put directories and files in the same list + permission handling

app/src/main/AndroidManifest.xml

@@ -2,6 +2,8 @@
 <manifest package="com.simplemobiletools.filemanager"
           xmlns:android="http://schemas.android.com/apk/res/android">
 
+    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
+
     <application
         android:allowBackup="true"
         android:icon="@mipmap/ic_launcher"

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

@@ -1,7 +1,21 @@
 package com.simplemobiletools.filemanager;
 
+import android.Manifest;
+import android.content.Context;
+import android.content.pm.PackageManager;
+import android.support.v4.content.ContextCompat;
+import android.widget.Toast;
+
 public class Utils {
     public static String getFilename(final String path) {
         return path.substring(path.lastIndexOf("/") + 1);
     }
+
+    public static void showToast(Context context, int resId) {
+        Toast.makeText(context, context.getResources().getString(resId), Toast.LENGTH_SHORT).show();
+    }
+
+    public static boolean hasStoragePermission(Context cxt) {
+        return ContextCompat.checkSelfPermission(cxt, Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED;
+    }
 }

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

@@ -1,12 +1,15 @@
 package com.simplemobiletools.filemanager.activities;
 
+import android.Manifest;
+import android.content.pm.PackageManager;
 import android.os.Bundle;
 import android.os.Environment;
+import android.support.v4.app.ActivityCompat;
 import android.support.v7.app.AppCompatActivity;
 
 import com.simplemobiletools.filemanager.R;
 import com.simplemobiletools.filemanager.Utils;
-import com.simplemobiletools.filemanager.models.Directory;
+import com.simplemobiletools.filemanager.models.FileDirItem;
 
 import java.io.File;
 import java.util.ArrayList;
@@ -14,27 +17,57 @@ import java.util.Collections;
 import java.util.List;
 
 public class MainActivity extends AppCompatActivity {
+    private static final int STORAGE_PERMISSION = 1;
 
     @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() {
+    @Override
-        final List<Directory> dirs = new ArrayList<>();
+    protected void onResume() {
+        super.onResume();
+        tryInitFileManager();
+    }
+
+    private void tryInitFileManager() {
+        if (Utils.hasStoragePermission(getApplicationContext())) {
+            initializeFileManager();
+        } else {
+            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, STORAGE_PERMISSION);
+        }
+    }
+
+    private void initializeFileManager() {
+        List<FileDirItem> items = getItems();
+        Collections.sort(items);
+    }
+
+    @Override
+    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
+        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
+
+        if (requestCode == STORAGE_PERMISSION) {
+            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
+                initializeFileManager();
+            } else {
+                Utils.showToast(getApplicationContext(), R.string.no_permissions);
+                finish();
+            }
+        }
+    }
+
+    private List<FileDirItem> getItems() {
+        final List<FileDirItem> items = 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 curPath = file.getAbsolutePath();
-                final String dirPath = file.getAbsolutePath();
+            final String curName = Utils.getFilename(curPath);
-                final String dirName = Utils.getFilename(dirPath);
+            items.add(new FileDirItem(curPath, curName, file.isDirectory()));
-                dirs.add(new Directory(dirPath, dirName));
         }
-        }
+        return items;
-        return dirs;
     }
 }

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

@@ -1,32 +0,0 @@
-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() + "}";
-    }
-}

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

@@ -0,0 +1,45 @@
+package com.simplemobiletools.filemanager.models;
+
+public class FileDirItem implements Comparable {
+    private final String mPath;
+    private final String mName;
+    private final boolean mIsDirectory;
+
+    public FileDirItem(String path, String name, boolean isDirectory) {
+        mPath = path;
+        mName = name;
+        mIsDirectory = isDirectory;
+    }
+
+    public String getPath() {
+        return mPath;
+    }
+
+    public String getName() {
+        return mName;
+    }
+
+    public boolean getIsDirectory() {
+        return mIsDirectory;
+    }
+
+    @Override
+    public int compareTo(Object object) {
+        final FileDirItem item = (FileDirItem) object;
+        if (mIsDirectory && !item.getIsDirectory()) {
+            return -1;
+        } else if (!mIsDirectory && item.getIsDirectory()) {
+            return 1;
+        }
+
+        return mName.compareToIgnoreCase(item.getName());
+    }
+
+    @Override
+    public String toString() {
+        return "FileDirItem {" +
+                "name=" + getName() +
+                ", isDirectory=" + getIsDirectory() +
+                ", path=" + getPath() + "}";
+    }
+}

app/src/main/res/values/strings.xml

@@ -1,3 +1,4 @@
 <resources>
     <string name="app_name">Simple File Manager</string>
+    <string name="no_permissions">We need the permission to access your storage</string>
 </resources>