1.Rx思维 (起点到终点链条不断,响应式编程)
起点(分发事件(Path): 我饿了)--下楼--去餐厅---点餐--->终点(吃饭消费事件)
程序中的例子
起点(分发事件,点击登录)---登录API---请求服务器---获取响应码---->终点(更新UI登录成功 消费事件)
2.核心思想
有一个起点 和 一个终点, 起点开始流向我们的"事件" 把事件流向到终点,只不过在流向的过程中,可以增加拦截,
拦截时可以对"事件进行改变", 终点只关心它上一个拦截;
---------------------------------------------------------------
Observable 根据上层变化而变化过滤 Observer
被观察者 订阅(上层区域 和 下层区域 关联) 观察者
起点 终点
---------------------------------------------------------------
标准观察者: RxJava的观察者模式:
3.RxJava配合Retrofit
1> 数据模块
// 总数据Bean
public class ProjectBean {
private int errorCode;
private String errorMsg;
private List
public static class DataBean {
private int courseId;
private int id;
private String name;
private int order;
private int parentChapterId;
private boolean userControlSetTop;
private int visible;
private List children;
}
}
// Item数据
public class ProjectItem {
private DataBean data;
private int errorCode;
private String errorMsg;
public static class DataBean {
private int curPage;
private int offset;
private boolean over;
private int pageCount;
private int size;
private int total;
private List
public static class DatasBean {
private String apkLink;
private String desc;
private String envelopePic;
private boolean fresh;
private int id;
private String link;
private String niceDate;
private String origin;
private String prefix;
private String projectLink;
private List
public static class TagsBean {
private String name; // 项目
private String url; ///project/list/1?cid=294
}
}
}
}
2> Api模块
public interface WanAndroidApi {
//总数据
@GET("project/tree/json")
Observable
//Item数据
@GET("project/list/{pageIndex}/json") //?cid=294 异步线程 耗时操作
Observable
}
3> 业务操作
public class UseActivity extends AppCompatActivity {
private WanAndroidApi api;
public static final String TAG = "rxJava";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_use);
api = HttpUtil.getOnlineCookieRetrofit().create(WanAndroidApi.class);
antiShakeAction();
}
//TODO Retrofit+RxJava 查询 项目分类 (总数据查询)
Disposable disposable;
public void getProjectAction(View view) {
disposable = api.getProject()
.subscribeOn(Schedulers.io()) //给上面分配异步线程
.observeOn(AndroidSchedulers.mainThread())//给下面主线程
.subscribe(new Consumer
@Override
public void accept(ProjectBean projectBean) throws Exception {
Log.d(TAG, "accept: " + projectBean.toString());//可以做UI操作
}
});
}
//TODO Retrofit+RxJava 查询 项目分类的 去获取项目列表数据
public void getProjectListAction(View view) {
disposable = api.getProjectItem(1, 294)
.compose(rxUD())
.subscribe(projectItem -> {
Log.d(TAG, "accept: " + projectItem.toString());//可以做UI操作
});
}
/**
* 封装我们线程调度的操作
* UD : upstream 上游 , downstream 下游
*/
public static
return upstream -> {
return upstream.subscribeOn(Schedulers.io()) //给上面代码(subscribeOn)分配异步线程
.observeOn(AndroidSchedulers.mainThread()); //给下面代码(observeOn)分配主线程
};
}
@Override
protected void onDestroy() {
super.onDestroy();
if (disposable != null && !disposable.isDisposed()) {
disposable.dispose();
}
}
4.防抖 rxBinding 与 网络嵌套
public class UseActivity extends AppCompatActivity {
private WanAndroidApi api;
public static final String TAG = "rxJava";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_use);
api = HttpUtil.getOnlineCookieRetrofit().create(WanAndroidApi.class);
antiShakeAction();
}
//TODO Retrofit+RxJava 查询 项目分类 (总数据查询)
Disposable disposable;
/**
* TODO 自定义 功能防抖
*/
private void antiShakeAction() {
//对Button防抖动
Button btn = findViewById(R.id.bt_anti_shake);
disposable = RxView.clicks(btn)
.throttleFirst(2000, TimeUnit.MILLISECONDS) //两秒内 响应一次
.subscribe(new Consumer
@Override
public void accept(Object o) throws Exception {
Log.d(TAG, "accept: 我响应了一次");
}
});
}
//TODO 防抖功能 + 网络嵌套 (解决网络嵌套问题) flatMap
private void antiShakeActionUpdate() {
