fragment/fragment/src/main/java/androidx/fragment/app/FragmentContainerView.kt - platform/frameworks/support - Git at Google

 /*
  * Copyright 2019 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.animation.LayoutTransition
 import android.content.Context
 import android.graphics.Canvas
 import android.util.AttributeSet
 import android.view.View
 import android.view.ViewGroup
 import android.view.WindowInsets
 import android.widget.FrameLayout
 import androidx.annotation.RequiresApi
 import androidx.core.content.withStyledAttributes
 import androidx.core.view.ViewCompat
 import androidx.core.view.WindowInsetsCompat
 import androidx.fragment.R

 /**
  * FragmentContainerView is a customized Layout designed specifically for Fragments. It extends
  * [FrameLayout], so it can reliably handle Fragment Transactions, and it also has additional
  * features to coordinate with fragment behavior.
  *
  * FragmentContainerView should be used as the container for Fragments, commonly set in the xml
  * layout of an activity, e.g.:
  * ```
  * <androidx.fragment.app.FragmentContainerView
  * xmlns:android="http://schemas.android.com/apk/res/android"
  * xmlns:app="http://schemas.android.com/apk/res-auto"
  * android:id="@+id/fragment_container_view"
  * android:layout_width="match_parent"
  * android:layout_height="match_parent">
  * </androidx.fragment.app.FragmentContainerView>
  * ```
  *
  * FragmentContainerView can also be used to add a Fragment by using the `android:name` attribute.
  * FragmentContainerView will perform a one time operation that:
  * 1. Creates a new instance of the Fragment
  * 2. Calls [Fragment.onInflate]
  * 3. Executes a FragmentTransaction to add the Fragment to the appropriate FragmentManager
  *
  * You can optionally include an `android:tag` which allows you to use
  * [FragmentManager.findFragmentByTag] to retrieve the added Fragment.
  *
  * ```
  * <androidx.fragment.app.FragmentContainerView
  * xmlns:android="http://schemas.android.com/apk/res/android"
  * xmlns:app="http://schemas.android.com/apk/res-auto"
  * android:id="@+id/fragment_container_view"
  * android:layout_width="match_parent"
  * android:layout_height="match_parent"
  * android:name="com.example.MyFragment"
  * android:tag="my_tag">
  * </androidx.fragment.app.FragmentContainerView>
  * ```
  *
  * FragmentContainerView should not be used as a replacement for other ViewGroups (FrameLayout,
  * LinearLayout, etc) outside of Fragment use cases.
  *
  * FragmentContainerView will only allow views returned by a Fragment's [Fragment.onCreateView].
  * Attempting to add any other view will result in an [IllegalStateException].
  *
  * Layout animations and transitions are disabled for FragmentContainerView for APIs above 17.
  * Otherwise, Animations should be done through [FragmentTransaction.setCustomAnimations]. If
  * animateLayoutChanges is set to `true` or [setLayoutTransition] is called directly an
  * [UnsupportedOperationException] will be thrown.
  *
  * Fragments using exit animations are drawn before all others for FragmentContainerView. This
  * ensures that exiting Fragments do not appear on top of the view.
  */
 public class FragmentContainerView : FrameLayout {
     private val disappearingFragmentChildren: MutableList<View> = mutableListOf()
     private val transitioningFragmentViews: MutableList<View> = mutableListOf()
     private var applyWindowInsetsListener: OnApplyWindowInsetsListener? = null

     // Used to indicate whether the FragmentContainerView should override the default ViewGroup
     // drawing order.
     private var drawDisappearingViewsFirst = true

     public constructor(context: Context) : super(context)

