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/**
flatMap 處理一對多關係的轉換
*/
private void flatmap() {
//嵌套的List,
ArrayList<ArrayList<String>> list = new ArrayList<>();
for (int i = 0; i < 5; i++) {
ArrayList<String> l = new ArrayList<>();
for (int j = 0; j < 3; j++) {
l.add(i + "FLATMAP" + j);
}
list.add(l);
}
//flatMap將Observable轉換爲Observable,無嵌套結構,更加符合響應式
//處理一對多的數據
Observable.from(list).flatMap(new Func1<ArrayList<String>, Observable<String>>() {
@Override
public Observable<String> call(ArrayList<String> strings) {
return Observable.from(strings);
}
}).subscribe(new Action1<String>() {
@Override
public void call(String o) {
Log.d(TAG, "call: o = " + o);
}
});
//這裏爲上述的方式的,基本實現過程
//Subscriber決定獲取的參數類型,最終決定返回的參數類型
Subscriber<String> subscriber = new Subscriber<String>() {
//忽略之...
@Override
public void onNext(String s) {
Log.d(TAG, "call: s = " + s);
}
};
Observable.from(list).flatMap(new Func1<ArrayList<String>, Observable<String>>() {
@Override
public Observable<String> call(ArrayList<String> strings) {
return Observable.from(strings);
}
}).subscribe(subscriber);
}
/**
map 處理一對一關係的轉換
*/
private void map() {
//處理一個運算,將int數組轉換爲字符串
int[] arr = {1, 2, 3, 4, 5};
Observable.just(arr)
.subscribeOn(Schedulers.computation())
.observeOn(AndroidSchedulers.mainThread())
//map操作,將輸入類型轉換爲所需類型,類似於Action,
//Func1<T,R> extends Function 將T轉換爲R,做爲返回值
.map(new Func1<int[], String>() {
@Override
public String call(int[] ints) {
StringBuilder sb = new StringBuilder();
//
for (int i : ints) {
sb.append(i);
}
return sb.toString();
}
})
.subscribe(new Action1<String>() {
@Override
public void call(String s) {
Log.d(TAG, "call: " + s);
}
});
}
/**
線程調度器,Schedulers是封裝了Scheduler的工廠方法
Schedulers.io()在新線程處理任務,與Schedulers.newThread()類似,區別有2:
1、用於阻塞式的IO處理
2、會維護線程池,根據需要增加線程數量,有着更好的性能
*/
private void scheduler1() {
Observable.just(1, 2, 3)
.subscribeOn(Schedulers.io())//在新線程產生事件
.observeOn(AndroidSchedulers.mainThread())//在MainThread消費事件
.subscribe(new Subscriber<Integer>() {
//...
@Override
public void onNext(Integer integer) {
int i = integer.intValue();
Log.d(TAG, "onNext: " + i);
}
});
}
/**
練習。體會鏈式編程(響應式編程)
*/
private void chain_rx() {
Observable.create(new Observable.OnSubscribe<Integer>() {
@Override
public void call(Subscriber<? super Integer> subscriber) {
//被觀察者去請求數據,通過傳進來的subscriber對象,將數據傳過去
subscriber.onNext(200);
}
}).subscribe(new Subscriber<Integer>() {
@Override
public void onCompleted() {
}
@Override
public void onError(Throwable e) {
Toast.makeText(MainActivity.this, "錯誤!", Toast.LENGTH_SHORT).show();
}
@Override
public void onNext(Integer integer) {
int i = integer.intValue();
Log.d(TAG, "onNext: "+i);
}
});
}
/**
Action0-Action1接口,Subscriber的簡單實現替代
*/
private void action1() {
//Action1(Action0無參數) extends Action extends Function(空接口)
//Action1或Action0爲Subscriber的簡寫形式,分別提供一個和沒有參數的方法,
//可等價於onNext,onError或者onCompleted的使用
String [] strings = {"hello","rx_java","! with action1"};
Observable.from(strings).subscribe(new Action1<String>() {
@Override
public void call(String s) {
Log.d(TAG, "call: "+s);
}
});
}
/**
一個典型的RxJava應用
*/
private void rxjava() {
//1、創建觀察者(Observer也可)
//實現了Observer接口,實現了Subscription接口,增加了onStart方法
Subscriber<String> subscriber = new Subscriber<String>() {
@Override
public void onCompleted() {
}
@Override
public void onError(Throwable e) {
}
@Override
public void onNext(String s) {
Log.d(TAG, "onNext: " + s);
}
//總是在事件產生的線程,不保證MainThread
@Override
public void onStart() {
super.onStart();
}
};
//2、創建被觀察者(回調)
// 此處傳入OnSubscribe內部接口,Invoked when Observable.subscribe is called.
// 簡便方法,傳入可變參數或者數組:Observable.just(T ...)或者Observable.from(T [] array)
//此二者與create方法等價,封裝後的結果
Observable observable = Observable.create(new Observable.OnSubscribe<String>() {
@Override
public void call(Subscriber<? super String> subscriber) {
subscriber.onNext("hello");
subscriber.onNext("rx_java");
subscriber.onNext("!");
subscriber.onCompleted();
}
});
//3、訂閱
observable.subscribe(subscriber);
}