Support delete/undo in the File browser mode

Bug: 111863032
Test: atest FileUndoDeletionUiTest
Change-Id: If9a4a9ff8e44caa23d8f6ed140d6404080d76772

16 files changed, 308 insertions, 154 deletions

diff --git a/src/com/android/documentsui/ActionModeAddons.java b/src/com/android/documentsui/ActionModeAddons.java
index 83eba78bb..ef8ae1999 100644
--- a/src/com/android/documentsui/ActionModeAddons.java
+++ b/src/com/android/documentsui/ActionModeAddons.java
@@ -21,6 +21,4 @@ package com.android.documentsui;
 public interface ActionModeAddons {
 
     void finishActionMode();
-
-    void finishOnConfirmed(int code);
 }
diff --git a/src/com/android/documentsui/ActionModeController.java b/src/com/android/documentsui/ActionModeController.java
index 1c371fe30..4e0baef45 100644
--- a/src/com/android/documentsui/ActionModeController.java
+++ b/src/com/android/documentsui/ActionModeController.java
@@ -29,8 +29,6 @@ import android.view.MenuItem;
 import android.view.View;
 
 import com.android.documentsui.MenuManager.SelectionDetails;
-import com.android.documentsui.base.ConfirmationCallback;
-import com.android.documentsui.base.ConfirmationCallback.Result;
 import com.android.documentsui.base.EventHandler;
 import com.android.documentsui.base.Menus;
 import com.android.documentsui.selection.Selection;
@@ -185,13 +183,6 @@ public class ActionModeController extends SelectionObserver
         }
     }
 
-    @Override
-    public void finishOnConfirmed(@Result int code) {
-        if (code == ConfirmationCallback.CONFIRM) {
-            finishActionMode();
-        }
-    }
-
     public ActionModeController reset(
             SelectionDetails selectionDetails, EventHandler<MenuItem> menuItemClicker) {
         assert(mActionMode == null);
diff --git a/src/com/android/documentsui/Metrics.java b/src/com/android/documentsui/Metrics.java
index 838ebf8b7..12df0bf1d 100644
--- a/src/com/android/documentsui/Metrics.java
+++ b/src/com/android/documentsui/Metrics.java
@@ -318,6 +318,7 @@ public final class Metrics {
     public static final int USER_ACTION_EXTRACT_TO = 28;
     public static final int USER_ACTION_VIEW_IN_APPLICATION = 29;
     public static final int USER_ACTION_INSPECTOR = 30;
+    public static final int USER_ACTION_UNDO_DELETE = 31;
 
     @IntDef(flag = false, value = {
             USER_ACTION_OTHER,
@@ -349,7 +350,8 @@ public final class Metrics {
             USER_ACTION_COMPRESS,
             USER_ACTION_EXTRACT_TO,
             USER_ACTION_VIEW_IN_APPLICATION,
-            USER_ACTION_INSPECTOR
+            USER_ACTION_INSPECTOR,
+            USER_ACTION_UNDO_DELETE
     })
     @Retention(RetentionPolicy.SOURCE)
     public @interface UserAction {}
diff --git a/src/com/android/documentsui/Model.java b/src/com/android/documentsui/Model.java
index 96dfc5dec..f02c324a1 100644
--- a/src/com/android/documentsui/Model.java
+++ b/src/com/android/documentsui/Model.java
@@ -32,7 +32,6 @@ import androidx.annotation.Nullable;
 import androidx.annotation.VisibleForTesting;
 import android.util.Log;
 
-import com.android.documentsui.DirectoryResult;
 import com.android.documentsui.base.DocumentFilters;
 import com.android.documentsui.base.DocumentInfo;
 import com.android.documentsui.base.EventListener;
@@ -45,6 +44,7 @@ import java.lang.annotation.RetentionPolicy;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -73,6 +73,7 @@ public class Model {
     private @Nullable Cursor mCursor;
     private int mCursorCount;
     private String mIds[] = new String[0];
+    private Set<Selection> mDocumentsToBeDeleted = new HashSet<>();
 
     public Model(Features features) {
         mFeatures = features;
@@ -109,13 +110,13 @@ public class Model {
         doc = null;
         mIsLoading = false;
         mFileNames.clear();
+        mDocumentsToBeDeleted.clear();
         notifyUpdateListeners();
     }
 
