Merge pull request #9221 from JosJuice/android-saf-sd-card

Android: Use storage access framework for custom SD card paths

13 files changed, 307 insertions, 35 deletions

diff --git a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/activities/EmulationActivity.java b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/activities/EmulationActivity.java
index 0602128a56..9bb3be3878 100644
--- a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/activities/EmulationActivity.java
+++ b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/activities/EmulationActivity.java
@@ -35,6 +35,7 @@ import org.dolphinemu.dolphinemu.R;
 import org.dolphinemu.dolphinemu.features.settings.model.BooleanSetting;
 import org.dolphinemu.dolphinemu.features.settings.model.IntSetting;
 import org.dolphinemu.dolphinemu.features.settings.model.Settings;
+import org.dolphinemu.dolphinemu.features.settings.model.StringSetting;
 import org.dolphinemu.dolphinemu.features.settings.ui.MenuTag;
 import org.dolphinemu.dolphinemu.features.settings.ui.SettingsActivity;
 import org.dolphinemu.dolphinemu.features.settings.utils.SettingsFile;
@@ -169,13 +170,38 @@ public final class EmulationActivity extends AppCompatActivity
     if (sIgnoreLaunchRequests)
       return;
 
+    new AfterDirectoryInitializationRunner().run(activity, true, () ->
+    {
+      if (FileBrowserHelper.isPathEmptyOrValid(StringSetting.MAIN_DEFAULT_ISO) &&
+              FileBrowserHelper.isPathEmptyOrValid(StringSetting.MAIN_FS_PATH) &&
+              FileBrowserHelper.isPathEmptyOrValid(StringSetting.MAIN_DUMP_PATH) &&
+              FileBrowserHelper.isPathEmptyOrValid(StringSetting.MAIN_LOAD_PATH) &&
+              FileBrowserHelper.isPathEmptyOrValid(StringSetting.MAIN_RESOURCEPACK_PATH) &&
+              FileBrowserHelper.isPathEmptyOrValid(StringSetting.MAIN_SD_PATH))
+      {
+        launchWithoutChecks(activity, filePaths);
+      }
+      else
+      {
+        AlertDialog.Builder builder = new AlertDialog.Builder(activity, R.style.DolphinDialogBase);
+        builder.setMessage(R.string.unavailable_paths);
+        builder.setPositiveButton(R.string.yes, (dialogInterface, i) ->
+                SettingsActivity.launch(activity, MenuTag.CONFIG_PATHS));
+        builder.setNeutralButton(R.string.continue_anyway, (dialogInterface, i) ->
+                launchWithoutChecks(activity, filePaths));
+        builder.show();
+      }
+    });
+  }
+
+  private static void launchWithoutChecks(FragmentActivity activity, String[] filePaths)
+  {
     sIgnoreLaunchRequests = true;
 
     Intent launcher = new Intent(activity, EmulationActivity.class);
     launcher.putExtra(EXTRA_SELECTED_GAMES, filePaths);
 
-    new AfterDirectoryInitializationRunner().run(activity, true,
-            () -> activity.startActivity(launcher));
+    activity.startActivity(launcher);
   }
 
   public static void stopIgnoringLaunchRequests()
diff --git a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/settings/ui/SettingsActivity.java b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/settings/ui/SettingsActivity.java
index e043b36f24..29d992a156 100644
--- a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/settings/ui/SettingsActivity.java
+++ b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/settings/ui/SettingsActivity.java
@@ -3,6 +3,7 @@ package org.dolphinemu.dolphinemu.features.settings.ui;
 import android.app.ProgressDialog;
 import android.content.Context;
 import android.content.Intent;
+import android.net.Uri;
 import android.os.Bundle;
 import android.provider.Settings;
 import android.view.Menu;
@@ -18,6 +19,7 @@ import androidx.lifecycle.ViewModelProvider;
 
