Fixes issue 939

Heavily inspired from Gmail implementation. Currently implemented only for MessageView delete operation.

res/values/ids.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+
+    <item type="id" name="dialog_confirm_delete"/>
+
+</resources>

res/values/strings.xml

@@ -319,6 +319,13 @@ Welcome to K-9 Mail setup.  K-9 is an open source mail client for Android origin
     <string name="global_settings_messageview_return_to_list_label">Return to list after delete</string>
     <string name="global_settings_messageview_return_to_list_summary">Return to message list after message deletion</string>
 
+    <string name="global_settings_confirm_actions_title">Confirm actions</string>
+    <string name="global_settings_confirm_actions_summary">Show a dialog whenever you perform selected actions</string>
+    <string name="global_settings_confirm_action_archive">Archive</string>
+    <string name="global_settings_confirm_action_delete">Delete (message view only)</string>
+    <string name="global_settings_confirm_action_spam">Spam</string>
+    <string name="global_settings_confirm_action_send">Send</string>
+
     <string name="account_setup_basics_title">Set up a new account</string>
     <string name="account_setup_basics_instructions">Enter this account\'s email address:</string>
     <string name="account_setup_basics_instructions2_fmt">(You may add <xliff:g id="number_accounts">%d</xliff:g> more accounts.)</string>
@@ -933,4 +940,10 @@ Welcome to K-9 Mail setup.  K-9 is an open source mail client for Android origin
     <string name="charset_not_found">This message can\'t be displayed because the charset \"<xliff:g id="charset">%s</xliff:g>\" wasn\'t found.</string>
 
     <string name="select_text_now">Select text to copy.</string>
+
+    <string name="dialog_confirm_delete_title">Confirm deletion</string>
+    <string name="dialog_confirm_delete_message">Do you want to delete this message?</string>
+    <string name="dialog_confirm_delete_confirm_button">Delete</string>
+    <string name="dialog_confirm_delete_cancel_button">Do not delete</string>
+
 </resources>

res/xml/global_preferences.xml

@@ -70,6 +70,15 @@
             android:title="@string/start_integrated_inbox_title"
             android:summary="@string/start_integrated_inbox_summary" />
 
+        <com.fsck.k9.preferences.CheckboxListPreference
+            android:key="confirm_actions"
+            android:title="@string/global_settings_confirm_actions_title"
+            android:summary="@string/global_settings_confirm_actions_summary"
+            android:dialogTitle="@string/global_settings_confirm_actions_title"
+            android:positiveButtonText="@android:string/ok"
+            android:negativeButtonText="@android:string/cancel"
+        />
+
     </PreferenceCategory>
 
     <PreferenceCategory android:title="@string/accountlist_preferences" android:key="accountlist_preferences">

src/com/fsck/k9/K9.java

@@ -106,6 +106,7 @@ public class K9 extends Application
 
     private static boolean mAnimations = true;
 
+    private static boolean mConfirmDelete = false;
 
     private static boolean mMessageListStars = true;
     private static boolean mMessageListCheckboxes = false;
@@ -353,6 +354,8 @@ public class K9 extends Application
         editor.putInt("theme", theme);
         editor.putBoolean("useGalleryBugWorkaround", useGalleryBugWorkaround);
 
+        editor.putBoolean("confirmDelete", mConfirmDelete);
+
         fontSizes.save(editor);
     }
 
@@ -384,6 +387,8 @@ public class K9 extends Application
 
         useGalleryBugWorkaround = sprefs.getBoolean("useGalleryBugWorkaround", K9.isGalleryBuggy());
 
+        mConfirmDelete = sprefs.getBoolean("confirmDelete", false);
+
         fontSizes.load(sprefs);
 
         try
@@ -684,6 +689,16 @@ public class K9 extends Application
         return galleryBuggy;
     }
 