     /**
      * Do not call this constructor directly. Doing so will result in an
      * [UnsupportedOperationException].
      */
     @JvmOverloads
     public constructor(
         context: Context,
         attrs: AttributeSet?,
         defStyleAttr: Int = 0
     ) : super(context, attrs, defStyleAttr) {
         if (attrs != null) {
             var name = attrs.classAttribute
             var attribute = "class"
             context.withStyledAttributes(attrs, R.styleable.FragmentContainerView) {
                 if (name == null) {
                     name = getString(R.styleable.FragmentContainerView_android_name)
                     attribute = "android:name"
                 }
             }
             if (name != null && !isInEditMode) {
                 throw UnsupportedOperationException(
                     "FragmentContainerView must be within a FragmentActivity to use $attribute" +
                         "=\"$name\""
                 )
             }
         }
     }

     internal constructor(
         context: Context,
         attrs: AttributeSet,
         fm: FragmentManager
     ) : super(context, attrs) {
         var name = attrs.classAttribute
         var tag: String? = null
         context.withStyledAttributes(attrs, R.styleable.FragmentContainerView) {
             if (name == null) {
                 name = getString(R.styleable.FragmentContainerView_android_name)
             }
             tag = getString(R.styleable.FragmentContainerView_android_tag)
         }
         val id = id
         val existingFragment: Fragment? = fm.findFragmentById(id)
         // If there is a name and there is no existing fragment,
         // we should add an inflated Fragment to the view.
         if (name != null && existingFragment == null) {
             if (id == View.NO_ID) {
                 val tagMessage = if (tag != null) " with tag $tag" else ""
                 throw IllegalStateException(
                     "FragmentContainerView must have an android:id to add Fragment $name$tagMessage"
                 )
             }
             val containerFragment: Fragment =
                 fm.fragmentFactory.instantiate(context.classLoader, name)
             containerFragment.mFragmentId = id
             containerFragment.mContainerId = id
             containerFragment.mTag = tag
             containerFragment.mFragmentManager = fm
             containerFragment.mHost = fm.host
             containerFragment.onInflate(context, attrs, null)
             fm.beginTransaction()
                 .setReorderingAllowed(true)
                 .add(this, containerFragment, tag)
                 .commitNowAllowingStateLoss()
         }
         fm.onContainerAvailable(this)
     }

     /**
      * When called, this method throws a [UnsupportedOperationException] on APIs above 17. On APIs
      * 17 and below, it calls [FrameLayout.setLayoutTransition]. This can be called either
      * explicitly, or implicitly by setting animateLayoutChanges to `true`.
      *
      * View animations and transitions are disabled for FragmentContainerView for APIs above 17. Use
      * [FragmentTransaction.setCustomAnimations] and [FragmentTransaction.setTransition].
      *
      * @param transition The LayoutTransition object that will animated changes in layout. A value
      *   of `null` means no transition will run on layout changes.
      * @attr ref android.R.styleable#ViewGroup_animateLayoutChanges
      */
     public override fun setLayoutTransition(transition: LayoutTransition?) {
         throw UnsupportedOperationException(
             "FragmentContainerView does not support Layout Transitions or " +
                 "animateLayoutChanges=\"true\"."
         )
     }

     public override fun setOnApplyWindowInsetsListener(listener: OnApplyWindowInsetsListener) {
         applyWindowInsetsListener = listener
     }

     @RequiresApi(20)
     public override fun onApplyWindowInsets(insets: WindowInsets): WindowInsets = insets

     /**
      * {@inheritDoc}
      *
      * The sys ui flags must be set to enable extending the layout into the window insets.
      */
     @RequiresApi(20)
     public override fun dispatchApplyWindowInsets(insets: WindowInsets): WindowInsets {
         val insetsCompat = WindowInsetsCompat.toWindowInsetsCompat(insets)
         val dispatchInsets =
             if (applyWindowInsetsListener != null) {
                 WindowInsetsCompat.toWindowInsetsCompat(
                     Api20Impl.onApplyWindowInsets(applyWindowInsetsListener!!, this, insets)
                 )
             } else {
                 ViewCompat.onApplyWindowInsets(this, insetsCompat)
             }
         if (!dispatchInsets.isConsumed) {
             for (i in 0 until childCount) {
                 ViewCompat.dispatchApplyWindowInsets(getChildAt(i), dispatchInsets)
             }
         }
         return insets
     }

