3rd Fragment 在不使用 addToBackStack 的情况下，会覆盖 1st Fragment 的返回操作。

huangapple
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英文:

3rd Fragment override 1st on backPress, when don't use addToBackStack in 2nd fragment

问题

I open fragments like this: [1]+with addToBackStack) > [2](without addToBackStack) > [3]

在打开 fragment 时我这样做：[1]（使用 addToBackStack） > [2]（不使用 addToBackStack） > [3]

in Fragment 3 when click onBackPress Button then 2nd is not visible but 3rd override 1.
在 Fragment 3 中点击 onBackPress 按钮时，2nd 不可见，但 3rd 覆盖了 1。

If I use addToBackStack in 2nd fragment also, then everything is fine(No override issue).
如果我在 2nd fragment 中也使用 addToBackStack，那么一切都正常（没有覆盖问题）。

> But I have to hide 2nd fragment when user visit 3rd fragment and
> direct come back to 1st fragment.
> 但是当用户访问 3rd fragment 并直接返回 1st fragment 时，我必须隐藏 2nd fragment。

here is my code:
以下是我的代码：

open root fragment[1] from activity with fragmentTransaction.add
从 activity 中使用 fragmentTransaction.add 打开 root fragment[1]

  1. FragmentManager fragmentManager = getSupportFragmentManager();
  2.     FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
  3.     fragmentTransaction.setCustomAnimations(R.anim.enter_from_right, R.anim.exit_to_right, R.anim.enter_from_right, R.anim.exit_to_right);
  4.     fragmentTransaction.add(R.id.abbcHomeFragmentContainer, new FragmentHomeAbbc(), null);
  5.     //fragmentTransaction.addToBackStack(null);
  6.     fragmentTransaction.commit();

[1](with addToBackStack) >[2] :opening 2nd fragment
[1]（使用 addToBackStack） >[2] : 打开 2nd fragment

  1. FragmentListOfBankAbbc fragment= new FragmentListOfBankAbbc();
  2. fragment.setArguments(bundle);
  3. if (getActivity()!=null){
  4.     FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
  5.     FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
  6.     fragmentTransaction.setCustomAnimations(R.anim.enter_from_right, R.anim.exit_to_right, R.anim.enter_from_right, R.anim.exit_to_right);
  7.     fragmentTransaction.replace(R.id.abbcHomeFragmentContainer, fragment, null);
  8.     fragmentTransaction.addToBackStack(null);
  9.     fragmentTransaction.commit();
  10. } else {
  11.     Toast.makeText(getContext(), "Something went wrong (#201)", Toast.LENGTH_SHORT).show();
  12. }

[2](without addToBackStack) > [3]
[2]（不使用 addToBackStack） > [3]

  1. private void  funOpenFragments(Fragment fragment, Bundle bundle){
  2.     fragment.setArguments(bundle);
  3.     if (getActivity()!=null){
  4.         FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
  5.         FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
  6.         fragmentTransaction.setCustomAnimations(R.anim.enter_from_right, R.anim.exit_to_right, R.anim.enter_from_right, R.anim.exit_to_right);
  7.         fragmentTransaction.replace(R.id.abbcHomeFragmentContainer, fragment, null);
  8.         //fragmentTransaction.addToBackStack(null);
  9.         fragmentTransaction.commit();
  11.     } else {
  12.         Toast.makeText(getContext(), "Something went wrong (#202)", Toast.LENGTH_SHORT).show();
  13.     }
  14. }

Now open 3rd fragment and click showing 3rd fragment+1st fragment.
现在打开 3rd fragment，并单击显示第三个 fragment + 第一个 fragment。

英文:

I open fragments like this: [1]+with addToBackStack) > [2](without addToBackStack) > [3]

in Fragment 3 when click onBackPress Button then 2nd is not visible but 3rd override 1.
3rd Fragment 在不使用 addToBackStack 的情况下，会覆盖 1st Fragment 的返回操作。

If I use addToBackStack in 2nd fragment also, then everything is fine(No override issue).

> But I have to hide 2nd fragment when user visit 3rd fragment and
> direct come back to 1st fragment.

here is my code:

open root fragment[1] from activity with fragmentTransaction.add

  1. FragmentManager fragmentManager = getSupportFragmentManager();
  2.     FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
  3.     fragmentTransaction.setCustomAnimations(R.anim.enter_from_right, R.anim.exit_to_right, R.anim.enter_from_right, R.anim.exit_to_right);
  4.     fragmentTransaction.add(R.id.abbcHomeFragmentContainer, new FragmentHomeAbbc(), null);
  5.     //fragmentTransaction.addToBackStack(null);
  6.     fragmentTransaction.commit();

