity(intent);
and this is the code to go back an refresh:
Intent intent = new Intent(getBaseContext(), TestListActivity.class);
startActivity(intent);
But the code to goback is useful, because the activity don't refresh.
I have to call the new activity in a diferent way? Or go back to previus activity in a diferent way? Or go back normally and refresh the activity when I'm back in the previus activity?
Well...this is all.
Sorry for my bad english and, if this question has been answered in another thread, give me the link to read, because I can't find it :)
PS: I started with android in December.
Thanks for your help.
When you are going to start new activity you shouldn't close a current one until you actually need this behaviour. (remove this.finish(); row from your code)
Also you shouldn't close an active activity manually until you actually need it. When the user presses the "back" button on the device Android pops the previous activity from the "back stack". Read once more Activity documentation.
According to your description you have a list of elements. So in order to refresh the list you need to update your dataset and notify the list about it by ListView.notifyDataSetChanged() method call.
Before getting to a real answer, I'd like to show some improvements to your code.
First, when creating an Intent (or when you need a context in general) from an Activity there is no need to call getBaseContext(), you can just use this:
intent = new Intent(this, NewTestActivity.class);
Second, android is good at handling Activities, you do not have to close your first activity manually with finish(). Android will automatically pause or stop your first activity and bring it back when you return to it.
Third, in your case you might want to use startActivityForResult() instead of startActivity() for reasons I will explain below.
This will make your code look like the following:
private static final int MY_REQUEST_CODE = 33487689; //put this at the top of your Activity-class, with any unique value.
intent = new Intent(this, NewTestActivity.class);
startActivityForResult(intent, MY_REQUEST_CODE);
Now, the startActivityForResult() starts an activity and waits for a result from that new Activity. When you call finsih() in the new Activity you will end up in the first Activitys onActivityResult()-method, with data supplied from the new Activty that is now closed:
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if(requestCode != MY_REQUEST_CODE) return; //We got a result from another request, so for this example we can return.
if(resultCode != RESULT_OK) return; //The user aborted the action, so we won't get any data.
//After the above if-statements we know that the activity that gives us a result was requested with the correct request code, and it's action was successful, we can begin extracting the data, which is in the data-intent:
Item item = (Item) data.getSerializableExtra("customData"); //casts the data object to the custom Item-class. This can be any class, as long as it is serializable. There are many other kinds of data that can be put into an intent, but for this example a serializable was used.
itemList.add(item); //This is the list that was specified in onCreate()
//If you use an Adapter, this is the place to call notifyDataSetChanged();
}
For this all to work, we need to do some things in the second Activity:
When the item has been created, we must set a result:
//We begin by packing our item in an Intent (the Item class is an example that is expected to implement Serializable)
Item theCreatedItem; //This is what was created in the activity
Intent data = new Intent();
data.putSerializable(theCreatedItem);
setResult(RESULT_OK, data);
finish();
This should return to the first Activitys onActivityResult()-method with the item, as explained above.
Having real issue understanding how to sort my issue out.
On the Home screen I have 2 buttons
When the user clicks the first button it starts a new Activity. What I am looking for is if the user clicks back the app returns to the home screen. If the user clicks the first button again it starts a new activity.
If the user clicks the second button it returns to the activity that was last started by clicking button 1
What I am having issue with is how to save the state of the activity when the user clicks back
Also how to call that activity when the second button is pressed
Thanks for your Time
UPDATE
I have gone down part of this but still having issues. If I put some of the code I am using perhaps someone can point where I gone wrong.
Code for calling the new activity from main menu
Intent intent = new Intent(MainMenu.this, NewClass.class);
intent.putExtra("value1", value1);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
Within the new class I have added the following :
#Override
public void onBackPressed() {
//super.onBackPressed();
Intent intent = new Intent(RoundScoring.this, MainMenu.class);
intent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
startActivity(intent);
Toast.makeText(this, "Back Button Pressed", Toast.LENGTH_LONG).show();
}
I do not have either a onrestoreinstancestate or onresumne in this class. only a oncreate. Do I have to add something like this to bring back the instance
On the second button on the main menu I have added this
Intent intentContiune = new Intent(MainMenu.this, NewClass.class);
intentContiune.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
startActivity(intentContiune);
Thanks
Try this:
Home Screen Left Button:
Open the new activity with an intent flag, FLAG_ACTIVITY_NEW_TASK
Activity:
Override onBackClick() on the started activity to call the home screen with an Intent instead of finishing it. Use the flag FLAG_ACTIVITY_REORDER_TO_FRONT
Save activity state overriding OnSaveInstanceState
Home Screen Right Button:
Call the activity with the flag FLAG_ACTIVITY_SINGLE_TOP
More info about flags:
http://blog.akquinet.de/2010/04/15/android-activites-and-tasks-series-intent-flags/
One solution may involve passing bundles around that include the state of your activity. Using startActivityForResult(), you can return a bundle with the activity's state. When the user clicks your second button, pass in that bundle and have the activity set itself up with respect to the contents of the bundle. If the bundle doesn't contain the information you're looking for, then use the default values as if you were just starting it.
For more information:
Android: Capturing the return of an activity