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我从 android 世界的小部件开始。我有这个布局,名为“widget.xml”:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:padding="5dip" >

<ImageButton
    android:id="@+id/icono"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:src="@drawable/ic_launcher" />

如您所见,它只是一个按钮。这是小部件的配置 xml:

<?xml version="1.0" encoding="utf-8"?>
<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android" 
android:initialLayout="@layout/widget"
android:minWidth="72dip"
android:minHeight="72dip"
android:updatePeriodMillis="7000"
android:label="Widget_azafata"
/>

这是扩展 AppWidgetProvider 的类,它没有被改动:

public class WidgetAppProvider extends AppWidgetProvider{

@Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager,
        int[] appWidgetIds) {


    super.onUpdate(context, appWidgetManager, appWidgetIds);
}


   }

这是配置活动:

public class WidgetConfig extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    setContentView(R.layout.main);
    super.onCreate(savedInstanceState);
    ImageButton boton=(ImageButton) findViewById(R.id.icono);
            //stuff here
      }

清单中的行:

<receiver 

        android:name=".WidgetAppProvider"
        android:label="Widget_azafata">
        <intent-filter>
            <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
        </intent-filter>
        <meta-data 

            android:name="android.appwidget.provider"
            android:resource="@xml/widget_azafata_xml"   />


    </receiver>

好吧,我启动小部件并显示此异常:

05-04 10:21:14.144: E/AndroidRuntime(320): FATAL EXCEPTION: main
05-04 10:21:14.144: E/AndroidRuntime(320): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.publidirecta.Azafata/com.publidirecta.Azafata.WidgetAppProvider}: java.lang.ClassCastException: com.publidirecta.Azafata.WidgetAppProvider
05-04 10:21:14.144: E/AndroidRuntime(320):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2585)
05-04 10:21:14.144: E/AndroidRuntime(320):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
05-04 10:21:14.144: E/AndroidRuntime(320):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
05-04 10:21:14.144: E/AndroidRuntime(320):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
05-04 10:21:14.144: E/AndroidRuntime(320):  at android.os.Handler.dispatchMessage(Handler.java:99)
05-04 10:21:14.144: E/AndroidRuntime(320):  at android.os.Looper.loop(Looper.java:123)
05-04 10:21:14.144: E/AndroidRuntime(320):  at android.app.ActivityThread.main(ActivityThread.java:4627)
05-04 10:21:14.144: E/AndroidRuntime(320):  at java.lang.reflect.Method.invokeNative(Native Method)
05-04 10:21:14.144: E/AndroidRuntime(320):  at java.lang.reflect.Method.invoke(Method.java:521)
05-04 10:21:14.144: E/AndroidRuntime(320):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
05-04 10:21:14.144: E/AndroidRuntime(320):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
05-04 10:21:14.144: E/AndroidRuntime(320):  at dalvik.system.NativeStart.main(Native Method)
05-04 10:21:14.144: E/AndroidRuntime(320): Caused by: java.lang.ClassCastException: com.publidirecta.Azafata.WidgetAppProvider
05-04 10:21:14.144: E/AndroidRuntime(320):  at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
05-04 10:21:14.144: E/AndroidRuntime(320):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2577)

它没有显示任何错误行,只是启动异常的类。而且我不知道为什么会启动此异常。任何帮助将不胜感激。

非常感谢!

4

3 回答 3

2

Activity在清单中声明你的吗?

你应该像这样切换行的顺序onCreate()

super.onCreate(savedInstanceState);  // this should be first call
setContentView(R.layout.main);    
ImageButton boton=(ImageButton) findViewById(R.id.icono);
于 2012-05-04T11:44:01.123 回答
1

我认为您的 XML 名称是“widget.xml”,但您在活动中调用 main.xml。您必须更改 SetContentView(R.layout.widget);

于 2012-05-04T11:44:19.033 回答
0

在某个地方,您正在调用startActivity()start WidgetAppProviderWidgetAppProvider是一个BroadcastReceiver,不是一个Activity

于 2012-05-04T11:42:00.757 回答