Get navigation bar (TSB bar) height

The dim value is defined as com.android.internal.R.dimen.navigation_bar_height.

 final int naviHeight = mContext.getResources().getDimensionPixelSize(
                    com.android.internal.R.dimen.navigation_bar_height);

How to exclude activity from recent application list on Android

To forbidden your activity in the recent application list, just define this parameter in AndroidManifest.xml for the activity:

android:excludeFromRecents="true"

for example:
        <activity
            android:name="com.test.MainActivity"
            android:noHistory="true"
            android:screenOrientation="portrait"
            android:excludeFromRecents="true"
            android:label="@string/app_name">
            ......
         </activity>