单击返回按钮时，该应用在seceond之后崩溃
我自定义了后退按钮。当我点击它时，应用程序在一秒钟后崩溃。 这是代码： 错误日志
private var mBackPressed: Long = 0
private val timeInterval = 2000
private fun configBackPress() {
requireActivity().onBackPressedDispatcher.addCallback(this, true) {
when {
mBackPressed + timeInterval > System.currentTimeMillis() -> {
requireActivity().onBackPressedDispatcher.onBackPressed()
}
else -> {
Snackbar.make(
requireActivity().findViewById(android.R.id.content),
getString(R.string.press_once_again_back_button_to_exit),
Snackbar.LENGTH_SHORT
)
.setAnchorView(viewBinding.vSnackBarHelper)
.show()
mBackPressed = System.currentTimeMillis()
}
}
}
}
当用户单击后退按钮两次时，后退应该可以工作。
I have customized back button. when I click on it, the application crashes after a second.
here is the code:
error log
private var mBackPressed: Long = 0
private val timeInterval = 2000
private fun configBackPress() {
requireActivity().onBackPressedDispatcher.addCallback(this, true) {
when {
mBackPressed + timeInterval > System.currentTimeMillis() -> {
requireActivity().onBackPressedDispatcher.onBackPressed()
}
else -> {
Snackbar.make(
requireActivity().findViewById(android.R.id.content),
getString(R.string.press_once_again_back_button_to_exit),
Snackbar.LENGTH_SHORT
)
.setAnchorView(viewBinding.vSnackBarHelper)
.show()
mBackPressed = System.currentTimeMillis()
}
}
}
}
when the user click two times on back button, the back should work.
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评论（2）
在调用 requireActivity().onBackPressedDispatcher.onBackPressed() 之前。您应该将
isEnabled设置为 false，因为如果我们查看 onBackPressed 源代码，我们会看到：它查找活动回调，如果找到任何回调，则调用它们并返回。这就是循环的原因。
你的代码应该是：
before calling
requireActivity().onBackPressedDispatcher.onBackPressed(). you should setisEnabledto false because if we go through the onBackPressed source code we see:it looks for active callbacks and if found any calls them and returns. that's what makes the loop.
your code should be:
）
d
fragment在（onbackpressedin（requiend> required requecredecrip /code>，最初将尝试将此事件传播到拥有儿童 -fragments。因此，再次，将触发onbackpresseddispatcher，它将再次调用活动s方法，这是您的日志屏幕截图中描述的无尽循环（btw。从不post code/log/log/log/log/log/log/log/文本为图像！）编辑：
isEnabled = false是一种更好的方法，只想留下一些案例描述replace
with just
currently your
onBackPressedDispatcherset inFragmentis callingonBackPressedin (required)Activity, which will at first try to propagate this event to own childrens -Fragments. so, again,onBackPressedDispatcherwill be triggered, again it will callActivitys method and this is an endless loop depicted in your log screenshot (btw. never post code/log/text as image!)edit:
isEnabled = falseis a better approach, just wanted to leave you some case description