Add blacklist option and minor code improvements

app/src/main/java/com/kabouzeid/gramophone/dialogs/BlacklistFolderChooserDialog.java

@@ -0,0 +1,176 @@
+package com.kabouzeid.gramophone.dialogs;
+
+import android.Manifest;
+import android.app.Dialog;
+import android.content.pm.PackageManager;
+import android.os.Build;
+import android.os.Bundle;
+import android.os.Environment;
+import android.support.annotation.NonNull;
+import android.support.v4.app.ActivityCompat;
+import android.support.v4.app.DialogFragment;
+import android.view.View;
+
+import com.afollestad.materialdialogs.DialogAction;
+import com.afollestad.materialdialogs.MaterialDialog;
+import com.kabouzeid.gramophone.R;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+/**
+ * @author Aidan Follestad (afollestad), modified by Karim Abou Zeid
+ */
+public class BlacklistFolderChooserDialog extends DialogFragment implements MaterialDialog.ListCallback {
+
+    private File parentFolder;
+    private File[] parentContents;
+    private boolean canGoUp = false;
+
+    private FolderCallback callback;
+
+    String initialPath = Environment.getExternalStorageDirectory().getAbsolutePath();
+
+    private String[] getContentsArray() {
+        if (parentContents == null) {
+            if (canGoUp) {
+                return new String[]{".."};
+            }
+            return new String[]{};
+        }
+        String[] results = new String[parentContents.length + (canGoUp ? 1 : 0)];
+        if (canGoUp) {
+            results[0] = "..";
+        }
+        for (int i = 0; i < parentContents.length; i++) {
+            results[canGoUp ? i + 1 : i] = parentContents[i].getName();
+        }
+        return results;
+    }
+
+    private File[] listFiles() {
+        File[] contents = parentFolder.listFiles();
+        List<File> results = new ArrayList<>();
+        if (contents != null) {
+            for (File fi : contents) {
+                if (fi.isDirectory()) {
+                    results.add(fi);
+                }
+            }
+            Collections.sort(results, new FolderSorter());
+            return results.toArray(new File[results.size()]);
+        }
+        return null;
+    }
+
+    public static BlacklistFolderChooserDialog create() {
+        return new BlacklistFolderChooserDialog();
+    }
+
+    @NonNull
+    @Override
+    public Dialog onCreateDialog(Bundle savedInstanceState) {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M
+                && ActivityCompat.checkSelfPermission(
+                getActivity(), Manifest.permission.READ_EXTERNAL_STORAGE)
+                != PackageManager.PERMISSION_GRANTED) {
+            return new MaterialDialog.Builder(getActivity())
+                    .title(R.string.md_error_label)
+                    .content(R.string.md_storage_perm_error)
+                    .positiveText(android.R.string.ok)
+                    .build();
+        }
+        if (savedInstanceState == null) {
+            savedInstanceState = new Bundle();
+        }
+        if (!savedInstanceState.containsKey("current_path")) {
+            savedInstanceState.putString("current_path", initialPath);
+        }
+        parentFolder = new File(savedInstanceState.getString("current_path", File.pathSeparator));
+        checkIfCanGoUp();
+        parentContents = listFiles();
+        MaterialDialog.Builder builder =
+                new MaterialDialog.Builder(getActivity())
+                        .title(parentFolder.getAbsolutePath())
+                        .items((CharSequence[]) getContentsArray())
+                        .itemsCallback(this)
+                        .autoDismiss(false)
+                        .onPositive(new MaterialDialog.SingleButtonCallback() {
+                            @Override
+                            public void onClick(@NonNull MaterialDialog dialog, @NonNull DialogAction which) {
+                                dismiss();
+                                callback.onFolderSelection(BlacklistFolderChooserDialog.this, parentFolder);
+                            }
+                        })
+                        .onNegative(new MaterialDialog.SingleButtonCallback() {
+                            @Override
+                            public void onClick(@NonNull MaterialDialog materialDialog, @NonNull DialogAction dialogAction) {
+                                dismiss();
+                            }
+                        })
+                        .positiveText(R.string.add_action)
+                        .negativeText(android.R.string.cancel);
+        if (File.pathSeparator.equals(initialPath)) {
+            canGoUp = false;
+        }
+        return builder.build();
+    }
+
+    @Override
+    public void onSelection(MaterialDialog materialDialog, View view, int i, CharSequence s) {
+        if (canGoUp && i == 0) {
+            parentFolder = parentFolder.getParentFile();
+            if (parentFolder.getAbsolutePath().equals("/storage/emulated")) {
+                parentFolder = parentFolder.getParentFile();
+            }
+            canGoUp = parentFolder.getParent() != null;
+        } else {
+            parentFolder = parentContents[canGoUp ? i - 1 : i];
+            canGoUp = true;
+            if (parentFolder.getAbsolutePath().equals("/storage/emulated")) {
+                parentFolder = Environment.getExternalStorageDirectory();
+            }
+        }
+        reload();
+    }
+
+    private void checkIfCanGoUp() {
+        try {
+            canGoUp = parentFolder.getPath().split(File.pathSeparator).length > 1;
+        } catch (IndexOutOfBoundsException e) {
+            canGoUp = false;
+        }
+    }
+
+    private void reload() {
+        parentContents = listFiles();
+        MaterialDialog dialog = (MaterialDialog) getDialog();
+        dialog.setTitle(parentFolder.getAbsolutePath());
+        dialog.setItems((CharSequence[]) getContentsArray());
+    }
+
+    @Override
+    public void onSaveInstanceState(Bundle outState) {
+        super.onSaveInstanceState(outState);
+        outState.putString("current_path", parentFolder.getAbsolutePath());
+    }
+
+    public void setCallback(FolderCallback callback) {
+        this.callback = callback;
+    }
+
+    public interface FolderCallback {
+        void onFolderSelection(@NonNull BlacklistFolderChooserDialog dialog, @NonNull File folder);
+    }
+
+    private static class FolderSorter implements Comparator<File> {
+
+        @Override
+        public int compare(File lhs, File rhs) {
+            return lhs.getName().compareTo(rhs.getName());
+        }
+    }
+}