 import org.dolphinemu.dolphinemu.R;
 import org.dolphinemu.dolphinemu.ui.main.MainActivity;
+import org.dolphinemu.dolphinemu.ui.main.MainPresenter;
 import org.dolphinemu.dolphinemu.ui.main.TvMainActivity;
 import org.dolphinemu.dolphinemu.utils.FileBrowserHelper;
 import org.dolphinemu.dolphinemu.utils.TvUtil;
@@ -170,11 +172,33 @@ public final class SettingsActivity extends AppCompatActivity implements Setting
     // If the user picked a file, as opposed to just backing out.
     if (resultCode == MainActivity.RESULT_OK)
     {
-      String path = FileBrowserHelper.getSelectedPath(result);
-      getFragment().getAdapter().onFilePickerConfirmation(path);
+      if (requestCode == MainPresenter.REQUEST_SD_FILE)
+      {
+        Uri uri = canonicalizeIfPossible(result.getData());
+        int takeFlags = result.getFlags() &
+                (Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
+
+        FileBrowserHelper.runAfterExtensionCheck(this, uri, FileBrowserHelper.RAW_EXTENSION, () ->
+        {
+          getContentResolver().takePersistableUriPermission(uri, takeFlags);
+          getFragment().getAdapter().onFilePickerConfirmation(uri.toString());
+        });
+      }
+      else
+      {
+        String path = FileBrowserHelper.getSelectedPath(result);
+        getFragment().getAdapter().onFilePickerConfirmation(path);
+      }
     }
   }
 
+  @NonNull
+  private Uri canonicalizeIfPossible(@NonNull Uri uri)
+  {
+    Uri canonicalizedUri = getContentResolver().canonicalize(uri);
+    return canonicalizedUri != null ? canonicalizedUri : uri;
+  }
+
   @Override
   public void showLoading()
   {
diff --git a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/settings/ui/SettingsAdapter.java b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/settings/ui/SettingsAdapter.java
index c751a7750e..3442c72fa5 100644
--- a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/settings/ui/SettingsAdapter.java
+++ b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/settings/ui/SettingsAdapter.java
@@ -2,6 +2,9 @@ package org.dolphinemu.dolphinemu.features.settings.ui;
 
 import android.content.Context;
 import android.content.DialogInterface;
+import android.content.Intent;
+import android.os.Build;
+import android.provider.DocumentsContract;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
@@ -289,33 +292,42 @@ public final class SettingsAdapter extends RecyclerView.Adapter<SettingViewHolde
     dialog.show();
   }
 
-  public void onFilePickerDirectoryClick(SettingsItem item)
+  public void onFilePickerDirectoryClick(SettingsItem item, int position)
   {
     mClickedItem = item;
+    mClickedPosition = position;
 
     FileBrowserHelper.openDirectoryPicker(mView.getActivity(), FileBrowserHelper.GAME_EXTENSIONS);
   }
 
-  public void onFilePickerFileClick(SettingsItem item)
+  public void onFilePickerFileClick(SettingsItem item, int position)
   {
     mClickedItem = item;
+    mClickedPosition = position;
     FilePicker filePicker = (FilePicker) item;
 
-    HashSet<String> extensions;
     switch (filePicker.getRequestType())
     {
       case MainPresenter.REQUEST_SD_FILE:
-        extensions = FileBrowserHelper.RAW_EXTENSION;
+        Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
+        intent.addCategory(Intent.CATEGORY_OPENABLE);
+        intent.setType("*/*");
+
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O)
+        {
+          intent.putExtra(DocumentsContract.EXTRA_INITIAL_URI,
+                  filePicker.getSelectedValue(mView.getSettings()));
+        }
+
+        mView.getActivity().startActivityForResult(intent, filePicker.getRequestType());
         break;
       case MainPresenter.REQUEST_GAME_FILE:
-        extensions = FileBrowserHelper.GAME_EXTENSIONS;
+        FileBrowserHelper.openFilePicker(mView.getActivity(), filePicker.getRequestType(), false,
+                FileBrowserHelper.GAME_EXTENSIONS);
         break;
       default:
         throw new InvalidParameterException("Unhandled request code");
     }
-
-    FileBrowserHelper.openFilePicker(mView.getActivity(), filePicker.getRequestType(), false,
-            extensions);
   }
 
   public void onFilePickerConfirmation(String selectedFile)
@@ -323,7 +335,10 @@ public final class SettingsAdapter extends RecyclerView.Adapter<SettingViewHolde
     FilePicker filePicker = (FilePicker) mClickedItem;
 
     if (!filePicker.getSelectedValue(mView.getSettings()).equals(selectedFile))
+    {
+      notifyItemChanged(mClickedPosition);
       mView.onSettingChanged();
+    }
 
     filePicker.setSelectedValue(mView.getSettings(), selectedFile);
 
diff --git a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/settings/ui/viewholder/FilePickerViewHolder.java b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/settings/ui/viewholder/FilePickerViewHolder.java
index 790ce1acf9..1ee60b30b5 100644
--- a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/settings/ui/viewholder/FilePickerViewHolder.java
+++ b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/settings/ui/viewholder/FilePickerViewHolder.java
@@ -1,5 +1,6 @@
 package org.dolphinemu.dolphinemu.features.settings.ui.viewholder;
 