[1](with addToBackStack) >[2] :opening 2nd fragment

  1. FragmentListOfBankAbbc fragment= new FragmentListOfBankAbbc();
  2. fragment.setArguments(bundle);
  3. if (getActivity()!=null){
  4.     FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
  5.     FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
  6.     fragmentTransaction.setCustomAnimations(R.anim.enter_from_right, R.anim.exit_to_right, R.anim.enter_from_right, R.anim.exit_to_right);
  7.     fragmentTransaction.replace(R.id.abbcHomeFragmentContainer, fragment, null);
  8.     fragmentTransaction.addToBackStack(null);
  9.     fragmentTransaction.commit();
  10. } else {
  11.     Toast.makeText(getContext(), "Something went wrong (#201)", Toast.LENGTH_SHORT).show();
  12. }

[2](without addToBackStack) > [3]

  1. private void  funOpenFragments(Fragment fragment, Bundle bundle){
  2.     fragment.setArguments(bundle);
  3.     if (getActivity()!=null){
  4.         FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
  5.         FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
  6.         fragmentTransaction.setCustomAnimations(R.anim.enter_from_right, R.anim.exit_to_right, R.anim.enter_from_right, R.anim.exit_to_right);
  7.         fragmentTransaction.replace(R.id.abbcHomeFragmentContainer, fragment, null);
  8.         //fragmentTransaction.addToBackStack(null);
  9.         fragmentTransaction.commit();
  11.     } else {
  12.         Toast.makeText(getContext(), "Something went wrong (#202)", Toast.LENGTH_SHORT).show();
  13.     }
  14. }

Now open 3rd fragment and click showing 3rd fragment+1st fragment.

答案1

得分: 1

MainActivity.kt

  1. override fun onCreate(savedInstanceState: Bundle?) {
  2.     super.onCreate(savedInstanceState)
  3.     binding = ActivityMainBinding.inflate(layoutInflater)
  4.     setContentView(binding.root)
  5.     loadFragment(FirstFragment())    // add this line
  6. }
  8. private fun loadFragment(fragment: Fragment) {
  9.     val fragmentManager = supportFragmentManager
  10.     val fragmentTransaction = fragmentManager.beginTransaction()
  11.     fragmentTransaction.replace(R.id.frameLayout, fragment)
  12.     fragmentManager.popBackStack()
  13.     fragmentTransaction.commit()
  14. }

FirstFragment.kt

  1. binding.btnNext.setOnClickListener {
  2.     val fragmentManager = fragmentManager
  3.     val fragmentTransaction = fragmentManager?.beginTransaction()
  4.     fragmentTransaction?.add(R.id.frameLayout, SecondFragment(), getString(R.string.fragment_tag_title_second_fragment))
  5.     fragmentTransaction?.addToBackStack("Second")
  6.     fragmentTransaction?.commitAllowingStateLoss()
  7. }

SecondFragment.kt

  1. private fun onClick() {
  2.     binding.apply {
  3.         btnNext.setOnClickListener { loadFragment(ThirdFragment()) }
  4.         btnPrevious.setOnClickListener { activity?.onBackPressed() }
  5.     }
  6. }
  8. private fun loadFragment(fragment: Fragment) {
  9.     val fragmentTransaction = fragmentManager?.beginTransaction()
  10.     fragmentTransaction?.add(R.id.frameLayout, fragment, getString(R.string.fragment_tag_title_third_fragment))
  11.     fragmentTransaction?.addToBackStack("third")
  12.     fragmentTransaction?.commitAllowingStateLoss()
  13. }

ThirdFragment.kt

  1. private fun onClick() {
  2.     binding.apply {
  3.         btnPrevious.setOnClickListener {
  4.             activity?.onBackPressed()
  5.         }
  6.     }
  7. }
英文:

Try this

MainActivity.kt

  1. override fun onCreate(savedInstanceState: Bundle?) {
  2.     super.onCreate(savedInstanceState)
  3.     binding = ActivityMainBinding.inflate(layoutInflater)
  4.     setContentView(binding.root)
  5.     loadFragment(FirstFragment())    // add this line
  6. }
  9. private fun loadFragment(fragment: Fragment) {
  10.     val fragmentManager = supportFragmentManager
  11.     val fragmentTransaction = fragmentManager.beginTransaction()
  12.     fragmentTransaction.replace(R.id.frameLayout, fragment)
  13.     fragmentManager.popBackStack()
  14.     fragmentTransaction.commit()
  15. }

FirstFragment.kt

  1.  binding.btnNext.setOnClickListener {
  2.         val fragmentManager = fragmentManager
  3.         val fragmentTransaction = fragmentManager?.beginTransaction()
  4.         fragmentTransaction?.add(R.id.frameLayout, SecondFragment(), getString(R.string.fragment_tag_title_second_fragment))
  5.         fragmentTransaction?.addToBackStack("Second")
  6.         fragmentTransaction?.commitAllowingStateLoss()
  7.     }

