本篇文章給大家分享的是有關(guān)EventBus 3.0.0如何在Android 應(yīng)用中使用,小編覺(jué)得挺實(shí)用的,因此分享給大家學(xué)習(xí),希望大家閱讀完這篇文章后可以有所收獲,話不多說(shuō),跟著小編一起來(lái)看看吧。
創(chuàng)新互聯(lián)是一家集網(wǎng)站建設(shè),武陵源企業(yè)網(wǎng)站建設(shè),武陵源品牌網(wǎng)站建設(shè),網(wǎng)站定制,武陵源網(wǎng)站建設(shè)報(bào)價(jià),網(wǎng)絡(luò)營(yíng)銷(xiāo),網(wǎng)絡(luò)優(yōu)化,武陵源網(wǎng)站推廣為一體的創(chuàng)新建站企業(yè),幫助傳統(tǒng)企業(yè)提升企業(yè)形象加強(qiáng)企業(yè)競(jìng)爭(zhēng)力??沙浞譂M足這一群體相比中小企業(yè)更為豐富、高端、多元的互聯(lián)網(wǎng)需求。同時(shí)我們時(shí)刻保持專(zhuān)業(yè)、時(shí)尚、前沿,時(shí)刻以成就客戶成長(zhǎng)自我,堅(jiān)持不斷學(xué)習(xí)、思考、沉淀、凈化自己,讓我們?yōu)楦嗟钠髽I(yè)打造出實(shí)用型網(wǎng)站。
EventBus框架
EventBus是一個(gè)通用的叫法,例如Google出品的Guava,Guava是一個(gè)龐大的庫(kù),EventBus只是它附帶的一個(gè)小功能,因此實(shí)際項(xiàng)目中使用并不多。用的最多的是greenrobot/EventBus,這個(gè)庫(kù)的優(yōu)點(diǎn)是接口簡(jiǎn)潔,集成方便,但是限定了方法名,不支持注解。另一個(gè)庫(kù)square/otto修改自 Guava ,用的人也不少。所以今天我們研究的目標(biāo)是greenrobot的EventBus.
EventBus 簡(jiǎn)介
1、EventBus3.0.0 是最新的版本。
2、EventBus 是Android 發(fā)布/訂閱事件總線,可簡(jiǎn)化 Activities, Fragments, Threads, Services 等組件間的消息傳遞。
3、可替代 Intent, Handler, BroadCast ,接口等傳統(tǒng)方案,更快,代碼更小,50K 左右的 jar 包,代碼更優(yōu)雅,徹底解耦。
github地址:https://github.com/greenrobot/EventBus
EventBus原理圖
如何添加依賴
在module的build.gredle 文件中的dependencies標(biāo)簽中添加
compile 'org.greenrobot:eventbus:3.0.0'
例如
apply plugin: 'com.android.application' android { compileSdkVersion 24 buildToolsVersion "24.0.3" defaultConfig { applicationId "com.eventbus.app" minSdkVersion 14 targetSdkVersion 24 versionCode 1 versionName "1.0" } buildTypes { release { minifyEnabled false proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' } } } dependencies { compile fileTree(dir: 'libs', include: ['*.jar']) compile 'com.android.support:appcompat-v7:24.2.1' compile 'org.greenrobot:eventbus:3.0.0' }
如何使用
注冊(cè)事件
EventBus.getDefault().register( this );
取消注冊(cè)
EventBus.getDefault().unregister( this );
發(fā)送數(shù)據(jù)
EventBus.getDefault().post( "我發(fā)射了");
簡(jiǎn)單小例子:使用EventBus傳遞簡(jiǎn)單字符串
package com.eventbus.app; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.view.View; import android.widget.Toast; import org.greenrobot.eventbus.EventBus; import org.greenrobot.eventbus.Subscribe; import org.greenrobot.eventbus.ThreadMode; public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); //注冊(cè) EventBus.getDefault().register( this ); findViewById( R.id.button).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { EventBus.getDefault().post( "我發(fā)射了"); } }); } /** * 自定義一個(gè)方法 hello() ,用來(lái)接收事件。 * 方法名字可以隨便寫(xiě) * @return */ @Subscribe(threadMode = ThreadMode.MAIN) public void hello ( String event){ /* Do something */ Toast.makeText( this , event , Toast.LENGTH_SHORT).show(); }; @Override protected void onDestroy() { super.onDestroy(); //取消注冊(cè) , 防止Activity內(nèi)存泄漏 EventBus.getDefault().unregister( this ); } }
線程模型
在接收事件消息的方法中,可以通過(guò)注解的方式設(shè)置線程模型,EventBus內(nèi)置了4中線程模型,分別是ThreadMode.POSTING 、ThreadMode.MAIN、ThreadMode.BACKGROUND、ThreadMode.ASYNC
比如:
@Subscribe(threadMode = ThreadMode.POSTING) public void onMessageEventPostThread(String event) { Log.e( "event PostThread", "消息: " + event + " thread: " + Thread.currentThread().getName() ); } @Subscribe(threadMode = ThreadMode.MAIN) public void onMessageEventMainThread(String event) { Log.e( "event MainThread", "消息: " + event + " thread: " + Thread.currentThread().getName()); } @Subscribe(threadMode = ThreadMode.BACKGROUND) public void onMessageEventBackgroundThread(String event) { Log.e( "event BackgroundThread", "消息: " + event + " thread: " + Thread.currentThread().getName()); } @Subscribe(threadMode = ThreadMode.ASYNC) public void onMessageEventAsync(String event) { Log.e( "event Async", "消息: " + event + " thread: " + Thread.currentThread().getName()); }