+import android.graphics.drawable.Drawable;
 import android.text.TextUtils;
 import android.view.View;
 import android.widget.TextView;
@@ -12,6 +13,7 @@ import org.dolphinemu.dolphinemu.features.settings.model.view.SettingsItem;
 import org.dolphinemu.dolphinemu.features.settings.ui.SettingsAdapter;
 import org.dolphinemu.dolphinemu.ui.main.MainPresenter;
 import org.dolphinemu.dolphinemu.utils.DirectoryInitialization;
+import org.dolphinemu.dolphinemu.utils.FileBrowserHelper;
 
 public final class FilePickerViewHolder extends SettingViewHolder
 {
@@ -21,6 +23,8 @@ public final class FilePickerViewHolder extends SettingViewHolder
   private TextView mTextSettingName;
   private TextView mTextSettingDescription;
 
+  private Drawable mDefaultBackground;
+
   public FilePickerViewHolder(View itemView, SettingsAdapter adapter)
   {
     super(itemView, adapter);
@@ -31,6 +35,8 @@ public final class FilePickerViewHolder extends SettingViewHolder
   {
     mTextSettingName = root.findViewById(R.id.text_setting_name);
     mTextSettingDescription = root.findViewById(R.id.text_setting_description);
+
+    mDefaultBackground = root.getBackground();
   }
 
   @Override
@@ -39,6 +45,17 @@ public final class FilePickerViewHolder extends SettingViewHolder
     mFilePicker = (FilePicker) item;
     mItem = item;
 
+    String path = mFilePicker.getSelectedValue(getAdapter().getSettings());
+
+    if (FileBrowserHelper.isPathEmptyOrValid(path))
+    {
+      itemView.setBackground(mDefaultBackground);
+    }
+    else
+    {
+      itemView.setBackgroundResource(R.drawable.invalid_setting_background);
+    }
+
     mTextSettingName.setText(item.getNameId());
 
     if (item.getDescriptionId() > 0)
@@ -47,8 +64,6 @@ public final class FilePickerViewHolder extends SettingViewHolder
     }
     else
     {
-      String path = mFilePicker.getSelectedValue(getAdapter().getSettings());
-
       if (TextUtils.isEmpty(path))
       {
         String defaultPathRelative = mFilePicker.getDefaultPathRelativeToUserDirectory();
@@ -73,13 +88,14 @@ public final class FilePickerViewHolder extends SettingViewHolder
       return;
     }
 
+    int position = getAdapterPosition();
     if (mFilePicker.getRequestType() == MainPresenter.REQUEST_DIRECTORY)
     {
-      getAdapter().onFilePickerDirectoryClick(mItem);
+      getAdapter().onFilePickerDirectoryClick(mItem, position);
     }
     else
     {
-      getAdapter().onFilePickerFileClick(mItem);
+      getAdapter().onFilePickerFileClick(mItem, position);
     }
 
     setStyle(mTextSettingName, mItem);
diff --git a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/ui/main/MainActivity.java b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/ui/main/MainActivity.java
index 53306d8e4d..cd5dd80c75 100644
--- a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/ui/main/MainActivity.java
+++ b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/ui/main/MainActivity.java
@@ -205,7 +205,9 @@ public final class MainActivity extends AppCompatActivity implements MainView
           break;
 
         case MainPresenter.REQUEST_WAD_FILE:
-          mPresenter.installWAD(result.getData().toString());
+          FileBrowserHelper.runAfterExtensionCheck(this, result.getData(),
+                  FileBrowserHelper.WAD_EXTENSION,
+                  () -> mPresenter.installWAD(result.getData().toString()));
           break;
       }
     }
diff --git a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/ui/main/TvMainActivity.java b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/ui/main/TvMainActivity.java
index f1c8c37a41..23d1050d04 100644
--- a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/ui/main/TvMainActivity.java
+++ b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/ui/main/TvMainActivity.java
@@ -229,7 +229,9 @@ public final class TvMainActivity extends FragmentActivity implements MainView
           break;
 
         case MainPresenter.REQUEST_WAD_FILE:
-          mPresenter.installWAD(result.getData().toString());
+          FileBrowserHelper.runAfterExtensionCheck(this, result.getData(),
+                  FileBrowserHelper.WAD_EXTENSION,
+                  () -> mPresenter.installWAD(result.getData().toString()));
           break;
       }
     }
diff --git a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/utils/ContentHandler.java b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/utils/ContentHandler.java
index 62d36553c8..dbeb410079 100644
--- a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/utils/ContentHandler.java
+++ b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/utils/ContentHandler.java
@@ -1,8 +1,13 @@
 package org.dolphinemu.dolphinemu.utils;
 
 import android.content.ContentResolver;
+import android.database.Cursor;
 import android.net.Uri;
 import android.provider.DocumentsContract;
+import android.provider.DocumentsContract.Document;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 
 import androidx.annotation.Keep;
 