//对Button防抖动
Button btn = findViewById(R.id.bt_anti_shake);
disposable = RxView.clicks(btn)//使用RxView来进行防抖
.throttleFirst(2000, TimeUnit.MILLISECONDS) //两秒内 响应一次
//我只给下面切换 异步线程
.observeOn(Schedulers.io())
//使用flatMap 自己分发 10个数据 onNext(1)-> 给下面 1-->多分发 10个数据
//将Object 转换成 ObservableSource
.flatMap(new Function
@Override
public ObservableSource
return api.getProject(); //返回 Observable
}
})
//将 ProjectBean 转换为 ObservableSource
.flatMap(new Function
@Override
public ObservableSource
return Observable.fromIterable(projectBean.getData());//自己搞一个发射器 发多次;;
}
})
// 将ProjectBean.DataBean 转换成 ObservableSource
.flatMap(new Function
@Override
public ObservableSource
return api.getProjectItem(1, dataBean.getId()); //获取Item数据
}
})
.observeOn(AndroidSchedulers.mainThread()) //给下面使用的线程
.subscribe(new Consumer
@Override
public void accept(ProjectItem projectItem) {
//如果我要更新UI,要切会主线程
Log.d(TAG, "antiShakeAction: " + projectItem.toString());
}
});
}
@Override
protected void onDestroy() {
super.onDestroy();
if (disposable != null && !disposable.isDisposed()) {
disposable.dispose();
}
}
5.doOnNext(频繁的线程切换)
请求服务器注册(耗时操作)
↓
更新注册UI(main线程)
↓
请求服务器登录(耗时操作)
↓
更新注册UI(main线程)
GitHub - ReactiveX/RxJava: RxJava – Reactive Extensions for the JVM – a library for composing asynchronous and event-based programs using observable sequences for the Java VM.
ReactiveX
玩Android 开放API-玩Android - wanandroid.com
https://www.bejson.com/json2javapojo/new/%27
玩Android 开放API-玩Android - wanandroid.com
https://www.bejson.com/json2javapojo/new/%27
1> RxJava Hook
RxJava 1.x
@NonNull
public static
//预留给2.x
return source;
}
RxJava2.x RxJavaPlugins中
@NonNull
public static
//默认情况下 f==null
Function f = onObservableAssembly;
if (f != null) {
return apply(f, source);
}
return source;
}
public static void setOnObservableAssembly(@Nullable Function onObservableAssembly) {
if (lockdown) throw new IllegalStateException("Plugins can't be changed anymore");
RxJavaPlugins.onObservableAssembly = onObservableAssembly;
}
public static void main(String[] args) {
//Hook之前的监听 是static 全局的 Hook 很多操作符都会经过[RxJavaPlugins.onAssembly]
RxJavaPlugins.setOnObservableAssembly(new Function
@Override
public Observable apply(Observable observable) throws Exception {
System.out.println("apply: 整个项目全局监听到底有多少地方使用了 RxJava"+observable);
return observable;//不破坏人家的功能
}
});
testJust();
}
public static void testJust(){
Observable.just(1, 2, 4).subscribe(new Consumer
@Override
public void accept(Integer integer) throws Exception {
System.out.println("integer==>" + integer);
}
});
}
//执行结果
整个项目全局监听 observable: io.reactivex.internal.operators.observable.ObservableFromArray@64a294a6
integer==>1
integer==>2
integer==>4
2> RxJava的观察者模式
//起点被观察者
Observable.just(PATH) //TODO 第二步 内部会分发 返回 Observable
//TODO 第三步 卡片式拦截 将String 转换为 Bitmap
.map(new Function
@Override
public Bitmap apply(String s) throws Exception {
URL url = new URL(PATH);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(5000);
int responseCode = conn.getResponseCode();
if (responseCode == HttpURLConnection.HTTP_OK) {
InputStream inputStream = conn.getInputStream();
return BitmapFactory.decodeStream(inputStream);
}
return null;
}
})
//日志记录
.map(new Function
@Override
public Bitmap apply(Bitmap bitmap) throws Exception {
Log.d(TAG, "apply: " + getNormalTime(System.currentTimeMillis()) + "下载了图片");
return bitmap;//将上个返回的数据继续流给下游;
}
})
.map(new Function
@Override
public Bitmap apply(Bitmap bitmap) throws Exception {
Paint paint = new Paint();
paint.setTextSize(88);
paint.setColor(Color.RED);
return drawTextToBitmap(bitmap, "NorthStar", paint, 88, 88);
}
})
//TODO 将上下游调度网络的操作放入compose中
//.subscribeOn(Schedulers.io()) //给上面代码 分配异步线程
