如何修复"variable used in lambda expression should be final"？

Question

我正在制作一个 android 应用程序，如果它是第一次调用 api 调用，则尝试将地图标记添加到地图中，或者只是重新设置标记的位置。我正在使用 RxJava2 重复调用 API。问题是我无法检查它是否是第一个 API 调用，因为我无法访问非最终布尔值。

boolean firstReposition = true;
        //Create position call
        ISSPositionService service = ServiceGenerator.createService(ISSPositionService.class);
        //create observable
        Observable<ISSPositionData> issPositionCall = service.getPosition();
        Disposable disposable = issPositionCall.subscribeOn(Schedulers.io())
                .repeatWhen(completed -> completed.delay(30, java.util.concurrent.TimeUnit.SECONDS))
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(positionData -> {
                    LatLng currentIssPosition = new LatLng(positionData.getIssPosition().getLatitude(), positionData.getIssPosition().getLongitude());
                    if (firstReposition) {
                        issMarkerOptions.position(currentIssPosition);
                        map.addMarker(issMarkerOptions);
                        firstReposition = false;
                    }
                    else {
                        issMarker.setPosition(currentIssPosition);
                    }
                    //animate camera so it shows current position
                    map.animateCamera(CameraUpdateFactory.newLatLng(currentIssPosition));
                });

我将如何重写代码以便能够检查和设置布尔值？

Answer 1

使用AtomicBoolean，可以使用set()和get()方法 java-docs

AtomicBoolean firstReposition = new AtomicBoolean(true);
    //Create position call
    ISSPositionService service = ServiceGenerator.createService(ISSPositionService.class);
    //create observable
    Observable<ISSPositionData> issPositionCall = service.getPosition();
    Disposable disposable = issPositionCall.subscribeOn(Schedulers.io())
            .repeatWhen(completed -> completed.delay(30, java.util.concurrent.TimeUnit.SECONDS))
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe(positionData -> {
                LatLng currentIssPosition = new LatLng(positionData.getIssPosition().getLatitude(), positionData.getIssPosition().getLongitude());
                if (firstReposition) {
                    issMarkerOptions.position(currentIssPosition);
                    map.addMarker(issMarkerOptions);
                    firstReposition.set(false);
                }
                else {
                    issMarker.setPosition(currentIssPosition);
                }
                //animate camera so it shows current position
                map.animateCamera(CameraUpdateFactory.newLatLng(currentIssPosition));
            });