java - Android Screen Turns Black -

i looking reason happening. writing image-stitching app android. have decided use opencv4android , had android ndk stuff in order work (i sure somehow causing problem). problem having when code reaches opencv ndk portion of program, screen on android device turns black , logcat stops displaying anything. crashes without telling me of errors @ all. unusual because in .cpp portion of project if there problem, logcat @ least display vague fatal signal 11 , end.

because of this, have no idea begin searching solution. beginner when comes android programming, may can overlooked beginner. appreciated!

more info on blank screen:

• android device not frozen, can exit app
• if try enter app again through multitasking button, takes 5 seconds enter
• logcat or android studio not frozen

edit: after leaving black screen on android device said [app name] wasn't responding, , gave me option either close it, or keep waiting. suspicion line

mat img = imread("/storage/emulated/0/appname/test" + id + ".jpg"); 

in .cpp portion of project causing behavior, not sure. omitted line , app ran should have. after using line again, broke, after omitting second time app kept black screen behavior.

edit edit: here logcat no filters selected (apologies wall of text):

04-19 14:23:16.943 14240-14240/aaron.picstitch d/in stitchimages: begin 04-19 14:23:16.943 14240-14240/aaron.picstitch d/dalvikvm: trying load lib /data/app-lib/aaron.picstitch-183/libmylibrary.so 0x41f7ba28 04-19 14:23:16.943 14240-14240/aaron.picstitch d/dalvikvm: added shared lib /data/app-lib/aaron.picstitch-183/libmylibrary.so 0x41f7ba28 04-19 14:23:16.943 14240-14240/aaron.picstitch d/dalvikvm: no jni_onload found in /data/app-lib/aaron.picstitch-183/libmylibrary.so 0x41f7ba28, skipping init 04-19 14:23:18.114 563-681/? d/sensorservice: -0.2 0.2 9.7 04-19 14:23:19.946 763-978/? d/keyguardupdatemonitor: sendkeyguardvisibilitychanged(true) 04-19 14:23:19.946 763-978/? i/keyguardupdatemonitor: visibility same 04-19 14:23:19.956 144-198/? i/surfaceflinger: id=159 removed fxternalpic (10/14) 04-19 14:23:19.956 144-703/? i/surfaceflinger: id=159 removed fxternalpic (-2/14) 04-19 14:23:19.956 763-976/? d/keyguardupdatemonitor: sendkeyguardvisibilitychanged(true) 04-19 14:23:19.956 763-976/? i/keyguardupdatemonitor: visibility same 04-19 14:23:19.966 763-777/? d/keyguardupdatemonitor: sendkeyguardvisibilitychanged(true) 04-19 14:23:19.966 763-777/? i/keyguardupdatemonitor: visibility same 04-19 14:23:19.966 144-3490/? i/surfaceflinger: id=160 removed fxternalpic (11/13) 04-19 14:23:19.966 144-198/? i/surfaceflinger: id=160 removed fxternalpic (-2/13) 04-19 14:23:19.976 763-978/? d/keyguardupdatemonitor: sendkeyguardvisibilitychanged(true) 04-19 14:23:19.976 763-978/? i/keyguardupdatemonitor: visibility same 04-19 14:23:19.986 763-1308/? d/keyguardupdatemonitor: sendkeyguardvisibilitychanged(true) 04-19 14:23:19.986 763-1308/? i/keyguardupdatemonitor: visibility same 04-19 14:23:20.286 763-978/? d/keyguardupdatemonitor: sendkeyguardvisibilitychanged(true) 04-19 14:23:20.286 763-978/? i/keyguardupdatemonitor: visibility same 04-19 14:23:20.286 144-1100/? i/surfaceflinger: id=158 removed qickeractiv (10/12) 04-19 14:23:20.286 144-196/? i/surfaceflinger: id=158 removed qickeractiv (-2/12) 04-19 14:23:20.286 763-777/? d/keyguardupdatemonitor: sendkeyguardvisibilitychanged(true) 04-19 14:23:20.296 763-777/? i/keyguardupdatemonitor: visibility same 04-19 14:23:20.296 144-144/? w/surfaceflinger: couldn't log binary event log: overflow. 04-19 14:23:21.627 563-681/? d/sensorservice: -0.2 0.2 9.8 04-19 14:23:23.449 563-3587/? d/batteryservice: level:90, scale:100, status:3, health:2, present:true, voltage: 4209, temperature: 270, technology: li-ion, ac powered:false, usb powered:true, wireless powered:false, icon:17303544, invalid charger:0, online:4, current avg:0, charge type:1, power sharing:false 04-19 14:23:23.449 763-763/? d/keyguardupdatemonitor: received broadcast android.intent.action.battery_changed 04-19 14:23:23.449 763-763/? d/keyguardupdatemonitor: handlebatteryupdate 04-19 14:23:23.449 763-763/? d/cmasmessage: [update] mshowingcmastext false 04-19 14:23:23.449 763-763/? d/cmasmessage: cmasicon gone : 04-19 14:23:23.449 563-563/? d/batteryservice: sending action_battery_changed. 