After learning about the pre-knowledge of class loading in Android, take a look at the specific implementation of Dexclassloader in Android
The specific loading process is as follows:
The host program will go to the file system such as SD card to load the APK "1", and then through an activity called Proxy to perform activity in the APK
On the dynamic loading AP, it can theoretically be used to dexclassload, Pathclassloader, URLClassLoader;
Dexclassloader: Can load jar, Dex, apk on file system
Pathclassloader: The APK can be loaded in the/data/app directory, which also means that it can only load the installed APK
URLClassLoader: The jar in Java can be loaded, but because the Dalvik in Android does not recognize the jar directly, all of the methods are not available in Android, although there is this class
Get Assetsmanager
The method of loading is through reflection, by calling the Addassetpath method in Assetmanager, we can load a resource in an apk into the resources, because Addassetpath is a hidden API that we cannot call directly, so we can only pass the reflection, Here is its declaration, through the comments we can see that the path can be a zip file or a resource directory, and the APK is a zip, so directly to the APK path to it, the resources are loaded into the Assetmanager, And then create a new resources object through Assetmanager, which is the resource in the apk we can use.
Encapsulating data:
1: ClassLoader, Assetmanager, resource as a member of the plug-in, encapsulated into beans
2: Multiple plugins are maintained via map, where key is apk packagename
Plug-in loading into memory flow:
Load plug-in activity:
? PluginsActivityitself (life cycle, resources, etc.) is provided by the hostproxyactivityto load the. ? when we sendIntentto start the plugin whenActivityWhen the substance started isproxyactivity? Encapsulated in order to encapsulate the detailsdxintent? all plugins are implementedIdxpluginInterfacePrxoyactivity took over all the plugins activity
Dxpluginbean encapsulated Bean
?encapsulates each of thePluginalsoapkof Data? Maintenance inDxpluginmangerClass ofMapin
Dxpluginmanager plug-in Management core class ? Load plug-ins,Start plug-ins,plug-in maintenance
Idxplugin:
?put each plugin'sActivityabstract into a "plugin"? Idxpluginrealized theActivitythe Main method? Onattachmethod is a plugin-specific callback method that when the plug- inActivitywasProxyload When,putProxyis assigned a reference value to the that
dxintent:? Pluginpackgename:Jump toPluginthe package name, i.e.Manifestin thePackageName
pluginclassname: Jump plugin specified in the Activityname, can be passed NULL, the default is jump main Activity
dxpluginbaseactivity, dxpluginbasefragmentactivity:
All plugins activity inherits these two activity
The activity implements the Idxplugin interface
Get proxyactivity references in the Onattach method
? AllActivityThe inheritance method needs to determine whether the plug-in itself starts or is started in the host----"From_internal and from_external
dxproxyactivity,dxproxyfragmentactivity:. ? HostActivity? in theHostcalling plug-ins inActivityThe jump, the essence is these twoActivityThe jump between? provides the plug-in with a trueContext? to reduce the duplication of code, place the initialization of the plug-inDxplugininitializerin class
Dxplugininitializer ?FixThemeThe crash problem that brought ? Launch PluginActivity
1 get plug-ins with reflection Activity the default constructor
2 by Reflection New out a plugin and turn it into a strong Idxplugin
3 Callback Onattach method Incoming Prxoy the reference
4 called onCreate method to adjust the plug-in
You can directly refer to the demo:
http://download.csdn.net/detail/yaya_soft/8858645
Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced.
Android APK Dynamic Loading technology Research (2) Android plugin and implementation