//.observeOn(AndroidSchedulers.mainThread()) //给下面代码分配主线程
.compose(rxUD())
//TODO 订阅 起点 和 终点 订阅起来 上层改变 下层会响应改变
.subscribe(
//终点观察者
new Observer
@Override//TODO 第一步 订阅开始 预备开始要分发
public void onSubscribe(Disposable d) {
progressDialog = new ProgressDialog(DownloadActivity.this);
progressDialog.setTitle("下载图片中...");
progressDialog.show();
}
@Override// TODO 第四步 拿到事件
public void onNext(Bitmap bitmap) {
iv.setImageBitmap(bitmap);
}
@Override//错误事件
public void onError(Throwable e) {
Log.d(TAG, "onError: " + e.getMessage());
}
@Override//TODO 第五步 完成事件
public void onComplete() {
if (progressDialog != null) {
progressDialog.dismiss();
}
}
});
/**
* 封装我们线程调度的操作
* UD : upstream 上游 , downstream 下游
*/
public static
return new ObservableTransformer
@Override
public ObservableSource
return upstream.subscribeOn(Schedulers.io()) //给上面代码分配异步线程
.observeOn(AndroidSchedulers.mainThread()) //给下面代码分配主线程
.map(new Function
@Override
public UD apply(UD ud) throws Exception {
Log.d(TAG, "apply: 我监听到你了, 居然在执行");
return ud;
}
});
}
};
}
//2.Observable 被观察者/发布者 起点 创建过程 : new ObservableCreate(){source=自定义source}
//传入自定义source → creat(ObservableOnSubscribe
//ObservableCreate
Observable.create(
// 传入自定义source → creat(ObservableOnSubscribe
new ObservableOnSubscribe
@Override
public void subscribe(ObservableEmitter
emitter.onNext("A");
}
})
// ObservableCreate.map
// ObservableMap
// AbstractObservableWithUpstream
// ObservableSource
.map(new Function
@Override
public Bitmap apply(String s) throws Exception {
return null;
}
})
.flatMap(new Function
@Override
public ObservableSource
ObservableSource
@Override
protected void subscribeActual(Observer observer) {
}
};
return bmp;
}
})
.doOnNext(new Consumer
@Override
public void accept(Bitmap o) throws Exception {
}
})
.subscribeOn(Schedulers.io()) //给上面调度 异步线程
.observeOn(AndroidSchedulers.mainThread()) //给下面调度 主线程
//3.subscribe 订阅过程 ObservableMap.subscribe
.subscribe(
//1.自定义观察者 Observer 终点
new Observer
@Override // 谁调subscribe 就在那个线程中,不参与调度
public void onSubscribe(Disposable d) {
}
@Override
public void onNext(Bitmap aBoolean) {
}
@Override
public void onError(Throwable e) {
}
@Override
public void onComplete() {
}
});
}
自定义source ObservableCreate subscribe订阅 ← 自定义观察者
CreateEmitter.OnNext() subscribeActual(自定义观察者) ← subscribeActual new Observer
↖ ↘ ↓ 创建发射器
↖ ↘CreateEmitter(自定义观察者)---------------------------->onNext();
↖ ↓ 调用
[new ObservableOnSubscribe
callback ↖ ↓
↖source.subscribe(发射器)
3> Observable 创建过程时序图如下
Observable(被观察者) ObservableOnSubscribe RxJavaPlugins ObservableCreate
| | | |
|1.new ObservableOnSubscribe() | | |
|------------------------------------->| | |
|─┐2.Create | | |
|<┘ | | |
| 3.onAssembly(new ObservableCreate
|------------------------------------------------------->|4.new ObservableCreate()|
| | |----------------------->|
| 6.返回ObservableCreate对象 | 5.ObservableCreate |
|<-------------------------------------------------------|<-----------------------|
| | | |
Observable(被观察者) ObservableOnSubscribe RxJavaPlugins ObservableCreate
标准观察者模式 RxJava(耦合度低)
↙Observer1 被观察者(发布) 抽象层(发射器) map
Observable ← Observer2 ObservableOnSubscribe CreateEmitter map
List observers ↖Observer3 source.onNext()------->.onNext() ↓
add observer ... ↘ 自定义观察者(订阅)
remove observer Observer
notify observer .onNext()
4>ObservableMap源码分析
一个Map源码分析:
代码区域 流程区域
Observable.create | | ObservableCreate ObservableMap Observable
↓ | |← subscribeActual(obse) ← subscribeActual(obse) ← .subscribe
ObservableCreate |ObservableOnSubscribe|
↓ | 自定义 source | ↓ ↓ ↓
ObservableMap | |
↓ | |--->CreateEmitter--------->MapObserver--------->自定义Observer
Observable.subscribe | |
5>RxJava线程切换
/**
* Calls the associated hook function.