@@ -17,10 +22,16 @@ public class ContentHandler
   {
     try
     {
-      return DolphinApplication.getAppContext().getContentResolver()
-              .openFileDescriptor(Uri.parse(uri), mode).detachFd();
+      return getContentResolver().openFileDescriptor(Uri.parse(uri), mode).detachFd();
+    }
+    catch (SecurityException e)
+    {
+      Log.error("Tried to open " + uri + " without permission");
+      return -1;
     }
-    catch (FileNotFoundException | NullPointerException e)
+    // Some content providers throw IllegalArgumentException for invalid modes,
+    // despite the documentation saying that invalid modes result in a FileNotFoundException
+    catch (FileNotFoundException | IllegalArgumentException | NullPointerException e)
     {
       return -1;
     }
@@ -31,8 +42,12 @@ public class ContentHandler
   {
     try
     {
-      ContentResolver resolver = DolphinApplication.getAppContext().getContentResolver();
-      return DocumentsContract.deleteDocument(resolver, Uri.parse(uri));
+      return DocumentsContract.deleteDocument(getContentResolver(), Uri.parse(uri));
+    }
+    catch (SecurityException e)
+    {
+      Log.error("Tried to delete " + uri + " without permission");
+      return false;
     }
     catch (FileNotFoundException e)
     {
@@ -40,4 +55,46 @@ public class ContentHandler
       return true;
     }
   }
+
+  public static boolean exists(@NonNull String uri)
+  {
+    try
+    {
+      final String[] projection = new String[]{Document.COLUMN_MIME_TYPE, Document.COLUMN_SIZE};
+      try (Cursor cursor = getContentResolver().query(Uri.parse(uri), projection, null, null, null))
+      {
+        return cursor != null && cursor.getCount() > 0;
+      }
+    }
+    catch (SecurityException e)
+    {
+      Log.error("Tried to check if " + uri + " exists without permission");
+    }
+
+    return false;
+  }
+
+  @Nullable
+  public static String getDisplayName(@NonNull Uri uri)
+  {
+    final String[] projection = new String[]{Document.COLUMN_DISPLAY_NAME};
+    try (Cursor cursor = getContentResolver().query(uri, projection, null, null, null))
+    {
+      if (cursor != null && cursor.moveToFirst())
+      {
+        return cursor.getString(0);
+      }
+    }
+    catch (SecurityException e)
+    {
+      Log.error("Tried to get display name of " + uri + " without permission");
+    }
+
+    return null;
+  }
+
+  private static ContentResolver getContentResolver()
+  {
+    return DolphinApplication.getAppContext().getContentResolver();
+  }
 }
diff --git a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/utils/FileBrowserHelper.java b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/utils/FileBrowserHelper.java
index 949cee554c..79ec49deae 100644
--- a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/utils/FileBrowserHelper.java
+++ b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/utils/FileBrowserHelper.java
@@ -1,23 +1,29 @@
 package org.dolphinemu.dolphinemu.utils;
 
+import android.content.Context;
 import android.content.Intent;
 import android.net.Uri;
 import android.os.Environment;
 
 import androidx.annotation.Nullable;
+import androidx.appcompat.app.AlertDialog;
 import androidx.fragment.app.FragmentActivity;
 
 import com.nononsenseapps.filepicker.FilePickerActivity;
 import com.nononsenseapps.filepicker.Utils;
 
+import org.dolphinemu.dolphinemu.R;
 import org.dolphinemu.dolphinemu.activities.CustomFilePickerActivity;
+import org.dolphinemu.dolphinemu.features.settings.model.StringSetting;
 import org.dolphinemu.dolphinemu.ui.main.MainPresenter;
 
 import java.io.File;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 
 public final class FileBrowserHelper
 {
@@ -27,6 +33,9 @@ public final class FileBrowserHelper
   public static final HashSet<String> RAW_EXTENSION = new HashSet<>(Collections.singletonList(
           "raw"));
 
