diff --git a/app/src/main/java/androidx/fragment/app/FragmentStatePagerAdapterMenuWorkaround.java b/app/src/main/java/androidx/fragment/app/FragmentStatePagerAdapterMenuWorkaround.java new file mode 100644 index 000000000..9fd32b735 --- /dev/null +++ b/app/src/main/java/androidx/fragment/app/FragmentStatePagerAdapterMenuWorkaround.java @@ -0,0 +1,318 @@ +/* + * Copyright 2018 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package androidx.fragment.app; + +import android.os.Bundle; +import android.os.Parcelable; +import android.util.Log; +import android.view.View; +import android.view.ViewGroup; + +import androidx.annotation.IntDef; +import androidx.annotation.NonNull; +import androidx.annotation.Nullable; +import androidx.lifecycle.Lifecycle; +import androidx.viewpager.widget.PagerAdapter; + +import java.lang.annotation.Retention; +import java.lang.annotation.RetentionPolicy; +import java.util.ArrayList; + +// TODO: Replace this deprecated class with its ViewPager2 counterpart + +/** + * This is a copy from {@link androidx.fragment.app.FragmentStatePagerAdapter}. + *
+ * It includes a workaround to fix the menu visibility when the adapter is restored. + *
+ * When restoring the state of this adapter, all the fragments' menu visibility were set to false, + * effectively disabling the menu from the user until he switched pages or another event that triggered the + * menu to be visible again happened. + *
+ *
Check out the changes in:
+ *
Fragments will have {@link Fragment#setUserVisibleHint(boolean)} called whenever the + * current Fragment changes.
+ * + * @param fm fragment manager that will interact with this adapter + * @deprecated use {@link #FragmentStatePagerAdapterMenuWorkaround(FragmentManager, int)} with + * {@link #BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT} + */ + @Deprecated + public FragmentStatePagerAdapterMenuWorkaround(@NonNull FragmentManager fm) { + this(fm, BEHAVIOR_SET_USER_VISIBLE_HINT); + } + + /** + * Constructor for {@link FragmentStatePagerAdapterMenuWorkaround}. + * + * If {@link #BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT} is passed in, then only the current + * Fragment is in the {@link Lifecycle.State#RESUMED} state, while all other fragments are + * capped at {@link Lifecycle.State#STARTED}. If {@link #BEHAVIOR_SET_USER_VISIBLE_HINT} is + * passed, all fragments are in the {@link Lifecycle.State#RESUMED} state and there will be + * callbacks to {@link Fragment#setUserVisibleHint(boolean)}. + * + * @param fm fragment manager that will interact with this adapter + * @param behavior determines if only current fragments are in a resumed state + */ + public FragmentStatePagerAdapterMenuWorkaround(@NonNull FragmentManager fm, + @Behavior int behavior) { + mFragmentManager = fm; + mBehavior = behavior; + } + + /** + * Return the Fragment associated with a specified position. + */ + @NonNull + public abstract Fragment getItem(int position); + + @Override + public void startUpdate(@NonNull ViewGroup container) { + if (container.getId() == View.NO_ID) { + throw new IllegalStateException("ViewPager with adapter " + this + + " requires a view id"); + } + } + + @SuppressWarnings("deprecation") + @NonNull + @Override + public Object instantiateItem(@NonNull ViewGroup container, int position) { + // If we already have this item instantiated, there is nothing + // to do. This can happen when we are restoring the entire pager + // from its saved state, where the fragment manager has already + // taken care of restoring the fragments we previously had instantiated. + if (mFragments.size() > position) { + Fragment f = mFragments.get(position); + if (f != null) { + return f; + } + } + + if (mCurTransaction == null) { + mCurTransaction = mFragmentManager.beginTransaction(); + } + + Fragment fragment = getItem(position); + if (DEBUG) Log.v(TAG, "Adding item #" + position + ": f=" + fragment); + if (mSavedState.size() > position) { + Fragment.SavedState fss = mSavedState.get(position); + if (fss != null) { + fragment.setInitialSavedState(fss); + } + } + while (mFragments.size() <= position) { + mFragments.add(null); + } + fragment.setMenuVisibility(false); + if (mBehavior == BEHAVIOR_SET_USER_VISIBLE_HINT) { + fragment.setUserVisibleHint(false); + } + + mFragments.set(position, fragment); + mCurTransaction.add(container.getId(), fragment); + + if (mBehavior == BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT) { + mCurTransaction.setMaxLifecycle(fragment, Lifecycle.State.STARTED); + } + + return fragment; + } + + @Override + public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) { + Fragment fragment = (Fragment) object; + + if (mCurTransaction == null) { + mCurTransaction = mFragmentManager.beginTransaction(); + } + if (DEBUG) Log.v(TAG, "Removing item #" + position + ": f=" + object + + " v=" + ((Fragment)object).getView()); + while (mSavedState.size() <= position) { + mSavedState.add(null); + } + mSavedState.set(position, fragment.isAdded() + ? mFragmentManager.saveFragmentInstanceState(fragment) : null); + mFragments.set(position, null); + + mCurTransaction.remove(fragment); + if (fragment == mCurrentPrimaryItem) { + mCurrentPrimaryItem = null; + } + } + + @Override + @SuppressWarnings({"ReferenceEquality", "deprecation"}) + public void setPrimaryItem(@NonNull ViewGroup container, int position, @NonNull Object object) { + Fragment fragment = (Fragment)object; + if (fragment != mCurrentPrimaryItem) { + if (mCurrentPrimaryItem != null) { + mCurrentPrimaryItem.setMenuVisibility(false); + if (mBehavior == BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT) { + if (mCurTransaction == null) { + mCurTransaction = mFragmentManager.beginTransaction(); + } + mCurTransaction.setMaxLifecycle(mCurrentPrimaryItem, Lifecycle.State.STARTED); + } else { + mCurrentPrimaryItem.setUserVisibleHint(false); + } + } + fragment.setMenuVisibility(true); + if (mBehavior == BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT) { + if (mCurTransaction == null) { + mCurTransaction = mFragmentManager.beginTransaction(); + } + mCurTransaction.setMaxLifecycle(fragment, Lifecycle.State.RESUMED); + } else { + fragment.setUserVisibleHint(true); + } + + mCurrentPrimaryItem = fragment; + } + } + + @Override + public void finishUpdate(@NonNull ViewGroup container) { + if (mCurTransaction != null) { + mCurTransaction.commitNowAllowingStateLoss(); + mCurTransaction = null; + } + } + + @Override + public boolean isViewFromObject(@NonNull View view, @NonNull Object object) { + return ((Fragment)object).getView() == view; + } + + //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! + private final String SELECTED_FRAGMENT = "selected_fragment"; + //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! + + @Override + @Nullable + public Parcelable saveState() { + Bundle state = null; + if (mSavedState.size() > 0) { + state = new Bundle(); + Fragment.SavedState[] fss = new Fragment.SavedState[mSavedState.size()]; + mSavedState.toArray(fss); + state.putParcelableArray("states", fss); + } + for (int i=0; i