Question

我想在加载片段之前查看视图是否存在。在我加载片段的方法中，我有以下内容：

 public void loadFragment(Fragment fragment){
    FragmentManager fragmentManager = Objects.requireNonNull(getActivity()).getSupportFragmentManager();

    // Begin Fragment transaction.
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();// Replace the layout holder with the required Fragment object.


    fragmentTransaction.replace(R.id.outbound_dashboard_hourly_queued, fragment);
    // Commit the Fragment replace action.
    fragmentTransaction.commit();

}

我想要的是在加载之前检查R.id.outbound_dashboard_hourly_queued是否存在

我该如何进行？

Answer 1

只需执行protected String doInBackground(String...url) { return Update(url[0]); }，然后在视图不为Null的情况下加载片段，请保留if检查。

findViewById(R.id.outbound_dashboard_hourly_queued)

Answer 2

尝试

检查是否添加了Fragmnet

=TEXT(A1,"MMM D")&" - "&TEXT(B1,"MMM D")

添加Framgnet

 if (getCurrentFragment() instanceof YourFragment)

方法

replaceFragment(new HomeFragment(), "YourFragment");

Answer 3

您可以使用FragmentManager提供的findFragmentByTag（String tag）方法来检查片段是否已经存在。

Fragment fragment = getSupportFragmentManager().findFragmentByTag(TAG);

要使其正常工作，您需要使用-

将该片段与该TAG一起提交

fragmentTransaction.replace(R.id.outbound_dashboard_hourly_queued, fragment, TAG);

Answer 4

如果count == 0，请先进行计数检查，然后再添加，否则必须替换代码。

public void loadFragment(Fragment fragment){
    FragmentManager fragmentManager = Objects.requireNonNull(getActivity()).getSupportFragmentManager();

    // Begin Fragment transaction.
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();// Replace the layout holder with the required Fragment object.

    if(fragmentManager.getFragments().size() == 0){
        fragmentTransaction.add(R.id.outbound_dashboard_hourly_queued, fragment).commit();
    }else {
        fragmentTransaction.replace(R.id.outbound_dashboard_hourly_queued, fragment).commit();
    }
    // Commit the Fragment replace action.

}

请尝试一下，让我知道。

加载片段之前检查视图是否存在

4 个答案: