android - getLastLocation does not work on second time -


i'm using google play services user's last known connection.

@override public void onconnected(bundle connectionhint) {     final location lastlocation = locationservices.fusedlocationapi.getlastlocation(                 _googleapiclient); }   @override     protected void onresume() {         super.onresume();          connecttogoogleplay();        }  @override     protected void onpause() {         super.onpause();         if (_googleapiclient != null) {             _googleapiclient.disconnect();         }     }

works expected.

the problem occurs whenever i'm clicking on button , starting application again. app crashes because getlastlocation return null. formal documentation states -

if location not available, should happen rarely, null returned.

fine, know sure location exists, retrieved second ago.

i did quick experiment , removed _googleapiclient.disconnect(); , works, somehow disconnect erases last location

why ? missing ?

a few things consider:

1) should connect googleapiclient in onstart() , disconnect in onstop(): 

@override protected void onstart() {     super.onstart();     mgoogleapiclient.connect(); }  @override protected void onstop() {     mgoogleapiclient.disconnect();     super.onstop(); }

2) code should assume getlastlocation() may return null. null check.

3) use islocationavailable() when working getlastlocation(). if returns true, location returned getlastlocation() can assumed reasonably date.


Comments

Post a Comment

Popular posts from this blog

resizing Telegram inline keyboard -

telegram's inline keyboard great feature lots of different use cases. inline buttons added list of items this: inline_keyboard = [[inlinekeyboardbutton(text="button", callback_data="button"), inlinekeyboardbutton(text="reset",callback_data="reset")]] inline_keyboard_markup = inlinekeyboardmarkup(inline_keyboard) update.message.reply_text("hi", reply_markup=inline_keyboard_markup) the above code adds 2 buttons each half width of chat screen. i know the normal keyboard button there resize_keyboard parameter somehow can used. my question is there way resize inline buttons ? example make full width or quarter width. unfortunately, can't now. :( you can suggest @botsupport , might add feature next version.
Read more

recursion - Can every recursive algorithm be improved with dynamic programming? -

i first year undergraduate csc student looking competitive programming. recursion involves defining , solving sub problems. understand, top down dynamic programming (dp) involves memoizing solutions sub problems reduce time complexity of algorithm. can top down dp used improve efficiency of every recursive algorithm overlapping sub problems? dp fail work , how can identify this? the short answer is: yes. however, there constraints. obvious 1 recursive calls must overlap. i.e. during execution of algorithm, recursive function must called multiple times same parameters. lets truncate recursion tree memoization. can use memoization reduce number of calls. however, reduction of calls comes price. need store results somewhere. next obvious constraint need have enough memory. comes not-so obvious constraint. memory access requires time. first need find result stored , maybe copy location. in cases, might faster let recursion calculate result instead of loading somewher...
Read more

javascript - How to bind ViewModel Store to View? -

i'm pretty new ext js , trying embed multiselect inside panel . the viewmodel has stores property can see here: ext.define('test.view.controls.search.searchfiltermodel', { extend: 'ext.app.viewmodel', alias: 'viewmodel.filter', data: { title: '' }, stores: { test: { fields: [ 'id', 'name' ], proxy: { type: 'ajax', url: 'api/test', reader: 'array' }, autoload: true } } }); i bind in view this: viewmodel: { type: 'filter' }, layout: 'fit', border: 1, plain: true, scrollable: 'y', layout: 'fit', bind: { title: '{title}', }, items: { xtype: 'multiselect', scrollable: false, allowblank: true, ddreorder: true, bind: { store: '{test}' }, valuefield: 'id', displayfield: 'name' } ...
Read more