[英]Back press fragments issue in android
I have four Fragments: A, B, C, D. Now I am moving from A --> B so my code will be我有四个片段:A、B、C、D。现在我从 A --> B 移动,所以我的代码将是
from A to B从A 到 B
getActivity().getSupportFragmentManager()
.beginTransaction()
.replace(R.id.content_frame, new B())
.addToBackStack("A")
.commit();
Now from B to C so code will be现在从B 到 C所以代码将是
getActivity().getSupportFragmentManager()
.beginTransaction()
.replace(R.id.content_frame, new C())
.addToBackStack("B")
.commit();
Now from C to D .现在从C 到 D 。 But I don't want to include C in backstack because on back press I don't want C fragment to be shown.但我不想在 backstack 中包含 C,因为在按下时我不想显示 C 片段。
getActivity().getSupportFragmentManager()
.beginTransaction()
.replace(R.id.content_frame, new D())
.commit();
Now when I press Back button it will work perfectly upto A. Now if I repeat same process again.现在,当我按下“返回”按钮时,它将完美地工作到 A。现在,如果我再次重复相同的过程。 Now again on back press From D Fragment, I will be sent directly on A fragment instead of B fragment.现在再次按下 From D Fragment,我将直接发送到 A 片段而不是 B 片段。 Can you please figure it out the mistake that I am doing in above code?你能找出我在上面代码中做的错误吗?
You have to provide same String value for addToBackStack for single Stack.您必须为单个堆栈的 addToBackStack 提供相同的字符串值。
.replace(R.id.content_frame, new B())
.addToBackStack("stack")
.replace(R.id.content_frame, new C())
.addToBackStack("stack")
Here is the code of BackStackChangedListener.这是 BackStackChangedListener 的代码。
public static void performNoBackStackTransaction( final FragmentManager fragmentManager, String tag, Fragment fragment) {
final int newBackStackLength = fragmentManager.getBackStackEntryCount() +1;
fragmentManager.beginTransaction()
.replace(R.id.content_frame, fragment, tag)
.addToBackStack(tag)
.commit();
fragmentManager.addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
@Override
public void onBackStackChanged() {
int nowCount = fragmentManager.getBackStackEntryCount();
if (newBackStackLength != nowCount) {
// we don't really care if going back or forward. we already performed the logic here.
fragmentManager.removeOnBackStackChangedListener(this);
if ( newBackStackLength > nowCount ) { // user pressed back
fragmentManager.popBackStackImmediate();
}
}
}
});
}
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