Cause of handler memory leak

Cause of memory leak ： When an object is no longer used , It should be recycled but because another object in use holds its reference , As a result, it cannot be recycled .

Solution 1： stay Java in , Non static inner classes or anonymous inner classes hold references to external classes by default , Use Handler when , Need to Handler Objects are declared as static variables or use weak references . When Handler The internal message queue has not been processed （ Or delay the processing of messages ）, Don't hold external references , It does not affect the logoff recycling of external objects .

Solution 2： When an external class object ends its life cycle , Empty Handler Inside the message queue . For example Activity Of onDestroy() Method to empty the message queue ：

@Override
protected void onDestroy() {
    super.onDestroy();
    //  External class Activity At the end of the life cycle , Empty message queue , end Handler Life cycle 
    mHandler.removeCallbacksAndMessages(null);
    mHandler = null;
}