RxJava/RxAndroid：repeatUntil

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

import io.reactivex.Observable;
import io.reactivex.Observer;
import io.reactivex.disposables.Disposable;
import io.reactivex.functions.BooleanSupplier;
import io.reactivex.schedulers.Schedulers;

public class MainActivity extends AppCompatActivity {
    private String TAG = "输出";

    private Observer<Integer> mObserver = new Observer<Integer>() {
        @Override
        public void onSubscribe(Disposable d) {

        }

        @Override
        public void onNext(Integer i) {
            Log.d(TAG, "onNext:" + i);
        }

        @Override
        public void onComplete() {
            Log.d(TAG, "onComplete");
        }

        @Override
        public void onError(Throwable e) {
            Log.e(TAG, e.toString(), e);
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        Integer[] numbers = new Integer[]{0, 1, 2, 3, 4};

        Observable.fromArray(numbers)
                .repeatUntil(new BooleanSupplier() {
                    @Override
                    public boolean getAsBoolean() throws Exception {
                        boolean b;
                        int rand = (int) (Math.random() * 10);
                        Log.d(TAG, "随机数:" + rand);

                        //如果随机产生的整数大于5，停止重复。
                        if (rand > 5) {
                            b = true;
                        } else {
                            b = false;
                        }

                        Log.d(TAG, "getAsBoolean:" + b);
                        return b;
                    }
                })
                .subscribeOn(Schedulers.io())
                .observeOn(Schedulers.io())
                .subscribeWith(mObserver);
    }
}

output:

01-24 14:57:16.630 9047-9067/zhangphil.book D/输出: 随机数:2
01-24 14:57:16.631 9047-9067/zhangphil.book D/输出: getAsBoolean:false
01-24 14:57:16.631 9047-9067/zhangphil.book D/输出: 随机数:9
01-24 14:57:16.631 9047-9067/zhangphil.book D/输出: getAsBoolean:true
01-24 14:57:16.647 9047-9068/zhangphil.book D/输出: onNext:0
01-24 14:57:16.647 9047-9068/zhangphil.book D/输出: onNext:1
01-24 14:57:16.647 9047-9068/zhangphil.book D/输出: onNext:2
01-24 14:57:16.647 9047-9068/zhangphil.book D/输出: onNext:3
01-24 14:57:16.647 9047-9068/zhangphil.book D/输出: onNext:4
01-24 14:57:16.647 9047-9068/zhangphil.book D/输出: onNext:0
01-24 14:57:16.647 9047-9068/zhangphil.book D/输出: onNext:1
01-24 14:57:16.647 9047-9068/zhangphil.book D/输出: onNext:2
01-24 14:57:16.647 9047-9068/zhangphil.book D/输出: onNext:3
01-24 14:57:16.647 9047-9068/zhangphil.book D/输出: onNext:4
01-24 14:57:16.647 9047-9068/zhangphil.book D/输出: onComplete