Small problems with Android development

One

Need to use a theme.appcompat Theme (or descendant) and this activity workaround

The error is as follows:
Java.lang.RuntimeException:Unable to start activitycomponentinfo{com.example.test2/com.example.test2.mainactivity }:java.lang.illegalstateexception:you need to use a theme.appcompat Theme (ordescendant) and this activity.

Workaround:
The activity created is Mainactivityextends actionbaractivity. Change the back of the actionbaractivity to activity, and then guide the package, the following error where the deletion of the operation will not be.

In a higher version of ADT, it inherits from the Actionbaractivity, and if you need to change the theme, you need to change the inheritance to the activity.

Second, the problem of installation Error:install_failed_version_downgrade appears

Recently toss a bit of robotium automated testing framework, found that the problem is quite many, just solved a problem, finally, the environment is done, but a run test cases, found also reported installation error install_failed_version_ Downgrade was wrong. Online check, said is Androidmanifest.xml versioncode a bit small, should be changed a little bit on the line. The default is the following:

package="Com.test.apppage"

android:versioncode="1"

Android:versionname="1.0"

The issue occurs when the low version cannot be released with a high version of replace installation. It's possible that your last beta version was a high version, and the next test you tuned to a lower version. Therefore, the lower version cannot be replaced by the installation high version.

Small problems with Android development