android - ボタンを LinearLayout に追加中にエラーが発生しました

Question

プログラムで線形レイアウトにボタンを追加する必要があります。しかし、プログラムの力は閉じます。これが私が試しているコードです:

protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_remove_contact);

        LinearLayout ll = (LinearLayout) findViewById(R.id.vertic);
        Button button = new Button(this.getApplicationContext());
        LinearLayout.LayoutParams params = (LayoutParams) button.getLayoutParams();
        params.weight = 1;
        button.setText("MR. ABC");
        button.setLayoutParams(params);
        ll.addView(button, params);

    }

LogCat は次のとおりです。

04-13 22:16:44.484: D/dalvikvm(12596): GC_EXTERNAL_ALLOC freed 70K, 50% free 2698K/5379K, external 2013K/2108K, paused 53ms
04-13 22:16:46.000: D/AndroidRuntime(12596): Shutting down VM
04-13 22:16:46.000: W/dalvikvm(12596): threadid=1: thread exiting with uncaught exception (group=0x40015578)
04-13 22:16:46.011: E/AndroidRuntime(12596): FATAL EXCEPTION: main
04-13 22:16:46.011: E/AndroidRuntime(12596): java.lang.RuntimeException: Unable to start activity ComponentInfo{maju.project.tourguide/maju.project.tourguide.RemoveContact}: java.lang.NullPointerException
04-13 22:16:46.011: E/AndroidRuntime(12596):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1651)
04-13 22:16:46.011: E/AndroidRuntime(12596):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1667)
04-13 22:16:46.011: E/AndroidRuntime(12596):    at android.app.ActivityThread.access$1500(ActivityThread.java:117)
04-13 22:16:46.011: E/AndroidRuntime(12596):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935)
04-13 22:16:46.011: E/AndroidRuntime(12596):    at android.os.Handler.dispatchMessage(Handler.java:99)
04-13 22:16:46.011: E/AndroidRuntime(12596):    at android.os.Looper.loop(Looper.java:123)
04-13 22:16:46.011: E/AndroidRuntime(12596):    at android.app.ActivityThread.main(ActivityThread.java:3687)
04-13 22:16:46.011: E/AndroidRuntime(12596):    at java.lang.reflect.Method.invokeNative(Native Method)
04-13 22:16:46.011: E/AndroidRuntime(12596):    at java.lang.reflect.Method.invoke(Method.java:507)
04-13 22:16:46.011: E/AndroidRuntime(12596):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:842)
04-13 22:16:46.011: E/AndroidRuntime(12596):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
04-13 22:16:46.011: E/AndroidRuntime(12596):    at dalvik.system.NativeStart.main(Native Method)
04-13 22:16:46.011: E/AndroidRuntime(12596): Caused by: java.lang.NullPointerException
04-13 22:16:46.011: E/AndroidRuntime(12596):    at maju.project.tourguide.RemoveContact.onCreate(RemoveContact.java:31)
04-13 22:16:46.011: E/AndroidRuntime(12596):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
04-13 22:16:46.011: E/AndroidRuntime(12596):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1615)
04-13 22:16:46.011: E/AndroidRuntime(12596):    ... 11 more

誰でも問題を指摘できますか? 前もって感謝します

XML ファイルは次のとおりです。

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="@drawable/car_wallpaper"
    android:paddingLeft="16dp"
    android:paddingRight="16dp"
    android:id="@+id/vertic"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Your Emergency Contacts"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:textColor="#FFFF" />

</LinearLayout>