     protected override fun dispatchDraw(canvas: Canvas) {
         if (drawDisappearingViewsFirst) {
             disappearingFragmentChildren.forEach { child ->
                 super.drawChild(canvas, child, drawingTime)
             }
         }
         super.dispatchDraw(canvas)
     }

     protected override fun drawChild(canvas: Canvas, child: View, drawingTime: Long): Boolean {
         if (drawDisappearingViewsFirst && disappearingFragmentChildren.isNotEmpty()) {
             // If the child is disappearing, we have already drawn it so skip.
             if (disappearingFragmentChildren.contains(child)) {
                 return false
             }
         }
         return super.drawChild(canvas, child, drawingTime)
     }

     public override fun startViewTransition(view: View) {
         if (view.parent === this) {
             transitioningFragmentViews.add(view)
         }
         super.startViewTransition(view)
     }

     public override fun endViewTransition(view: View) {
         transitioningFragmentViews.remove(view)
         if (disappearingFragmentChildren.remove(view)) {
             drawDisappearingViewsFirst = true
         }
         super.endViewTransition(view)
     }

     // Used to indicate the container should change the default drawing order.
     @JvmName("setDrawDisappearingViewsLast")
     internal fun setDrawDisappearingViewsLast(drawDisappearingViewsFirst: Boolean) {
         this.drawDisappearingViewsFirst = drawDisappearingViewsFirst
     }

     /**
      * FragmentContainerView will only allow views returned by a Fragment's [Fragment.onCreateView].
      * Attempting to add any other view will result in an [IllegalStateException].
      *
      * {@inheritDoc}
      */
     public override fun addView(child: View, index: Int, params: ViewGroup.LayoutParams?) {
         checkNotNull(FragmentManager.getViewFragment(child)) {
             ("Views added to a FragmentContainerView must be associated with a Fragment. View " +
                 "$child is not associated with a Fragment.")
         }
         super.addView(child, index, params)
     }

     public override fun removeViewAt(index: Int) {
         val view = getChildAt(index)
         addDisappearingFragmentView(view)
         super.removeViewAt(index)
     }

     public override fun removeViewInLayout(view: View) {
         addDisappearingFragmentView(view)
         super.removeViewInLayout(view)
     }

     public override fun removeView(view: View) {
         addDisappearingFragmentView(view)
         super.removeView(view)
     }

     public override fun removeViews(start: Int, count: Int) {
         for (i in start until start + count) {
             val view = getChildAt(i)
             addDisappearingFragmentView(view)
         }
         super.removeViews(start, count)
     }

     public override fun removeViewsInLayout(start: Int, count: Int) {
         for (i in start until start + count) {
             val view = getChildAt(i)
             addDisappearingFragmentView(view)
         }
         super.removeViewsInLayout(start, count)
     }

     public override fun removeAllViewsInLayout() {
         for (i in childCount - 1 downTo 0) {
             val view = getChildAt(i)
             addDisappearingFragmentView(view)
         }
         super.removeAllViewsInLayout()
     }

     /**
      * This method adds a [View] to the list of disappearing views only if it meets the proper
      * conditions to be considered a disappearing view.
      *
      * @param v [View] that might be added to list of disappearing views
      */
     private fun addDisappearingFragmentView(v: View) {
         if (transitioningFragmentViews.contains(v)) {
             disappearingFragmentChildren.add(v)
         }
     }

     /**
      * This method grabs the [Fragment] whose view was most recently added to the container. This
      * may used as an alternative to calling [FragmentManager.findFragmentById] and passing in the
      * [FragmentContainerView]'s id.
      *
      * @return The fragment if any exist, null otherwise.
      */
     @Suppress("UNCHECKED_CAST") // a ClassCastException is automatically thrown if the given type
     // of F is wrong
     public fun <F : Fragment?> getFragment(): F =
         FragmentManager.findFragmentManager(this).findFragmentById(this.id) as F

