use FlexibleAdapter with LiveData in KeyListFragment

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/livedata/KeyRingDao.java

@@ -0,0 +1,41 @@
+package org.sufficientlysecure.keychain.livedata;
+
+
+import java.util.ArrayList;
+import java.util.List;
+
+import android.arch.persistence.db.SupportSQLiteDatabase;
+import android.content.Context;
+import android.database.Cursor;
+
+import com.squareup.sqldelight.SqlDelightQuery;
+import org.sufficientlysecure.keychain.model.Key;
+import org.sufficientlysecure.keychain.model.Key.UnifiedKeyInfo;
+import org.sufficientlysecure.keychain.provider.KeychainDatabase;
+
+
+public class KeyRingDao {
+    private final SupportSQLiteDatabase db;
+
+    public static KeyRingDao getInstance(Context context) {
+        KeychainDatabase keychainDatabase = new KeychainDatabase(context);
+
+        return new KeyRingDao(keychainDatabase.getWritableDatabase());
+    }
+
+    private KeyRingDao(SupportSQLiteDatabase writableDatabase) {
+        this.db = writableDatabase;
+    }
+
+    public List<UnifiedKeyInfo> getUnifiedKeyInfo() {
+        SqlDelightQuery query = Key.FACTORY.selectAllUnifiedKeyInfo();
+        List<UnifiedKeyInfo> result = new ArrayList<>();
+        try (Cursor cursor = db.query(query)) {
+            while (cursor.moveToNext()) {
+                UnifiedKeyInfo unifiedKeyInfo = Key.UNIFIED_KEY_INFO_MAPPER.map(cursor);
+                result.add(unifiedKeyInfo);
+            }
+        }
+        return result;
+    }
+}