起因：無(wú)意間看到AvoidOnResult纱昧，大概就是說(shuō)瘪撇，用類似RxPermissions的方式，將原來(lái)需要在Activity里面回調(diào)的方式改成rx的方式履恩。
也就是說(shuō)锰茉，可以直接使用像下面這樣的代碼來(lái)處理onActivityResult。

AvoidOnResult(this)
    .startForResult(FetchDataActivity::class.java, REQUEST_CODE_RXJAVA)
    //下面可自由變換
    .filter { it.resultCode == Activity.RESULT_OK }
    .flatMap {
        val text = it.data.getStringExtra("text")
        Observable.fromIterable(text.asIterable())
    }
    .subscribe({
        Log.d("-------> ", it.toString())
    }, {
        Toast.makeText(this, "error", Toast.LENGTH_SHORT).show()
    }, {
        Toast.makeText(this, "complete", Toast.LENGTH_SHORT).show()
    })

經(jīng)過(guò)：我找了一圈README切心，發(fā)現(xiàn)并沒(méi)有上傳到中央倉(cāng)庫(kù)飒筑，然后我就把代碼復(fù)制過(guò)來(lái)，自己改了改绽昏，扔到了jcenter上面协屡。（申明：代碼是復(fù)制過(guò)來(lái)的，我自己改了一部分代碼之后放到了jcenter上面）全谤。

//原來(lái)的代碼
private Map<Integer, PublishSubject<ActivityResultInfo>> mSubjects = new HashMap<>();
private Map<Integer, AvoidOnResult.Callback> mCallbacks = new HashMap<>();

public Observable<ActivityResultInfo> startForResult(final Intent intent, final int requestCode) {
    PublishSubject<ActivityResultInfo> subject = PublishSubject.create();
    mSubjects.put(requestCode, subject);
    return subject.doOnSubscribe(new Consumer<Disposable>() {
        @Override
        public void accept(Disposable disposable) throws Exception {
            startActivityForResult(intent, requestCode);
        }
    });
}

public void startForResult(Intent intent, int requestCode, AvoidOnResult.Callback callback) {
    mCallbacks.put(requestCode, callback);
    startActivityForResult(intent, requestCode);
}

//修改后的代碼
private PublishSubject<AResultMessage> mSubject;
private Disposable mDisposable;
private AResult.Callback mCallback;

public Observable<AResultMessage> startForResult(final Intent intent, final int requestCode) {
    mCallback = null;
    mSubject = PublishSubject.create();
    return mSubject.doOnSubscribe(new Consumer<Disposable>() {
        @Override
        public void accept(Disposable disposable) throws Exception {
            mDisposable = disposable;
            startActivityForResult(intent, requestCode);
        }
    });
}

public void startForResult(Intent intent, int requestCode, AResult.Callback callback) {
    mSubject = null;
    mCallback = callback;
    startActivityForResult(intent, requestCode);
}

@Override
public void onDetach() {
    super.onDetach();
    if (mDisposable != null && !mDisposable.isDisposed())
        mDisposable.dispose();
}

為什么不用map存儲(chǔ)requestCode呢肤晓？其實(shí)我們可以思考一下requestCode的作用，是為了在onActivityResult的時(shí)候進(jìn)行區(qū)分啼县，但是當(dāng)我們使用RxJava的方式時(shí)材原，已經(jīng)變成一對(duì)一的回調(diào)了，所以requestCode就算去掉都沒(méi)關(guān)系季眷。所以我們完全可以像下面這樣寫(xiě)余蟹，不用requestCode。

private AResult mResult;
mResult = new AResult(this);

//RxJava
mResult.startForResult(SecondActivity.class)
    .filter(AResultMessage::isOk)
    .map(AResultMessage::getData)
    .subscribe(it -> Log.i("AResult", it.toString()));

//Callback
mResult.startForResult(SecondActivity.class, result -> Log.i("AResult", result.toString()));

當(dāng)然我也保留了傳入requestCode的接口子刮，以及所有的resultCode威酒，requestCode窑睁，data這些返回?cái)?shù)據(jù)。

public class AResultMessage {
    private int resultCode;
    private int requestCode;
    private Intent data;

    AResultMessage(Intent data, int resultCode, int requestCode) {
        this.data = data;
        this.resultCode = resultCode;
        this.requestCode = requestCode;
    }

    public Intent getData() {
        return data;
    }

    public int getResultCode() {
        return resultCode;
    }

    public int getRequestCode() {
        return requestCode;
    }

    public boolean isOk() {
        return resultCode == Activity.RESULT_OK;
    }

    public boolean isCancel() {
        return resultCode == Activity.RESULT_CANCELED;
    }

    public boolean isFirstUser() {
        return resultCode == Activity.RESULT_FIRST_USER;
    }

    @Override
    public String toString() {
        return "AResultMessage{" +
                "isOk=" + isOk() +
                ", isCancel=" + isCancel() +
                ", isFirstUser=" + isFirstUser() +
                ", resultCode=" + resultCode +
                ", requestCode=" + requestCode +
                ", data=" + data +
                '}';
    }
}

結(jié)果：GitHub

<dependency>
    <groupId>com.linyuzai</groupId>
    <artifactId>aresult</artifactId>
    <version>1.0.3</version>
    <type>pom</type>
</dependency>

compile 'com.linyuzai:aresult:1.0.3'

坑：在startActivityForResult()中葵孤，如果requestCode傳的值小于0担钮，那么不會(huì)回調(diào)到onActivityResult。