Android ble app crash if bluetooth is turned off in android lollipop -


hello try scan bluetooth ble device android lollipop. working fine if turned off bluetotooth run app crash , give pop enable bluetooth.ideally should give pop enable bluetooth if turned off.

this method, should enable bluetooth:

   private void enablebluetooth() {     if(bluetoothadapter == null) {      //bluetoothstate.settext("bluetooth not supported"); }     else if(!bluetoothadapter.isenabled()) {      //bluetoothadapter.enable();       intent enablebtintent = new intent(bluetoothadapter.action_request_enable);       activity.startactivityforresult(enablebtintent, request_enable_bt);       }     }

code start scan

public void handlescanstart(view view) {         founddevices.clear();         btarrayadapter.clear();         ble.startblescan();         scanbutton.setenabled(false);        stopscanbutton.setenabled(true); }

enable start scan 

  public void startblescan() {         if(getscanning()) {            return;        }            enablebluetooth();          scanning = true;            scanfilter.builder filterbuilder = new scanfilter.builder();                     //todo default, scans devices         scansettings.builder settingsbuilder = new               scansettings.builder();         settingsbuilder.setscanmode(scansettings.scan_mode_low_latency);              list<scanfilter> filters = new arraylist<scanfilter>();                   filters.add(filterbuilder.build());                    bluetoothlescanner.startscan(filters, settingsbuilder.build(), scancallback);             log.d(tag, "bluetooth scanning...");                       }

below log file

    04-29 18:09:11.415: e/androidruntime(26155): fatal exception: main     04-29 18:09:11.415: e/androidruntime(26155): process: com.android.androidble5, pid: 26155     04-29 18:09:11.415: e/androidruntime(26155): java.lang.illegalstateexception: not execute method of activity     04-29 18:09:11.415: e/androidruntime(26155):    @ android.view.view$1.onclick(view.java:4020)     04-29 18:09:11.415: e/androidruntime(26155):    @ android.view.view.performclick(view.java:4780)     04-29 18:09:11.415: e/androidruntime(26155):    @ android.view.view$performclick.run(view.java:19866)     04-29 18:09:11.415: e/androidruntime(26155):    @ android.os.handler.handlecallback(handler.java:739)     04-29 18:09:11.415: e/androidruntime(26155):    @ android.os.handler.dispatchmessage(handler.java:95)     04-29 18:09:11.415: e/androidruntime(26155):    @ android.os.looper.loop(looper.java:135)      04-29 18:09:11.415: e/androidruntime(26155):    @ android.app.activitythread.main(activitythread.java:5254)     04-29 18:09:11.415: e/androidruntime(26155):    @ java.lang.reflect.method.invoke(native method)     04-29 18:09:11.415: e/androidruntime(26155):    @ java.lang.reflect.method.invoke(method.java:372)     04-29 18:09:11.415: e/androidruntime(26155):    @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:903)     04-29 18:09:11.415: e/androidruntime(26155):    @ com.android.internal.os.zygoteinit.main(zygoteinit.java:698)     04-29 18:09:11.415: e/androidruntime(26155): caused by: java.lang.reflect.invocationtargetexception     04-29 18:09:11.415: e/androidruntime(26155):    @ java.lang.reflect.method.invoke(native method)     04-29 18:09:11.415: e/androidruntime(26155):    @ java.lang.reflect.method.invoke(method.java:372)     04-29 18:09:11.415: e/androidruntime(26155):    @ android.view.view$1.onclick(view.java:4015)     04-29 18:09:11.415: e/androidruntime(26155):    ... 10 more     04-29 18:09:11.415: e/androidruntime(26155): caused by: java.lang.nullpointerexception: attempt invoke virtual method 'void android.bluetooth.le.bluetoothlescanner.startscan(java.util.list, android.bluetooth.le.scansettings, android.bluetooth.le.scancallback)' on null object reference     04-29 18:09:11.415: e/androidruntime(26155):    @ com.android.androidble5.bluetoothutility.startblescan(bluetoothutility.java:204)     04-29 18:09:11.415: e/androidruntime(26155):    @ com.android.androidble5.myactivity.handlescanstart(myactivity.java:247)

the correct approach before starting scan have check bluetoothlescanner object null or not check bluetoothadapter

sample

if(bluetoothlescanner != null){              bluetoothlescanner.startscan(filters,settingsbuilder.build(),scancallback);      }

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