基礎(chǔ)結(jié)篇之一activity生命周期

Activityservlet有些相似之處，Androidservlet容器，ActivityservletActivity處在這個(gè)容器中，一切創(chuàng)建實(shí)例、初始化、銷毀實(shí)例等過(guò)程都是容器來(lái)調(diào)用的，這也就是所謂的“Don'tcallme,I'llcallyou.”機(jī)制。onResume，Activity進(jìn)入運(yùn)行狀onResume，Activity進(jìn)入運(yùn)行狀用onPause方法，然后調(diào)用onStop方法，進(jìn)入停滯狀態(tài)。調(diào)用onResume方法，再次進(jìn)入運(yùn)行狀態(tài)。Activity處于被覆蓋狀態(tài)或者后臺(tái)不可見(jiàn)狀態(tài)，即第24步，系統(tǒng)內(nèi)存不法、onResume方法，進(jìn)入運(yùn)行狀態(tài)。packageimportimportimportimport11.publicclassLifeCycleActivityextendsActivityprivatestaticfinalStringTAG=privateintparam= privateContextcontext=8.import6.import4.import[java]viewpublicvoidonCreate(BundlesavedInstanceState)Log.i(TAG,"onCreateButtonbtn=(Button)Intentintent=new}}protectedvoidonStart()Log.i(TAG,"onStart}protectedvoidonResume()Log.i(TAG,"onResumepublicvoidonCreate(BundlesavedInstanceState)Log.i(TAG,"onCreateButtonbtn=(Button)Intentintent=new}}protectedvoidonStart()Log.i(TAG,"onStart}protectedvoidonResume()Log.i(TAG,"onResume Log.i(TAG,"onWindowFocusChanged publicvoidonWindowFocusChanged(booleanhasFocus) //Activity窗口獲得或失去焦點(diǎn)時(shí)被調(diào)用,在onResume之后或onPause Log.i(TAG,"onRestart protectedvoidonRestart() publicvoidonClick(Viewv) btn.setOnClickListener(newView.OnClickListener() protectedvoidonPause()Log.i(TAG,"onPause}//退出當(dāng)前Activity或者跳轉(zhuǎn)到新ActivityprotectedvoidonStop()Log.i(TAG,"onStop}*例如:屏幕方向改變時(shí),Activity被銷毀再重建;當(dāng)前Activity處于后臺(tái),張將其殺死*在onPause之前被調(diào)用protectedvoidonPause()Log.i(TAG,"onPause}//退出當(dāng)前Activity或者跳轉(zhuǎn)到新ActivityprotectedvoidonStop()Log.i(TAG,"onStop}*例如:屏幕方向改變時(shí),Activity被銷毀再重建;當(dāng)前Activity處于后臺(tái),張將其殺死*在onPause之前被調(diào)用outState.putInt("param",*Activity被系統(tǒng)殺死后再重建時(shí)被調(diào)用*這兩種情況下onRestoreInstanceState都會(huì)被調(diào)用,在onStart之后 *例如:屏幕方向改變時(shí),Activity被銷毀再重建;當(dāng)前Activity處于后臺(tái),系統(tǒng)資源 Log.i(TAG,"onSaveInstanceStatecalled.putparam:"+ protectedvoidonSaveInstanceState(BundleoutState) *另外,當(dāng)跳轉(zhuǎn)到其他ActivityHome鍵回到主屏?xí)r該方法也會(huì)被調(diào)用,系統(tǒng)是為了保存當(dāng)前View組件的狀態(tài). *Activity被系統(tǒng)殺死時(shí)被調(diào)用 Log.i(TAG,"onDestory protectedvoidonDestroy() //退出當(dāng)前Activity時(shí)被調(diào)用,調(diào)用之后Activity //onPause或onStop后,系統(tǒng)資源緊張將Activity殺死,所以有必 param=}onSaveInstanceState、onRestoreInstanceState方法：param=}onSaveInstanceState、onRestoreInstanceState方法：1.onWindowFocusChangedActivity窗口獲得或失去焦點(diǎn)時(shí)被調(diào)用，例如創(chuàng)建時(shí)ActivityActivityActivityActivity或按Home鍵回到主屏，自身退居后臺(tái)；用戶退出當(dāng)前Activity。