不断“检查” Android片段可见性/键盘可见性的最佳方法

Question

I would like to continuously check if a fragment is visible or better yet. If the keyboard is present in an Android application. What would be the best method to go about this?

I'm not too familiar with the activity lifecycle, but I'm hoping this is correct way. The code below is written in the OnCreate method. I need it to run constantly though.

if (timeFragment.isVisible()){
    Toast.makeText(getApplicationContext(), "Time visible", Toast.LENGTH_LONG).show();
}

Answer 1

For a fragment, the function setUserVisibleHint(boolean isVisible) is fired everytime the fragment becomes visible or invisible.

This will conserve resources compared to polling. In timeFragment:

public void setUserVisibleHint(boolean isVisible) {
    if (isVisible)
        Toast.makeText(getActivity(), "Time becoming visible", Toast.LENGTH_LONG).show();
    else
        Toast.makeText(getActivity(), "Time becoming invisible", Toast.LENGTH_LONG).show();
}

Hope this helps...

Answer 2

如果您真正想要的是检查软键盘当前是否在屏幕上（正如我从上面对我的评论的答复中所假定的那样），则可以使用这种颇为不客气的侦听器方法。