RxJava2 / RxAndroid2的过滤器filter
filter完成一个条件过滤和筛选，从Observable的输出数据中，经过filter筛选一层，如果filter判断的值为真，则交给观察者，否则跳过，例如代码：
package zhangphil.app;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import io.reactivex.Observable;
import io.reactivex.android.schedulers.AndroidSchedulers;
import io.reactivex.disposables.CompositeDisposable;
import io.reactivex.functions.Predicate;
import io.reactivex.observers.DisposableObserver;
import io.reactivex.schedulers.Schedulers;
public class MainActivity extends AppCompatActivity {
private final String TAG = getClass().getSimpleName();
private CompositeDisposable mCompositeDisposable = new CompositeDisposable();
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
test();
}
private void test() {
DisposableObserver disposableObserver = new DisposableObserver<Integer>() {
@Override
public void onNext(Integer i) {
Log.d(TAG, "#####开始#####");
Log.d(TAG + "数据", String.valueOf(i));
Log.d(TAG, "#####结束#####");
}
@Override
public void onComplete() {
Log.d(TAG, "onComplete");
}
@Override
public void onError(Throwable e) {
Log.e(TAG, e.toString(), e);
}
};
mCompositeDisposable.add(
getObservable().filter(new Predicate<Integer>() {
@Override
public boolean test(Integer integer) throws Exception {
int result = integer % 10;
boolean b = (result == 0);
return b; // 此处返回的条件若为true，则数据交给观察者 ,否则跳过
}
})
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribeWith(disposableObserver));
}
private Observable<Integer> getObservable() {
return Observable.range(0, 100);
}
@Override
protected void onDestroy() {
super.onDestroy();
// 如果退出程序，就清除后台任务
mCompositeDisposable.clear();
}
}
代码输出：
05-15 17:15:49.664 29872-29872/zhangphil.app D/MainActivity: #####开始#####
05-15 17:15:49.664 29872-29872/zhangphil.app D/MainActivity数据: 0
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity: #####结束#####
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity: #####开始#####
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity数据: 10
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity: #####结束#####
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity: #####开始#####
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity数据: 20
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity: #####结束#####
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity: #####开始#####
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity数据: 30
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity: #####结束#####
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity: #####开始#####
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity数据: 40
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity: #####结束#####
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity: #####开始#####
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity数据: 50
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity: #####结束#####
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity: #####开始#####
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity数据: 60
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity: #####结束#####
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity: #####开始#####
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity数据: 70
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity: #####结束#####
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity: #####开始#####
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity数据: 80
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity: #####结束#####
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity: #####开始#####
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity数据: 90
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity: #####结束#####
05-15 17:15:49.665 29872-29872/zhangphil.app D/MainActivity: onComplete