+    public static boolean confirmDelete()
+    {
+        return mConfirmDelete;
+    }
+
+    public static void setConfirmDelete(final boolean confirm)
+    {
+        mConfirmDelete = confirm;
+    }
+
     /**
      * Check if this system contains a buggy Gallery 3D package.
      *
@@ -706,4 +721,5 @@ public class K9 extends Application
             return false;
         }
     }
+
 }

src/com/fsck/k9/activity/MessageView.java

@@ -16,8 +16,11 @@ import java.util.regex.Pattern;
 
 import org.apache.commons.io.IOUtils;
 
+import android.app.AlertDialog;
+import android.app.Dialog;
 import android.content.ContentResolver;
 import android.content.Context;
+import android.content.DialogInterface;
 import android.content.Intent;
 import android.content.pm.ResolveInfo;
 import android.content.res.Configuration;
@@ -1291,7 +1294,54 @@ public class MessageView extends K9Activity implements OnClickListener
         super.onResume();
     }
 
+    /**
+     * Called from UI thread when user select Delete
+     */
     private void onDelete()
+    {
+        if (K9.confirmDelete())
+        {
+            showDialog(R.id.dialog_confirm_delete);
+        }
+        else
+        {
+            delete();
+        }
+    }
+
+    /**
+     * @param id
+     * @return Never <code>null</code>
+     */
+    protected Dialog createConfirmDeleteDialog(final int id)
+    {
+        final AlertDialog.Builder builder = new AlertDialog.Builder(this);
+        builder.setTitle(R.string.dialog_confirm_delete_title);
+        builder.setMessage(R.string.dialog_confirm_delete_message);
+        builder.setPositiveButton(R.string.dialog_confirm_delete_confirm_button,
+                new DialogInterface.OnClickListener()
+                {
+                    @Override
+                    public void onClick(DialogInterface dialog, int which)
+                    {
+                        dismissDialog(id);
+                        delete();
+                    }
+                });
+        builder.setNegativeButton(R.string.dialog_confirm_delete_cancel_button,
+                new DialogInterface.OnClickListener()
+                {
+                    @Override
+                    public void onClick(DialogInterface dialog, int which)
+                    {
+                        dismissDialog(id);
+                    }
+                });
+        final AlertDialog dialog = builder.create();
+        return dialog;
+    }
+
+    private void delete()
     {
         if (mMessage != null)
         {
@@ -1923,6 +1973,27 @@ public class MessageView extends K9Activity implements OnClickListener
         return super.onPrepareOptionsMenu(menu);
     }
 
+    // XXX when switching to API version 8, override onCreateDialog(int, Bundle)
+    /**
+     * @param id
+     *            The id of the dialog.
+     * @return The dialog. If you return null, the dialog will not be created.
+     * @see android.app.Activity#onCreateDialog(int, Bundle)
+     */
+    @Override
+    protected Dialog onCreateDialog(final int id)
+    {
+        switch (id)
+        {
+            case R.id.dialog_confirm_delete:
+            {
+                final Dialog dialog = createConfirmDeleteDialog(id);
+                return dialog;
+            }
+        }
+        return super.onCreateDialog(id);
+    }
+
     private void prepareMenuItems()
     {
         Menu menu = optionsMenu;

src/com/fsck/k9/activity/setup/Prefs.java

@@ -20,6 +20,7 @@ import com.fsck.k9.R;
 import com.fsck.k9.activity.Accounts;
 import com.fsck.k9.activity.DateFormatter;
 import com.fsck.k9.activity.K9PreferenceActivity;
+import com.fsck.k9.preferences.CheckboxListPreference;
 import com.fsck.k9.service.MailService;
 
 public class Prefs extends K9PreferenceActivity
@@ -53,6 +54,9 @@ public class Prefs extends K9PreferenceActivity
     private static final String PREFERENCE_MEASURE_ACCOUNTS = "measure_accounts";
     private static final String PREFERENCE_COUNT_SEARCH = "count_search";
     private static final String PREFERENCE_GALLERY_BUG_WORKAROUND = "use_gallery_bug_workaround";
+
+    private static final String PREFERENCE_CONFIRM_ACTIONS = "confirm_actions";
+
     private ListPreference mLanguage;
     private ListPreference mTheme;
     private ListPreference mDateFormat;
@@ -75,6 +79,7 @@ public class Prefs extends K9PreferenceActivity
     private CheckBoxPreference mCountSearch;
     private CheckBoxPreference mUseGalleryBugWorkaround;
 