     @RequiresApi(20)
     internal object Api20Impl {
         fun onApplyWindowInsets(
             onApplyWindowInsetsListener: OnApplyWindowInsetsListener,
             v: View,
             insets: WindowInsets
         ): WindowInsets = onApplyWindowInsetsListener.onApplyWindowInsets(v, insets)
     }
 }
	/*
	* Copyright 2019 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.animation.LayoutTransition
	import android.content.Context
	import android.graphics.Canvas
	import android.util.AttributeSet
	import android.view.View
	import android.view.ViewGroup
	import android.view.WindowInsets
	import android.widget.FrameLayout
	import androidx.annotation.RequiresApi
	import androidx.core.content.withStyledAttributes
	import androidx.core.view.ViewCompat
	import androidx.core.view.WindowInsetsCompat
	import androidx.fragment.R

	/**
	* FragmentContainerView is a customized Layout designed specifically for Fragments. It extends
	* [FrameLayout], so it can reliably handle Fragment Transactions, and it also has additional
	* features to coordinate with fragment behavior.
	*
	* FragmentContainerView should be used as the container for Fragments, commonly set in the xml
	* layout of an activity, e.g.:
	* ```
	* <androidx.fragment.app.FragmentContainerView
	* xmlns:android="http://schemas.android.com/apk/res/android"
	* xmlns:app="http://schemas.android.com/apk/res-auto"
	* android:id="@+id/fragment_container_view"
	* android:layout_width="match_parent"
	* android:layout_height="match_parent">
	* </androidx.fragment.app.FragmentContainerView>
	* ```
	*
	* FragmentContainerView can also be used to add a Fragment by using the `android:name` attribute.
	* FragmentContainerView will perform a one time operation that:
	* 1. Creates a new instance of the Fragment
	* 2. Calls [Fragment.onInflate]
	* 3. Executes a FragmentTransaction to add the Fragment to the appropriate FragmentManager
	*
	* You can optionally include an `android:tag` which allows you to use
	* [FragmentManager.findFragmentByTag] to retrieve the added Fragment.
	*
	* ```
	* <androidx.fragment.app.FragmentContainerView
	* xmlns:android="http://schemas.android.com/apk/res/android"
	* xmlns:app="http://schemas.android.com/apk/res-auto"
	* android:id="@+id/fragment_container_view"
	* android:layout_width="match_parent"
	* android:layout_height="match_parent"
	* android:name="com.example.MyFragment"
	* android:tag="my_tag">
	* </androidx.fragment.app.FragmentContainerView>
	* ```
	*
	* FragmentContainerView should not be used as a replacement for other ViewGroups (FrameLayout,
	* LinearLayout, etc) outside of Fragment use cases.
	*
	* FragmentContainerView will only allow views returned by a Fragment's [Fragment.onCreateView].
	* Attempting to add any other view will result in an [IllegalStateException].
	*
	* Layout animations and transitions are disabled for FragmentContainerView for APIs above 17.
	* Otherwise, Animations should be done through [FragmentTransaction.setCustomAnimations]. If
	* animateLayoutChanges is set to `true` or [setLayoutTransition] is called directly an
	* [UnsupportedOperationException] will be thrown.
	*
	* Fragments using exit animations are drawn before all others for FragmentContainerView. This
	* ensures that exiting Fragments do not appear on top of the view.
	*/
	public class FragmentContainerView : FrameLayout {
	private val disappearingFragmentChildren: MutableList<View> = mutableListOf()
	private val transitioningFragmentViews: MutableList<View> = mutableListOf()
	private var applyWindowInsetsListener: OnApplyWindowInsetsListener? = null

	// Used to indicate whether the FragmentContainerView should override the default ViewGroup
	// drawing order.
	private var drawDisappearingViewsFirst = true

	public constructor(context: Context) : super(context)

