button - 2番目のボタンが意図的に機能しない

Question

2 番目のボタンで 2 番目のアクティビティが開始されない理由がわかりません

package com.example.lettere;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class MainMenu extends Activity{

Button button1;
Button button2;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_start);

}
public void addListenerOnButton() {

    button1 = (Button) findViewById(R.id.button1);
    button2 = (Button) findViewById(R.id.button2);
    }
    public boolean ButtonOnClick(View v) {
     {
        switch (v.getId()) {
          case R.id.button1:
            startActivity(new Intent(this, MainActivity.class));
            return true;
          case R.id.button2:
            startActivity(new Intent(this, MainActivity2.class));
              return true;

          }
    }
    return true;}}

2 つのアクティビティは同じ xml レイアウト ファイルを使用します。私が宣言したxmlレイアウトのコンテキストで

android:context=".MainActivity|.MainActivity2"

そして、これは私の最初の活動であり、2 番目の活動とまったく同じです。

package com.example.lettere;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;

public class MainActivity extends FragmentActivity {


SectionsPagerAdapter mSectionsPagerAdapter;

/**
 * The {@link ViewPager} that will host the section contents.
 */
ViewPager mViewPager;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());


    // Set up the ViewPager with the sections adapter.
    mViewPager = (ViewPager) findViewById(R.id.pager);
    mViewPager.setAdapter(mSectionsPagerAdapter);

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.activity_main, menu);
    return true;
}





public class SectionsPagerAdapter extends FragmentPagerAdapter {

    public SectionsPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int i) {
        Fragment fragment = new DummySectionFragment();
        Bundle args = new Bundle();
        args.putInt(DummySectionFragment.ARG_SECTION_NUMBER, i + 1);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public int getCount() {
        return 9;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        switch (position) {
            case 0: return getString(R.string.title_section1).toUpperCase();
            case 1: return getString(R.string.title_section2).toUpperCase();
            case 2: return getString(R.string.title_section3).toUpperCase();
            case 3: return getString(R.string.title_section1).toUpperCase();
            case 4: return getString(R.string.title_section2).toUpperCase();
            case 5: return getString(R.string.title_section3).toUpperCase();
            case 6: return getString(R.string.title_section1).toUpperCase();
            case 7: return getString(R.string.title_section2).toUpperCase();
            case 8: return getString(R.string.title_section3).toUpperCase();
        }
        return null;
    }
}


public static class DummySectionFragment extends Fragment {
    public DummySectionFragment() {
    }

    public static final String ARG_SECTION_NUMBER = "section_number";

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.activity_inter, null);
        return v;
    }
}
}

ここにマニフェストがあります

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.lettere"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
    android:minSdkVersion="14"
    android:targetSdkVersion="15" />

<application
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity android:name=".MainMenu" android:label="@string/title_activity_main">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
        </activity>
    <activity
        android:name=".MainActivity"
        android:label="@string/title_activity_main" >
        </activity>
        <activity
        android:name=".MainActivity2"
        android:label="@string/title_activity_main" >
        </activity>
</application>

</manifest>