一段很简单的代码 Eclipse没有报错 可是手机上一点按钮就意外停止

Question

(https://img-ask.csdn.net/upload/201505/31/1433054546_331226.png) 和书上对比了好多次了-。-
第一个

```package com.example.ex04_01;

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

public class MainActivity extends Activity {
Button but;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    but = (Button) findViewById(R.id.but);
    but.setOnClickListener(new mClick());
}

class mClick implements OnClickListener {

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        Intent intent = new Intent(MainActivity.this, Second.class);
        startActivity(intent);
    }

}

}

第二个

```package com.example.ex04_01;

import android.app.Activity;
import android.os.Bundle;

class Second extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.second);

}

}

---

Answer 1

你没有在你的AndroidManifest.xml中 声明你的第二个activity吧

例如：

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

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

                <!-- 第二个activity -->
                    <activity
                            android:name="xxx">
                    </activity>

    </application>