	/**
	* Do not call this constructor directly. Doing so will result in an
	* [UnsupportedOperationException].
	*/
	@JvmOverloads
	public constructor(
	context: Context,
	attrs: AttributeSet?,
	defStyleAttr: Int = 0
	) : super(context, attrs, defStyleAttr) {
	if (attrs != null) {
	var name = attrs.classAttribute
	var attribute = "class"
	context.withStyledAttributes(attrs, R.styleable.FragmentContainerView) {
	if (name == null) {
	name = getString(R.styleable.FragmentContainerView_android_name)
	attribute = "android:name"
	}
	}
	if (name != null && !isInEditMode) {
	throw UnsupportedOperationException(
	"FragmentContainerView must be within a FragmentActivity to use $attribute" +
	"=\"$name\""
	)
	}
	}
	}

	internal constructor(
	context: Context,
	attrs: AttributeSet,
	fm: FragmentManager
	) : super(context, attrs) {
	var name = attrs.classAttribute
	var tag: String? = null
	context.withStyledAttributes(attrs, R.styleable.FragmentContainerView) {
	if (name == null) {
	name = getString(R.styleable.FragmentContainerView_android_name)
	}
	tag = getString(R.styleable.FragmentContainerView_android_tag)
	}
	val id = id
	val existingFragment: Fragment? = fm.findFragmentById(id)
	// If there is a name and there is no existing fragment,
	// we should add an inflated Fragment to the view.
	if (name != null && existingFragment == null) {
	if (id == View.NO_ID) {
	val tagMessage = if (tag != null) " with tag $tag" else ""
	throw IllegalStateException(
	"FragmentContainerView must have an android:id to add Fragment $name$tagMessage"
	)
	}
	val containerFragment: Fragment =
	fm.fragmentFactory.instantiate(context.classLoader, name)
	containerFragment.mFragmentId = id
	containerFragment.mContainerId = id
	containerFragment.mTag = tag
	containerFragment.mFragmentManager = fm
	containerFragment.mHost = fm.host
	containerFragment.onInflate(context, attrs, null)
	fm.beginTransaction()
	.setReorderingAllowed(true)
	.add(this, containerFragment, tag)
	.commitNowAllowingStateLoss()
	}
	fm.onContainerAvailable(this)
	}

	/**
	* When called, this method throws a [UnsupportedOperationException] on APIs above 17. On APIs
	* 17 and below, it calls [FrameLayout.setLayoutTransition]. This can be called either
	* explicitly, or implicitly by setting animateLayoutChanges to `true`.
	*
	* View animations and transitions are disabled for FragmentContainerView for APIs above 17. Use
	* [FragmentTransaction.setCustomAnimations] and [FragmentTransaction.setTransition].
	*
	* @param transition The LayoutTransition object that will animated changes in layout. A value
	* of `null` means no transition will run on layout changes.
	* @attr ref android.R.styleable#ViewGroup_animateLayoutChanges
	*/
	public override fun setLayoutTransition(transition: LayoutTransition?) {
	throw UnsupportedOperationException(
	"FragmentContainerView does not support Layout Transitions or " +
	"animateLayoutChanges=\"true\"."
	)
	}

	public override fun setOnApplyWindowInsetsListener(listener: OnApplyWindowInsetsListener) {
	applyWindowInsetsListener = listener
	}

	@RequiresApi(20)
	public override fun onApplyWindowInsets(insets: WindowInsets): WindowInsets = insets

	/**
	* {@inheritDoc}
	*
	* The sys ui flags must be set to enable extending the layout into the window insets.
	*/
	@RequiresApi(20)
	public override fun dispatchApplyWindowInsets(insets: WindowInsets): WindowInsets {
	val insetsCompat = WindowInsetsCompat.toWindowInsetsCompat(insets)
	val dispatchInsets =
	if (applyWindowInsetsListener != null) {
	WindowInsetsCompat.toWindowInsetsCompat(
	Api20Impl.onApplyWindowInsets(applyWindowInsetsListener!!, this, insets)
	)
	} else {
	ViewCompat.onApplyWindowInsets(this, insetsCompat)
	}
	if (!dispatchInsets.isConsumed) {
	for (i in 0 until childCount) {
	ViewCompat.dispatchApplyWindowInsets(getChildAt(i), dispatchInsets)
	}
	}
	return insets
	}

	protected override fun dispatchDraw(canvas: Canvas) {
	if (drawDisappearingViewsFirst) {
	disappearingFragmentChildren.forEach { child ->
	super.drawChild(canvas, child, drawingTime)
	}
	}
	super.dispatchDraw(canvas)
	}