SecondFragment.kt

  1. private fun onClick() {
  2.     binding.apply {
  3.         btnNext.setOnClickListener { loadFragment(ThirdFragment()) }
  4.         btnPrevious.setOnClickListener {   activity?.onBackPressed() }
  5.     }
  6. }
  8. private fun loadFragment(fragment: Fragment) {
  9.     val fragmentTransaction = fragmentManager?.beginTransaction()
  10.     fragmentTransaction?.add(R.id.frameLayout, fragment,getString(R.string.fragment_tag_title_third_fragment))
  11.     fragmentTransaction?.addToBackStack("third")
  12.     fragmentTransaction?.commitAllowingStateLoss()
  13. }

ThirdFragment.kt

  1.  private fun onClick() {
  2.     binding.apply {
  3.         btnPrevious.setOnClickListener {
  4.             activity?.onBackPressed()
  5.         }
  6.     }
  7. }

答案2

得分: 0

用户在进行操作时，按顺序转至 [1] > [2] > [3] 。

然后在 onBackPress 时，用户会返回到 [3] > [1] 。

>最后，我找到了解决方案。
>>在 [第二] 片段 内遵循这两个步骤：
>
> 步骤1. 在调用 [3] fragment 之前，只需添加 fragmentManager.popBackStack();。 (此行后，
> 它会销毁/弹出第二片段并重新打开第一片段，然后再打开第三片段。也就是说，当用户在第三片段上按返回按钮时，
> 在最近的片段中，有第一片段而不是第二片段)
> 步骤2. 也在 fragmentTransaction 中加入 .addToBackStack(null)。

[第二] 片段：在此处，单击按钮后我们将打开 第三片段。

  1. if (getActivity()!=null){
  2.     FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
  4.     //此 popBackStack 将关闭这个 [2] 片段。
  5.     fragmentManager.popBackStack(); //<<<<<<<在 "fragmentTransaction" 之前添加此行。
  7.     //现在在这里打开 [3] 片段，现在最近的片段只有 [1] 片段，没有 [2] 片段。
  8.     FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
  9.     fragmentTransaction.setCustomAnimations(R.anim.enter_from_right, R.anim.exit_to_right, R.anim.enter_from_right, R.anim.exit_to_right);
  10.     fragmentTransaction.replace(R.id.abbcHomeFragmentContainer, fragment, null);
  11.     fragmentTransaction.addToBackStack(null); //<<<<<<<<<也添加这个
  12.     fragmentTransaction.commit();
  14. } else {
  15.     Toast.makeText(getContext(), "出现了一些问题 (#202)", Toast.LENGTH_SHORT).show();
  16. }

(^_^) 祝您编码愉快

英文:

When user go [1] > [2] > [3]

Then onBackPress user will be [3] > [1].

>Finally, I got Solution.
>> follow these 2 steps inside [2nd] fragment:
>
> Step1. Just add fragmentManager.popBackStack(); before fragmentTransaction mean calling [3] fragment. (after this line,
> It destroy/pop 2nd fragment and open 1st fragment again before open
> 3rd fragment. It mean when users press back button on 3rd fragment.
> then in recent fragment, there is 1st fragment not 2nd)
> Step2. add .addToBackStack(null) also with fragmentTransaction

3rd Fragment 在不使用 addToBackStack 的情况下，会覆盖 1st Fragment 的返回操作。

[2] Fragment : here on button click we will open 3rd fragment .

  1. if (getActivity()!=null){
  2.     FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
  4.     //this popBackStack will close this [2]fragment.
  5.     fragmentManager.popBackStack(); //<<<<<<<just add this before "fragmentTransaction".
  7.     //now open [3]fragment here, Now in recent fragment is only [1]fragment not [2].
  8.     FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
  9.     fragmentTransaction.setCustomAnimations(R.anim.enter_from_right, R.anim.exit_to_right, R.anim.enter_from_right, R.anim.exit_to_right);
  10.     fragmentTransaction.replace(R.id.abbcHomeFragmentContainer, fragment, null);
  11.     fragmentTransaction.addToBackStack(null); //<<<<<<<<<add this also
  12.     fragmentTransaction.commit();
  14. } else {
  15.     Toast.makeText(getContext(), "Something went wrong (#202)", Toast.LENGTH_SHORT).show();
  16. }

(^_^) Happy Coding

huangapple
  • 本文由 发表于 2023年4月17日 15:06:32
  • 转载请务必保留本文链接：https://go.coder-hub.com/76032479.html
  • android
  • android-fragments
  • android-studio
  • fragment-backstack
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