get a sorted list of directories

app/src/main/AndroidManifest.xml

@@ -8,7 +8,7 @@
         android:label="@string/app_name"
         android:supportsRtl="true"
         android:theme="@style/AppTheme">
-        <activity android:name=".MainActivity">
+        <activity android:name=".activities.MainActivity">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN"/>
 
@@ -16,5 +16,4 @@
             </intent-filter>
         </activity>
     </application>
-
-</manifest>
+</manifest>

app/src/main/java/com/simplemobiletools/filemanager/MainActivity.java

@@ -1,13 +0,0 @@
-package com.simplemobiletools.filemanager;
-
-import android.support.v7.app.AppCompatActivity;
-import android.os.Bundle;
-
-public class MainActivity extends AppCompatActivity {
-
-    @Override
-    protected void onCreate(Bundle savedInstanceState) {
-        super.onCreate(savedInstanceState);
-        setContentView(R.layout.activity_main);
-    }
-}

app/src/main/java/com/simplemobiletools/filemanager/Utils.java

@@ -0,0 +1,7 @@
+package com.simplemobiletools.filemanager;
+
+public class Utils {
+    public static String getFilename(final String path) {
+        return path.substring(path.lastIndexOf("/") + 1);
+    }
+}

app/src/main/java/com/simplemobiletools/filemanager/activities/MainActivity.java

@@ -0,0 +1,40 @@
+package com.simplemobiletools.filemanager.activities;
+
+import android.os.Bundle;
+import android.os.Environment;
+import android.support.v7.app.AppCompatActivity;
+
+import com.simplemobiletools.filemanager.R;
+import com.simplemobiletools.filemanager.Utils;
+import com.simplemobiletools.filemanager.models.Directory;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public class MainActivity extends AppCompatActivity {
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_main);
+        List<Directory> dirs = getDirectories();
+        Collections.sort(dirs);
+    }
+
+    private List<Directory> getDirectories() {
+        final List<Directory> dirs = new ArrayList<>();
+        final String path = Environment.getExternalStorageDirectory().toString();
+        final File root = new File(path);
+        File[] files = root.listFiles();
+        for (File file : files) {
+            if (file.isDirectory()) {
+                final String dirPath = file.getAbsolutePath();
+                final String dirName = Utils.getFilename(dirPath);
+                dirs.add(new Directory(dirPath, dirName));
+            }
+        }
+        return dirs;
+    }
+}

app/src/main/java/com/simplemobiletools/filemanager/models/Directory.java

@@ -0,0 +1,32 @@
+package com.simplemobiletools.filemanager.models;
+
+public class Directory implements Comparable {
+    private final String path;
+    private final String name;
+
+    public Directory(String path, String name) {
+        this.path = path;
+        this.name = name;
+    }
+
+    public String getPath() {
+        return path;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public int compareTo(Object object) {
+        final Directory directory = (Directory) object;
+        return this.name.compareToIgnoreCase(directory.getName());
+    }
+
+    @Override
+    public String toString() {
+        return "Directory {" +
+                "name=" + getName() +
+                ", path=" + getPath() + "}";
+    }
+}