Can't run android applications
<p>I have a helloworld android application. But it can't run.</p>

<p>(Same code ran well yesterday. I don't know what configuration I changed..)</p>

<p>When I pressed "run as android application" in eclipse, nothing happened.</p>

<p>I used command line to run it:
<code>$adb install -rv HelloAndroid.apk</code>
But nothing happened, either.</p>

<p>I can see my emulator from <code>$adb devices</code></p>

<pre><code>List of devices attached 
emulator-5554   device
</code></pre>

<p>How can I find the problem?</p>