* @param defaultScheduler the hook's input value
* @return the value returned by the hook
*/
@NonNull
public static Scheduler onIoScheduler(@NonNull Scheduler defaultScheduler) {
Function f = onIoHandler;
//默认是null
if (f == null) {
return defaultScheduler;
}
return apply(f, defaultScheduler);
}
最终 Scheduler IO scheduler.io()
/**
* Sets the specific hook function.
* @param handler the hook function to set, null allowed
*/
public static void setIoSchedulerHandler(@Nullable Function handler) {
if (lockdown) {
throw new IllegalStateException("Plugins can't be changed anymore");
}
onIoHandler = handler;
}
Schedulers有很多细节
//TODO 1.Schedulers.io() 线程策略机制
Schedulers----> Scheduler IO---->new IOTask()--->DEFAULT =new IoScheduler()-->线程池 ExecutorService
.subscribeOn(
//RxJavaPlugins.onIoScheduler(IO); HOOK技术 Calls the associated hook function.
Schedulers.io() //策略机制
)
@NonNull
public static Scheduler io() {
return RxJavaPlugins.onIoScheduler(IO);
}
IO = RxJavaPlugins.initIoScheduler(new IOTask());
static final class IOTask implements Callable
@Override
public Scheduler call() throws Exception {
return IoHolder.DEFAULT;
}
}
static final Scheduler DEFAULT = new IoScheduler();
public IoScheduler() { this(WORKER_THREAD_FACTORY); }
public IoScheduler(ThreadFactory threadFactory) {
this.threadFactory = threadFactory;
this.pool = new AtomicReference
start();
}
//TODO 2.subscribeOn() new IoScheduler---线程池 传入
public final Observable
ObjectHelper.requireNonNull(scheduler, "scheduler is null");
return RxJavaPlugins.onAssembly(new ObservableSubscribeOn
}
public ObservableSubscribeOn(ObservableSource
super(source);
this.scheduler = scheduler;
}
//在终点 订阅时 会调用 subscribeActual()
public final void subscribe(Observer observer) {
subscribeActual(observer);
}
//这个在ObservableSubscribeOn中
@Override
public void subscribeActual(final Observer s) {
final SubscribeOnObserver
s.onSubscribe(parent);
parent.setDisposable(scheduler.scheduleDirect(new SubscribeTask(parent)));
}
final class SubscribeTask implements Runnable {
private final SubscribeOnObserver
SubscribeTask(SubscribeOnObserver
this.parent = parent;
}
@Override
public void run() {
source.subscribe(parent);
}
}
//ioScheduler(线程池).scheduleDirect(new SubscribeTask(parent))
public Disposable scheduleDirect(@NonNull Runnable run, long delay, @NonNull TimeUnit unit) {
final Worker w = createWorker(); == IoScheduler.createWorker(){return new EventLoopWorker(pool.get());}
final Runnable decoratedRun = RxJavaPlugins.onSchedule(run);//自己包装了 Runnable
DisposeTask task = new DisposeTask(decoratedRun, w);//包装一层 Runnable
w.schedule(task, delay, unit);//↓ EventLoopWorker.schedule
return task;
}
public Disposable schedule(@NonNull Runnable action, long delayTime, @NonNull TimeUnit unit) {
return threadWorker.scheduleActual(action, delayTime, unit, tasks);//↓
}
@NonNull
public ScheduledRunnable scheduleActual(final Runnable run, long delayTime,
@NonNull TimeUnit unit, @Nullable DisposableContainer parent) {
Runnable decoratedRun = RxJavaPlugins.onSchedule(run);
ScheduledRunnable sr = new ScheduledRunnable(decoratedRun, parent);
Future f;
try {
if (delayTime <= 0) {
f = executor.submit((Callable
} else {
f = executor.schedule((Callable
}
sr.setFuture(f);
}
return sr;
}
6>SubscribeOn(Schedulers.io()) 时序图
属于异步线程
自定义 ObservableCreate SubscribeTask ObservableSubscribeOn<--subscribe(订阅)<-- 终点
source subscribeActual(包裹1) subscribeActual(终点) subscribeActual Observer
↖ ↓ run{ ↓
包裹2.onNext source.subXX(包裹2) <--source.subXX() SubscribeOnObserver(Observer)
↘ ↓ } 终点存放
CreateEmitter ↓
包裹1存放 包裹2 线程池
onNext(){ executor.submit((Callable
包裹1.onNext() 这时从线程池中执行异步任务
}
异步线程
Scheduler MAIN_THREAD <---------------------------- ObserverOn(AndroidSchedulers.mainThread())
↓
DEFAULT = new HandlerScheduler(new Handler(Looper.getMainLooper()));-> HandlerScheduler$.HandlerWork
scheduler{handler.sendMessage(run)}
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