fix 快速双击返回 crash

Author: wangpeng

.gitignore

@@ -1,10 +1,10 @@
 *.iml
 .gradle
-/local.properties
-/.idea/caches/build_file_checksums.ser
-/.idea/libraries
-/.idea/modules.xml
-/.idea/workspace.xml
+local.properties
+.idea/caches/build_file_checksums.ser
+.idea/libraries
+.idea/modules.xml
+.idea/workspace.xml
 .DS_Store
 /build
 /captures

README.md

@@ -11,7 +11,7 @@
 
 #### 使用
 ```
-implementation 'com.github.iielse:imageviewer:2.0.7'
+implementation 'com.github.iielse:imageviewer:2.0.8'
 ```
 ```
 val builder = ImageViewerBuilder(

imageviewer/src/main/java/com/github/iielse/imageviewer/ImageViewerDialogFragment.kt

@@ -5,7 +5,6 @@ import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
-import android.widget.ImageView
 import androidx.lifecycle.Observer
 import androidx.lifecycle.ViewModelProvider
 import androidx.recyclerview.widget.RecyclerView
@@ -29,6 +28,11 @@ class ImageViewerDialogFragment : BaseDialogFragment() {
     private val transformer by lazy { requireTransformer() }
     private val adapter by lazy { ImageViewerAdapter(initKey) }
 
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        if (!Components.working) dismissAllowingStateLoss()
+    }
+
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
         return inflater.inflate(R.layout.fragment_image_viewer_dialog, container, false)
     }
@@ -82,7 +86,9 @@ class ImageViewerDialogFragment : BaseDialogFragment() {
 
             override fun onRelease(viewHolder: RecyclerView.ViewHolder, view: View) {
                 val startView = (view.getTag(R.id.viewer_adapter_item_key) as? Long?)?.let { transformer.getView(it) }
-                release(startView, viewHolder, view)
+                TransitionEndHelper.end(this@ImageViewerDialogFragment, startView, viewHolder)
+                background.changeToBackgroundColor(Color.TRANSPARENT)
+                userCallback.onRelease(viewHolder, view)
             }
         }
     }
@@ -107,22 +113,22 @@ class ImageViewerDialogFragment : BaseDialogFragment() {
         super.onDestroyView()
         adapter.setListener(null)
         viewer.unregisterOnPageChangeCallback(pagerCallback)
+        Components.release()
     }
 
     override fun onBackPressed() {
+        if (TransitionStartHelper.animating || TransitionEndHelper.animating) return
         log { "onBackPressed ${viewer.currentItem}" }
+
         val currentKey = adapter.getItemId(viewer.currentItem)
-        val startView = transformer.getView(currentKey)
-        val endView = viewer.findViewWithKeyTag(R.id.viewer_adapter_item_key, currentKey)
-        val viewHolder = endView?.getTag(R.id.viewer_adapter_item_holder) as? RecyclerView.ViewHolder?
-        release(startView, viewHolder, endView)
-    }
+        viewer.findViewWithKeyTag(R.id.viewer_adapter_item_key, currentKey)?.let { endView ->
+            val startView = transformer.getView(currentKey)
+            background.changeToBackgroundColor(Color.TRANSPARENT)
 
-    private fun release(startView: ImageView?, viewHolder: RecyclerView.ViewHolder?, endView: View?) {
-        if (viewHolder == null || endView == null) return
-        TransitionEndHelper.end(this, startView, viewHolder)
-        background.changeToBackgroundColor(Color.TRANSPARENT)
-        userCallback.onRelease(viewHolder, endView)
-        Components.release()
+            (endView.getTag(R.id.viewer_adapter_item_holder) as? RecyclerView.ViewHolder?)?.let {
+                TransitionEndHelper.end(this, startView, it)
+                userCallback.onRelease(it, endView)
+            }
+        }
     }
 }

imageviewer/src/main/java/com/github/iielse/imageviewer/adapter/ImageViewerAdapter.kt

@@ -6,13 +6,14 @@ import androidx.paging.PagedListAdapter
 import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.RecyclerView
 import androidx.recyclerview.widget.RecyclerView.NO_ID
-import com.github.iielse.imageviewer.*