     @VisibleForTesting
     protected void update(DirectoryResult result) {
         assert(result != null);
-
         if (DEBUG) Log.i(TAG, "Updating model with new result set.");
 
         if (result.exception != null) {
@@ -141,9 +142,56 @@ public class Model {
         notifyUpdateListeners();
     }
 
+    public void markDocumentsToBeDeleted(Selection selection) {
+        if (mDocumentsToBeDeleted.contains(selection)) {
+            return;
+        }
+        mDocumentsToBeDeleted.add(selection);
+        updateModelData();
+        notifyUpdateListeners();
+    }
+
+    public void restoreDocumentsToBeDeleted(Selection selection) {
+        if (!mDocumentsToBeDeleted.contains(selection)) {
+            return;
+        }
+        mDocumentsToBeDeleted.remove(selection);
+        updateModelData();
+        notifyUpdateListeners();
+    }
+
+    private boolean isDocumentToBeDeleted(String id) {
+        for (Selection s : mDocumentsToBeDeleted) {
+            if (s.contains(id)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private void updateDocumentsToBeDeleted() {
+        for (Iterator<Selection> i = mDocumentsToBeDeleted.iterator(); i.hasNext();) {
+            Selection selection = i.next();
+            for (String id : selection) {
+                if (!mPositions.containsKey(id)) {
+                    i.remove();
+                    break;
+                }
+            }
+        }
+    }
+
+    private int getDocumentsToBeDeletedCount() {
+        int count = 0;
+        for (Selection s : mDocumentsToBeDeleted) {
+            count += s.size();
+        }
+        return count;
+    }
+
     @VisibleForTesting
     public int getItemCount() {
-        return mCursorCount;
+        return mCursorCount - getDocumentsToBeDeletedCount();
     }
 
     /**
@@ -151,9 +199,10 @@ public class Model {
      * according to the current sort order.
      */
     private void updateModelData() {
-        mIds = new String[mCursorCount];
         mFileNames.clear();
         mCursor.moveToPosition(-1);
+        mPositions.clear();
+        String[] tmpIds = new String[mCursorCount];
         for (int pos = 0; pos < mCursorCount; ++pos) {
             if (!mCursor.moveToNext()) {
                 Log.e(TAG, "Fail to move cursor to next pos: " + pos);
@@ -164,18 +213,24 @@ public class Model {
             // If the cursor is a merged cursor over multiple authorities, then prefix the ids
             // with the authority to avoid collisions.
             if (mCursor instanceof MergeCursor) {
-                mIds[pos] = getCursorString(mCursor, RootCursorWrapper.COLUMN_AUTHORITY)
+                tmpIds[pos] = getCursorString(mCursor, RootCursorWrapper.COLUMN_AUTHORITY)
                         + "|" + getCursorString(mCursor, Document.COLUMN_DOCUMENT_ID);
             } else {
-                mIds[pos] = getCursorString(mCursor, Document.COLUMN_DOCUMENT_ID);
+                tmpIds[pos] = getCursorString(mCursor, Document.COLUMN_DOCUMENT_ID);
             }
+            mPositions.put(tmpIds[pos], pos);
             mFileNames.add(getCursorString(mCursor, Document.COLUMN_DISPLAY_NAME));
         }
 
-        // Populate the positions.
-        mPositions.clear();
+        updateDocumentsToBeDeleted();
+
+        mIds = new String[mCursorCount - getDocumentsToBeDeletedCount()];
+        int index = 0;
         for (int i = 0; i < mCursorCount; ++i) {
-            mPositions.put(mIds[i], i);
+            if (!isDocumentToBeDeleted(tmpIds[i])) {
+                mIds[index] = tmpIds[i];
+                index++;
+            }
         }
     }
 
diff --git a/src/com/android/documentsui/files/ActionHandler.java b/src/com/android/documentsui/files/ActionHandler.java
index 21926561f..19c812ffd 100644
--- a/src/com/android/documentsui/files/ActionHandler.java
+++ b/src/com/android/documentsui/files/ActionHandler.java
@@ -25,11 +25,11 @@ import android.content.ContentProviderClient;
 import android.content.ContentResolver;
 import android.content.Intent;
 import android.net.Uri;
-import android.os.Build;
 import android.provider.DocumentsContract;
 import android.text.TextUtils;
 import android.util.Log;
 import android.view.DragEvent;
+import android.view.View;
 
