我是 Java Android 开发的初学者。我正在使用 Eclipse SDK 3.6.1 版本。我正在尝试调用新意图，但我的应用程序总是意外停止。我是否正确地调用了新意图？
一级：
public class first extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button SignIn = (Button) findViewById(R.id.SignIn);
SignIn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
EditText pw = (EditText) findViewById(R.id.editPasswd);
if(pw.getText().toString().equals("123")) {
Intent intent = new Intent(first.this, second.class);
startActivity(intent);
}
else {
Toast.makeText(getBaseContext(), "Wrong PIN" ,
Toast.LENGTH_LONG).show();
}
}});
}
}
二等：
public class second extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.loginas);
Button Button01 = (Button) findViewById(R.id.Button01);
Button01.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
if(v.getId() == R.id.Button01) {
Intent intent = new Intent(second.this, third.class);
startActivity(intent);
}}
});
}
}
第三类：
public class third extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.lock);
}}
当我输入正确的密码时，应用程序显示消息“应用程序（）已意外停止。请重试”。首先我想知道我的代码是正确的。