back
fi
althesevariablesismakesurethemi
itializei
co
structora
dwill
otcha
gei
wholelifecycle
22Message
Ha
dlertargetThecallbackHa
dleri
loopTherearetwocha
cestosetmessagetarget1Ha
dlerobtai
MessageMessageobtai
thismethodwillsetcurre
tHa
dlerasthe
ewmessage’stargetWhiche
suretargetiscurre
tHa
dleri
createstage2Ha
dlerse
dMessagesetcurre
tHa
dlerastargeti
thismethode
suretargetiscurre
tHa
dleri
se
dMessagestageHa
dlerwillsetitselfasmessagei
itsmethodWedo
’t
eedtosettargetformessagema
uallyusuallyi
twhatTheco
ditio
i
Ha
dlerha
dleMessage
23PostRu
able
publicvoiddispatchMessageMessagemsgifmsgcallback
ullha
dleCallbackmsgelseifmCallback
ullifmCallbackha
dleMessagemsgretur
ha
dleMessagemsgprivatefi
alvoidha
dleCallbackMessagemessagemessagecallbackru
Ha
dlera
dLooper
Page6of10
fWhe
ha
dlerpostaRu
ableitwillNOTcreatea
ewthreadforthisRu
ablebecauseitcallmessagecallbackru
i
steadof
ewthreadmessagecallbackstartIsupposegooglewa
ttouserco
trolthreadviaLooper
24Ha
dlera
dLooper
ThemQueueisthebridgebetwee
Ha
dlera
dLooper
Ha
dler
MessageQueuemQueue
Looper
se
dMessageadda
ewmessagetomQueue
LooploopthismQueus
25Messagemecha
ism
Ha
dlera
dLooper
Page7of10
f3Looperi
Usbservice
Ha
dlerThreadthr
ewHa
dlerThread