致命傷を避けるための例外実例集

Transcript

1. க໋ইΛආ͚ΔͨΊͷ ྫ֎࣮ྫू Keishin Yokomaku / Startup Android #1
2. க໋ইΛආ͚ΔͨΊͷྫ֎࣮ྫू About Me ▸ Keishin Yokomaku ▸ Drivemode, Inc. / Principal Engineer ▸ KeithYokoma: GitHub / Twitter / Qiita / Tumblr / Stack Overflow ▸ Books: Mobile App Dev Guide / Android Academia / Grimoire of Android ▸ Fun: Gymnastics / Cycling / Photography / Motorsport ▸ Today’s Quote: “࣌୅͸ے೑” 2
3. ྫ֎ 3
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5. 5 ˒ˑˑˑˑ This app keeps crashing. Uninstalled.
6. க໋ইΛආ͚ΔͨΊͷྫ֎࣮ྫू ই͸ઙ͍͏ͪʹ࠹͙ ▸ ϦϦʔεઓུͱΫϥογϡݕ஌ͷ࢓૊Έ͸ඞਢςΫχοΫ ▸ Fabric(Crashlytics) ͰΫϥογϡϩάͷऩू ▸ Google Play Developer Console Ͱஈ֊తϦϦʔε ▸ ϢʔβϑΟʔυόοΫͷมԽʹؾ෇͘ ▸ ʮ࠷ۙ͜ΜͳϑΟʔυόοΫ͕Α͘དྷͯΔʯ ▸ ʮ͋ͷϑΟʔυόοΫݮͬͨʯ 6
7. க໋ইΛආ͚ΔͨΊͷྫ֎࣮ྫू ෆ৚ཧͱઓ͏ ▸ ໌Β͔ʹΫϥογϡ͢Δͱ෼͔Δ΋ͷ͚͕ͩݪҼͰ͸ͳ͍ ▸ Ϣʔβͷ࢖༻ঢ়گʹΑͬͯΫϥογϡͨ͠Γ͠ͳ͔ͬͨΓ͢Δ΋ͷ΋͋Δ ▸ ୺຤ͷҧ͍ɺ࢖͍ํͷҧ͍ɺଞʹΠϯετʔϧ͍ͯ͠ΔΞϓϦͷҧ͍ ▸ ༷ʑͳཁҼ͕༧૝֎ͷΫϥογϡΛ༠ൃ͢Δ ▸ ͱ͖ʹ͸ݟ஌Β͵ྫ֎͕ݪҼͰ͋Δ͜ͱ΋͋Δ ▸ ྫ֎ͷ໊લ΍ϝοηʔδ͔Βঢ়گ΍ཧ༝ΛಡΈऔΔεΩϧΛ਎ʹண͚Α͏ 7
8. க໋ইΛආ͚ΔͨΊͷྫ֎࣮ྫू Let’s get started! ▸ ຊ೔ͷྫ֎Ϩγϐ ▸ ༗໊Ͳ͜Ζ͔ΒͲϚΠφʔͳ΋ͷ·ͰϞϦϞϦίʔε 8 NullPointerException OutOfMemoryError StackOverflowError Illegal**Exception CursorWindowAllocationException TransactionTooLargeException DeadObjectException
9. NullPointerException 9
10. க໋ইΛආ͚ΔͨΊͷྫ֎࣮ྫू NullPointerException ▸ Ұ൪Α͋͘ΔΫϥογϡͷݪҼ ▸ ى͖Δཧ༝͸༷ʑ ▸ ίʔυ্Ͱͷݕࠪ࿙Ε ▸ Nullable Ͱͳ͍৔ॴʹ null Λ୅ೖ ▸ ΦϒδΣΫτͷϥΠϑαΠΫϧʹର͢Δߟྀ࿙Ε 10
11. க໋ইΛආ͚ΔͨΊͷྫ֎࣮ྫू NullPointerException ▸ Ή΍ΈʹରࡦΛऔͬͯ͸͍͚ͳ͍ ▸ e.g. ͋ΒΏΔϝιουͰ null νΣοΫΛೖΕΔ ▸ ๷ޚతʹͳΓ͗͢ΔͱޙʑͷϝϯςφϯεͰ଍ΛҾͬுͬͯ͠·͏ 11
