Android -如何使用.removeOnGlobalFocusChangeListener删除ViewTreeObserver GlobalLayoutListener

von4xj4u 于 2023-06-20 发布在 Android

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如何删除viewTreeObserver？有3个不同的removeOnGlobalFocusChangeListener回调

class MyFragment: Fragment() {
    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
    
        binding.root.viewTreeObserver.addOnGlobalLayoutListener {
            doSomething()
        }
    }
    
    override fun onDestroy() {
        super.onDestroy()
        // I don't know if this is the correct one to call
        binding.root.viewTreeObserver.removeOnGlobalFocusChangeListener { oldFocus, newFocus ->  }
    }
}

android

来源：https://stackoverflow.com/questions/76452239/android-how-to-remove-viewtreeobserver-globallayoutlistener-with-removeongloba

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按热度按时间

q5iwbnjs1#

你应该保持对这个监听器的引用（当在onViewCreated中创建时），并使用removeOnGlobalFocusChangeListener(..)方法在onViewDestroyed中释放它，并将监听器作为victim传递。或更早，如果doSomething()调用不需要如此频繁地调用（一次？）

var globalListener: ViewTreeObserver.OnGlobalLayoutListener? = null
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    super.onViewCreated(view, savedInstanceState)
    globalListener = ViewTreeObserver.OnGlobalLayoutListener { doSomething() }
    binding.root.viewTreeObserver.addOnGlobalLayoutListener(globalListener)
}
override fun onDestroy() {
    globalListener?.let { binding.root.viewTreeObserver.removeOnGlobalFocusChangeListener(it) }
    globalListener = null
    super.onDestroy()
}

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Android -如何使用.removeOnGlobalFocusChangeListener删除ViewTreeObserver GlobalLayoutListener

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