Rename Android project package issue in Eclipse - R cannot be resolved to a variable

1.) Open DDMS via Menu Tools > Android > Android Device Monitor
2.) Select Device
3.) In DDMS click Menu Window > Show View > File Exlporer
4.) Device > Storage folder
5.) Emulator > data > data folder

[2013-07-06 16:10:29 - SDK Manager] [SDK Manager] Error: Error parsing the sdk.
[2013-07-06 16:10:29 - SDK Manager] [SDK Manager] Error: Failed to create C:\Program Files\android\sdk\add-ons.
[2013-07-06 16:10:29 - SDK Manager] [SDK Manager] Error: Unable to parse SDK content.

You have to create add-ons folder as admin of PC

File->Settings->Plugins and disable some plugins:

• Google Cloud Testing


• Google Cloud Tools Core


• Google Cloud Tools for Android Studio


• CVS Integration


• Git Integration


• GitHub


• hg4idea


• Subversion Integration

Use Emulator AVD with small memmory usage. For example: Virtual tablet with hight resolution have big memmory usage. Virtual phone with 240x320 resolution have small memmory usage.

Use instaed of Emulator, real device connected by USB (smarphone Samsung Galaxy or other recommended by Google whit debugable mode).

If you notice that Android Studio works slowly, consider the possibility to reduce the number of folders under antivirus protection.
Each antivirus check in your project consumes resources. You can significantly improve the performance, if you exclude certain folders from the antivirus protection.

ListFragment show only one item issue

Try to change layout_width to 0dp

   <fragment android:name="cz.okhelp.android.fragchangfromlist.ArticleFragment"
              android:id="@+id/article_fragment"
              android:layout_weight="2"
              android:layout_width="0dp"
              android:layout_height="match_parent" />
<!--todo LAYOUT_WIDTH have to be 0dp !!!!!!!!!!!!!!!!!!!!! -->

    <FrameLayout android:id="@+id/article_fragment"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="2" />

Error for example:
webcoreglue(2075): The real object has been deleted

Solution:
If this error message shows if orientation the screen is changed
try insert into AndroidManifest.xml this code:
android:configChanges="keyboard|keyboardHidden|orientation"

      <activity
            android:label="@string/app_name"
            android:name=".MyActivity" 
            android:screenOrientation="portrait"
            android:configChanges="keyboard|keyboardHidden|orientation"
            >