java - startActivity 使应用程序强制关闭

Question

我刚刚开始 Android 开发，我被这段代码困住了:

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);
        }
    };
}

这是 Activity 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)

除非我注释了 startActivity(intent); 行，否则当我按下 Foo 按钮时应用程序会强制关闭。

Answer 1

<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>

这是我最喜欢的部分:

07-18 19:53:35.043: 错误/AndroidRuntime(4656): android.content.ActivityNotFoundException: 无法找到显式 Activity 类 {com.github.progval.openquote/com.github.progval.openquote.sites。 Vdm Activity }; 您是否在 AndroidManifest.xml 中声明了此 Activity ？

我不知道这是否是实现按钮的最佳方式，但我是这样做的:

findViewById(R.id.buttonFoo).setOnClickListener(new OnClickListener() {
    public void onClick(View v) {
        Intent i = new Intent(v.getContext(), Foo.class);
        startActivity(i);
    }
});