 import com.android.documentsui.AbstractActionHandler;
 import com.android.documentsui.ActionModeAddons;
@@ -42,8 +42,6 @@ import com.android.documentsui.Metrics;
 import com.android.documentsui.Model;
 import com.android.documentsui.R;
 import com.android.documentsui.TimeoutTask;
-import com.android.documentsui.base.ConfirmationCallback;
-import com.android.documentsui.base.ConfirmationCallback.Result;
 import com.android.documentsui.base.DebugFlags;
 import com.android.documentsui.base.DocumentFilters;
 import com.android.documentsui.base.DocumentInfo;
@@ -69,11 +67,15 @@ import com.android.documentsui.services.FileOperation;
 import com.android.documentsui.services.FileOperationService;
 import com.android.documentsui.services.FileOperations;
 import com.android.documentsui.ui.DialogController;
+import com.android.documentsui.ui.Snackbars;
+
 import androidx.annotation.VisibleForTesting;
+import android.support.design.widget.Snackbar;
 
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.Executor;
+import java.util.function.Consumer;
 
 import javax.annotation.Nullable;
 
@@ -93,6 +95,8 @@ public class ActionHandler<T extends Activity & Addons> extends AbstractActionHa
     private final DragAndDropManager mDragAndDropManager;
     private final Model mModel;
 
+    private Snackbar mDeletionSnackbar;
+
     ActionHandler(
             T activity,
             State state,
@@ -301,44 +305,57 @@ public class ActionHandler<T extends Activity & Addons> extends AbstractActionHa
 
         final @Nullable DocumentInfo srcParent = mState.stack.peek();
 
-        // Model must be accessed in UI thread, since underlying cursor is not threadsafe.
-        List<DocumentInfo> docs = mModel.getDocuments(selection);
-
-        ConfirmationCallback result = (@Result int code) -> {
-            // share the news with our caller, be it good or bad.
-            mActionModeAddons.finishOnConfirmed(code);
-
-            if (code != ConfirmationCallback.CONFIRM) {
-                return;
-            }
-
-            UrisSupplier srcs;
-            try {
-                srcs = UrisSupplier.create(
-                        selection,
-                        mModel::getItemUri,
-                        mClipStore);
-            } catch (Exception e) {
-                Log.e(TAG,"Failed to delete a file because we were unable to get item URIs.", e);
-                mDialogs.showFileOperationStatus(
-                        FileOperations.Callback.STATUS_FAILED,
-                        FileOperationService.OPERATION_DELETE,
-                        selection.size());
-                return;
+        UrisSupplier srcs;
+        try {
+            srcs = UrisSupplier.create(
+                    selection,
+                    mModel::getItemUri,
+                    mClipStore);
+        } catch (Exception e) {
+            Log.e(TAG, "Failed to delete a file because we were unable to get item URIs.", e);
+            mDialogs.showFileOperationStatus(
+                    FileOperations.Callback.STATUS_FAILED,
+                    FileOperationService.OPERATION_DELETE,
+                    selection.size());
+            return;
+        }
+        mModel.markDocumentsToBeDeleted(selection);
+        Consumer<View> action = v -> {
+            Metrics.logUserAction(mActivity, Metrics.USER_ACTION_UNDO_DELETE);
+            mModel.restoreDocumentsToBeDeleted(selection);
+        };
+        Snackbar.Callback callback = new Snackbar.Callback() {
+            @Override
+            public void onDismissed(Snackbar snackbar, int event) {
+                super.onDismissed(snackbar, event);
+                if (event != Snackbar.Callback.DISMISS_EVENT_ACTION) {
+                    FileOperation operation = new FileOperation.Builder()
+                            .withOpType(FileOperationService.OPERATION_DELETE)
+                            .withDestination(mState.stack)
+                            .withSrcs(srcs)
+                            .withSrcParent(srcParent == null ? null : srcParent.derivedUri)
+                            .build();
+
+                    FileOperations.start(mActivity, operation, null,
+                            FileOperations.createJobId());
+                }
+                if (mDeletionSnackbar == snackbar) {
+                    mDeletionSnackbar = null;
+                }
             }
-
-            FileOperation operation = new FileOperation.Builder()
-                    .withOpType(FileOperationService.OPERATION_DELETE)
-                    .withDestination(mState.stack)
-                    .withSrcs(srcs)
-                    .withSrcParent(srcParent == null ? null : srcParent.derivedUri)
-                    .build();
-
-            FileOperations.start(mActivity, operation, mDialogs::showFileOperationStatus,
-                    FileOperations.createJobId());
         };
+        mDeletionSnackbar = showDeletionSnackbar(mActivity, selection.size(), action, callback);
+    }
 
