本文整理了Java中io.reactivex.Observable.filter()方法的一些代码示例，展示了Observable.filter()的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。Observable.filter()方法的具体详情如下：
包路径：io.reactivex.Observable
类名称：Observable
方法名：filter

Observable.filter介绍

[英]Filters items emitted by an ObservableSource by only emitting those that satisfy a specified predicate.

Scheduler: filter does not operate by default on a particular Scheduler.
[中]通过仅发送满足指定谓词的项来过滤ObservableSource发出的项。
调度程序：默认情况下，过滤器不会在特定调度程序上运行。

代码示例

代码示例来源：origin: ReactiveX/RxJava

@Override
  public ObservableSource<Object> apply(Observable<Object> o) throws Exception {
    return o.filter(Functions.alwaysTrue());
  }
});

代码示例来源：origin: ReactiveX/RxJava

@Test
public void testFirstOrElseWithPredicateOfNoneMatchingThePredicate() {
  Observable<String> src = Observable.just("a", "b", "c");
  src.filter(IS_D).first("default").subscribe(wo);
  verify(wo, times(1)).onSuccess(anyString());
  verify(wo, times(1)).onSuccess("default");
  verify(wo, never()).onError(any(Throwable.class));
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void testFirstOrElseWithPredicateOfSome() {
  Observable<String> src = Observable.just("a", "b", "c", "d", "e", "f");
  src.filter(IS_D).first("default").subscribe(wo);
  verify(wo, times(1)).onSuccess(anyString());
  verify(wo, times(1)).onSuccess("d");
  verify(wo, never()).onError(any(Throwable.class));
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void testTakeFirstWithPredicateOfNoneMatchingThePredicate() {
  Observable<Integer> o = Observable.just(1, 3, 5, 7, 9, 7, 5, 3, 1);
  o.filter(IS_EVEN).take(1).subscribe(w);
  verify(w, never()).onNext(anyInt());
  verify(w, times(1)).onComplete();
  verify(w, never()).onError(any(Throwable.class));
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void testFirstOrElseWithPredicateOfSomeObservable() {
  Observable<String> src = Observable.just("a", "b", "c", "d", "e", "f");
  src.filter(IS_D).first("default").toObservable().subscribe(w);
  verify(w, times(1)).onNext(anyString());
  verify(w, times(1)).onNext("d");
  verify(w, never()).onError(any(Throwable.class));
  verify(w, times(1)).onComplete();
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void testFirstOrElseWithPredicateOfNoneMatchingThePredicateObservable() {
  Observable<String> src = Observable.just("a", "b", "c");
  src.filter(IS_D).first("default").toObservable().subscribe(w);
  verify(w, times(1)).onNext(anyString());
  verify(w, times(1)).onNext("default");
  verify(w, never()).onError(any(Throwable.class));
  verify(w, times(1)).onComplete();
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void testFirstWithPredicateOfNoneMatchingThePredicate() {
  Observable<Integer> o = Observable.just(1, 3, 5, 7, 9, 7, 5, 3, 1);
  o.filter(IS_EVEN).firstElement().subscribe(wm);
  verify(wm, never()).onSuccess(anyInt());
  verify(wm).onComplete();
  verify(wm, never()).onError(any(Throwable.class));
}

代码示例来源：origin: ReactiveX/RxJava

@Override
  public Observable<Object> apply(Observable<Object> f) throws Exception {
    return f.doFinally(ObservableDoFinallyTest.this).filter(Functions.alwaysTrue());
  }
});

代码示例来源：origin: ReactiveX/RxJava

@Test
public void justConditional() {
  Observable.just(1)
  .doAfterNext(afterNext)
  .filter(Functions.alwaysTrue())
  .subscribeWith(to)
  .assertResult(1);
  assertEquals(Arrays.asList(1, -1), values);
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void normalJustConditional() {
  Observable.just(1)
  .doFinally(this)
  .filter(Functions.alwaysTrue())
  .test()
  .assertResult(1);
  assertEquals(1, calls);
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void asyncFusedRejectedConditional() {
  TestObserver<Integer> to0 = ObserverFusion.newTest(QueueFuseable.ASYNC);
  Observable.range(1, 5)
  .doAfterNext(afterNext)
  .filter(Functions.alwaysTrue())
  .subscribe(to0);
  ObserverFusion.assertFusion(to0, QueueFuseable.NONE)
  .assertResult(1, 2, 3, 4, 5);
  assertEquals(Arrays.asList(-1, -2, -3, -4, -5), values);
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void syncFusedConditional() {
  TestObserver<Integer> to0 = ObserverFusion.newTest(QueueFuseable.SYNC);
  Observable.range(1, 5)
  .doAfterNext(afterNext)
  .filter(Functions.alwaysTrue())
  .subscribe(to0);
  ObserverFusion.assertFusion(to0, QueueFuseable.SYNC)
  .assertResult(1, 2, 3, 4, 5);
  assertEquals(Arrays.asList(-1, -2, -3, -4, -5), values);
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void rangeConditional() {
  Observable.range(1, 5)
  .doAfterNext(afterNext)
  .filter(Functions.alwaysTrue())
  .subscribeWith(to)
  .assertResult(1, 2, 3, 4, 5);
  assertEquals(Arrays.asList(1, -1, 2, -2, 3, -3, 4, -4, 5, -5), values);
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void emptyConditional() {
  Observable.<Integer>empty()
  .doAfterNext(afterNext)
  .filter(Functions.alwaysTrue())
  .subscribeWith(to)
  .assertResult();
  assertTrue(values.isEmpty());
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void syncFusedBoundaryConditional() {
  TestObserver<Integer> to = ObserverFusion.newTest(QueueFuseable.SYNC | QueueFuseable.BOUNDARY);
  Observable.range(1, 5)
  .doFinally(this)
  .filter(Functions.alwaysTrue())
  .subscribe(to);
  ObserverFusion.assertFusion(to, QueueFuseable.NONE)
  .assertResult(1, 2, 3, 4, 5);
  assertEquals(1, calls);
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void syncFusedConditional() {
  TestObserver<Integer> to = ObserverFusion.newTest(QueueFuseable.SYNC);
  Observable.range(1, 5)
  .doFinally(this)
  .filter(Functions.alwaysTrue())
  .subscribe(to);
  ObserverFusion.assertFusion(to, QueueFuseable.SYNC)
  .assertResult(1, 2, 3, 4, 5);
  assertEquals(1, calls);
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void errorConditional() {
  Observable.<Integer>error(new TestException())
  .doAfterNext(afterNext)
  .filter(Functions.alwaysTrue())
  .subscribeWith(to)
  .assertFailure(TestException.class);
  assertTrue(values.isEmpty());
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void normalEmptyConditional() {
  Observable.empty()
  .doFinally(this)
  .filter(Functions.alwaysTrue())
  .test()
  .assertResult();
  assertEquals(1, calls);
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void normalTakeConditional() {
  Observable.range(1, 10)
  .doFinally(this)
  .filter(Functions.alwaysTrue())
  .take(5)
  .test()
  .assertResult(1, 2, 3, 4, 5);
  assertEquals(1, calls);
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void normalErrorConditional() {
  Observable.error(new TestException())
  .doFinally(this)
  .filter(Functions.alwaysTrue())
  .test()
  .assertFailure(TestException.class);
  assertEquals(1, calls);
}