I'm building a native UI component for Android that uses a view that extends a ReactRootView.
On the constructor of my view (named SyncRootView) if I check the thread I get Thread curThread = Thread.current(); // main
so we're on the main thread.
The problem is that if I try to run any uiManager calls (for example uiManager.createView, I receive that error:
FATAL EXCEPTION: main
Process: com.rnexample, PID: 16424
java.lang.AssertionError
at com.facebook.infer.annotation.Assertions.assertCondition(Assertions.java:66)
at com.facebook.react.common.SingleThreadAsserter.assertNow(SingleThreadAsserter.java:27)
at com.facebook.react.uimanager.ShadowNodeRegistry.getNode(ShadowNodeRegistry.java:67)
at com.facebook.react.uimanager.UIImplementation.createView(UIImplementation.java:278)
at com.facebook.react.uimanager.UIManagerModule.createView(UIManagerModule.java:364)
at com.sudoplz.rnsynchronouslistmanager.Sync.SyncRootView$3.run(SyncRootView.java:177)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at com.facebook.react.bridge.queue.MessageQueueThreadHandler.dispatchMessage(MessageQueueThreadHandler.java:31)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
So basically the problem is a class called SingleThreadAsserter part of react-native which I'm not even sure why it's there.
It's mThread value is set to native_module_thread... therefore I get an AssertionError because I'm on the main thread.
If I try to run those uiManager calls on the native_module thread (by using ctx.runOnNativeModulesQueueThread(myRunnable)), at first it seems to work, but later on (I guess once the module initialisation is over??) I get
Tried to enqueue runnable on already finished thread: 'native_modules... dropping Runnable.
02-21 01:55:36.415 17126-17126/com.rnexample W/MessageQueue: Handler (com.facebook.react.bridge.queue.MessageQueueThreadHandler) {bda653f} sending message to a Handler on a dead thread
java.lang.IllegalStateException: Handler (com.facebook.react.bridge.queue.MessageQueueThreadHandler) {bda653f} sending message to a Handler on a dead thread
at android.os.MessageQueue.enqueueMessage(MessageQueue.java:543)
at android.os.Handler.enqueueMessage(Handler.java:643)
at android.os.Handler.sendMessageAtTime(Handler.java:612)
at android.os.Handler.sendMessageDelayed(Handler.java:582)
at android.os.Handler.post(Handler.java:338)
at com.facebook.react.bridge.queue.MessageQueueThreadImpl.runOnQueue(MessageQueueThreadImpl.java:61)
at com.facebook.react.bridge.ReactContext.runOnNativeModulesQueueThread(ReactContext.java:287)
at com.sudoplz.rnsynchronouslistmanager.Sync.SyncRootView.dispatchInUIThread(SyncRootView.java:516)
at com.sudoplz.rnsynchronouslistmanager.Sync.SyncRootView.runApplication(SyncRootView.java:188)
at com.sudoplz.rnsynchronouslistmanager.Sync.SyncRootView.<init>(SyncRootView.java:97)
at com.sudoplz.rnsynchronouslistmanager.Sync.SyncRootView.<init>(SyncRootView.java:61)
at com.sudoplz.rnsynchronouslistmanager.List.SPView.<init>(SPView.java:20)
at com.sudoplz.rnsynchronouslistmanager.SynchronousListManager.createViewInstance(SynchronousListManager.java:37)
at com.sudoplz.rnsynchronouslistmanager.SynchronousListManager.createViewInstance(SynchronousListManager.java:19)
at com.facebook.react.uimanager.ViewManager.createView(ViewManager.java:44)
at com.facebook.react.uimanager.NativeViewHierarchyManager.createView(NativeViewHierarchyManager.java:224)
at com.facebook.react.uimanager.UIViewOperationQueue$CreateViewOperation.execute(UIViewOperationQueue.java:153)
at com.facebook.react.uimanager.UIViewOperationQueue$1.run(UIViewOperationQueue.java:813)
at com.facebook.react.uimanager.UIViewOperationQueue.flushPendingBatches(UIViewOperationQueue.java:926)
at com.facebook.react.uimanager.UIViewOperationQueue.access$2100(UIViewOperationQueue.java:47)
at com.facebook.react.uimanager.UIViewOperationQueue$DispatchUIFrameCallback.doFrameGuarded(UIViewOperationQueue.java:986)
at com.facebook.react.uimanager.GuardedFrameCallback.doFrame(GuardedFrameCallback.java:31)
at com.facebook.react.modules.core.ReactChoreographer$ReactChoreographerDispatcher.doFrame(ReactChoreographer.java:136)
at com.facebook.react.modules.core.ChoreographerCompat$FrameCallback$1.doFrame(ChoreographerCompat.java:107)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:872)
at android.view.Choreographer.doCallbacks(Choreographer.java:686)
at android.view.Choreographer.doFrame(Choreographer.java:618)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:860)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
any ideas?
I ended up doing this:
on the constructor of my ReactRootView I did:
nativeModulesThread = (MessageQueueThreadImpl) ctx.getCatalystInstance().getReactQueueConfiguration().getNativeModulesQueueThread();
where ctx is the ReactContext available to every UI Native component.
Then I created this method:
protected void dispatchInAppropriateThread(Runnable runnable) {
if (runnable == null) {
return;
}
if (nativeModulesThread.getLooper().getThread().isAlive()) {
ctx.runOnNativeModulesQueueThread(runnable);
} else {
this.post(runnable);
}
}
so now whenever I need to run a runnable I do:
dispatchInAppropriateThread(new Runnable() {
@Override
public void run() {
// do cool stuff
}
});