+  public static final HashSet<String> WAD_EXTENSION = new HashSet<>(Collections.singletonList(
+          "wad"));
+
   public static void openDirectoryPicker(FragmentActivity activity, HashSet<String> extensions)
   {
     Intent i = new Intent(activity, CustomFilePickerActivity.class);
@@ -85,4 +94,83 @@ public final class FileBrowserHelper
 
     return null;
   }
+
+  public static boolean isPathEmptyOrValid(StringSetting path)
+  {
+    return isPathEmptyOrValid(path.getStringGlobal());
+  }
+
+  public static boolean isPathEmptyOrValid(String path)
+  {
+    return !path.startsWith("content://") || ContentHandler.exists(path);
+  }
+
+  public static void runAfterExtensionCheck(Context context, Uri uri, Set<String> validExtensions,
+          Runnable runnable)
+  {
+    String extension = null;
+
+    String path = uri.getLastPathSegment();
+    if (path != null)
+      extension = getExtension(new File(path).getName());
+
+    if (extension == null)
+      extension = getExtension(ContentHandler.getDisplayName(uri));
+
+    if (extension != null && validExtensions.contains(extension))
+    {
+      runnable.run();
+      return;
+    }
+
+    String message;
+    if (extension == null)
+    {
+      message = context.getString(R.string.no_file_extension);
+    }
+    else
+    {
+      int messageId = validExtensions.size() == 1 ?
+              R.string.wrong_file_extension_single : R.string.wrong_file_extension_multiple;
+
+      ArrayList<String> extensionsList = new ArrayList<>(validExtensions);
+      Collections.sort(extensionsList);
+
+      message = context.getString(messageId, extension, join(", ", extensionsList));
+    }
+
+    new AlertDialog.Builder(context, R.style.DolphinDialogBase)
+            .setMessage(message)
+            .setPositiveButton(R.string.yes, (dialogInterface, i) -> runnable.run())
+            .setNegativeButton(R.string.no, null)
+            .setCancelable(false)
+            .show();
+  }
+
+  @Nullable
+  private static String getExtension(@Nullable String fileName)
+  {
+    if (fileName == null)
+      return null;
+
+    int dotIndex = fileName.lastIndexOf(".");
+    return dotIndex != -1 ? fileName.substring(dotIndex + 1) : null;
+  }
+
+  // TODO: Replace this with String.join once we can use Java 8
+  private static String join(CharSequence delimiter, Iterable<? extends CharSequence> elements)
+  {
+    StringBuilder sb = new StringBuilder();
+
+    boolean first = true;
+    for (CharSequence element : elements)
+    {
+      if (!first)
+        sb.append(delimiter);
+      first = false;
+      sb.append(element);
+    }
+
+    return sb.toString();
+  }
 }
diff --git a/Source/Android/app/src/main/res/drawable/invalid_setting_background.xml b/Source/Android/app/src/main/res/drawable/invalid_setting_background.xml
new file mode 100644
index 0000000000..ad58c2e30a
--- /dev/null
+++ b/Source/Android/app/src/main/res/drawable/invalid_setting_background.xml
@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+    <item android:drawable="?android:attr/selectableItemBackground"/>
+    <item>
+        <shape>
+            <solid android:color="@color/invalid_setting_overlay" />
+        </shape>
+    </item>
+</layer-list>
diff --git a/Source/Android/app/src/main/res/values/colors.xml b/Source/Android/app/src/main/res/values/colors.xml
index b62030758e..111c03802b 100644
--- a/Source/Android/app/src/main/res/values/colors.xml
+++ b/Source/Android/app/src/main/res/values/colors.xml
@@ -11,4 +11,6 @@
 
     <color name="tv_card_unselected">#444444</color>
 
+    <color name="invalid_setting_overlay">#36ff0000</color>
+
 </resources>
diff --git a/Source/Android/app/src/main/res/values/strings.xml b/Source/Android/app/src/main/res/values/strings.xml
index db5d6e9bf3..4cb7c09a17 100644
--- a/Source/Android/app/src/main/res/values/strings.xml
+++ b/Source/Android/app/src/main/res/values/strings.xml
@@ -315,6 +315,7 @@
     <string name="clear">Clear</string>
     <string name="disabled">Disabled</string>
     <string name="other">Other</string>
+    <string name="continue_anyway">Continue Anyway</string>
 
     <!-- Game Grid Screen-->
     <string name="add_directory_title">Add Folder to Library</string>
@@ -433,6 +434,12 @@ It can efficiently compress both junk data and encrypted Wii data.
 
