在Android上动态改变线性布局的宽度或高度

我正在尝试动态更改线性布局或任何其他小部件宽度或高度，但抛出异常。

我的布局是：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/abc"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView   
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="ghghjkgj ghjg hjgj ghj g hjgjgh jhg "
    />
</LinearLayout>

我的活动是：

public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        LinearLayout ll = (LinearLayout)findViewById(R.id.abc);
        ll.setLayoutParams(new LinearLayout.LayoutParams(30,60));
    }

抛出以下异常：

E/AndroidRuntime(16052): java.lang.ClassCastException: android.widget.LinearLayout$LayoutParams
E/AndroidRuntime(16052):    at android.widget.FrameLayout.onLayout(FrameLayout.java:288)
E/AndroidRuntime(16052):    at android.view.View.layout(View.java:7035)
E/AndroidRuntime(16052):    at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1249)
E/AndroidRuntime(16052):    at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1125)
E/AndroidRuntime(16052):    at android.widget.LinearLayout.onLayout(LinearLayout.java:1042)
E/AndroidRuntime(16052):    at android.view.View.layout(View.java:7035)
E/AndroidRuntime(16052):    at android.widget.FrameLayout.onLayout(FrameLayout.java:333)
E/AndroidRuntime(16052):    at android.view.View.layout(View.java:7035)
E/AndroidRuntime(16052):    at android.view.ViewRoot.performTraversals(ViewRoot.java:1045)
E/AndroidRuntime(16052):    at android.view.ViewRoot.handleMessage(ViewRoot.java:1727)
E/AndroidRuntime(16052):    at android.os.Handler.dispatchMessage(Handler.java:99)
E/AndroidRuntime(16052):    at android.os.Looper.loop(Looper.java:123)
E/AndroidRuntime(16052):    at android.app.ActivityThread.main(ActivityThread.java:4627)
E/AndroidRuntime(16052):    at java.lang.reflect.Method.invokeNative(Native Method)
E/AndroidRuntime(16052):    at java.lang.reflect.Method.invoke(Method.java:521)
E/AndroidRuntime(16052):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
E/AndroidRuntime(16052):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
E/AndroidRuntime(16052):    at dalvik.system.NativeStart.main(Native Method)

那么如何动态改变尺寸呢？

检查这个 -http://smartandroidians.blogspot.com/2010/04/changing-layout-height-dynamically.html http://smartandroidians.blogspot.com/2010/04/changing-layout-height-dynamically.html

ll.getLayoutParams().height = 300;
ll.getLayoutParams().width = 200;
ll.requestLayout();

这也适用于事件处理程序。