Android ListActivity doesn't center the items - android-layout

Question

I have a ListActivity which displays an image and some text.
The imageView has a fixed size and I want to center the list horizontally.
After endless tries, I set any gravity to center_horinzontal, but nothing works.
The list is shown over the whole screen, as I can see by the scrollbar on the right side. But my frame remains on the left side.
In the adapter class, which entends ArrayAdapter, I even tried to set the gravity during runtime, but when I try to manipulate then basic LinearLayout, I get the error:
"java.lang.ClassCastException: android.widget.LinearLayout$LayoutParams cannot be cast to android.widget.AbsListView$LayoutParams"
My attempt to change gravity in the method getView() which throws the error:
LinearLayout layout = (LinearLayout) rowView.findViewById(R.id.bootsFrameLayout);
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT);
params.gravity = Gravity.CENTER_HORIZONTAL;
layout.setLayoutParams(params);
The list row is designed in a layout file:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/bootsFrameLayout"
android:layout_width="300dp"
android:layout_height="250dp"
android:layout_gravity="center_horizontal"
android:layout_marginEnd="20dp"
android:layout_marginStart="20dp"
android:background="#drawable/card_blank2"
android:gravity="center_horizontal"
android:orientation="vertical" >
<TextView
android:id="#+id/bootsName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:text="TextView"
android:textAppearance="#style/BootNameStyle" />
<FrameLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:layout_marginEnd="30dp"
android:layout_marginLeft="30dp"
android:layout_marginRight="30dp"
android:layout_marginStart="30dp" >
<ImageView
android:id="#+id/bootImage"
android:layout_width="240dp"
android:layout_height="180dp"
android:layout_gravity="center_horizontal"
android:scaleType="centerCrop"
android:src="#drawable/test_boot" />
<TextView
android:id="#+id/textWatchList"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom|center_horizontal"
android:background="#color/gray_transparent"
android:gravity="end"
android:lines="2"
android:text="#string/watchlist"
android:textAppearance="#style/BootWatchListStyle" />
<ProgressBar
android:id="#+id/bootProgressbar"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical|center_horizontal"
android:visibility="invisible" />
</FrameLayout>
<TableLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginEnd="25dp"
android:layout_marginLeft="25dp"
android:layout_marginRight="25dp"
android:layout_marginStart="25dp" >
<TableRow
android:id="#+id/tableRow1"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
<TextView
android:id="#+id/bootMasse"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="left"
android:layout_weight="70"
android:text="TextView"
android:textAppearance="#style/BootInfoStyle" />
<TextView
android:id="#+id/bootBaujahr"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="right"
android:layout_weight="30"
android:gravity="right"
android:text="TextView"
android:textAppearance="#style/BootInfoStyle" />
</TableRow>
<TableRow
android:id="#+id/tableRow2"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
<TextView
android:id="#+id/bootLand"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="70"
android:text="TextView"
android:textAppearance="#style/BootInfoStyle" />
<TextView
android:id="#+id/bootPreis"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="right"
android:layout_weight="30"
android:gravity="right"
android:text="TextView"
android:textAppearance="#style/BootPreisStyle" />
</TableRow>
</TableLayout>
The ListView is defined here:
<ListView
android:id="#android:id/list"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_gravity="center_horizontal"
android:layout_marginEnd="12dp"
android:layout_marginLeft="12dp"
android:layout_marginRight="12dp"
android:layout_marginStart="12dp"
android:layout_weight="8" >
</ListView>
The activity occupies the whole screen, as it should do.
But although there is place enough, the frame won't center.
Any ideas?