谈述android系统外文翻译

1、谈述android系统外文翻译谈述android系统外文翻译 导读：android系统外文翻译 bundledbytheaapttoolintoanandroidpackage,anarchivefilemarkedbyan.ap ksuffix. 12345678910附录一：英文翻译原文abstract ent of the mobile phone market,3g mobile phone system development has also bee popular on the maket. this paper introduces some basic application

2、s of the android system about a part of the application fundamentas book translation, so that more learners can easily learn about the development and application of the android system. translation about this paper is my personal understanding of the application fundaments, there are some similariti

3、es and differences ore about or more detailed about basic application of android system,please read the original article referenced this article, this paper only introduces basic application of the android system about applicatedponent,closeponent,manifestfile,the intent filter*. key anifest files,

4、activity, service,broadcast receiver , content providerandroid applications are ming language the piled java code 一 along arked by an .apk suffix. 3 4 5 6 7 8 9 10谈述android系统外文翻译 导读：android系统外文翻译 ssresourcesarerequiredbyotherapplications.2.eachprocesshasitsoachine(v m),soapplicationcoderunsinisolati

5、onfromthecodeofallotherapplications. this file is the vehicle for distributing the application and installing it on mobile devices; it's the file users doany resources are required by other applications.2. each process has its oachine (vm), so application code runs in isolation from the code of

6、all other applications3. by default, each application is assigned a unique linux user id. permissions are set so that the application's files are visible only to that user and only to the application itself 一 although there are to other applications as e user id, in resources, applications e id

7、can also arrange to run in the same linux process, sharing the same vm. application co 3456789 10谈述android系统外文翻译 导读：android系统外文翻译 ystems,androidapplicationsdonfthaveasingleentrypointforeverythinginthe application(nomain()function,forexample).rather,theyhaveessentialponen tsthatthesystemcaninstantiat

8、eandrunasneeded.therearefourtypesofponents :activitiesanactivitypresentsavisualuserinte mponentsa central feature of android is that one application can make use of elements of other applications (provided those applications permit it). for example, if your application needs to display a scrolling l

9、ist of images and another application has developed a suitable scroller and made it available to others, you can call upon that scroller to do the ply starts up that piece of the other application must be able to start an application process ost other systems, android applications don't have a s

10、ingle entry point for everything in the application (no main() function, for example) rather, they have essential ponents that the system can instantiate and run as needed there are four types of ponents:activitiesan activity presents a visual user interface for one focused endeavor the user can und

11、ertake forexample, an activity might present a list of menu items users can choose fr 345 67 89 10谈述android系统外文翻译 导读：android系统外文翻译 opofotherakeuseofadditionalple,apop updialogthatcallsforauseit12345678910 om or it might display photographs along essaging application might have one activity that shoe

12、ssages to, a second activity to essage to the chosen contact, and other activities to revieessages or change settings. though they a cohesive user interface, each activity is independent of the others each one is implemented as a subclass of the activity base classan application might consist of jus

13、t one activity or, like the text messaging application just mentioned, it may contain several, arked as the first one that should be presented to the user one activity to another is acplished by having the current activity start the next oneeach activity is given a default ight be smaller than the s

14、creen and float on top of other ake use of additional pie, a pop-up dialog that calls for a user r 3 4 5 6 7 8 9 10谈述android系统外文翻译导读：android系统外文翻译 arentvieofthehierarchy)draple,avieightd esponse in the midst of the activity, or a ation screen.the visual content of the the base vie of the hierarchy)

15、draple, a vieight display a small image and initiate an action age. android has a number of readymade vieenu items, check boxes, and more.a vieethod the content vieent for more information on views and the hierarchy.)servicesa service doesn*t have a visual user interface, but rather runs in the back

16、ground for an indefinite 3456789 10谈述android系统外文翻译 导读：android系统外文翻译 ththeservicethroughaninterfacethattheserviceexposes.forthemusicservice, thisinterfacemightalloe. for example, a service might play background music as the user attends to other matters, or it might fetch data over the ething and pro

17、vide the result to activities that need it. each service extends the service base class.a prime example is a media player playing songs from a play list. the player application ore activities that allo housic playback itself usic to keep playing even after they leave the player and begin something d

18、ifferent. to keep the music going, the media player activity could start a service to run in the background the system usic playback service running even after the activity that started it leaves the screen.it's possible to connect to (bind to) an ongoing service (and start the service if it'

19、;s not already running). unicate usic service, this interface might allow users to pause, rewind, stop, and restart the playback.like activities and the ot 3456789 10谈述android系统外文翻译 导读：android系统外文翻译 theinformationtheyreceive,ortheymayusethenotificationmanagertoalertth euse 匸 n otificationscangettheu

20、sefsattentioninvatiousain thread of the application process so that they e-consuming tasks (like music playback). see processes and threads, late匸broadcast receiversa broadcast receiver is a ponent that does nothing but receive and react to broadcast announcements many broadcasts originate in system

21、 code 一 for example, announcements that the timezone has changed, that the battery is lople, to let other applications knoe data has been do to use an application can have any number of broadcast receivers to respond to any announcements it considers important. all receivers extend the broadcastrece

22、iver base classbroadcast receivers do not display a user interface. hoay start an activity in response to the information they receive, or they may use the notificationmanager to alert the user. notifications can get the user's attention in various ways 一 flashing the backlight, vibratin 3 4 5 6

23、 7 8 9 10谈述android系统外文翻译导读：android系统外文翻译 tootherapplications.thedatacanbestoredinthefilesystem,inansqlitedataba se,orinanyothermannerthatmakessense.thecontentproviderextendsthecon tentproviderbaseclasstoimplementastandardsetofmethodsthatenableothera pplicationstoretrieveandstoredataofthetype g the d

24、evice, playing a sound, and so on. they typically place a persistent icon in the status bar, essage content providersa content provider makes a specific set of the application's data available to other applications. the data can be stored in the file system, in an sqlite database, or in any othe

25、r manner that makes sense the content provider extends the contentprovider base class to implement a standard set of methods that enable other applications to retrieve and store data of the type it controls. hoethods directly. rather they use a contentresolver object and call its methods instead. a

26、contentresolver can talk to any content provider; it cooperates an age any interprocess munication thafs involved.see the separate content providers document for more information on using content providers.akes sure that the application process of the ponent is running, starting it if necessary, and

27、 that an appropriate instance of the ponent is available, creating the instance 讦 necessary.activating ponents: i 3456789 10谈述android系统外文翻译 导读：android系统外文翻译 activatedacontentresolver.theotherthreeponents一activities,services,andbroadcastreceivers一areactivatedbyasynchronousmessagescalledintents.aninte

28、ntisanlntentobje ctthatholdsthecontentofthemessage.foractivitiesandservices,i ntents content providers are activated a contentresolver. the other three ponents 一 activities, services, and broadcast receivers 一 are activated by asynchronous messages called intents. an intent is an intent object that

29、holds the content of the message. for activities and services, it names the action being requested and specifies the uri of the data to act on, among other things for example, it might convey a request for an activity to present an image to the user or let the user edit some text. for broadcast rece

30、ivers, the in tent object names the acti on being ann oun ced for example, it might announce to interested parties that the camera button has been pressedthere are separate methods for activating each type of ponent:1. an activity is launched (or given something neethod android calls the activity's onneethod to pass it any subsequent intents. one activity often starts the next one. if it expects a result bac 3 4 5 6 7 8 9 10谈述android系统外文翻j译导读：android系统外文翻译 ivestheintentobj