	protected override fun drawChild(canvas: Canvas, child: View, drawingTime: Long): Boolean {
	if (drawDisappearingViewsFirst && disappearingFragmentChildren.isNotEmpty()) {
	// If the child is disappearing, we have already drawn it so skip.
	if (disappearingFragmentChildren.contains(child)) {
	return false
	}
	}
	return super.drawChild(canvas, child, drawingTime)
	}

	public override fun startViewTransition(view: View) {
	if (view.parent === this) {
	transitioningFragmentViews.add(view)
	}
	super.startViewTransition(view)
	}

	public override fun endViewTransition(view: View) {
	transitioningFragmentViews.remove(view)
	if (disappearingFragmentChildren.remove(view)) {
	drawDisappearingViewsFirst = true
	}
	super.endViewTransition(view)
	}

	// Used to indicate the container should change the default drawing order.
	@JvmName("setDrawDisappearingViewsLast")
	internal fun setDrawDisappearingViewsLast(drawDisappearingViewsFirst: Boolean) {
	this.drawDisappearingViewsFirst = drawDisappearingViewsFirst
	}

	/**
	* FragmentContainerView will only allow views returned by a Fragment's [Fragment.onCreateView].
	* Attempting to add any other view will result in an [IllegalStateException].
	*
	* {@inheritDoc}
	*/
	public override fun addView(child: View, index: Int, params: ViewGroup.LayoutParams?) {
	checkNotNull(FragmentManager.getViewFragment(child)) {
	("Views added to a FragmentContainerView must be associated with a Fragment. View " +
	"$child is not associated with a Fragment.")
	}
	super.addView(child, index, params)
	}

	public override fun removeViewAt(index: Int) {
	val view = getChildAt(index)
	addDisappearingFragmentView(view)
	super.removeViewAt(index)
	}

	public override fun removeViewInLayout(view: View) {
	addDisappearingFragmentView(view)
	super.removeViewInLayout(view)
	}

	public override fun removeView(view: View) {
	addDisappearingFragmentView(view)
	super.removeView(view)
	}

	public override fun removeViews(start: Int, count: Int) {
	for (i in start until start + count) {
	val view = getChildAt(i)
	addDisappearingFragmentView(view)
	}
	super.removeViews(start, count)
	}

	public override fun removeViewsInLayout(start: Int, count: Int) {
	for (i in start until start + count) {
	val view = getChildAt(i)
	addDisappearingFragmentView(view)
	}
	super.removeViewsInLayout(start, count)
	}

	public override fun removeAllViewsInLayout() {
	for (i in childCount - 1 downTo 0) {
	val view = getChildAt(i)
	addDisappearingFragmentView(view)
	}
	super.removeAllViewsInLayout()
	}

	/**
	* This method adds a [View] to the list of disappearing views only if it meets the proper
	* conditions to be considered a disappearing view.
	*
	* @param v [View] that might be added to list of disappearing views
	*/
	private fun addDisappearingFragmentView(v: View) {
	if (transitioningFragmentViews.contains(v)) {
	disappearingFragmentChildren.add(v)
	}
	}

	/**
	* This method grabs the [Fragment] whose view was most recently added to the container. This
	* may used as an alternative to calling [FragmentManager.findFragmentById] and passing in the
	* [FragmentContainerView]'s id.
	*
	* @return The fragment if any exist, null otherwise.
	*/
	@Suppress("UNCHECKED_CAST") // a ClassCastException is automatically thrown if the given type
	// of F is wrong
	public fun <F : Fragment?> getFragment(): F =
	FragmentManager.findFragmentManager(this).findFragmentById(this.id) as F

	@RequiresApi(20)
	internal object Api20Impl {
	fun onApplyWindowInsets(
	onApplyWindowInsetsListener: OnApplyWindowInsetsListener,
	v: View,
	insets: WindowInsets
	): WindowInsets = onApplyWindowInsetsListener.onApplyWindowInsets(v, insets)
	}
	}