43 lines
1.7 KiB
Kotlin
43 lines
1.7 KiB
Kotlin
package com.keylesspalace.tusky.pager
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import androidx.fragment.app.Fragment
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import androidx.fragment.app.FragmentActivity
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import com.keylesspalace.tusky.ViewMediaAdapter
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import com.keylesspalace.tusky.entity.Attachment
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import com.keylesspalace.tusky.fragment.ViewMediaFragment
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import java.lang.ref.WeakReference
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class ImagePagerAdapter(
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activity: FragmentActivity,
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private val attachments: List<Attachment>,
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private val initialPosition: Int
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) : ViewMediaAdapter(activity) {
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private var didTransition = false
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private val fragments = MutableList<WeakReference<ViewMediaFragment>?>(attachments.size) { null }
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override fun getItemCount() = attachments.size
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override fun createFragment(position: Int): Fragment {
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if (position >= 0 && position < attachments.size) {
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// Fragment should not wait for or start transition if it already happened but we
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// instantiate the same fragment again, e.g. open the first photo, scroll to the
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// forth photo and then back to the first. The first fragment will try to start the
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// transition and wait until it's over and it will never take place.
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val fragment = ViewMediaFragment.newInstance(
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attachment = attachments[position],
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shouldStartPostponedTransition = !didTransition && position == initialPosition
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)
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fragments[position] = WeakReference(fragment)
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return fragment
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} else {
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throw IllegalStateException()
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}
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}
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override fun onTransitionEnd(position: Int) {
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this.didTransition = true
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fragments[position]?.get()?.onTransitionEnd()
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}
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}
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