For you.. This is Perfect Tutorial. Here step by step explained Troubleshooting Eclipse Issues
First, try simply running Project => Clean... from the top-menu on the project and then re-running the app. If it still doesn't work, it might be the issue explained in the next paragraph.
This happens when the Android project was generated with a minimum SDK of 10 or below. One fix is to simply generate new projects with a minimum SDK of 14 instead. However when generating with a lower minSDK, in order to maintain compatibility with older versions, you'll notice that the activity Java class (i.e src/.../MainActivity.java) extends from AppCompatActivity rather than the standard Activity class. When an activity extends from AppCompatActivity, this requires the app to use a "backwards compatible theme".
Easiest fix is to change the theme for the application within the AndroidManifest.xml such that application:theme is set to @style/Theme.AppCompat.Light.DarkActionBar as shown below:

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