-        mDialogs.confirmDelete(docs, result);
+    public Snackbar showDeletionSnackbar(Activity activity, int docCount, Consumer<View> action,
+                               Snackbar.Callback callback) {
+        return Snackbars.showDelete(mActivity, docCount, action, callback);
+    }
+
+    public void dismissDeletionSnackBar() {
+        if (mDeletionSnackbar != null) {
+            mDeletionSnackbar.dismiss();
+        }
     }
 
     @Override
@@ -394,6 +411,12 @@ public class ActionHandler<T extends Activity & Addons> extends AbstractActionHa
     }
 
     @Override
+    public void loadDocumentsForCurrentStack() {
+        dismissDeletionSnackBar();
+        super.loadDocumentsForCurrentStack();
+    }
+
+    @Override
     public void initLocation(Intent intent) {
         assert(intent != null);
 
diff --git a/src/com/android/documentsui/files/FilesActivity.java b/src/com/android/documentsui/files/FilesActivity.java
index 3f1f47495..f27f0174f 100644
--- a/src/com/android/documentsui/files/FilesActivity.java
+++ b/src/com/android/documentsui/files/FilesActivity.java
@@ -262,6 +262,12 @@ public class FilesActivity extends BaseActivity implements ActionHandler.Addons
     }
 
     @Override
+    protected void onPause() {
+        super.onPause();
+        mInjector.actions.dismissDeletionSnackBar();
+    }
+
+    @Override
     public String getDrawerTitle() {
         Intent intent = getIntent();
         return (intent != null && intent.hasExtra(Intent.EXTRA_TITLE))
diff --git a/src/com/android/documentsui/services/FileOperations.java b/src/com/android/documentsui/services/FileOperations.java
index edb6d3757..5c9c62b37 100644
--- a/src/com/android/documentsui/services/FileOperations.java
+++ b/src/com/android/documentsui/services/FileOperations.java
@@ -62,9 +62,10 @@ public final class FileOperations {
 
         String newJobId = jobId != null ? jobId : createJobId();
         Intent intent = createBaseIntent(context, newJobId, operation);
-
-        callback.onOperationResult(Callback.STATUS_ACCEPTED, operation.getOpType(),
-                operation.getSrc().getItemCount());
+        if (callback != null) {
+            callback.onOperationResult(Callback.STATUS_ACCEPTED, operation.getOpType(),
+                    operation.getSrc().getItemCount());
+        }
 
         context.startService(intent);
 
diff --git a/src/com/android/documentsui/ui/DialogController.java b/src/com/android/documentsui/ui/DialogController.java
index 0de98683f..24a0b5155 100644
--- a/src/com/android/documentsui/ui/DialogController.java
+++ b/src/com/android/documentsui/ui/DialogController.java
@@ -24,7 +24,6 @@ import android.widget.Button;
 import android.widget.TextView;
 
 import com.android.documentsui.R;
-import com.android.documentsui.base.ConfirmationCallback;
 import com.android.documentsui.base.DocumentInfo;
 import com.android.documentsui.base.Features;
 import com.android.documentsui.picker.OverwriteConfirmFragment;
@@ -35,12 +34,9 @@ import com.android.documentsui.services.FileOperations.Callback.Status;
 import com.android.documentsui.services.FileOperations;
 
 import java.util.List;
-import javax.annotation.Nullable;
 
 public interface DialogController {
 
-    // Dialogs used in FilesActivity
-    void confirmDelete(List<DocumentInfo> docs, ConfirmationCallback callback);
     void showFileOperationStatus(int status, int opType, int docCount);
 