+    private CheckboxListPreference mConfirmActions;
 
     private String initBackgroundOps;
 
@@ -233,6 +238,10 @@ public class Prefs extends K9PreferenceActivity
 
         mUseGalleryBugWorkaround = (CheckBoxPreference)findPreference(PREFERENCE_GALLERY_BUG_WORKAROUND);
         mUseGalleryBugWorkaround.setChecked(K9.useGalleryBugWorkaround());
+
+        mConfirmActions = (CheckboxListPreference) findPreference(PREFERENCE_CONFIRM_ACTIONS);
+        mConfirmActions.setItems(new CharSequence[] {getString(R.string.global_settings_confirm_action_delete)});
+        mConfirmActions.setCheckedItems(new boolean[] {K9.confirmDelete()});
     }
 
     @Override
@@ -267,6 +276,8 @@ public class Prefs extends K9PreferenceActivity
 
         K9.setUseGalleryBugWorkaround(mUseGalleryBugWorkaround.isChecked());
 
+        K9.setConfirmDelete(mConfirmActions.getCheckedItems()[0]);
+
         Editor editor = preferences.edit();
         K9.save(editor);
         DateFormatter.setDateFormat(editor, mDateFormat.getValue());

src/com/fsck/k9/preferences/CheckboxListPreference.java

@@ -0,0 +1,84 @@
+package com.fsck.k9.preferences;
+
+import android.app.AlertDialog.Builder;
+import android.content.Context;
+import android.content.DialogInterface;
+import android.preference.DialogPreference;
+import android.util.AttributeSet;
+
+public class CheckboxListPreference extends DialogPreference
+{
+
+    private CharSequence[] mItems;
+
+    private boolean[] mCheckedItems;
+
+    /**
+     * checkboxes state when the dialog is displayed
+     */
+    private boolean[] mPendingItems;
+
+    /**
+     * @param context
+     * @param attrs
+     * @param defStyle
+     */
+    public CheckboxListPreference(Context context, AttributeSet attrs, int defStyle)
+    {
+        super(context, attrs, defStyle);
+    }
+
+    /**
+     * @param context
+     * @param attrs
+     */
+    public CheckboxListPreference(Context context, AttributeSet attrs)
+    {
+        super(context, attrs);
+    }
+
+    @Override
+    protected void onPrepareDialogBuilder(final Builder builder)
+    {
+        mPendingItems = new boolean[mItems.length];
+
+        System.arraycopy(mCheckedItems, 0, mPendingItems, 0, mCheckedItems.length);
+
+        builder.setMultiChoiceItems(mItems, mPendingItems,
+                new DialogInterface.OnMultiChoiceClickListener()
+                {
+                    @Override
+                    public void onClick(final DialogInterface dialog, final int which,
+                            final boolean isChecked)
+                    {
+                        mPendingItems[which] = isChecked;
+                    }
+                });
+    }
+
+    @Override
+    protected void onDialogClosed(boolean positiveResult)
+    {
+        if (positiveResult)
+        {
+            System.arraycopy(mPendingItems, 0, mCheckedItems, 0, mPendingItems.length);
+        }
+        mPendingItems = null;
+    }
+
+    public void setItems(final CharSequence[] items)
+    {
+        mItems = items;
+    }
+
+    public void setCheckedItems(final boolean[] items)
+    {
+        mCheckedItems = items;
+    }
+
+    public boolean[] getCheckedItems()
+    {
+        return mCheckedItems;
+    }
+
+}