java - Android:NPE 在尝试使用 ACTION_APPWIDGET_PICK Intent 进行 activityForResult 时

Question

我有一个问题，然后尝试用 AppWidgetManager.ACTION_APPWIDGET_PICK 放置一个 Intent ，正如我从日志中看到的那样，android AppWidget 生态系统内部存在问题。那我做错了吗？
请参阅下面的示例代码和堆栈跟踪

public class NPEDemoActivity extends Activity {

    private final static int HOST_CODE = 1024;

    private AppWidgetHost host;
    private AppWidgetManager manager;
    private int PICK_WIDGET_RC = 1;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);        
        setContentView(R.layout.main);
        host = new AppWidgetHost(this, HOST_CODE);
        host.startListening();
        manager = AppWidgetManager.getInstance(this);
        Button b = (Button)findViewById(R.id.Button01);
        b.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                int nextId = host.allocateAppWidgetId();
                Intent pickIntent = new Intent(AppWidgetManager.ACTION_APPWIDGET_PICK);             
                pickIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, nextId);
                startActivityForResult(pickIntent, PICK_WIDGET_RC);   
            }
        });
    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
    }
}

来自 log cat 的堆栈跟踪:

10-15 17:33:06.873: ERROR/AndroidRuntime(821): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.android.settings/com.android.settings.AppWidgetPickActivity}: java.lang.NullPointerException
10-15 17:33:06.873: ERROR/AndroidRuntime(821):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2401)
10-15 17:33:06.873: ERROR/AndroidRuntime(821):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2417)
10-15 17:33:06.873: ERROR/AndroidRuntime(821):     at android.app.ActivityThread.access$2100(ActivityThread.java:116)
10-15 17:33:06.873: ERROR/AndroidRuntime(821):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1794)
10-15 17:33:06.873: ERROR/AndroidRuntime(821):     at android.os.Handler.dispatchMessage(Handler.java:99)
10-15 17:33:06.873: ERROR/AndroidRuntime(821):     at android.os.Looper.loop(Looper.java:123)
10-15 17:33:06.873: ERROR/AndroidRuntime(821):     at android.app.ActivityThread.main(ActivityThread.java:4203)
10-15 17:33:06.873: ERROR/AndroidRuntime(821):     at java.lang.reflect.Method.invokeNative(Native Method)
10-15 17:33:06.873: ERROR/AndroidRuntime(821):     at java.lang.reflect.Method.invoke(Method.java:521)
10-15 17:33:06.873: ERROR/AndroidRuntime(821):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791)
10-15 17:33:06.873: ERROR/AndroidRuntime(821):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:549)
10-15 17:33:06.873: ERROR/AndroidRuntime(821):     at dalvik.system.NativeStart.main(Native Method)
10-15 17:33:06.873: ERROR/AndroidRuntime(821): Caused by: java.lang.NullPointerException
10-15 17:33:06.873: ERROR/AndroidRuntime(821):     at com.android.settings.AppWidgetPickActivity.putAppWidgetItems(AppWidgetPickActivity.java:170)
10-15 17:33:06.873: ERROR/AndroidRuntime(821):     at com.android.settings.AppWidgetPickActivity.putCustomAppWidgets(AppWidgetPickActivity.java:132)
10-15 17:33:06.873: ERROR/AndroidRuntime(821):     at com.android.settings.AppWidgetPickActivity.getItems(AppWidgetPickActivity.java:208)
10-15 17:33:06.873: ERROR/AndroidRuntime(821):     at com.android.settings.ActivityPicker.onCreate(ActivityPicker.java:99)
10-15 17:33:06.873: ERROR/AndroidRuntime(821):     at com.android.settings.AppWidgetPickActivity.onCreate(AppWidgetPickActivity.java:63)
10-15 17:33:06.873: ERROR/AndroidRuntime(821):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1123)
10-15 17:33:06.873: ERROR/AndroidRuntime(821):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2364)

另外一个小问题，com.android.settings 在哪个android 项目中？ (我被 Windows 困住了，所以不幸的是不能使用 repo)非常感谢您的帮助。

Answer 1

看起来像是 android 设置中的一个错误，如果您尝试在没有指定任何额外小部件的情况下选择 appwidget，您将会失败，请在 google code link 处填写一个问题