+import com.github.iielse.imageviewer.ImageViewerAdapterListener
+import com.github.iielse.imageviewer.R
 import com.github.iielse.imageviewer.core.Photo
 import com.github.iielse.imageviewer.utils.inflate
 import com.github.iielse.imageviewer.utils.log
-import com.github.iielse.imageviewer.viewholders.UnknownViewHolder
 import com.github.iielse.imageviewer.viewholders.PhotoViewHolder
 import com.github.iielse.imageviewer.viewholders.SubsamplingViewHolder
+import com.github.iielse.imageviewer.viewholders.UnknownViewHolder
 import java.util.*
 
 class ImageViewerAdapter(initKey: Long) : PagedListAdapter<Item, RecyclerView.ViewHolder>(diff) {
@@ -45,8 +46,8 @@ class ImageViewerAdapter(initKey: Long) : PagedListAdapter<Item, RecyclerView.Vi
         }
     }
 
-    override fun getItemId(position: Int): Long = getItem(position)?.id ?: NO_ID
-    override fun getItemViewType(position: Int) = getItem(position)?.type ?: ItemType.UNKNOWN
+    override fun getItemId(position: Int): Long = provideItem(position)?.id ?: NO_ID
+    override fun getItemViewType(position: Int) = provideItem(position)?.type ?: ItemType.UNKNOWN
     private val callback: ImageViewerAdapterListener = object : ImageViewerAdapterListener {
         override fun onInit(viewHolder: RecyclerView.ViewHolder) {
             listener?.onInit(viewHolder)
@@ -64,6 +65,12 @@ class ImageViewerAdapter(initKey: Long) : PagedListAdapter<Item, RecyclerView.Vi
             listener?.onRestore(viewHolder, view, fraction)
         }
     }
+
+    private fun provideItem(position: Int) = try {
+        getItem(position) // IndexOutOfBoundsException Item count is zero, getItem() call is invalid
+    } catch (e: Exception) {
+        null
+    }
 }
 
 private val diff = object : DiffUtil.ItemCallback<Item>() {

imageviewer/src/main/java/com/github/iielse/imageviewer/core/Components.kt

@@ -1,6 +1,5 @@
 package com.github.iielse.imageviewer.core
 
-import androidx.lifecycle.LifecycleOwner
 import com.github.iielse.imageviewer.utils.log
 import kotlin.IllegalStateException
 
@@ -37,10 +36,10 @@ object Components {
         Components.overlayCustomizer = overlayCustomizer
     }
 
-    fun requireImageLoader() = imageLoader!!
-    fun requireDataProvider() = dataProvider!!
+    fun requireImageLoader() = imageLoader ?: object : ImageLoader {}
+    fun requireDataProvider() = dataProvider ?: object : DataProvider {}
     fun requireTransformer() = transformer ?: object : Transformer {}
-    fun requireInitKey() = initKey!!
+    fun requireInitKey() = initKey ?: 0
     fun requireVHCustomizer() = vhCustomizer ?: object : VHCustomizer {}
     fun requireViewerCallback() = viewerCallback ?: object : ViewerCallback {}
     fun requireOverlayCustomizer() = overlayCustomizer ?: object : OverlayCustomizer {}

imageviewer/src/main/java/com/github/iielse/imageviewer/core/DataProvider.kt

@@ -1,7 +1,7 @@
 package com.github.iielse.imageviewer.core
 
 interface DataProvider {
-    fun loadInitial(): List<Photo>
-    fun loadAfter(key: Long, callback: (List<Photo>) -> Unit)
-    fun loadBefore(key: Long, callback: (List<Photo>) -> Unit)
+    fun loadInitial(): List<Photo> = emptyList()
+    fun loadAfter(key: Long, callback: (List<Photo>) -> Unit) {}
+    fun loadBefore(key: Long, callback: (List<Photo>) -> Unit) {}
 }

imageviewer/src/main/java/com/github/iielse/imageviewer/core/ImageLoader.kt

@@ -5,6 +5,6 @@ import androidx.recyclerview.widget.RecyclerView
 import com.davemorrissey.labs.subscaleview.SubsamplingScaleImageView
 
 interface ImageLoader {
-    fun load(view: ImageView, data: Photo, viewHolder: RecyclerView.ViewHolder)
-    fun load(subsamplingView: SubsamplingScaleImageView, data: Photo, viewHolder: RecyclerView.ViewHolder)
+    fun load(view: ImageView, data: Photo, viewHolder: RecyclerView.ViewHolder) {}
+    fun load(subsamplingView: SubsamplingScaleImageView, data: Photo, viewHolder: RecyclerView.ViewHolder) {}
 }