On Checked Change Listener导致应用崩溃

Question

我是android的初学者。我试图在我的广播组中实现一个on checked change listener，但它导致我的应用程序崩溃。它的工作正常，没有听众。代码如下：

package com.vogella.android.testapp;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.*;
import android.widget.RadioGroup;
import android.widget.RadioGroup.OnCheckedChangeListener;
public class MainActivity extends AppCompatActivity{
@Override
protected void onCreate(Bundle savedInstanceState) {
    final RadioGroup layoutChoice=(RadioGroup)findViewById(R.id.orientation);
    layoutChoice.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener()
    {
        @Override
        public void onCheckedChanged(RadioGroup group,int checkedId)
        {
            switch(checkedId)
            {
                case R.id.horizontal:
                    group.setOrientation(LinearLayout.HORIZONTAL);
                    break;
                case R.id.vertical:
                    group.setOrientation(LinearLayout.VERTICAL);
                    break;
            }
        }

    });
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
}
public void onClick (View view) {
    EditText text=(EditText)findViewById(R.id.main_input);
    String input=text.getText().toString();
    Toast.makeText(this,input,Toast.LENGTH_LONG).show();
   }

}