     /**
@@ -72,44 +68,7 @@ public interface DialogController {
         }
 
         @Override
-        public void confirmDelete(List<DocumentInfo> docs, ConfirmationCallback callback) {
-            assert(!docs.isEmpty());
-
-            TextView message =
-                    (TextView) mActivity.getLayoutInflater().inflate(
-                            R.layout.dialog_delete_confirmation, null);
-            message.setText(mMessages.generateDeleteMessage(docs));
-
-            // For now, we implement this dialog NOT
-            // as a fragment (which can survive rotation and have its own state),
-            // but as a simple runtime dialog. So rotating a device with an
-            // active delete dialog...results in that dialog disappearing.
-            // We can do better, but don't have cycles for it now.
-            final AlertDialog alertDialog = new AlertDialog.Builder(mActivity)
-                    .setView(message)
-                    .setPositiveButton(
-                            android.R.string.ok,
-                            new DialogInterface.OnClickListener() {
-                                @Override
-                                public void onClick(DialogInterface dialog, int id) {
-                                    callback.accept(ConfirmationCallback.CONFIRM);
-                                }
-                            })
-                    .setNegativeButton(android.R.string.cancel, null)
-                    .create();
-
-            alertDialog.setOnShowListener(
-                    (DialogInterface) -> {
-                        Button positive = alertDialog.getButton(AlertDialog.BUTTON_POSITIVE);
-                        positive.setFocusable(true);
-                        positive.requestFocus();
-                    });
-            alertDialog.show();
-        }
-
-        @Override
-        public void showFileOperationStatus(@Status int status, @OpType int opType,
-                int docCount) {
+        public void showFileOperationStatus(@Status int status, @OpType int opType, int docCount) {
             if (status == FileOperations.Callback.STATUS_REJECTED) {
                 showOperationUnsupported();
                 return;
@@ -143,9 +102,6 @@ public interface DialogController {
                 case FileOperationService.OPERATION_EXTRACT:
                     Snackbars.showExtract(mActivity, docCount);
                     break;
-                case FileOperationService.OPERATION_DELETE:
-                    Snackbars.showDelete(mActivity, docCount);
-                    break;
                 default:
                     throw new UnsupportedOperationException("Unsupported Operation: " + opType);
             }
diff --git a/src/com/android/documentsui/ui/Snackbars.java b/src/com/android/documentsui/ui/Snackbars.java
index 005e3ef32..c587e0053 100644
--- a/src/com/android/documentsui/ui/Snackbars.java
+++ b/src/com/android/documentsui/ui/Snackbars.java
@@ -26,7 +26,11 @@ import android.widget.TextView;
 import com.android.documentsui.R;
 import com.android.documentsui.base.Shared;
 
+import java.util.function.Consumer;
+
 public final class Snackbars {
+    public static final int DELETION_TIMEOUT = 10000;
+
     private Snackbars() {}
 
     public static final void showDocumentsClipped(Activity activity, int docCount) {
@@ -55,9 +59,14 @@ public final class Snackbars {
         makeSnackbar(activity, message, Snackbar.LENGTH_SHORT).show();
     }
 
-    public static final void showDelete(Activity activity, int docCount) {
+    public static final Snackbar showDelete(Activity activity, int docCount, Consumer<View> action,
+            Snackbar.Callback callback) {
         CharSequence message = Shared.getQuantityString(activity, R.plurals.deleting, docCount);
-        makeSnackbar(activity, message, Snackbar.LENGTH_SHORT).show();
+        CharSequence actionText = activity.getResources().getText(R.string.undo);
+        Snackbar snackbar = makeSnackbarWithAction(activity, docCount, message, DELETION_TIMEOUT,
+                actionText, action, callback);
+        snackbar.show();
+        return snackbar;
     }
 
     public static final void showOperationRejected(Activity activity) {
@@ -73,7 +82,6 @@ public final class Snackbars {
     }
 
     public static final void showInspectorError(Activity activity) {
-
         //Document Inspector uses a different view from other files app activities.
         final View view = activity.findViewById(R.id.fragment_container);
         Snackbar.make(view, R.string.inspector_load_error, Snackbar.LENGTH_INDEFINITE).show();
@@ -90,6 +98,14 @@ public final class Snackbars {
         snackbar.show();
     }
 
+    public static final Snackbar makeSnackbarWithAction(Activity activity, int docCount,
+            CharSequence message, int duration, CharSequence actionText,
+            Consumer<View> action, final Snackbar.Callback callback) {
+        return makeSnackbar(activity, message, duration)
+                .setAction(actionText, action::accept)
+                .addCallback(callback);
+    }
+
     public static final Snackbar makeSnackbar(Activity activity, @StringRes int messageId,
             int duration) {
         return Snackbars.makeSnackbar(
diff --git a/tests/common/com/android/documentsui/TestActionModeAddons.java b/tests/common/com/android/documentsui/TestActionModeAddons.java
index 5379bbb4c..c928d6f23 100644
--- a/tests/common/com/android/documentsui/TestActionModeAddons.java
+++ b/tests/common/com/android/documentsui/TestActionModeAddons.java
@@ -15,20 +15,12 @@
  */
 package com.android.documentsui;
 
