我一定做错了什么。我在第一个活动中有这个代码:
package com.Trenton.waziapp;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
public class WaziLoginScreen extends Activity implements OnClickListener{
EditText etUsername, etPassword;
Button bLogin;
Class ourClass;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.wazi_login_screen);
    etUsername = (EditText) findViewById(R.id.etUsername);
    etPassword = (EditText) findViewById(R.id.etPassword);
    bLogin = (Button) findViewById(R.id.bLogin);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.wazi_login_screen, menu);
    return true;
}
@Override
public void onClick(View v) {
    // TODO Auto-generated method stub
    switch(v.getId()){
    case R.id.bLogin:
        Intent a = new Intent(WaziLoginScreen.this, ProfileScreen.class);
        startActivity(a);
        break;
    }
}
我在上面做错了什么来打开另一个 Activity,ProfileScreen?
我的清单文件包含这样的活动条目-
    <activity
        android:name=".ProfileScreen"
        android:label="@string/title_activity_profile_screen">
    </activity>