12. க໋ইΛආ͚ΔͨΊͷྫ֎࣮ྫू NullPointerException ▸ ରࡦͷํ๏ ▸ ઃܭʹΑΔରࡦ ▸ ϝιου͕ null Λڐ༰͢Δ͔Ͳ͏͔ද໌͢Δ͜ͱͰɺ
 ୭͕null νΣοΫͷ੹຿Λෛ͏͔ܾΊΔ ▸ NullObject ύλʔϯΛ࢖ͬͯɺԿ΋ى͖ͳ͍Α͏ʹ޻෉͢Δ 12
13. க໋ইΛආ͚ΔͨΊͷྫ֎࣮ྫू NullPointerException ▸ ରࡦͷํ๏ ▸ ϑϨʔϜϫʔΫͷίʔυͷ೺Ѳ ▸ Ͳ͏͍͏ঢ়گͰϝιου͕ null Λฦ͔͢஌͓ͬͯ͘ ▸ Support Library ͷ࣮ଶΛ஌͓ͬͯ͘ ▸ ۭ࣮૷ͷ··ϦϦʔε͞Ε͍ͯΔ͕࣌͋Δ ▸ ϑϨʔϜϫʔΫͷ࡞๏ʹ४ͨ͡࡞ΓํΛ֮͑Δ 13
14. OutOfMemoryError 14
15. க໋ইΛආ͚ΔͨΊͷྫ֎࣮ྫू OutOfMemoryError ▸ ը૾΍ಈըͳͲେ͖ͳσʔλΛѻ͏ͱඞͣ໨ʹ͢Δྫ֎ ▸ จࣈ௨Γɺۭ͖ͷͳ͍ώʔϓʹΦϒδΣΫτΛ࡞Ζ͏ͱ͍ͯ͠Δͱ͖ʹى͖Δ ▸ ରࡦํ๏͸ΘΓͱ໌շ ▸ େ͖ͳΦϒδΣΫτΛখ͘͢͞Δ ▸ ಉ࣌ʹͨ͘͞ΜͷΦϒδΣΫτΛώʔϓʹೖΕͳ͍ ▸ ϝϞϦϦʔΫΛͳ͘͢ 15
16. StackOverflowError 16
17. க໋ইΛආ͚ΔͨΊͷྫ֎࣮ྫू StackOverflowError ▸ ελοΫΛ࢖͍௵ͨ͠ͱ͖ʹى͖Δྫ֎ ▸ e.g. ແݶ࠶ؼݺͼग़͠ ▸ ݟམͱ͕ͪ͠ͳՕॴ ▸ ਂ͗͢ΔϨΠΞ΢τͷωετ: ϨΠΞ΢τ΋݁ہ͸ Java ͷΦϒδΣΫτʹͳΔ ▸ ਂ͗͢Δґଘؔ܎: ա৒ͳϨΠϠԽͰϝιουͷίʔϧελοΫʹݶք͕͘Δ 17
18. க໋ইΛආ͚ΔͨΊͷྫ֎࣮ྫू StackOverflowError ▸ ରࡦํ๏ ▸ ϨΠΞ΢τͷ֊૚ߏ଄ΛݮΒ͢ ▸ RelativeLayout ΍ ConstraintLayout ͳͲͰϑϥοτͳߏ଄ʹ͢Δ ▸ ద੾ͳཻ౓ͰઃܭΛ͢Δ ▸ Clean Architecture ΍ DDD ͳͲΛࢀߟʹ 18
19. Illegal**Exception 19
20. க໋ইΛආ͚ΔͨΊͷྫ֎࣮ྫू Illegal**Exception ▸ छྨ͸৭ʑ ▸ IllegalStateException, IllegalArgumentException, etc… ▸ ݺͼग़͞ΕΔଆ͕૝ఆ͍ͯ͠ͳ͍ঢ়ଶɾҾ਺ʹ௚໘ͨ͠ͱ͖ʹى͖Δ ▸ ݺͼग़͢ଆ͕Ҿ਺νΣοΫ΍ঢ়ଶνΣοΫΛ͢Δ͜ͱΛཁٻ͍ͯ͠Δ ▸ ୺຤ґଘͰެࣜͷ Javadoc ʹॻ͍ͯͳ͍ͱ͖ʹඈΜͰ͘Δ͜ͱ͕͋Δ ▸ ո͍͠ͳʁͱࢥͬͨΒ͙͢ʹঢ়ଶ΍Ҿ਺ΛϩάʹͭΊͯूΊΒΕΔ࢓૊ΈΛ 20
21. க໋ইΛආ͚ΔͨΊͷྫ֎࣮ྫू Illegal**Exception ▸ ରࡦํ๏ ▸ ͙͢ʹ௚ͤΔ΋ͷ͹͔ΓͰ͸ͳ͍͜ͱʹཹҙ͢Δ ▸ ඞཁͳ৘ใΛूΊɺରࡦΛ࿅͔ͬͯΒ௚͢͜ͱ ▸ Crashlytics ͷϩάऩूػೳͰࣄલ৚݅ΛνΣοΫ͢ΔͱΑ͍ 21
22. CursorWindowAllocation Exception 22
