Java startActivity使应用程序强制关闭

我刚刚开始开发Android，我一直在使用以下代码：

public class Home extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.home);
        Button buttonFoo = (Button)findViewById(R.id.buttonFoo);
        buttonFoo.setOnClickListener(openFoo);
    }

    public OnClickListener openFoo = new OnClickListener() {
        public void onClick(View v) {
            Intent intent = new Intent(Home.this, Foo.class);
            startActivity(intent);
        }
    };
}

以下是活动Foo的代码：

public class Foo extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //populateWithLatest();
    }
}

以及错误日志：

07-18 19:53:35.043: ERROR/AndroidRuntime(4656): FATAL EXCEPTION: main
07-18 19:53:35.043: ERROR/AndroidRuntime(4656): android.content.ActivityNotFoundException: Unable to find explicit activity class {com.github.progval.openquote/com.github.progval.openquote.sites.FooActivity}; have you declared this activity in your AndroidManifest.xml?
07-18 19:53:35.043: ERROR/AndroidRuntime(4656):     at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1405)
07-18 19:53:35.043: ERROR/AndroidRuntime(4656):     at android.app.Instrumentation.execStartActivity(Instrumentation.java:1379)
07-18 19:53:35.043: ERROR/AndroidRuntime(4656):     at android.app.Activity.startActivityForResult(Activity.java:2827)
07-18 19:53:35.043: ERROR/AndroidRuntime(4656):     at android.app.Activity.startActivity(Activity.java:2933)
07-18 19:53:35.043: ERROR/AndroidRuntime(4656):     at com.github.progval.openquote.Home$1.onClick(Home.java:34)
07-18 19:53:35.043: ERROR/AndroidRuntime(4656):     at android.view.View.performClick(View.java:2501)
07-18 19:53:35.043: ERROR/AndroidRuntime(4656):     at android.view.View$PerformClick.run(View.java:9107)
07-18 19:53:35.043: ERROR/AndroidRuntime(4656):     at android.os.Handler.handleCallback(Handler.java:587)
07-18 19:53:35.043: ERROR/AndroidRuntime(4656):     at android.os.Handler.dispatchMessage(Handler.java:92)
07-18 19:53:35.043: ERROR/AndroidRuntime(4656):     at android.os.Looper.loop(Looper.java:130)
07-18 19:53:35.043: ERROR/AndroidRuntime(4656):     at android.app.ActivityThread.main(ActivityThread.java:3835)
07-18 19:53:35.043: ERROR/AndroidRuntime(4656):     at java.lang.reflect.Method.invokeNative(Native Method)
07-18 19:53:35.043: ERROR/AndroidRuntime(4656):     at java.lang.reflect.Method.invoke(Method.java:507)
07-18 19:53:35.043: ERROR/AndroidRuntime(4656):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:847)
07-18 19:53:35.043: ERROR/AndroidRuntime(4656):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:605)
07-18 19:53:35.043: ERROR/AndroidRuntime(4656):     at dalvik.system.NativeStart.main(Native Method)

---

除非我注释行

startActivity（intent），当我按下Foo按钮时，应用程序强制关闭。
所有活动都需要在清单文件中声明。首先检查那里。
查看您的清单文件。您没有在那里签署Foo活动。在主活动标记下

将
放到实现OnClickListener时，会更容易，代码也会更好看。因此，您只需添加onClick方法（视图v）。作为onClickListener设置“this”的上下文，以及意图的上下文。请参阅下面的代码。通常情况下，这会起作用

<application android:label="@string/app_name" android:icon="@drawable/icon">
    <activity android:name=".Home"
              android:label="@string/app_name">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

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

public class Home extends Activity implements OnClickListener {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.home);
        Button buttonFoo = (Button)findViewById(R.id.buttonFoo);
        buttonFoo.setOnClickListener(this);
    }

    public void onClick(View v) {
        Intent intent = new Intent(this, Foo.class);
        startActivity(intent);
    }
}

编辑：我也为您的Foo活动，在您的清单中声明活动时有一个前导点。删除此项以查找您的活动。在清单中声明活动的最佳方法是使用GUI（Android清单文件>应用程序>应用程序节点>添加>活动>名称：选择活动）

在安卓系统中进行编码，享受乐趣！
Grtz
您的Foo类应该设置ContentView。
就是

否则
“您是否在AndroidManifest.xml中声明了此活动？”您是否阅读了错误日志？实际上，这是因为一个愚蠢的错误：活动名称应该是
.sites.Foo
，但我在清单中声明了
。
public class Home extends Activity implements OnClickListener {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.home);
        Button buttonFoo = (Button)findViewById(R.id.buttonFoo);
        buttonFoo.setOnClickListener(this);
    }

    public void onClick(View v) {
        Intent intent = new Intent(this, Foo.class);
        startActivity(intent);
    }
}

public class Foo extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Foo.setContentView(R.layout.????)
        //populateWithLatest();
    }
}