[Feature] Add "Select range" menu to select a continuous subset quick…

app/src/main/java/me/zhanghai/android/files/filelist/FileListAdapter.kt

@@ -132,6 +132,39 @@ class FileListAdapter(
         listener.selectFiles(files, true)
     }
 
+    fun rangeSelectFiles() {
+        var firstSelectItem = -1
+        var lastSelectItem = -1
+        for (index in 0..<itemCount) {
+            val file = getItem(index)
+            if (file in selectedFiles) {
+                firstSelectItem = index
+                break
+            }
+        }
+        for (index in itemCount - 1 downTo firstSelectItem) {
+            val file = getItem(index)
+            if (file in selectedFiles) {
+                lastSelectItem = index
+                break
+            }
+        }
+        val files = fileItemSetOf()
+        if (firstSelectItem >= 0
+            && lastSelectItem >= 0
+            && lastSelectItem < itemCount
+            && firstSelectItem < lastSelectItem
+        ) {
+            for (index in firstSelectItem..lastSelectItem) {
+                val file = getItem(index)
+                if (isFileSelectable(file)) {
+                    files.add(file)
+                }
+            }
+        }
+        listener.selectFiles(files, true)
+    }
+
     private fun isFileSelectable(file: FileItem): Boolean {
         val pickOptions = pickOptions ?: return true
         return when (pickOptions.mode) {

app/src/main/java/me/zhanghai/android/files/filelist/FileListFragment.kt

@@ -950,6 +950,10 @@ class FileListFragment : Fragment(), BreadcrumbLayout.Listener, FileListAdapter.
                 selectAllFiles()
                 true
             }
+            R.id.action_select_range -> {
+                rangeSelectFiles()
+                true
+            }
             else -> false
         }
 
@@ -1023,6 +1027,10 @@ class FileListFragment : Fragment(), BreadcrumbLayout.Listener, FileListAdapter.
         adapter.selectAllFiles()
     }
 
+    private fun rangeSelectFiles() {
+        adapter.rangeSelectFiles()
+    }
+
     private fun onPasteStateChanged(pasteState: PasteState) {
         updateBottomToolbar()
     }

app/src/main/res/menu/file_list_select.xml

@@ -58,4 +58,9 @@
         android:orderInCategory="100"
         android:title="@string/select_all"
         app:showAsAction="never" />
+    <item
+        android:id="@+id/action_select_range"
+        android:orderInCategory="100"
+        android:title="@string/select_range"
+        app:showAsAction="never" />
 </menu>

app/src/main/res/values-zh-rCN/strings.xml

@@ -642,4 +642,5 @@
     <string name="about_author_name_title">张海</string>
     <string name="about_author_github_title">在 GitHub 上关注</string>
     <string name="about_author_twitter_title">在 Twitter 上关注</string>
+    <string name="select_range">区间选择</string>
 </resources>

app/src/main/res/values/strings.xml

@@ -799,4 +799,5 @@
 
     <string name="shortcut_downloads_title" translatable="false">@string/navigation_standard_directory_downloads</string>
     <string name="shortcut_ftp_server_title" translatable="false">@string/ftp_server_title</string>
+    <string name="select_range">Select range</string>
 </resources>