android:layout_height 50% of the screen size

Question

I just implemented a ListView inside a LinearLayout, but I need to define the height of the LinearLayout (it has to be 50% of the screen height).

<LinearLayout     android:id="@+id/widget34"     android:layout_width="300px"     android:layout_height="235px"     android:orientation="vertical"     android:layout_below="@+id/tv_scanning_for"     android:layout_centerHorizontal="true">      <ListView         android:id="@+id/lv_events"         android:textSize="18sp"                  android:cacheColorHint="#00000000"         android:layout_width="fill_parent"         android:layout_height="wrap_content"         android:layout_below="@+id/tv_scanning_for"         android:layout_centerHorizontal="true">     </ListView>  </LinearLayout> 

Is that possible?

I did something similar for a button and an EditText, but doesn't seem to work on Layouts.

This is my Code:

    //capture the size of the devices screen     Display display = getWindowManager().getDefaultDisplay();     double width = display.getWidth();      //my EditText will be smaller than full screen (80%)             double doubleSize = (width/5)*4;     int editTextSize = (int) doubleSize;      //define the EditText      userName = (EditText) this.findViewById(R.id.userName);     password = (EditText) this.findViewById(R.id.password);      //set the size     userName.setWidth(editTextSize);     password.setWidth(editTextSize); 

Answer 1

Set its layout_height="0dp"*, add a blank View beneath it (or blank ImageView or just a FrameLayout) with a layout_height also equal to 0dp, and set both Views to have a layout_weight="1"

This will stretch each View equally as it fills the screen. Since both have the same weight, each will take 50% of the screen.

*See adamp's comment for why that works and other really helpful tidbits.

Answer 2

This is easy to do in xml. Set your top container to be a LinearLayout and set the orientation attribute as you wish. Then inside of that place two linearlayouts that both have "fill parent" on width and height. Finally, set the weigth attribute of those two linearlayouts to 1.