I set a webview so:
<WebView
android:id="@+id/webView1"
android:layout_width="match_parent"
android:layout_height="500px"
android:layout_below="@+id/button1"
android:layout_centerHorizontal="true" />
but is this correct? if the resolution of the Android phone change, I should perhaps give a height in units of percent instead in pixel?