Model-based GUI exploration techniques are widely used to generate test cases for event-driven programs (such as Android apps). These techniques traverse the elements of screens during the user interaction and simultaneously construct the GUI model. Although there are a number of automatic model-based exploration tools, most of them pay more attention to the exploration procedure than the model reusing. This paper presents LAND, an effective and user-friendly test generation tool based on GUI exploration of Android apps, which constructs an elaborate window transition model ``LATTE'' that considers more Android specific characteristics and provides a customizable test generation interface by reusing the model. Experiments on 20 real-world Android apps are conducted to construct their models as well as test cases. The experimental results indicate that LAND can achieve higher code coverage and trigger exceptions in shorter sequence. It is also demonstrated that LATTE can be well reused under different requirements of test suite generation. A demo video of our tool can be found at the website https://www.youtube.com/watch?v=iqtr12eiJ_0.