-import com.android.documentsui.testing.TestConfirmationCallback;
-
 public class TestActionModeAddons implements ActionModeAddons {
 
     public boolean finishActionModeCalled;
-    public final TestConfirmationCallback finishOnConfirmed = new TestConfirmationCallback();
 
     @Override
     public void finishActionMode() {
         finishActionModeCalled = true;
     }
-
-    @Override
-    public void finishOnConfirmed(int code) {
-        finishOnConfirmed.accept(code);
-    }
 }
diff --git a/tests/common/com/android/documentsui/bots/DirectoryListBot.java b/tests/common/com/android/documentsui/bots/DirectoryListBot.java
index aaf5c8c79..dd8688360 100644
--- a/tests/common/com/android/documentsui/bots/DirectoryListBot.java
+++ b/tests/common/com/android/documentsui/bots/DirectoryListBot.java
@@ -56,7 +56,7 @@ public class DirectoryListBot extends Bots.BaseBot {
     private static final String DIR_LIST_ID = "com.android.documentsui:id/dir_list";
 
     private static final BySelector SNACK_DELETE =
-            By.desc(Pattern.compile("^Deleting [0-9]+ file.+"));
+            By.text(Pattern.compile("^Deleting [0-9]+ item.+"));
     private UiAutomation mAutomation;
 
     public DirectoryListBot(
@@ -222,6 +222,12 @@ public class DirectoryListBot extends Bots.BaseBot {
         return mDevice.wait(Until.findObject(By.text(message)), mTimeout);
     }
 
+    public void clickSnackbarAction() throws UiObjectNotFoundException {
+        UiObject snackbarAction =
+                findObject("com.android.documentsui:id/snackbar_action");
+        snackbarAction.click();
+    }
+
     public void waitForDeleteSnackbar() {
         mDevice.wait(Until.findObject(SNACK_DELETE), mTimeout);
     }
diff --git a/tests/common/com/android/documentsui/ui/TestDialogController.java b/tests/common/com/android/documentsui/ui/TestDialogController.java
index b67ce46dd..d87cd0c80 100644
--- a/tests/common/com/android/documentsui/ui/TestDialogController.java
+++ b/tests/common/com/android/documentsui/ui/TestDialogController.java
@@ -17,18 +17,15 @@ package com.android.documentsui.ui;
 
 import android.app.FragmentManager;
 
-import com.android.documentsui.base.ConfirmationCallback;
 import com.android.documentsui.base.DocumentInfo;
 import com.android.documentsui.services.FileOperation;
 import com.android.documentsui.services.FileOperations;
 
 import junit.framework.Assert;
 
-import java.util.List;
 
 public class TestDialogController implements DialogController {
 
-    public int mNextConfirmationCode;
     private int mFileOpStatus;
     private boolean mNoApplicationFound;
     private boolean mDocumentsClipped;
@@ -37,13 +34,6 @@ public class TestDialogController implements DialogController {
     private DocumentInfo mOverwriteTarget;
 
     public TestDialogController() {
-        // by default, always confirm
-        mNextConfirmationCode = ConfirmationCallback.CONFIRM;
-    }
-
-    @Override
-    public void confirmDelete(List<DocumentInfo> docs, ConfirmationCallback callback) {
-        callback.accept(mNextConfirmationCode);
     }
 
     @Override
@@ -107,12 +97,4 @@ public class TestDialogController implements DialogController {
     public void assertOverwriteConfirmed(DocumentInfo expected) {
         Assert.assertEquals(expected, mOverwriteTarget);
     }
-
-    public void confirmNext() {
-        mNextConfirmationCode = ConfirmationCallback.CONFIRM;
-    }
-
-    public void rejectNext() {
-        mNextConfirmationCode = ConfirmationCallback.REJECT;
-    }
 }
diff --git a/tests/functional/com/android/documentsui/FileDeleteUiTest.java b/tests/functional/com/android/documentsui/FileDeleteUiTest.java
index fbeaf3463..b86e417ac 100644
--- a/tests/functional/com/android/documentsui/FileDeleteUiTest.java
+++ b/tests/functional/com/android/documentsui/FileDeleteUiTest.java
@@ -155,16 +155,16 @@ public class FileDeleteUiTest extends ActivityTest<FilesActivity> {
         exec.shutdown();
     }
 