以上幾種情況都會(huì)調(diào)用onWindowFocusChanged，并且當(dāng)Activity被創(chuàng)建時(shí)是在onResume之后被調(diào)用，當(dāng)onCreateWindow對(duì)象還沒(méi)創(chuàng)建完成，這個(gè)時(shí)候我們就需要在onWindowFocusChanged里獲??；如果大家已經(jīng)看過(guò)我寫的Android動(dòng)畫之就是因?yàn)榇翱赪indow對(duì)象沒(méi)有初始化完成，所以最后我將加載動(dòng)畫的代碼放到了onWindowFocusChanged中，問(wèn)題迎刃而解。不過(guò)大家也許會(huì)有疑惑，為什么我在代碼2.onSaveInstanceState：(1)Activity被覆蓋或退居后臺(tái)之后，系統(tǒng)資源不足將其殺死，此方法會(huì)被調(diào)用；(2)在用戶改變屏幕方向時(shí)，此方法會(huì)被調(diào)用；(3)Activity跳轉(zhuǎn)到ActivityHome鍵回到主屏，自身退居后臺(tái)時(shí)，此方法會(huì)被調(diào)用。第一種情況數(shù)據(jù)；第三種情況系統(tǒng)調(diào)用此方法是為了保存當(dāng)前窗口各個(gè)View組件的狀態(tài)。onSaveInstanceState的調(diào)用順序是在onPause之前。3.onRestoreInstanceState：(1)在Activity死，然后用戶又回到了 Activity，此方法會(huì)被調(diào)用；(2)在用戶改變屏幕方向時(shí)，重建 Log.i(TAG,"onRestoreInstanceStatecalled.getparam:"+ protectedvoidonRestoreInstanceState(BundlesavedInstanceState) 臺(tái)時(shí)，onPause后onStop相繼被調(diào)用。4.TargetActivityAndroidManifest.xml中的配置，將android:theme屬性設(shè)置為了TargetActivity覆蓋到LifeCycleActivity之上了，此時(shí)調(diào)用的方法為：我們注意到，此時(shí)LifeCycleActivityOnPause方法被調(diào)用，并沒(méi)有調(diào)用onStop方法，因在onPause之前被調(diào)用。怪，因?yàn)橹拔覀兙驼f(shuō)過(guò)，onRestoreInstanceState只有在殺死不在前臺(tái)的Activity之后setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);//1.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);//橫屏1.package [java]view[java]view[java]view3.import5.importprivateintparam="onCreateprotectedonStart()"onStartprotectedonRestart()"onRestartprotectedonResume()"onResumeprotectedonPause()"onPauseprotectedonStop()3.import5.importprivateintparam="onCreateprotectedonStart()"onStartprotectedonRestart()"onRestartprotectedonResume()"onResumeprotectedonPause()"onPauseprotectedonStop() protectedvoidonCreate(BundlesavedInstanceState) privatestaticfinalStringTAG=8.publicclassOrientationActivityextendsActivity6.import4.importLog.i(TAG,"onStopprotectedvoidonDestroy()Log.i(TAG,"onDestoryprotectedvoidonSaveInstanceState(BundleoutState)Log.i(TAG,"onSaveInstanceStatecalled.put"}param=switch(newConfig.orientation)caseLog.i(TAG,"onStopprotectedvoidonDestroy()Log.i(TAG,"onDestoryprotectedvoidonSaveInstanceState(BundleoutState)Log.i(TAG,"onSaveInstanceStatecalled.put"}param=switch(newConfig.orientation)case}將當(dāng)前Activity銷毀，然后重建一個(gè)新的：84. case Log.i(TAG,"onConfigurationChanged publicvoidonConfigurationChanged(ConfigurationnewConfig) onConfigurationChanged被調(diào)用 Log.i(TAG,"onRestoreInstanceStatecalled.