GoTasks

Lightweight task management application, allows to sync your tasks with Google Tasks (aka gtasks, gtask).
Helps to organize Your tasks (TODO, Checklist) according to GTD (Getting Things Done) principles.
Not burdened with additional frameworks and therefore fast and low battery consumption. Maximum use of Android integrated functionality.
NO Ad, Free!

IMPORTANT:
After application installed You will receive message in Notification bar: "Permission requested" which requires you to approve authentication of GoTasks to Google™ Tasks service to allow sync.

GoTasks site:
https://plus.google.com/109117465685603822704

Features:
- Google™ Tasks integration (offline work with tasks, two-way synchronization)
- Widget (6 different sizes), create task by widget + click
- Multiple widgets on desktop support
- Local tasks account
- Subtasks, ident/unident
- Change task and checklist ordering using Drag and Drop
- Fast create multiple tasks (one by one)
- Multiple account sync and display simultaneously
- Allow to configure sync interval
- Force sync manually
- Task and tasklist different ordering options
- Search for tasks
- Share tasklist or task via sms,email,etc
- Theme support. Dark theme saves battery on AMOLED, White theme for old not LCD's with low contrast
- Create Google Calendar reminder via context menu
- Honeycomb+ support

Lightweight:
- Extremely fast (no additional frameworks overhead)
- Small storage/memory consumption
- Small battery drain

Simple and native:
- Native Android Look and Feel
- Native account and sync integration (System Settings->Accounts & Sync->inside each google account)
- Using system-wide date format and other settings
- All in one Screen: each tasklist (checklist) expanded or collapsed with it's tasks
- Actions by context menu(long tap) on items