-    public void testDeleteAllDocument() throws Exception {
+    public void testDeleteAllDocument_AfterSnackbarDismissed() throws Exception {
         bots.roots.openRoot(ROOT_0_ID);
         bots.main.clickToolbarOverflowItem(
                 context.getResources().getString(R.string.menu_select_all));
         device.waitForIdle();
 
         bots.main.clickToolbarItem(R.id.action_menu_delete);
-        bots.main.clickDialogOkButton();
         device.waitForIdle();
 
+        bots.directory.waitForDeleteSnackbarGone();
         try {
             mCountDownLatch.await(WAIT_TIME_SECONDS, TimeUnit.SECONDS);
         } catch (Exception e) {
@@ -179,4 +179,18 @@ public class FileDeleteUiTest extends ActivityTest<FilesActivity> {
         List<DocumentInfo> root1 = mDocsHelper.listChildren(rootDir0.documentId, 1000);
         assertTrue("Delete operation was not completed", root1.size() == 0);
     }
+
+    public void testDeleteAllDocument_BeforeSnackbarDismissed() throws Exception {
+        bots.roots.openRoot(ROOT_0_ID);
+        bots.main.clickToolbarOverflowItem(
+                context.getResources().getString(R.string.menu_select_all));
+        device.waitForIdle();
+
+        bots.main.clickToolbarItem(R.id.action_menu_delete);
+        device.waitForIdle();
+
+        bots.directory.waitForDeleteSnackbar();
+        List<DocumentInfo> root1 = mDocsHelper.listChildren(rootDir0.documentId, 1000);
+        assertTrue("Documents are deleted", root1.size() == 1000);
+    }
 }
diff --git a/tests/functional/com/android/documentsui/FileUndoDeletionUiTest.java b/tests/functional/com/android/documentsui/FileUndoDeletionUiTest.java
new file mode 100644
index 000000000..0da36ea55
--- /dev/null
+++ b/tests/functional/com/android/documentsui/FileUndoDeletionUiTest.java
@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.documentsui;
+
+import static com.android.documentsui.StubProvider.ROOT_0_ID;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.net.Uri;
+import android.os.Bundle;
+import android.os.RemoteException;
+import android.provider.DocumentsContract;
+import android.support.test.filters.LargeTest;
+import android.support.test.uiautomator.UiObject;
+import android.util.Log;
+
+import com.android.documentsui.base.DocumentInfo;
+import com.android.documentsui.files.FilesActivity;
+import com.android.documentsui.services.TestNotificationService;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+
+/**
+* This class test the below points
+* - Undo the deleted files
+*/
+@LargeTest
+public class FileUndoDeletionUiTest extends ActivityTest<FilesActivity> {
+    private static final String TAG = "FileUndoDeletionUiTest";
+
+    private static final int DUMMY_FILE_COUNT = 3;
+
+    private String[] filenames = new String[DUMMY_FILE_COUNT];
+
+    public FileUndoDeletionUiTest() {
+        super(FilesActivity.class);
+    }
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+
+        // Set a flag to prevent many refreshes.
+        Bundle bundle = new Bundle();
+        bundle.putBoolean(StubProvider.EXTRA_ENABLE_ROOT_NOTIFICATION, false);
+        mDocsHelper.configure(null, bundle);
+
+        initTestFiles();
+    }
+
+    @Override
+    public void initTestFiles() {
+        for (int i = 0; i < DUMMY_FILE_COUNT; i++) {
+            filenames[i] = "file" + i + ".log";
+            mDocsHelper.createDocument(rootDir0, "text/plain", filenames[i]);
+        }
+    }
+
+    public void testDeleteUndoDocumentsUI() throws Exception {
+        bots.roots.openRoot(ROOT_0_ID);
+        bots.main.clickToolbarOverflowItem(
+                context.getResources().getString(R.string.menu_select_all));
+        device.waitForIdle();
+
+        bots.main.clickToolbarItem(R.id.action_menu_delete);
+        device.waitForIdle();
+
+        bots.directory.waitForDeleteSnackbar();
+        for (String filename : filenames) {
+            assertFalse("files are not deleted", bots.directory.hasDocuments(filename));
+        }
+
+        bots.directory.clickSnackbarAction();
+        device.waitForIdle();
+
+        assertTrue("deleted files are not restored", bots.directory.hasDocuments(filenames));
+    }
+}
diff --git a/tests/unit/com/android/documentsui/files/ActionHandlerTest.java b/tests/unit/com/android/documentsui/files/ActionHandlerTest.java
index 1916924ed..00ca81bf0 100644
--- a/tests/unit/com/android/documentsui/files/ActionHandlerTest.java
+++ b/tests/unit/com/android/documentsui/files/ActionHandlerTest.java
@@ -29,6 +29,10 @@ import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertSame;
 import static org.junit.Assert.assertTrue;
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.ArgumentMatchers.anyObject;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.spy;
 
