Android: Hook up most of the settings interface mutators

android/app/src/main/java/com/github/stenzek/duckstation/AndroidHostInterface.java

@@ -1,6 +1,7 @@
 package com.github.stenzek.duckstation;
 
 import android.content.Context;
+import android.content.SharedPreferences;
 import android.content.res.AssetManager;
 import android.os.Environment;
 import android.util.Log;

android/app/src/main/java/com/github/stenzek/duckstation/PreferenceHelpers.java

@@ -0,0 +1,75 @@
+package com.github.stenzek.duckstation;
+
+import android.content.SharedPreferences;
+import android.util.ArraySet;
+
+import java.util.Set;
+
+public class PreferenceHelpers {
+    /**
+     * Clears all preferences in the specified section (starting with sectionName/).
+     * We really don't want to have to do this with JNI...
+     * @param prefs Preferences object.
+     * @param sectionName Section to clear keys for.
+     */
+    public static void clearSection(SharedPreferences prefs, String sectionName) {
+        String testSectionName = sectionName + "/";
+        SharedPreferences.Editor editor = prefs.edit();
+        for (String keyName : prefs.getAll().keySet()) {
+            if (keyName.startsWith(testSectionName)) {
+                editor.remove(keyName);
+            }
+        }
+
+        editor.commit();
+    }
+
+    public static Set<String> getStringSet(SharedPreferences prefs, String keyName) {
+        Set<String> values = null;
+        try {
+            values = prefs.getStringSet(keyName, null);
+        } catch (Exception e) {
+            try {
+                String singleValue = prefs.getString(keyName, null);
+                if (singleValue != null) {
+                    values = new ArraySet<>();
+                    values.add(singleValue);
+                }
+            } catch (Exception e2) {
+
+            }
+        }
+
+        return values;
+    }
+
+    public static boolean addToStringList(SharedPreferences prefs, String keyName, String valueToAdd)
+    {
+        Set<String> values = getStringSet(prefs, keyName);
+        if (values == null)
+            values = new ArraySet<>();
+
+        final boolean result = values.add(valueToAdd);
+        prefs.edit().putStringSet(keyName, values).commit();
+        return result;
+    }
+
+    public static boolean removeFromStringList(SharedPreferences prefs, String keyName, String valueToRemove)
+    {
+        Set<String> values = getStringSet(prefs, keyName);
+        if (values == null)
+            return false;
+
+        final boolean result = values.remove(valueToRemove);
+        prefs.edit().putStringSet(keyName, values).commit();
+        return result;
+    }
+
+    public static void setStringList(SharedPreferences prefs, String keyName, String[] values) {
+        Set<String> valueSet = new ArraySet<String>();
+        for (String value : values)
+            valueSet.add(value);
+
+        prefs.edit().putStringSet(keyName, valueSet).commit();
+    }
+}