Fix storing/restoring icon mappings

I am an idiot. Object serialization can't work (over app updates)
when the code is obfuscated, of course.

Object serialization works with the *name* of an object, and R8
shortens the names to some abbreviation that can and will vary
from build to build.

So yes, this means everyone will loose all icon mappings with the
next update. Sorry.

app/src/main/java/de/markusfisch/android/pielauncher/graphics/IconPack.java

@@ -187,8 +187,8 @@ public void selectPack(PackageManager pm, String packageName) {
 	}
 
 	public Drawable getIcon(String packageName) {
-		PackAndDrawable pad = mappings.get(packageName);
 		String drawableName = null;
+		PackAndDrawable pad = mappings.get(packageName);
 		if (pad != null) {
 			if (selectedPack != null &&
 					pad.packageName.equals(selectedPack.packageName)) {

app/src/main/java/de/markusfisch/android/pielauncher/io/IconMappings.java

@@ -2,43 +2,61 @@
 
 import android.content.Context;
 
-import java.io.FileInputStream;
-import java.io.FileOutputStream;
+import java.io.BufferedReader;
+import java.io.BufferedWriter;
+import java.io.FileNotFoundException;
 import java.io.IOException;
-import java.io.ObjectInputStream;
-import java.io.ObjectOutputStream;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
 import java.util.HashMap;
+import java.util.Map;
 
 import de.markusfisch.android.pielauncher.graphics.IconPack;
 
 public class IconMappings {
+	private static final String SEPARATOR = ";";
 	private static final String MAPPINGS_FILE = "mappings";
 
-	@SuppressWarnings("unchecked")
 	public static void restore(Context context,
 			HashMap<String, IconPack.PackAndDrawable> mappings) {
+		mappings.clear();
 		try {
-			FileInputStream fis = context.openFileInput(MAPPINGS_FILE);
-			ObjectInputStream ois = new ObjectInputStream(fis);
-			mappings.clear();
-			mappings.putAll((HashMap<String, IconPack.PackAndDrawable>)
-					ois.readObject());
-			ois.close();
-			fis.close();
-		} catch (IOException | ClassCastException | ClassNotFoundException e) {
-			// Ignore, can't do nothing about this.
+			BufferedReader reader = new BufferedReader(new InputStreamReader(
+					context.openFileInput(MAPPINGS_FILE)));
+			String line;
+			while ((line = reader.readLine()) != null) {
+				String[] parts = line.split(SEPARATOR);
+				if (parts.length < 3) {
+					continue;
+				}
+				mappings.put(parts[0], new IconPack.PackAndDrawable(
+						parts[1], parts[2]));
+			}
+			reader.close();
+		} catch (FileNotFoundException e) {
+			// Return an empty array.
+		} catch (IOException e) {
+			// Return an empty array.
 		}
 	}
 
 	public static void store(Context context,
 			HashMap<String, IconPack.PackAndDrawable> mappings) {
 		try {
-			FileOutputStream fos = context.openFileOutput(
-					MAPPINGS_FILE, Context.MODE_PRIVATE);
-			ObjectOutputStream oos = new ObjectOutputStream(fos);
-			oos.writeObject(mappings);
-			oos.close();
-			fos.close();
+			BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(
+					context.openFileOutput(MAPPINGS_FILE,
+							Context.MODE_PRIVATE)));
+			for (Map.Entry<String, IconPack.PackAndDrawable> mapping :
+					mappings.entrySet()) {
+				writer.write(mapping.getKey());
+				writer.write(SEPARATOR);
+				IconPack.PackAndDrawable pad = mapping.getValue();
+				writer.write(pad.packageName);
+				writer.write(SEPARATOR);
+				writer.write(pad.drawableName);
+				writer.newLine();
+			}
+			writer.close();
 		} catch (IOException e) {
 			// Ignore, can't do nothing about this.
 		}