1、去掉LiveData粘性事件主要是利用反射让mLastVersion = mVersion
package com.htf.jetpack;
import androidx.annotation.NonNull;
import androidx.lifecycle.LifecycleOwner;
import androidx.lifecycle.LiveData;
import androidx.lifecycle.MutableLiveData;
import androidx.lifecycle.Observer;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
/**
* Created by htf on 2021/6/16
* Describe:
*/
public class LiveDataBus {
private Map<String, BusMutableLiveData<Object>> bus;
private static LiveDataBus liveDataBus = new LiveDataBus();
private LiveDataBus() {
bus = new HashMap<>();
}
public static LiveDataBus getInstance() {
return liveDataBus;
}
public synchronized <T> BusMutableLiveData<T> with(String key, Class<T> type) {
if (!bus.containsKey(key)) {
bus.put(key, new BusMutableLiveData<Object>());
}
return (BusMutableLiveData) bus.get(key);
}
public static class BusMutableLiveData<T> extends MutableLiveData {
@Override
public void observe(@NonNull LifecycleOwner owner, @NonNull Observer observer) {
super.observe(owner, observer);
hook(observer);
}
private void hook(Observer<super T> observer) {
try {
Class<LiveData> liveDataClass = LiveData.class;
Field mObserversField = liveDataClass.getDeclaredField("mObservers");
mObserversField.setAccessible(true);
Object mObserversObject = mObserversField.get(this);
Class<?> mObserversObjectClass = mObserversObject.getClass();
//获取到mObservers对象的get方法
Method getMethod = mObserversObjectClass.getDeclaredMethod("get", Object.class);
getMethod.setAccessible(true);
//执行get方法
Object invokeEntry = getMethod.invoke(mObserversObject, observer);
Object observerWraper = null;
if (invokeEntry != null && invokeEntry instanceof Map.Entry) {
observerWraper = ((Map.Entry<?, ?>) invokeEntry).getValue();
}
if (observerWraper == null) {
throw new NullPointerException("observerWraper 为空");
}
Class<?> superclass = observerWraper.getClass().getSuperclass();
Field mLastVersion = superclass.getDeclaredField("mLastVersion");
mLastVersion.setAccessible(true);
Field mVersion = liveDataClass.getDeclaredField("mVersion");
mVersion.setAccessible(true);
Object mVersionValue = mVersion.get(this);
mLastVersion.set(observerWraper, mVersionValue);
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
2、使用
//绑定
LiveDataBus.getInstance().with("data", String.class).observe(this, new Observer<String>() {
@Override
public void onChanged(String s) {
Log.e("biubiubiu", "s == " + s);
}
});
发送
LiveDataBus.getInstance().with("data", String.class).setValue("哈哈哈" + (i++));