23. க໋ইΛආ͚ΔͨΊͷྫ֎࣮ྫू CursorWindowAllocationException ▸ σʔλϕʔεΛѻ͏ͱ໨ʹ͢Δྫ֎ ▸ Cursor ͕΋ͭσʔλ͕ڐ༰ൣғΛ௒͑ͨͱ͖ʹى͖Δ ▸ ϦϑΝϨϯεʹ Javadoc ͕ແ͍ྫ֎͕ͩɺࡶʹ࡞Δͱ໨ܸ͢Δϋϝʹ ▸ CursorWindow ΫϥεͷதͰϋϯυϦϯά͍ͯ͠Δ ▸ CursorWindow.java: http://bit.ly/2eKlL5y 23
24. க໋ইΛආ͚ΔͨΊͷྫ֎࣮ྫू CursorWindowAllocationException ▸ ରࡦํ๏ ▸ ҰؾʹେྔͷσʔλΛऔಘ͍ͯ͠Δ෦෼Λࡉ੾Εʹ͢Δ ▸ σʔλϕʔεʹڊେͳσʔλΛอ؅͠ͳ͍ ▸ ࢖͍ऴΘͬͨ Cursor ͸ close ͢Δ 24
25. TransactionTooLarge
 Exception 25
26. க໋ইΛආ͚ΔͨΊͷྫ֎࣮ྫू TransactionTooLargeException ▸ ϓϩηεؒ௨৴ͰϝϞϦΛ࢖͍͗ͨ͢ͱ͖ʹى͖Δྫ֎ ▸ 1ͭͷϓϩηεʹରׂͯ͠Γ౰ͯΒΕΔϓϩηεؒ௨৴༻ͷྖҬ͸1mB ▸ ҙ֎ͳͱ͜ΖͰϓϩηεؒ௨৴͸࢖ΘΕ͍ͯΔ ▸ Context#startActivity ▸ PackageManager#queryIntentActivities ▸ ଞଟ਺ 26
27. க໋ইΛආ͚ΔͨΊͷྫ֎࣮ྫू TransactionTooLargeException ▸ Intent ͷ extra ʹ 1mB Λ௒͑Δ String Λ౉͢͜ͱͰ΋ى͖Δఔ౓ʹ͸਎ۙͳͱ ͜ΖʹՄೳੑ͕͋Δ ▸ ରࡦํ๏ ▸ ڊେͳσʔλΛ௚઀ѻΘͳ͍ ▸ ϓϩηεؒ௨৴ͷ࣌ؒΛ୹͘͢Δ ▸ ϓϩηεؒ௨৴ͷճ਺ͦͷ΋ͷΛݮΒ͢ 27
28. DeadObjectException 28
29. க໋ইΛආ͚ΔͨΊͷྫ֎࣮ྫू DeadObjectException ▸ ࢮΜͩϓϩηεʹ࿩͔͚ͨ͠ͱ͖ʹى͖Δྫ֎ ▸ ௨৴૬खͷϓϩηε͕͍ͭ΋ੜ͖͍ͯΔͱ͸ݶΒͳ͍ ▸ ରࡦํ๏ ▸ ServiceConnection ΍ IBinder.DeathRecipient Ͱࢮ׆؂ࢹ ▸ ڊେͳσʔλΛ௨৴ʹͷͤͳ͍ ▸ System Service ͸ࢮ׆؂ࢹͰ͖ͳͦ͞͏…… 29
30. ·ͱΊ 30
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32. க໋ইΛආ͚ΔͨΊͷྫ֎࣮ྫू ·ͱΊ ▸ ରࡦํ๏ͦͷ΋ͷʹֵ৽తͳ͜ͱ͸΄ͱΜͲແ͍ ▸ Α͋͘Δ࣮ྫΛͦͷ··ద༻Ͱ͖Δ͜ͱ΋ଟ͍ ▸ ߟ͑ํͷجຊ ▸ ॲཧͷ୯Ґ΍σʔλΛখ͘͞ࡉ͔͘͢Δ ▸ ઃܭͱද໌Ͱ੹຿Λ໌Β͔ʹ͢Δ 32
33. க໋ইΛආ͚ΔͨΊͷྫ֎࣮ྫू ·ͱΊ ▸ ͍͔ʹૣ͘৘ใΛूΊͯରࡦ͕औΕΔ͔͕ॏཁ ▸ ஈ֊తϦϦʔε ▸ Ϋϥογϡϩάͷऩू ▸ ϢʔβϑΟʔυόοΫͷղੳ 33
34. க໋ইΛආ͚ΔͨΊͷ ྫ֎࣮ྫू Keishin Yokomaku / Startup Android #1
35. DroidKaigi Registration starts from mid-November! 35