【Android】如何判断一个fragment是否显示

总结一下，分为两种情况

1.在viewpager中添加的fragment

 //判断是否正在显示    protected boolean isVisible; @Override    public void setUserVisibleHint(boolean isVisibleToUser) {        super.setUserVisibleHint(isVisibleToUser);        if(isVisibleToUser){            isVisible = true;        }else{            isVisible = false;        }    }

重写fragment的setUserVisibleHint方法即可，通过 isVisibleToUser参数来判断是否显示

2.通过Hide or Show 方法设置的fragment

  FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();        if (currentFragment != null) {            transaction.hide(currentFragment);        }        if (!fragment.isAdded()) {            transaction.add(R.id.main_container, fragment);        }        transaction.show(fragment);        transaction.commitAllowingStateLoss();

重写这三个方法，当fragment初始化时候，调用了onAttach方法，之后通过onHiddenChanged方法来判断是否隐藏

    @Override    public void onAttach(Activity activity) {        super.onAttach(activity);        XLog.d(getClass().getName() + " visible onAttach");    }    @Override    public void onDetach() {        super.onDetach();        XLog.d(getClass().getName() + " visible onDetach");    }    @Override    public void onHiddenChanged(boolean hidden) {        XLog.d(getClass().getName() + " visible onHiddenChanged hidden = "+ hidden);        super.onHiddenChanged(hidden);    }

12-18 20:23:44.389 24014-24014/com.comic.comicmo D/ComicMeo: │ com.comic.comicmo.online.ui.main.mine.MineFragment visible onAttach12-18 20:23:58.296 24014-24014/com.comic.comicmo D/ComicMeo: │ com.comic.comicmo.online.ui.main.mine.MineFragment visible onDetach12-18 20:24:06.513 24014-24014/com.comic.comicmo D/ComicMeo: │ com.comic.comicmo.online.ui.main.mine.MineFragment visible onAttach12-18 20:24:08.375 24014-24014/com.comic.comicmo D/ComicMeo: │ com.comic.comicmo.online.ui.main.mine.MineFragment visible onHiddenChanged hidden = true12-18 20:24:13.028 24014-24014/com.comic.comicmo D/ComicMeo: │ com.comic.comicmo.online.ui.main.mine.MineFragment visible onHiddenChanged hidden = false12-18 20:24:17.594 24014-24014/com.comic.comicmo D/ComicMeo: │ com.comic.comicmo.online.ui.main.mine.MineFragment visible onHiddenChanged hidden = true12-18 20:24:19.505 24014-24014/com.comic.comicmo D/ComicMeo: │ com.comic.comicmo.online.ui.main.mine.MineFragment visible onHiddenChanged hidden = false12-18 20:24:24.668 24014-24014/com.comic.comicmo D/ComicMeo: │ com.comic.comicmo.online.ui.main.mine.MineFragment visible onHiddenChanged hidden = true12-18 20:24:26.132 24014-24014/com.comic.comicmo D/ComicMeo: │ com.comic.comicmo.online.ui.main.mine.MineFragment visible onHiddenChanged hidden = false12-18 20:24:27.473 24014-24014/com.comic.comicmo D/ComicMeo: │ com.comic.comicmo.online.ui.main.mine.MineFragment visible onHiddenChanged hidden = true12-18 20:24:27.943 24014-24014/com.comic.comicmo D/ComicMeo: │ com.comic.comicmo.online.ui.main.mine.MineFragment visible onHiddenChanged hidden = false

打印的LOG如下所示

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