android-lifecycle

I'm trying to do something using a boolean in a Fragment class each time the Fragment is displayed. Example My app launches, opens the FirstFragment and the boolean for the first time is always true , then I have an if clause that checks its value: if (FirstTime) { FirstTime = false; } else { // Other stuff here, cause it's not true. } Then, on the first time, when FirstTime is true , I do stuff like go to another Fragment . and when I return to Fragment1 and on my onCreate() , I do the same. It's always true , seems that it's refreshing or something. Then I thought that could be a problem

Do you guys have a workaround for the following problem? In the onDestroy of a registration activity (when the user presses the back button) I call a new activity so the user can put in some final production data of that day and then the report is being e-mailed. The problem is that on the just started activity the call to getIntent returns null and I have to get the data from there. public void onDestroy(){ //unregister listeners, cancel timers etc. logOff(); super.onDestroy(); } protected void logOff(){ // collect data etc. // open new activity that asks for final production numbers Intent

I have a pretty unique issue where I am trying to retrieve previous fragment that was there before I went to the homescreen via the current fragment( last visible fragment) Not to confuse any further, here's the steps to repro my issue 1 ) launch the mainactivity, from there open fragment A via a button click (say button A) 2) from fragment A , press another button ,say B, which will open fragment B. 3) Fragment B has a close and save button , pressing which leads me back to the previous backstack fragment A ( activity.backpressed()) 4) Now, I have a scenario where I am calling fragment B, by

When I pull down the quick settings drop down menu while my app is opened and in the foreground, are there any callback methods called? I tried a few quicks tests and Activity.onWindowFocusChanged(boolean hasFocus) might work for you. It fires when I drag down quick settings but it will also likely fire for other reasons, like AlertDialogs. onWindowFocusChanged void onWindowFocusChanged (boolean hasFocus) Called when the current Window of the activity gains or loses focus. This is the best indicator of whether this activity is visible to the user. 来源： https://stackoverflow.com/questions

I programmatically create a RelativeLayout with some other views inside it and add it to the parent which is defined in XML. But all the views (incl. the layout) that were created programmatically disappear after the activity is re-created. Do I need a SharedPreferences object to save the values and then re-create the layout or is there an easier way to save it? P.S. all new created views get an id assigned Do I need a SharedPreferences object to save the values and then re-create the layout You say that you are creating these widgets in onResume() . Your code in onResume() needs to know what

Is it a good idea to specifically set the instance variables to null in onDestroy() callback of the activity? Something like this: @Override protected void onDestroy() { super.onDestroy(); mClassVariable1 = null; mClassVariable2 = null; mClassVariable3 = null; } If I remember correctly from Java SE, any references that are isolated & not connected to a running program & can be garbage collected anyways. So does this make the above superfluous? On the other hand, the lifecycle in mobile devices being different, would the above be a best-practice? I know it cannot hurt to do it, but sometimes