android - viewPager.getChildCount() 在 onActivityResult 之后为零

Question

我有一个 MainActivity 和一个我在 onCreate() 中设置的 ViewPager。 MainActivity 启动 CatActivity 获取结果。在 onActivityResult 中，当我检查 viewPager 时，viewPager.getChildCount() 显示 0，而它应该显示 3。

Answer 1

onActivityResult 正在主线程上调用，但出于某种原因您无法从中访问 View (可能此时未重新创建 View )。因此，您应该设置调用 onActivityResult 的标志，而不是在 onResume 中调用您的代码。

• Presenter has a reference to View only between onResume/onPause.

• View has a reference to Presenter any time it wants, but it is highly advisable to not request for presenter before the view state has been restored.

• onActivityResult happens before onResume, so Presenter does not have View attached