getting an error for must implement the inherited abstract method

I am new to android and am getting The type LinearLayoutActivity must implement the inherited abstract method RadioGroup.OnC开发者_Go百科heckedChangeListener.onCheckedChanged(RadioGroup, int) for an error. I don't understand how I made RadioGroup an abstract method. Here is my code, I left a // by where I am getting the error

package com.commonsware.android.linear;

import com.commonsplace.android.skeleton.R;
import com.commonsplace.android.skeleton.R.id;
import com.commonsplace.android.skeleton.R.layout;

import android.app.Activity;
import android.os.Bundle;
import android.widget.LinearLayout;
import android.widget.RadioGroup.OnCheckedChangeListener;
import android.widget.RadioGroup;
import android.widget.EditText;
import android.view.Gravity;
import android.text.TextWatcher;

public class LinearLayoutActivity extends Activity  //I am getting the error for    LinearLayoutActivity
 implements RadioGroup.OnCheckedChangeListener{
RadioGroup orientation;
RadioGroup gravity;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle icicle) {
    super.onCreate(icicle);
    setContentView(R.layout.main);

    orientation=(RadioGroup)findViewById(R.id.orientation);
    orientation.setOnCheckedChangeListener(this);
    gravity=(RadioGroup)findViewById(R.id.gravity);
    gravity.setOnCheckedChangeListener(this);
}

public void OnCheckedChanged(RadioGroup group, int checkedId){
    switch(checkedId){
    case R.id.horizontal:
    orientation.setOrientation(LinearLayout.HORIZONTAL);
    break;
    case R.id.vertical:
    orientation.setOrientation(LinearLayout.VERTICAL);
    break;
    case R.id.left:
    orientation.setGravity(Gravity.LEFT);
    break;
    case R.id.center:
    orientation.setGravity(Gravity.CENTER);
    break;
    case R.id.right:
        orientation.setGravity(Gravity.RIGHT);
    break;
    }

}

}

The name of the method in your code is wrong. You have:

public void OnCheckedChanged(RadioGroup group, int checkedId)

You need:

public void onCheckedChanged(RadioGroup group, int checkedId)
            ^

Java is case sensitive.

You have done a little mistake on the name of the function OnCheckedChanged. In reality, it is onCheckedChanged, with a little "o" at the beginning.