获取Fragment的三种方式
fragmentManager = getSupportFragmentManager();
// 通过id查找对应的Fragment实例
fragment1 = (StudyFragment) fragmentManager.findFragmentById(R.id.fragment_study1);
// 通过tag找到对应的Fragment,在动态加载和静态加载中都可以使用
secondFragment = (SecondFragment) fragmentManager.findFragmentByTag("fragment_second");
// 获取添加到FragmentManager的所有Fragment,通过index访问,0代表最早添加的Fragment
fragmentManager.getFragments()
FragmentTransaction的一些常用方法
FragmentTransaction transaction = fm.benginTransatcion();//开启一个事务
transaction.add() //往Activity中添加一个Fragment
transaction.remove() //从Activity中移除一个Fragment,如果被移除的Fragment没有添加到回退栈(回退栈后面会详细说),这个Fragment实例将会被销毁。
transaction.replace()//使用另一个Fragment替换当前的,实际上就是remove()然后add()的合体~
transaction.hide() //当你的fragment数量固定很少时隐藏当前的Fragment,仅仅是设为不可见,并不会销毁,多的时候可能出现OOM异常,
transaction.show()//显示之前隐藏的Fragment
detach()会将view从UI中移除,和remove()不同,此时fragment的状态依然由FragmentManager维护。
attach()重建view视图,附加到UI上并显示。
transatcion.commit()//提交一个事务
FragmentTransaction的用例
//添加Fragment到FragmentList中
private void addFragment(Fragment fragment, String tag){
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.add(R.id.fragment_container,fragment,tag);
transaction.commit();
}
// 清空fragmentList的所有Fragment,替换成新的Fragment,注意Fragment里面的坑
private void replaceFragment(Fragment fragment, String tag){
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.replace(R.id.fragment_container,fragment,tag);
transaction.commit();
}
//移除指定的Fragment
private void removeFragment(Fragment fragment){
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.remove(fragment);
transaction.commit();
}
//把Fragment设置成显示状态,但是并没有添加到FragmentList中
private void showFragment(Fragment fragment){
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.show(fragment);
transaction.commit();
}
//把Fragment设置成显示状态,但是并没有添加到FragmentList中
private void hideFragment(Fragment fragment){
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.hide(fragment);
transaction.commit();
}
// 效果和show相近,创建视图,添加到containerid指定的Added列表,FragmentList依然保留,但是会引起生命周期的变化
private void attachFragment(Fragment fragment){
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.attach(fragment);
transaction.commit();
}
// 效果和hide相近,清除视图,从containerid指定的Added列表移除,FragmentList依然保留,但是会引起生命周期的变化
private void detachFragment(Fragment fragment){
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.detach(fragment);
transaction.commit();
}
原文:https://blog.csdn.net/u012241729/article/details/60969606