安卓自定义对话框强制关闭

Question

我正在实现一个自定义对话框来创建一个外观简单的关于屏幕（一旦我让它正常工作，可能会变得更加复杂）。我有一个xml布局，可以从R中加载一些文本和图标。然而，每当调用showDialog(int)时，我都会出现强制关闭。

我按照开发指南中的说明进行了操作：http://developer.android.com/intl/de/guide/topics/ui/dialogs.html 代码如下：

 @Override
 protected Dialog onCreateDialog(int id) {
   Dialog dialog;
      switch(id) {
      case DIAG_ABOUT:
       dialog = new Dialog(getApplicationContext());
       dialog.setContentView(R.layout.aboutdialog);
       dialog.setTitle(R.string.about_title);
       dialog.setOwnerActivity(this);
       break;
      default:
          dialog = null;
      }
      return dialog;
 }

DIAG_ABOUT被定义为private static final int DIAG_ABOUT = 0;

日志显示以下跟踪：

03-04 11:37:08.760: ERROR/AndroidRuntime(726): Uncaught handler: thread main exiting due to uncaught exception
03-04 11:37:08.780: ERROR/AndroidRuntime(726): android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at android.view.ViewRoot.setView(ViewRoot.java:429)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:178)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at android.app.Dialog.show(Dialog.java:231)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at android.app.Activity.showDialog(Activity.java:2407)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at uk.me.cpearson.runningLate.Home.onOptionsItemSelected(Home.java:143)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at android.app.Activity.onMenuItemSelected(Activity.java:2085)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at com.android.internal.policy.impl.PhoneWindow.onMenuItemSelected(PhoneWindow.java:820)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:139)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:813)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at com.android.internal.view.menu.IconMenuView.invokeItem(IconMenuView.java:519)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at com.android.internal.view.menu.IconMenuItemView.performClick(IconMenuItemView.java:122)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at android.view.View.onTouchEvent(View.java:3828)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at android.widget.TextView.onTouchEvent(TextView.java:6291)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at android.view.View.dispatchTouchEvent(View.java:3368)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:863)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:863)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1691)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at android.view.ViewRoot.handleMessage(ViewRoot.java:1525)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at android.os.Handler.dispatchMessage(Handler.java:99)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at android.os.Looper.loop(Looper.java:123)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at android.app.ActivityThread.main(ActivityThread.java:3948)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at java.lang.reflect.Method.invokeNative(Native Method)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at java.lang.reflect.Method.invoke(Method.java:521)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:782)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:540)
03-04 11:37:08.780: ERROR/AndroidRuntime(726):     at dalvik.system.NativeStart.main(Native Method)

有人能指出我哪里做错了吗？我正在使用SDK 1.5

- themaninthesuitcase

Answer 1

您需要使用您的Activity作为Dialog的Context，而不是使用Application。

Android正在寻找一个视图来显示对话框，而Application没有这样的视图，但是您的Activity会有。 Application是将您的应用程序组合在一起的对象，并具有Context，因为它知道您运行的语言环境等信息，但它依赖于Activities来向用户显示内容。

替换为：

dialog = new Dialog(getApplicationContext());

使用：

dialog = new Dialog(this);

- David Webb

---

Android文档提供了一个错误的示例，很久以前就有一张票，但这个问题仍然没有得到解决！ - Sander Versluys