Android 用LiveDataBus替代RxBus、EvenBus
最近使用Rxbus发现升级到33版本的时候，会出现报黄色，看着很不舒服。然后就想着找找替换的方案。查找了蛮多资料。发现版本大部分都是大同小异。就如下的链接的三个版本。第一个就是简单实现类型。也是之前Rxbus早期的原型。再就是后面我用来改良的版本。
但是跟之前用的Rxbus又有点不一样。因为原先都是习惯了的懒人写法。所以就用当前的类名（XXX.getClass().getSimpleName()）来替代需要一直定义的订阅键值。好吧，话不多说。直接上源码：
/*** LiveDataBus 数据交互帮助类** * Created by* Change*/
public class LiveDataBus {public static final Map> bus = new HashMap<>();public static synchronized MutableLiveData toObservable(Class type){String key = type.getSimpleName();if (!bus.containsKey(key)){bus.put(key, new BusMutableLiveData<>());}return (MutableLiveData) bus.get(key);}public static void post(Object type){String key = type.getClass().getSimpleName();if (!bus.containsKey(key)){bus.put(key, new BusMutableLiveData<>());}Objects.requireNonNull(bus.get(key)).postValue(type);}private static class ObserverWrapper implements Observer {private Observer observer;public ObserverWrapper(Observer observer) {this.observer = observer;}@Overridepublic void onChanged(@Nullable T t) {if (observer != null) {if (isCallOnObserve()) {return;}observer.onChanged(t);}}private boolean isCallOnObserve() {StackTraceElement[] stackTrace = Thread.currentThread().getStackTrace();if (stackTrace != null && stackTrace.length > 0) {for (StackTraceElement element : stackTrace) {if ("androidx.lifecycle.LiveData".equals(element.getClassName()) &&"observeForever".equals(element.getMethodName())) {return true;}}}return false;}}public static class BusMutableLiveData extends MutableLiveData {private Map observerMap = new HashMap<>();@Overridepublic void observe(@NonNull LifecycleOwner owner, @NonNull Observer observer) {super.observe(owner, observer);try {hook(observer);} catch (Exception e) {e.printStackTrace();}}@Overridepublic void observeForever(@NonNull Observer observer) {if (!observerMap.containsKey(observer)) {observerMap.put(observer, new ObserverWrapper(observer));}super.observeForever(Objects.requireNonNull(observerMap.get(observer)));}@Overridepublic void removeObserver(@NonNull Observer observer) {Observer realObserver = null;if (observerMap.containsKey(observer)) {realObserver = observerMap.remove(observer);} else {realObserver = observer;}super.removeObserver(realObserver);}private void hook(@NonNull Observer observer) throws Exception {//get wrapper's versionClass classLiveData = LiveData.class;Field fieldObservers = classLiveData.getDeclaredField("mObservers");fieldObservers.setAccessible(true);Object objectObservers = fieldObservers.get(this);Class classObservers = objectObservers.getClass();Method methodGet = classObservers.getDeclaredMethod("get", Object.class);methodGet.setAccessible(true);Object objectWrapperEntry = methodGet.invoke(objectObservers, observer);Object objectWrapper = null;if (objectWrapperEntry instanceof Map.Entry) {objectWrapper = ((Map.Entry) objectWrapperEntry).getValue();}if (objectWrapper == null) {throw new NullPointerException("Wrapper can not be bull!");}Class classObserverWrapper = objectWrapper.getClass().getSuperclass();Field fieldLastVersion = classObserverWrapper.getDeclaredField("mLastVersion");fieldLastVersion.setAccessible(true);//get livedata's versionField fieldVersion = classLiveData.getDeclaredField("mVersion");fieldVersion.setAccessible(true);Object objectVersion = fieldVersion.get(this);//set wrapper's versionfieldLastVersion.set(objectWrapper, objectVersion);}}
}
使用方法：
注册订阅：
LiveDataBus.toObservable(TokenEvent.class).observeForever(result -> {// 做退出登录的操作exit();LoginActivity.startActivity(this);});发送消息：
LiveDataBus.post(new TokenEvent());总结：
实践是检验真理的唯一标准----古人说的话没错。最后，希望能帮助到需要的人。有问题请指正，谢谢！下面是查阅的相关资料。有需要的可以去看看。原理什么的可以去了解一下下。我就不去复述照搬了。大家互相学习吧！共勉