Java 如何将登录按钮与另一个包含两个片段的活动连接

我无法将我的登录活动与包含片段的下一个活动连接。但每次我运行代码时，应用程序都会崩溃。有谁能告诉我我的密码出了什么问题吗？ 这个java类包含登录页面

MainActivity.java
import android.app.Activity;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;


public class MainActivity extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final EditText  edUsername  = (EditText) findViewById(R.id.editText1);
        final EditText  edPassword  = (EditText)findViewById(R.id.editText2);
        Button btnValidate = (Button)findViewById(R.id.btn1);
        btnValidate.setOnClickListener(new OnClickListener()
        {
            public void onClick(View arg0)
            {
                String uname  = edUsername.getText().toString();
                String pass = edPassword.getText().toString();
                if(uname.equals("sahu") && pass.equals("12345"))
                {
                    Intent intent = new Intent(MainActivity.this,MainActivity2.class);
                    /*intent.putExtra("UserName",edUsername.getText().toString());*/
                    startActivity(intent);
                }
                else
                {
                    Toast.makeText(MainActivity.this, "Invalid Usename password pair.", Toast.LENGTH_LONG).show();
                }
            }
        });
    }



}


This activity below is the main activity for the next two fragment classes:-

MainActivity2
import android.os.Bundle;
import android.app.Activity;
import android.support.v7.app.ActionBarActivity;
import android.support.v4.app.FragmentActivity;

public class MainActivity2 extends FragmentActivity  {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_activity2);
    }
}


MenuFragment
public class MenuFragment extends ListFragment {
    String[] food = new String[]{"Breakfast", "Lunch", "Dinner"};
    String[] item = new String[]{"Idli Sambar", "Dam Aloo", "Paneer Butter Masala"};

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.list_fragment, container, false);
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(),
                android.R.layout.simple_list_item_1, food);
        setListAdapter(adapter);
        return view;
    }

    @Override
    public void onListItemClick(ListView l, View v, int position, long id) {
        TextFragment txt = (TextFragment) getFragmentManager().findFragmentById(R.id.fragment2);
        txt.change(food[position], item[position]);
        getListView().setSelector(android.R.color.holo_blue_dark);
    }
}


This is the second fragment class

TextFragment

public class TextFragment extends Fragment{
    TextView foo,it;
    public View onCreateView(LayoutInflater inflater,ViewGroup container,Bundle savedInstanceState){
        View view = inflater.inflate(R.layout.text_fragment, container, false);
        foo= (TextView) view.findViewById(R.id.food);
        it= (TextView)view.findViewById(R.id.item);
        return view;
    }
    public void change(String txt, String txt1){
        foo.setText(txt);
        it.setText(txt1);
    }

}

当我运行应用程序并输入用户名和密码时，应用程序崩溃并显示以下错误 java.lang.RuntimeException:无法启动活动组件信息

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有人能帮我吗？？？plz

我认为您必须在manifest.xml中声明MainActivity2，以便系统能够找到活动并实例化它

尝试将此代码添加到manifest.xml：

<activity android:name=".MainActivity2"></activity>

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你在清单中注册了你的片段了吗？没有。但是我不知道怎么做，我是android新手。我删除了整个项目，创建了一个新项目，并在清单文件中注册了所有活动，它成功了。非常感谢你的帮助。