Feat: Add file picker UI

Author: ShaanNarendran

AnkiDroid/src/main/java/com/ichi2/preferences/ExternalDirectorySelectionPreference.kt

@@ -0,0 +1,131 @@
+/*
+ *  Copyright (c) 2024 David Allison <davidallisongithub@gmail.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify it under
+ *  the terms of the GNU General Public License as published by the Free Software
+ *  Foundation; either version 3 of the License, or (at your option) any later
+ *  version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY
+ *  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ *  PARTICULAR PURPOSE. See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with
+ *  this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.ichi2.preferences
+
+import android.content.Context
+import android.os.Build
+import android.os.Looper
+import android.util.AttributeSet
+import androidx.fragment.app.DialogFragment
+import androidx.preference.EditTextPreference
+import androidx.preference.R
+import com.ichi2.anki.CollectionHelper
+import com.ichi2.utils.Permissions
+import java.io.File
+
+class ExternalDirectorySelectionPreference(
+    context: Context,
+    attrs: AttributeSet?,
+) : EditTextPreference(
+        context,
+        attrs,
+        styleAttr(context),
+        android.R.attr.dialogPreferenceStyle,
+    ),
+    ListPreferenceTrait {
+    private var forceCustomSelector = false
+
+    private val initialLayoutResId = dialogLayoutResource
+
+    override fun makeDialogFragment(): DialogFragment? {
+        val useTextBox = (forceCustomSelector || isEditText(context))
+        forceCustomSelector = false
+        if (useTextBox) {
+            dialogLayoutResource = R.layout.preference_dialog_edittext
+            return null
+        } else {
+            dialogLayoutResource = initialLayoutResId
+            return FullWidthListPreferenceDialogFragment()
+        }
+    }
+
+    // only used if a user has no file access
+    override var listEntries: List<ListPreferenceTrait.Entry> =
+        CollectionHelper
+            .getAppSpecificExternalDirectories(context)
+            .filterNotNull()
+            .let { dirs ->
+                // This should ALWAYS start with the current AnkiDroid directory
+                listOf(File(CollectionHelper.getDefaultAnkiDroidDirectory(context).toString())) +
+                    dirs.flatMap { findAnkiDroidSubDirectories(it) }
+            }.distinct()
+            .map {
+                val label = it.absolutePath.replace("/Android/", "\n/Android/")
+                ListPreferenceTrait.Entry(label, it.absolutePath)
+            }.toMutableList()
+            .apply { add(ListPreferenceTrait.Entry("Select custom path...", "CUSTOM_PATH_SENTINEL")) }
+
+    override var listValue: String = getPersistedString(listEntries.firstOrNull()?.value ?: "")
+
+    override fun callChangeListener(newValue: Any?): Boolean {
+        if (newValue == "CUSTOM_PATH_SENTINEL") {
+            forceCustomSelector = true
+            android.os.Handler(Looper.getMainLooper()).post {
+                this.onClick()
+            }
+            return false
+        }
+        return super.callChangeListener(newValue)
+    }
+
+    // In future, we may want to disable this is there is only one selection
+    override fun isEnabled() = listEntries.isNotEmpty()
+
+    companion object {
+        fun findAnkiDroidSubDirectories(f: File): List<File> {
+            // either returns '/AnkiDroid1...AnkiDroid100' from storage migration
+            // OR returns '/AnkiDroid' if no directories are available
+            return (f.listFiles()?.toList() ?: listOf<File>())
+                .filter { it.isDirectory }
+                .filter { it.name.startsWith("AnkiDroid") }
+                .ifEmpty { listOf(File(f, "AnkiDroid")) }
+        }
+
+        /**
+         * Determines the UI mode for the preference.
+         *
+         * @return true if the user has full storage access (MANAGE_EXTERNAL_STORAGE),
+         * @return false if the user is restricted, forcing the Volume Picker UI.
+         */
+        private fun isEditText(context: Context): Boolean {
+            if (Build.VERSION.SDK_INT < Build.VERSION_CODES.R) {
+                return true
+            }
+            return Permissions.canManageExternalStorage(context)
+        }
+
+        fun styleAttr(context: Context): Int =
+            if (isEditText(context)) {
+                R.attr.editTextPreferenceStyle
+            } else {
+                ListPreferenceTrait.STYLE_ATTR
+            }
+    }
+}
+
+/**
+ * A custom DialogFragment that expands to fill the screen width.
+ */
+class FullWidthListPreferenceDialogFragment : ListPreferenceDialogFragment() {
+    override fun onStart() {
+        super.onStart()
+        dialog?.window?.setLayout(
+            android.view.ViewGroup.LayoutParams.MATCH_PARENT,
+            android.view.ViewGroup.LayoutParams.WRAP_CONTENT,
+        )
+    }
+}

AnkiDroid/src/main/java/com/ichi2/preferences/ListPreferenceTrait.kt

@@ -84,7 +84,7 @@ interface ListPreferenceTrait : DialogFragmentProvider {
  * Adapted from: [ListPreferenceDialogFragmentCompat]
  * @see ListPreferenceDialogFragmentCompat
  */
-class ListPreferenceDialogFragment : PreferenceDialogFragmentCompat() {
+open class ListPreferenceDialogFragment : PreferenceDialogFragmentCompat() {
     // synthetic access
     private var clickedDialogEntryIndex = 0
     private lateinit var entries: Array<CharSequence>

AnkiDroid/src/main/res/xml/preferences_advanced.xml

@@ -25,7 +25,7 @@
     xmlns:app1="http://schemas.android.com/apk/res-auto"
     android:title="@string/pref_cat_advanced"
     android:key="@string/pref_advanced_screen_key">
-        <EditTextPreference
+        <com.ichi2.preferences.ExternalDirectorySelectionPreference
             android:defaultValue="/sdcard/AnkiDroid"
             android:key="@string/pref_ankidroid_directory_key"
             android:title="@string/col_path"