"fourth article" Androideventbus Source code reading and analysis

Last Update:2015-07-27 Source: Internet

Author: User

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1, analyze Androideventbus's Registered source Code:our first step in using Androideventbus is to register Eventbus with the following code: <ol class="linenums" style="padding-left: 0px;"> <ol class="linenums" style="padding-left: 0px;"> <li class="L0" style="list-style-type: none; padding-left: 0px;"><pre>Eventbus.getdefault (). Register (this);</pre></li> </ol> </ol>first, The Eventbus object is obtained, and the object is obtained using simple interest mode:Eventbus.java inside <ol class="linenums" style="padding-left: 0px;"> <li class="L0" style="list-style-type: none; padding-left: 0px;"><code class="language-java"><code class="language-java"><code class="language-java"></code></code></code><pre><pre> public Static eventbus getdefault () { ifnull) { synchronized (eventbus. Class ){ifnull) { new Eventbus (); } } } return sdefaultbus; }</pre></pre><code class="language-java"><code class="language-java"><code class="language-java"></code></code></code><code class="language-java"><code class="language-java"> </code></code></li> </ol>then it is: <ol class="linenums" style="padding-left: 0px;"> <li class="L0" style="list-style-type: none; padding-left: 0px;"><code class="language-java"><code class="language-java"><code class="language-java"></code></code></code><pre>1 public voidRegister (Object subscriber) {2 if(subscriber = =NULL) {3 return;4 }5 synchronized( this) {6 mmethodhunter.findsubcribemethods (subscriber);7 }8}</pre><code class="language-java"><code class="language-java"><code class="language-java"></code></code></code><code class="language-java"><code class="language-java"> </code></code></li> </ol>track to<span class="pln" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;"><span class="pln" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;">Mmethodhunter<span class="pun" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;"><span class="pun" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;">.<span class="pln" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;"><span class="pln" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;">Findsubcribemethods<span class="pun" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;"><span class="pun" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;">(<span class="pln" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;"><span class="pln" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;">Subscriber<span class="pun" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;"><span class="pun" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;">); Keep Looking down:<span class="pun" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;">mmethodhunter Register at Code header: <ol class="linenums" style="padding-left: 0px;"> <ol class="linenums" style="padding-left: 0px;"> <li class="L0" style="list-style-type: none; padding-left: 0px;"><pre>1 /** 2 * The Subscriber method hunter, find all of the Subscriber ' s methods 3 * Annotated with @Subcriber 4 */ 5 subscibermethodhunter mmethodhunter =newsubscibermethodhunter (msubcribermap);</pre></li> </ol> </ol>used to find all annotation methods that use @subcriberand then we follow<span class="pln" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;"><span class="pln" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;">Findsubcribemethods<span class="pun" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;"><span class="pun" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;">(<span class="pln" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;"><span class="pln" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;">Subscriber<span class="pun" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;"><span class="pun" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;">) Look inside:<span class="pun" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;"><span class="pun" style="font-family: Consolas, ‘Liberation Mono‘, Menlo, Courier, monospace; font-size: 12.941176414489746px; line-height: 17.996322631835938px; white-space: pre; background-color: #f7f7f9;">Traverse <ol class="linenums" style="padding-left: 0px;"> <li class="L0" style="list-style-type: none; padding-left: 0px;"><code class="language-java"><code class="language-java"><code class="language-java"></code></code></code><pre>1 public voidfindsubcribemethods (Object Subscriber) {2 if(msubcribermap = =NULL) {3 Throw NewNullPointerException ("the Msubcribermap is Null."));4 }5Class<?> Clazz =Subscriber.getclass ();6 //find the registration method that meets the requirements in the class until the object class7 while(clazz! =NULL&&!ISSYSTEMCALSS (clazz.getname ())) {8 Finalmethod[] Allmethods =clazz.getdeclaredmethods ();9 for(inti = 0; I < allmethods.length; i++) {TenMethod method =allmethods[i]; one //parsing functions according to annotations asubscriber annotation = Method.getannotation (subscriber.class); - if(annotation! =NULL) { - //Get method Parameters theclass<?>[] Paramstypeclass =method.getparametertypes (); - //the Subscription function supports only one parameter - if(paramstypeclass! =NULL&& Paramstypeclass.length = = 1) { -class<?> Paramtype = Converttype (paramstypeclass[0]); +EventType EventType =Neweventtype (paramtype, Annotation.tag ()); -Targetmethod Subscribemethod =NewTargetmethod (method, eventtype, + Annotation.mode ()); a subscibe (eventtype, subscribemethod, subscriber); at } - } -}//End for - //gets the parent class to continue looking for methods that meet the requirements in the parent class -Clazz =Clazz.getsuperclass (); - } in}</pre><code class="language-java"><code class="language-java"><code class="language-java"></code></code></code><code class="language-java"><code class="language-java"> </code></code></li> </ol>and then subscibe (eventtype, subscribemethod, subscriber); Code inside the method: Msubcribermap is a map collection .  <ol class="linenums" style="padding-left: 0px;"> <li class="L0" style="list-style-type: none; padding-left: 0px;"><code class="language-c"><code class="language-c"><code class="language-c"></code></code></code><pre><pre>/** * The event bus 's Subscriber's map*/ map<eventtype, Copyonwritearraylist<subscription>> msubcribermap;</pre></pre><code class="language-c"><code class="language-c"><code class="language-c"></code></code></code><pre>1 /**2 * According to EventType storage subscriber list, Here EventType is the event type, an event corresponding to 0 to many Subscribers.3 * 4 * @paramEvent Events5 * @parammethod Subscription Methods Object6 * @paramSubscriber subscribers7 */8 Private voidsubscibe (eventtype event, targetmethod method, Object subscriber) {9Copyonwritearraylist<subscription> subscriptionlists =Msubcribermap.get (event);Ten if(subscriptionlists = =NULL) { oneSubscriptionlists =NewCopyonwritearraylist<subscription>(); a } -Subscription newsubscription =NewSubscription (subscriber, method); - if(subscriptionlists.contains (NEWSUBSCRIPTION)) { the return; - } - Subscriptionlists.add (newsubscription); - //Store Event Type key and subscriber information in map + msubcribermap.put (event, subscriptionlists); -}</pre></li> </ol> Here you can see that register is the way to iterate through all the annotations @Subcriber and store the event type key and subscriber information in the MAP. This is similar to Eventbus code in the register, but Eventbus is to start with the OnEvent method to find, and Androideventbus is @subcriber to do traversal retrieval, but ultimately is Store Event type key and subscriber information in MAP. "fourth article" Androideventbus Source code reading and analysis

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