本教學基於RxJava1.x版本進行全面講解，後續課程將陸續更新,敬請關注…
private ArrayList<Student> initPersons() {
ArrayList<Student> persons = new ArrayList<>();
persons.add(new Student("张三", 16));
persons.add(new Student("李四", 17));
persons.add(new Student("王二麻子", 18));
persons.add(new Student("张三", 22));
return persons;
}Observable
.from(initPersons())
//过滤重复名字的项
.distinct(new Func1<Student, String>() {
@Override
public String call(Student student) {
return student.name;
}
})
.subscribe(new Action1<Student>() {
@Override
public void call(Student student) {
Log.i(TAG, "call: "+student);
}
});IT520: call: Student{name='张三', age=16}
IT520: call: Student{name='李四', age=17}
IT520: call: Student{name='王二麻子', age=18}Observable.just(1, 2, 3, 4, 5)
.filter(new Func1<Integer, Boolean>() {
@Override
public Boolean call(Integer item) {
return( item < 4 );
}
})
.subscribe(new Subscriber<Integer>() {
@Override
public void onNext(Integer item) {
System.out.println("Next: " + item);
}
@Override
public void onError(Throwable error) {
System.err.println("Error: " + error.getMessage());
}
@Override
public void onCompleted() {
System.out.println("Sequence complete.");
}
});Next: 1 Next: 2 Next: 3 Sequence complete.
Observable.just(1, 2, 3)
.first()
.subscribe(new Subscriber<Integer>() {
@Override
public void onNext(Integer item) {
System.out.println("Next: " + item);
}
@Override
public void onError(Throwable error) {
System.err.println("Error: " + error.getMessage());
}
@Override
public void onCompleted() {
System.out.println("Sequence complete.");
}
});Next: 1 Sequence complete.
類似的函數還有firstOrDefault(),該函數在佇列發送的過程如果隊列為null，也就是找不到第一項，則會傳送一個預設值。
4.Last
呼叫了該函數可以讓傳送的資料佇列只傳送最後一項。 範例程式碼Observable.just(1, 2, 3)
.last()
.subscribe(new Subscriber<Integer>() {
@Override
public void onNext(Integer item) {
System.out.println("Next: " + item);
}
@Override
public void onError(Throwable error) {
System.err.println("Error: " + error.getMessage());
}
@Override
public void onCompleted() {
System.out.println("Sequence complete.");
}
});Next: 3 Sequence complete.
類似的函數還有lastOrDefault(T)
5.ElementAt
#ElementAt操作符取得原始Observable發射的資料序列指定索引位置的資料項，然後當做自己的唯一資料發射。 如果你傳遞的是負數，或是原始Observable的資料項數小於index+1，將會拋出一個IndexOutOfBoundsException例外。 範例程式碼如下：Observable.just(1, 2, 3, 4, 1, 4)
.elementAt(3)
.subscribe(new Action1<Integer>() {
@Override
public void call(Integer value) {
Log.i(TAG, "call: " + value);
}
});com.m520it.rxjava I/IT520: call: 4
Observable.just(1, 2, 3, 4, 5, 6, 7, 8)
.take(4)
.subscribe(new Subscriber<Integer>() {
@Override
public void onNext(Integer item) {
System.out.println("Next: " + item);
}
@Override
public void onError(Throwable error) {
System.err.println("Error: " + error.getMessage());
}
@Override
public void onCompleted() {
System.out.println("Sequence complete.");
}
});Next: 1 Next: 2 Next: 3 Next: 4 Sequence complete.
Observable.just(1, 2, 3, 4, 5, 6, 7, 8)
.takeLast(4)
.subscribe(new Subscriber<Integer>() {
@Override
public void onNext(Integer item) {
System.out.println("Next: " + item);
}
@Override
public void onError(Throwable error) {
System.err.println("Error: " + error.getMessage());
}
@Override
public void onCompleted() {
System.out.println("Sequence complete.");
}
});Next: 5 Next: 6 Next: 7 Next: 8 Sequence complete.
Observable
.interval(1000, TimeUnit.MILLISECONDS)//每秒发送1个数字
.sample(2000,TimeUnit.MILLISECONDS)//每2秒采样一次
.subscribe(new Action1<Long>() {
@Override
public void call(Long aLong) {
Log.i(TAG, "call: "+aLong);
}
});Observable.just(1, 2, 3, 4, 1)
.ignoreElements()//不发送任何信息 直接发送onCompleted()
.subscribe(new Subscriber<Integer>() {
@Override
public void onCompleted() {
Log.i(TAG, "onCompleted: ");
}
@Override
public void onError(Throwable e) {
}
@Override
public void onNext(Integer integer) {
Log.i(TAG, "onNext: "+integer);
}
});