PostThread:如果使用事件處理函數(shù)指定了線程模型為PostThread,那么該事件在哪個(gè)線程發(fā)布出來(lái)的,事件處理函數(shù)就會(huì)在這個(gè)線程中運(yùn)行,也就是說(shuō)發(fā)布事件和接收事件在同一個(gè)線程。在線程模型為PostThread的事件處理函數(shù)中盡量避免執(zhí)行耗時(shí)操作,因?yàn)樗鼤?huì)阻塞事件的傳遞,甚至有可能會(huì)引起ANR。
MainThread:如果使用事件處理函數(shù)指定了線程模型為MainThread,那么不論事件是在哪個(gè)線程中發(fā)布出來(lái)的,該事件處理函數(shù)都會(huì)在UI線程中執(zhí)行。該方法可以用來(lái)更新UI,但是不能處理耗時(shí)操作。
BackgroundThread:如果使用事件處理函數(shù)指定了線程模型為BackgroundThread,那么如果事件是在UI線程中發(fā)布出來(lái)的,那么該事件處理函數(shù)就會(huì)在新的線程中運(yùn)行,如果事件本來(lái)就是子線程中發(fā)布出來(lái)的,那么該事件處理函數(shù)直接在發(fā)布事件的線程中執(zhí)行。在此事件處理函數(shù)中禁止進(jìn)行UI更新操作。
Async:如果使用事件處理函數(shù)指定了線程模型為Async,那么無(wú)論事件在哪個(gè)線程發(fā)布,該事件處理函數(shù)都會(huì)在新建的子線程中執(zhí)行。同樣,此事件處理函數(shù)中禁止進(jìn)行UI更新操作。
小例子1: 在子線程發(fā)送數(shù)據(jù)
package com.eventbus.app; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.util.Log; import android.view.View; import org.greenrobot.eventbus.EventBus; import org.greenrobot.eventbus.Subscribe; import org.greenrobot.eventbus.ThreadMode; public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); //注冊(cè) EventBus.getDefault().register( this ); findViewById( R.id.button).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { new Thread(new Runnable() { @Override public void run() { Log.d( "event 發(fā)射數(shù)據(jù)線程 : " , Thread.currentThread().getName() ) ; EventBus.getDefault().post( "我發(fā)射了"); } }).start() ; } }); } @Subscribe(threadMode = ThreadMode.POSTING) public void onMessageEventPostThread(String event) { Log.e( "event PostThread", "消息: " + event + " thread: " + Thread.currentThread().getName() ); } @Subscribe(threadMode = ThreadMode.MAIN) public void onMessageEventMainThread(String event) { Log.e( "event MainThread", "消息: " + event + " thread: " + Thread.currentThread().getName()); } @Subscribe(threadMode = ThreadMode.BACKGROUND) public void onMessageEventBackgroundThread(String event) { Log.e( "event BackgroundThread", "消息: " + event + " thread: " + Thread.currentThread().getName()); } @Subscribe(threadMode = ThreadMode.ASYNC) public void onMessageEventAsync(String event) { Log.e( "event Async", "消息: " + event + " thread: " + Thread.currentThread().getName()); } @Override protected void onDestroy() { super.onDestroy(); //取消注冊(cè) , 防止Activity內(nèi)存泄漏 EventBus.getDefault().unregister( this ); } }
運(yùn)行結(jié)果:
D/event 發(fā)射數(shù)據(jù)線程 :: Thread-109
E/event BackgroundThread: 消息: 我發(fā)射了 thread: Thread-109
E/event PostThread: 消息: 我發(fā)射了 thread: Thread-109
E/event Async: 消息: 我發(fā)射了 thread: pool-1-thread-2
E/event MainThread: 消息: 我發(fā)射了 thread: main
小例子2: 在主線程發(fā)送數(shù)據(jù)
package com.eventbus.app; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.util.Log; import android.view.View; import org.greenrobot.eventbus.EventBus; import org.greenrobot.eventbus.Subscribe; import org.greenrobot.eventbus.ThreadMode; public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); //注冊(cè) EventBus.getDefault().register( this ); findViewById( R.id.button).