 import android.app.Activity;
 import android.app.PendingIntent;
@@ -38,11 +42,13 @@ import android.net.Uri;
 import android.os.Parcelable;
 import android.provider.DocumentsContract;
 import android.provider.DocumentsContract.Path;
+import android.support.design.widget.Snackbar;
 import android.support.test.InstrumentationRegistry;
 import android.support.test.filters.MediumTest;
 import android.support.test.runner.AndroidJUnit4;
 import android.util.Pair;
 import android.view.DragEvent;
+import android.view.View;
 
 import com.android.documentsui.AbstractActionHandler;
 import com.android.documentsui.R;
@@ -68,8 +74,11 @@ import androidx.core.util.Preconditions;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
+import org.mockito.invocation.InvocationOnMock;
+import org.mockito.stubbing.Answer;
 
 import java.util.Arrays;
+import java.util.function.Consumer;
 
 @RunWith(AndroidJUnit4.class)
 @MediumTest
@@ -99,9 +108,8 @@ public class ActionHandlerTest {
         ((TestActivityConfig) mEnv.injector.config).nextDocumentEnabled = true;
         mEnv.injector.dialogs = mDialogs;
 
-        mHandler = createHandler();
-
-        mDialogs.confirmNext();
+        ActionHandler<TestActivity> handler = createHandler();
+        mHandler = spy(handler);
 
         mEnv.selectDocument(TestEnv.FILE_GIF);
     }
@@ -161,31 +169,38 @@ public class ActionHandlerTest {
 
         mEnv.selectionMgr.clearSelection();
         mHandler.deleteSelectedDocuments();
-        mDialogs.assertNoFileFailures();
         mActivity.startService.assertNotCalled();
-        mActionModeAddons.finishOnConfirmed.assertNeverCalled();
     }
 
     @Test
-    public void testDeleteSelectedDocuments_Cancelable() {
+    public void testDeleteSelectedDocuments_Undo() {
         mEnv.populateStack();
-
-        mDialogs.rejectNext();
+        doAnswer(new Answer() {
+            @Override
+            public Object answer(InvocationOnMock invocation) throws Throwable {
+                Consumer<View> callback = invocation.getArgument(2);
+                callback.accept(null);
+                return null;
+            }
+        }).when(mHandler).showDeletionSnackbar(anyObject(), anyInt(), anyObject(), anyObject());
         mHandler.deleteSelectedDocuments();
-        mDialogs.assertNoFileFailures();
         mActivity.startService.assertNotCalled();
-        mActionModeAddons.finishOnConfirmed.assertRejected();
     }
 
     // Recents root means when deleting the srcParent will be null.
     @Test
     public void testDeleteSelectedDocuments_RecentsRoot() {
         mEnv.state.stack.changeRoot(TestProvidersAccess.RECENTS);
-
+        doAnswer(new Answer() {
+            @Override
+            public Object answer(InvocationOnMock invocation) throws Throwable {
+                Snackbar.Callback callback = invocation.getArgument(3);
+                callback.onDismissed(null, Snackbar.Callback.DISMISS_EVENT_MANUAL);
+                return null;
+            }
+        }).when(mHandler).showDeletionSnackbar(anyObject(), anyInt(), anyObject(), anyObject());
         mHandler.deleteSelectedDocuments();
-        mDialogs.assertNoFileFailures();
         mActivity.startService.assertCalled();
-        mActionModeAddons.finishOnConfirmed.assertCalled();
     }
 
     @Test
diff --git a/tests/unit/com/android/documentsui/picker/ActionHandlerTest.java b/tests/unit/com/android/documentsui/picker/ActionHandlerTest.java
index 5d4156558..99947e886 100644
--- a/tests/unit/com/android/documentsui/picker/ActionHandlerTest.java
+++ b/tests/unit/com/android/documentsui/picker/ActionHandlerTest.java
@@ -78,8 +78,6 @@ public class ActionHandlerTest {
                 mLastAccessed
         );
 
-        mEnv.dialogs.confirmNext();
-
         mEnv.selectionMgr.select("1");
 
         AsyncTask.setDefaultExecutor(mEnv.mExecutor);