Differences between the notify(), notifyall(), notifydatasetchanged(), notifydatasetinvalidated() methods in the adapter

1.notify() And notifyAll()

notify() and notifyAll() It is generally used to wake up the locked or waiting adapter, Both are object Object is used to notify the thread method waiting for the object .notify Wake up a thread waiting for the object ,notifyAll Wake up all threads waiting for the object . The biggest difference between the two is ,notifyAll Make all that were originally waiting on the object be deleted notify All threads of exit wait state , Become waiting for the lock on the object , Once the object is unlocked , They will compete .notify Just choose one wait Status thread notification , And make it acquire the lock of the thread , Do not disturb other threads that are also waiting for this thread notify The thread of , When the first thread finishes running , Release the lock on the object , At this time, if the object is not used again notify, Even if the object is idle , other wait The thread waiting for status did not receive the notification of this object , Will continue to be wait state , Until this object is emitted again notify perhaps notifyAll. What they are waiting for is to be notify perhaps notifyAll, Not waiting for a lock .

2.notifyDataSetInvalid() And notifyDataSetChanged()

notifyDataSetChanged() and notifyDataSetInvalid() Generally in adapter Called when the data changes .notifyDataSetChanged Force control through an external method , If adapter When the content of , You need to force a call to geiView() Method update item The content in , This method internally implements each event called on the observer , Whenever a change is found in the data set or a new state of the data is read , This method will be called .notifyDataSetInvalid Method internally implements the call on each observer onInvalidated event , Whenever the dataset is found to have changed , For example, the data is no longer valid , Call this method .（ notes ：notifyDataSetInvalid Will redraw the control and restore it to its original state ,notifyDataSetChanged Redraws the currently visible area .）

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