04-19 14:23:23.449 763-763/? d/statusbar-phonestatusbar: mbrightnessenablebysettings = true mbrightnessenablebybattery = true mbrightnessenablebydisableflag = true mpmsbrightnessenablebysettings = true 04-19 14:23:23.469 763-763/? d/statusbar-iconmerger: checkoverflow(544), more:false, req:false child:3 04-19 14:23:23.479 763-763/? d/batterymeterview: action_battery_changed : level:90 status:3 health:2 04-19 14:23:24.570 563-1583/? d/ssrmv2:siop: siop:: ap = 310, delta = 10 04-19 14:23:24.620 563-683/? w/activitymanager: launch timeout has expired, giving wake lock! 04-19 14:23:25.151 563-681/? d/sensorservice: -0.2 0.2 9.8 04-19 14:23:28.654 563-681/? d/sensorservice: -0.2 0.2 9.8 04-19 14:23:32.177 563-681/? d/sensorservice: -0.1 0.2 9.8 04-19 14:23:32.448 563-868/? e/watchdog: !@sync 115 04-19 14:23:34.590 563-1583/? d/ssrmv2:siop: siop:: ap = 310, delta = 0 04-19 14:23:35.681 563-681/? d/sensorservice: -0.2 0.2 9.8 04-19 14:23:39.184 563-681/? d/sensorservice: -0.2 0.2 9.8 04-19 14:23:42.698 563-681/? d/sensorservice: -0.2 0.2 9.8 04-19 14:23:43.448 563-3489/? d/batteryservice: level:90, scale:100, status:3, health:2, present:true, voltage: 4206, temperature: 280, technology: li-ion, ac powered:false, usb powered:true, wireless powered:false, icon:17303544, invalid charger:0, online:4, current avg:0, charge type:1, power sharing:false 04-19 14:23:43.448 763-763/? d/keyguardupdatemonitor: received broadcast android.intent.action.battery_changed 04-19 14:23:43.448 763-763/? d/keyguardupdatemonitor: handlebatteryupdate 04-19 14:23:43.448 763-763/? d/cmasmessage: [update] mshowingcmastext false 04-19 14:23:43.448 763-763/? d/cmasmessage: cmasicon gone : 04-19 14:23:43.448 563-563/? d/batteryservice: sending action_battery_changed. 04-19 14:23:43.458 763-763/? d/statusbar-phonestatusbar: mbrightnessenablebysettings = true mbrightnessenablebybattery = true mbrightnessenablebydisableflag = true mpmsbrightnessenablebysettings = true 04-19 14:23:43.468 763-763/? d/statusbar-iconmerger: checkoverflow(544), more:false, req:false child:3 04-19 14:23:43.479 763-763/? d/batterymeterview: action_battery_changed : level:90 status:3 health:2 04-19 14:23:44.600 563-1583/? d/ssrmv2:siop: siop:: ap = 300, delta = -10 04-19 14:23:46.191 563-681/? d/sensorservice: -0.2 0.2 9.8 04-19 14:23:49.695 563-681/? d/sensorservice: -0.2 0.2 9.8 04-19 14:23:53.218 563-681/? d/sensorservice: -0.2 0.2 9.8 04-19 14:23:53.448 563-2198/? d/batteryservice: level:90, scale:100, status:3, health:2, present:true, voltage: 4209, temperature: 290, technology: li-ion, ac powered:false, usb powered:true, wireless powered:false, icon:17303544, invalid charger:0, online:4, current avg:0, charge type:1, power sharing:false 04-19 14:23:53.448 763-763/? d/keyguardupdatemonitor: received broadcast android.intent.action.battery_changed 04-19 14:23:53.448 763-763/? d/keyguardupdatemonitor: handlebatteryupdate 04-19 14:23:53.448 563-563/? d/batteryservice: sending action_battery_changed. 04-19 14:23:53.458 763-763/? d/cmasmessage: [update] mshowingcmastext false 04-19 14:23:53.458 763-763/? d/cmasmessage: cmasicon gone : 04-19 14:23:53.458 763-763/? d/statusbar-phonestatusbar: mbrightnessenablebysettings = true mbrightnessenablebybattery = true mbrightnessenablebydisableflag = true mpmsbrightnessenablebysettings = true 04-19 14:23:53.458 763-763/? d/batterymeterview: action_battery_changed : level:90 status:3 health:2 04-19 14:23:53.468 763-763/? d/statusbar-iconmerger: checkoverflow(544), more:false, req:false child:3 04-19 14:23:54.609 563-1583/? d/ssrmv2:siop: siop:: ap = 310, delta = 10 04-19 14:23:56.721 563-681/? d/sensorservice: -0.2 0.2 9.8 04-19 14:23:59.985 563-698/? v/alarmmanager: waitforalarm result :8 04-19 14:23:59.995 763-763/? d/keyguardupdatemonitor: received broadcast android.intent.action.time_tick 04-19 14:23:59.995 763-763/? d/keyguardupdatemonitor: handletimeupdate 04-19 14:23:59.995 563-563/? v/alarmmanager: clockreceiver onreceive() action_time_tick 04-19 14:24:00.015 763-763/? d/statusbar-iconmerger: checkoverflow(544), more:false, req:false child:3 04-19 14:24:00.035 1606-1606/? d/accuweather: [accutab_magagine]>>> wcs:175 [0:0] action : androidintentactiontime_tick 04-19 14:24:00.045 1606-1606/? d/accuweather: [accutab_magagine]>>> wc:41 [0:0] action : actiontime_tick 04-19 14:24:00.045 1606-1606/? d/accuweather: [accutab_magagine]>>> wc:55 [0:0] settings ct : androidappreceiverrestrictedcontext@41f8d0e0 04-19 14:24:00.045 1606-1606/? d/accuweather: [accutab_magagine]>>> uim:146 [0:0] setcontext 04-19 14:24:00.055 1606-1606/? d/accuweather: [accutab_magagine]>>> uim:371 [0:0] isupdatewidget -> false 04-19 14:24:00.065 1606-1606/? d/accuweather: [accutab_magagine]>>> sem:742 [0:0] isshownextevent -> false