     <string name="select_dir">Select This Directory</string>
 
+    <!-- File Pickers -->
+    <string name="no_file_extension">The selected file does not appear to have a file name extension.\n\nContinue anyway?</string>
+    <string name="wrong_file_extension_single">The selected file has the file name extension \"%1$s\", but \"%2$s\" was expected.\n\nContinue anyway?</string>
+    <string name="wrong_file_extension_multiple">The selected file has the file name extension \"%1$s\", but one of these extensions was expected: %2$s\n\nContinue anyway?</string>
+    <string name="unavailable_paths">Dolphin does not have permission to access one or more configured paths. Would you like to fix this before starting?</string>
+
     <!-- Misc -->
     <string name="pitch">Total Pitch</string>
     <string name="yaw">Total Yaw</string>
diff --git a/Source/Android/jni/AndroidCommon/AndroidCommon.cpp b/Source/Android/jni/AndroidCommon/AndroidCommon.cpp
index 887ae4deab..310db6b1f7 100644
--- a/Source/Android/jni/AndroidCommon/AndroidCommon.cpp
+++ b/Source/Android/jni/AndroidCommon/AndroidCommon.cpp
@@ -10,6 +10,7 @@
 
 #include <jni.h>
 
+#include "Common/Assert.h"
 #include "Common/StringUtil.h"
 #include "jni/AndroidCommon/IDCache.h"
 
@@ -42,21 +43,35 @@ std::vector<std::string> JStringArrayToVector(JNIEnv* env, jobjectArray array)
   return result;
 }
 
+bool IsPathAndroidContent(const std::string& uri)
+{
+  return StringBeginsWith(uri, "content://");
+}
+
+std::string OpenModeToAndroid(std::string mode)
+{
+  // The 'b' specifier is not supported. Since we're on POSIX, it's fine to just skip it.
+  if (!mode.empty() && mode.back() == 'b')
+    mode.pop_back();
+
+  if (mode == "r+")
+    mode = "rw";
+  else if (mode == "w+")
+    mode = "rwt";
+  else if (mode == "a+")
+    mode = "rwa";
+  else if (mode == "a")
+    mode = "wa";
+
+  return mode;
+}
+
 int OpenAndroidContent(const std::string& uri, const std::string& mode)
 {
   JNIEnv* env = IDCache::GetEnvForThread();
-  const jint fd = env->CallStaticIntMethod(IDCache::GetContentHandlerClass(),
-                                           IDCache::GetContentHandlerOpenFd(), ToJString(env, uri),
-                                           ToJString(env, mode));
-
-  // We can get an IllegalArgumentException when passing an invalid mode
-  if (env->ExceptionCheck())
-  {
-    env->ExceptionDescribe();
-    abort();
-  }
-
-  return fd;
+  return env->CallStaticIntMethod(IDCache::GetContentHandlerClass(),
+                                  IDCache::GetContentHandlerOpenFd(), ToJString(env, uri),
+                                  ToJString(env, mode));
 }
 
 bool DeleteAndroidContent(const std::string& uri)
diff --git a/Source/Android/jni/AndroidCommon/AndroidCommon.h b/Source/Android/jni/AndroidCommon/AndroidCommon.h
index 2ab220eac7..7ff745f047 100644
--- a/Source/Android/jni/AndroidCommon/AndroidCommon.h
+++ b/Source/Android/jni/AndroidCommon/AndroidCommon.h
@@ -12,7 +12,16 @@ std::string GetJString(JNIEnv* env, jstring jstr);
 jstring ToJString(JNIEnv* env, const std::string& str);
 std::vector<std::string> JStringArrayToVector(JNIEnv* env, jobjectArray array);
 
+// Returns true if the given path should be opened as Android content instead of a normal file.
+bool IsPathAndroidContent(const std::string& uri);
+
+// Turns a C/C++ style mode (e.g. "rb") into one which can be used with OpenAndroidContent.
+std::string OpenModeToAndroid(std::string mode);
+
+// Opens a given file and returns a file descriptor.
 int OpenAndroidContent(const std::string& uri, const std::string& mode);
+
+// Deletes a given file.
 bool DeleteAndroidContent(const std::string& uri);
 int GetNetworkIpAddress();
 int GetNetworkPrefixLength();