DialogFragment getDialog() return null

最新推荐文章于 2021-09-18 11:00:24 发布

JasonBlavk

最新推荐文章于 2021-09-18 11:00:24 发布

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分类专栏： Android

本文链接：https://blog.youkuaiyun.com/Silk2018/article/details/51142626

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本文探讨了在使用DialogFragment时遇到getDialog()返回null的情况，并详细解释了这是因为在DialogFragment的生命周期中过早调用了此方法。文章指导如何正确地在合适的时机调用getDialog()以避免返回null。

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I am trying to get the Dialog I have created with an extended DialogFragment using DialogFragment.getDialog() but it returns null.

Basically I want to alter the text in the layout from the FragmentActivity which creates and shows the DialogFragment.

You're calling getDialog() too early in the DialogFragmen'ts life cycle.

getDialog() simply returns the private variable mDialog from the DialogFragment.

When a DialogFragment is instantiated mDialog is null, and then it gets set when onCreateDialog is fired inside getLayoutInflater(Bundle savedInstanceState), so you have to call getDialog after onCreateDialog.

For example, the order of some common methods called is onCreate, onCreateDialog, and onCreateView, onStart. So, you can call getDialog and have it return something in onCreateViewor onStart, but not in onCreate or onCreateDialog.

Eventhough onStart is called called when the Fragment is visible to the user, adjusting the layout of the fragment at that point looks fine.... for example setting the width and height using getDialog().getWindow().setLayout(..., ...); doesn't make the fragment appear to change size, but just appears to have the newly set size.