创建自定义对话框时出现问题

问题描述

我在创建自定义对话框时遇到问题.但我没有发现失败.希望有人可以帮助我...

I have a problem creating a custom dialog. But I don't find the failure. Hopefully anybody can help me ...

protected Dialog onCreateDialog(int id) {
    Dialog dialog = null;
    switch (id) {
    case DIALOG_ABOUT_ID:
        dialog = buildAboutDialog();
        break;
    default:
        dialog = null;
    }
    return dialog;
}

...

public Dialog buildAboutDialog() {
    Context mContext = getApplicationContext();
    Dialog dialog = new Dialog(mContext);

    dialog.setContentView(R.layout.about_dialog);
    dialog.setTitle("About this application");

    return dialog;
}

导致以下错误:

12-30 19:27:02.593: ERROR/AndroidRuntime(383): android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application

我检查了返回的对话框是否 == null - 但不是.

I checked if the returned dialog == null - but it isn't.

我还尝试了 http:///developer.android.com/guide/topics/ui/dialogs.html#CustomDialog

推荐答案

发现，对话框需要用

Dialog dialog = new Dialog(this);

而不是

Context mContext = getApplicationContext();
Dialog dialog = new Dialog(mContext);

我不知道为什么.也许有人可以向我解释一下?

I don't exactly know why. Perhaps anybody can explain it to me?

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