出现无法找到显式活动类的错误（从活动到片段的startactivity）

Question

my startactivity(i_back) has a problem , I am trying to startactivity from activity to fragment. so there is no need to declare in manifest since it is fragment so I don't know why I have the error Thx in advance

Answer 1

您必须在清单中声明活动（在<application>标记内），如下所示：

<activity android:name=".addressbook.ContactsFragment"/>

Answer 2

If your class ContactsFragment extends Fragment , you can't start it using startActivity method.

Check the docs on how to deal with fragments.

https://developer.android.com/guide/components/fragments

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If your class ContactsFragment extends Activity , you must declare it in AndroidManifest.xml inside application tag, just like that.

<activity android:name=".ContactsFragment"/>

Check if your class is inside any package.