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Log.d( "event 發(fā)射數(shù)據(jù)線程 : " , Thread.currentThread().getName() ) ; EventBus.getDefault().post( "我發(fā)射了"); } }); } @Subscribe(threadMode = ThreadMode.POSTING) public void onMessageEventPostThread(String event) { Log.e( "event PostThread", "消息: " + event + " thread: " + Thread.currentThread().getName() ); } @Subscribe(threadMode = ThreadMode.MAIN) public void onMessageEventMainThread(String event) { Log.e( "event MainThread", "消息: " + event + " thread: " + Thread.currentThread().getName()); } @Subscribe(threadMode = ThreadMode.BACKGROUND) public void onMessageEventBackgroundThread(String event) { Log.e( "event BackgroundThread", "消息: " + event + " thread: " + Thread.currentThread().getName()); } @Subscribe(threadMode = ThreadMode.ASYNC) public void onMessageEventAsync(String event) { Log.e( "event Async", "消息: " + event + " thread: " + Thread.currentThread().getName()); } @Override protected void onDestroy() { super.onDestroy(); //取消注冊(cè) , 防止Activity內(nèi)存泄漏 EventBus.getDefault().unregister( this ); } }
運(yùn)行結(jié)果:
D/event 發(fā)射數(shù)據(jù)線程 :: main
E/event MainThread: 消息: 我發(fā)射了 thread: main
E/event PostThread: 消息: 我發(fā)射了 thread: main
E/event Async: 消息: 我發(fā)射了 thread: pool-1-thread-3
E/event BackgroundThread: 消息: 我發(fā)射了 thread: pool-1-thread-4
黏性事件
除了上面講的普通事件外,EventBus還支持發(fā)送黏性事件。何為黏性事件呢?簡(jiǎn)單講,就是在發(fā)送事件之后再訂閱該事件也能收到該事件,跟黏性廣播類(lèi)似。具體用法如下:
注冊(cè)
EventBus.getDefault().register( this );
事件接收
@Subscribe(threadMode = ThreadMode.MAIN , sticky = true ) public void onMessageEventMainThread(String event) { Log.e( "event MainThread", "消息: " + event + " thread: " + > Thread.currentThread().getName()); }
取消注冊(cè)
EventBus.getDefault().unregister( this ) ;
發(fā)送事件
EventBus.getDefault().postSticky( "我發(fā)射了");
小例子:在MainActivity發(fā)送事件,在Activity2里注冊(cè)并且接收事件
MainActivity源碼
package com.eventbus.app; import android.content.Intent; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.util.Log; import android.view.View; import org.greenrobot.eventbus.EventBus; public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); findViewById( R.id.button).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Log.d( "event 發(fā)射數(shù)據(jù)線程 : " , Thread.currentThread().getName() ) ; EventBus.getDefault().postSticky( "我發(fā)射了"); startActivity( new Intent( MainActivity.this , Activity2.class )); } }); } }
Activity2源碼
package com.eventbus.app; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.util.Log; import org.greenrobot.eventbus.EventBus; import org.greenrobot.eventbus.Subscribe; import org.greenrobot.eventbus.ThreadMode; public class Activity2 extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_2); //注冊(cè) EventBus.getDefault().register( this ); } @Subscribe(threadMode = ThreadMode.MAIN , sticky = true ) public void onMessageEventMainThread(String event) { Log.e( "event MainThread", "消息: " + event + " thread: " + Thread.currentThread().getName()); } @Override protected void onDestroy() { super.onDestroy(); //取消注冊(cè) , 防止Activity內(nèi)存泄漏 EventBus.getDefault().unregister( this ) ; } }
這就是粘性事件,能夠收到訂閱之前發(fā)送的消息。但是它只能收到最新的一次消息,比如說(shuō)在未訂閱之前已經(jīng)發(fā)送了多條黏性消息了,然后再訂閱只能收到最近的一條消息。
EventBus源碼分析
Subscribe 接口源碼
