设置ListView宽度参数无效

下面带有注释“no effect”的行…没有效果,即宽度未设置为200。ListView将填充屏幕的整个宽度。我做错了什么?

RelativeLayout relativeLayout = (RelativeLayout) findViewById(R.id.list_alphabet_layout);
FrameLayout.LayoutParams layoutParams = new FrameLayout.LayoutParams(FrameLayout.LayoutParams.MATCH_PARENT, FrameLayout.LayoutParams.MATCH_PARENT );
relativeLayout.setLayoutParams(layoutParams);

ListView listView = new ListView(this);
// the following line as no effect
listView.setLayoutParams(new ViewGroup.LayoutParams(200, ViewGroup.LayoutParams.MATCH_PARENT)); 
listView.setFastScrollEnabled(true);

// side index
LinearLayout sideIndexLinearLayout = new LinearLayout(this);
sideIndexLinearLayout.setId(R.id.sideIndex);

LinearLayout.LayoutParams sideIndexLinearLayoutParams = new LinearLayout.LayoutParams(100, // width
                                                                                                                                                                                 LinearLayout.LayoutParams.MATCH_PARENT); // height
sideIndexLinearLayout.setLayoutParams(sideIndexLinearLayoutParams);
sideIndexLinearLayout.setGravity(Gravity.CENTER_HORIZONTAL);
sideIndexLinearLayout.setOrientation(LinearLayout.VERTICAL);

// add now so that sideIndexLinearLayout is a child of the RelativeLayout.
// This will enable us to get the RelativeLayout.LayoutParams to addRule()
relativeLayout.addView(listView);
relativeLayout.addView(sideIndexLinearLayout);

RelativeLayout.LayoutParams listViewParams = (RelativeLayout.LayoutParams)listView.getLayoutParams();
listViewParams.addRule(RelativeLayout.ALIGN_PARENT_LEFT);
listView.setLayoutParams(listViewParams); //causes layout update

RelativeLayout.LayoutParams sideIndexParams = (RelativeLayout.LayoutParams)sideIndexLinearLayout.getLayoutParams();
sideIndexParams.addRule(RelativeLayout.ALIGN_PARENT_RIGHT);
sideIndexLinearLayout.setLayoutParams(sideIndexParams); //causes layout update

XML格式

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
                android:id="@+id/list_alphabet_layout"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent">

</RelativeLayout>