java - Using Thread in Android for sending message -

java - Using Thread in Android for sending message -

i have code:

if (value) { thread = new thread() { @override public void run() { seek { while (!isconnected()) { synchronized (this) { wait(3000); } } } grab (interruptedexception ex) { } if(wifimanager.iswifienabled()){ sendmessagewidget(); } else { showwifisettingsalert(); } } }; thread.start(); }

i want app wait until google api client connected , send message.

the code isconnected method is:

public boolean isconnected() { mgoogleapiclient.connect(); if (mgoogleapiclient.isconnected()) { homecoming true; } homecoming false; }

but error message: nullpointerexception: can't create handler within thread has not called looper.prepare(), , says error somewhere id showwifisettingsalert()

here code:

public void showwifisettingsalert() { alertdialog.builder alertdialog = new alertdialog.builder(getactivity()); // setting dialog title alertdialog.settitle("location accuracy tips"); // setting dialog message alertdialog .setmessage("you can improve accuracy of location turning on\n- wi-fi"); // on pressing settings button alertdialog.setpositivebutton("turn on", new dialoginterface.onclicklistener() { public void onclick(dialoginterface dialog, int which) { wifimanager.setwifienabled(true); // posalji poruke al pre toga jos jednom azuriraj // lokaciju al ako je pozvana aplikacija iz widgeta if (value) { sendmessagewidget(); } } }); // on pressing cancel button alertdialog.setnegativebutton("cancel", new dialoginterface.onclicklistener() { public void onclick(dialoginterface dialog, int which) { wifimanager.setwifienabled(false); // posalji poruke al pre toga jos jednom azuriraj // lokaciju al ako je pozvana aplikacija iz widgeta if (value) { sendmessagewidget(); } } }); // showing alert message alertdialog.show(); }

i want, if wifi not enabled, user take enable or not, either way message should sent... can help please?

since can't touch ui thread other main thread, must post these changes ui thread , looper , associated handlers. can explicitly creating handler associated ui thread (which work anywhere, since looper.getmainlooper() static call) such as:

if (value) { handler uicallback = new handler(looper.getmainlooper()); thread = new thread() { @override public void run() { seek { while (!isconnected()) { synchronized (this) { wait(3000); } } } grab (interruptedexception ex) { } uicallback.post(new runnable() { @override public void run() { if(wifimanager.iswifienabled()){ sendmessagewidget(); } else { showwifisettingsalert(); } } }); } }; thread.start(); }

or instead of using handler @ all, can wrap part in run() method in runonuithread() if in activity same thing.

you should note however, don't need utilize threading here. if follow illustration on: https://developer.android.com/google/auth/api-client.html you'll find implementing connectioncallbacks, onconnectionfailedlistener can phone call mgoogleapis.connect() activity's onstart() , when connects or fails corresponding callback executed on calling thread. instance,

@override public void onconnected(bundle connectionhint) { if(wifimanager.iswifienabled()){ sendmessagewidget(); } else { showwifisettingsalert(); } }

achieves same thing...

java android multithreading alertdialog