我是Android开发的新手。
我正在使用Eclipse。
我从示例中复制了蛇游戏。
当我尝试运行它时，控制台上会显示以下内容：
11-06-01 20:11:32 - Snake] Android Launch!
[2011-06-01 20:11:32 - Snake] adb is running normally.
[2011-06-01 20:11:32 - Snake] Performing
com.example.android.snake.Snake activity launch
[2011-06-01 20:11:32 - Snake] Automatic Target Mode: Preferred AVD
'Pratyush_android' is not available. Launching new emulator.
[2011-06-01 20:11:32 - Snake] Launching a new emulator with Virtual
Device 'Pratyush_android'
[2011-06-01 20:11:33 - Snake] New emulator found: emulator-5554
[2011-06-01 20:11:33 - Snake] Waiting for HOME
('android.process.acore') to be launched...
[2011-06-01 20:11:54 - Snake] WARNING: Application does not specify an
API level requirement!
[2011-06-01 20:11:54 - Snake] Device API version is 4 (Android 1.6)
[2011-06-01 20:11:54 - Snake] HOME is up on device 'emulator-5554'
[2011-06-01 20:11:54 - Snake] Uploading Snake.apk onto device
'emulator-5554'
[2011-06-01 20:11:54 - Snake] Installing Snake.apk...
[2011-06-01 20:12:06 - Snake] Success!
[2011-06-01 20:12:06 - Snake] Starting activity
com.example.android.snake.Snake on device emulator-5554
[2011-06-01 20:12:11 - Snake] ActivityManager: Starting: Intent
{ act=android.intent.action.MAIN
cat=[android.intent.category.LAUNCHER]
cmp=com.example.android.snake/.Snake }
在模拟器的屏幕上，它说：
SCREEN is LOCKED ,Unlock it by pressing Menu
当我按下菜单时，会出现一个消息框：
The application(process com.example.android.snake) has stopped
unexpectedly.
Please try again.
导致这种情况的原因是什么？