@Documented @Retention(RetentionPolicy.RUNTIME) @Target({ElementType.METHOD}) public @interface Subscribe { ThreadMode threadMode() default ThreadMode.POSTING; /** * If true, delivers the most recent sticky event (posted with * {@link EventBus#postSticky(Object)}) to this subscriber (if event available). */ boolean sticky() default false; /** Subscriber priority to influence the order of event delivery. * Within the same delivery thread ({@link ThreadMode}), higher priority subscribers will receive events before * others with a lower priority. The default priority is 0. Note: the priority does *NOT* affect the order of * delivery among subscribers with different {@link ThreadMode}s! */ int priority() default 0; }
可以看出默認(rèn)的線程模型是ThreadMode.POSTING ;默認(rèn)黏性事件為false,也就是默認(rèn)不開(kāi)啟黏性事件;默認(rèn)的優(yōu)選級(jí)為0 。
EventBus 類(lèi)部分源碼
static volatile EventBus defaultInstance; /** Convenience singleton for apps using a process-wide EventBus instance. */ public static EventBus getDefault() { if (defaultInstance == null) { synchronized (EventBus.class) { if (defaultInstance == null) { defaultInstance = new EventBus(); } } } return defaultInstance; }
getDefault() 是一個(gè)單例模式 , 只有一個(gè)實(shí)例對(duì)象。
ThreadMode 類(lèi)源碼
public enum ThreadMode { /** * Subscriber will be called in the same thread, which is posting the event. This is the default. Event delivery * implies the least overhead because it avoids thread switching completely. Thus this is the recommended mode for * simple tasks that are known to complete is a very short time without requiring the main thread. Event handlers * using this mode must return quickly to avoid blocking the posting thread, which may be the main thread. */ POSTING, /** * Subscriber will be called in Android's main thread (sometimes referred to as UI thread). If the posting thread is * the main thread, event handler methods will be called directly. Event handlers using this mode must return * quickly to avoid blocking the main thread. */ MAIN, /** * Subscriber will be called in a background thread. If posting thread is not the main thread, event handler methods * will be called directly in the posting thread. If the posting thread is the main thread, EventBus uses a single * background thread, that will deliver all its events sequentially. Event handlers using this mode should try to * return quickly to avoid blocking the background thread. */ BACKGROUND, /** * Event handler methods are called in a separate thread. This is always independent from the posting thread and the * main thread. Posting events never wait for event handler methods using this mode. Event handler methods should * use this mode if their execution might take some time, e.g. for network access. Avoid triggering a large number * of long running asynchronous handler methods at the same time to limit the number of concurrent threads. EventBus * uses a thread pool to efficiently reuse threads from completed asynchronous event handler notifications. */ ASYNC }
以上就是EventBus 3.0.0如何在Android 應(yīng)用中使用,小編相信有部分知識(shí)點(diǎn)可能是我們?nèi)粘9ぷ鲿?huì)見(jiàn)到或用到的。希望你能通過(guò)這篇文章學(xué)到更多知識(shí)。更多詳情敬請(qǐng)關(guān)注創(chuàng)新互聯(lián)行業(yè)資訊頻道。
本文標(biāo)題:EventBus3.0.0如何在Android應(yīng)用中使用
分享鏈接:http://muchs.cn/article0/pisiio.html
成都網(wǎng)站建設(shè)公司_創(chuàng)新互聯(lián),為您提供定制開(kāi)發(fā)、手機(jī)網(wǎng)站建設(shè)、域名注冊(cè)、網(wǎng)站建設(shè)、定制網(wǎng)站、外貿(mào)建站
聲明:本網(wǎng)站發(fā)布的內(nèi)容(圖片、視頻和文字)以用戶投稿、用戶轉(zhuǎn)載內(nèi)容為主,如果涉及侵權(quán)請(qǐng)盡快告知,我們將會(huì)在第一時(shí)間刪除。文章觀點(diǎn)不代表本網(wǎng)站立場(chǎng),如需處理請(qǐng)聯(lián)系客服。電話:028-86922220;郵箱:631063699@qq.com。內(nèi)容未經(jīng)允許不得轉(zhuǎn)載,或轉(zhuǎn)載時(shí)需注明來(lái)源: 創(chuàng)新互聯(lián)
全網(wǎng)營(yíng)銷(xiāo)推廣知識(shí)