Android Can';从ProgressDialog转换视图

Android Can';从ProgressDialog转换视图,android,Android,您好,我正在尝试从XML转换ProgressDialog ProgressDialog progressBar =(ProgressDialog)findViewById(R.id.progressBar_first); 但出现了以下错误: Cannot cast from View to ProgressDialog 我的XML布局是: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="

您好,我正在尝试从XML转换ProgressDialog

ProgressDialog progressBar =(ProgressDialog)findViewById(R.id.progressBar_first);
但出现了以下错误:

Cannot cast from View to ProgressDialog
我的XML布局是:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal"
    android:background="@drawable/first_page" >

    <ProgressBar
        android:id="@+id/progressBar_first"
        style="?android:attr/progressBarStyleHorizontal"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical|center_horizontal" />
</LinearLayout>


请帮帮我,伙计们

这样写:

ProgressBar progressBar =(ProgressBar)findViewById(R.id.progressBar_first);

您应使用以下选项进行更改:

ProgressBar progressBar =(ProgressBar)findViewById(R.id.progressBar_first);

您正在定义进度条并将其强制转换为进度对话框类型不匹配,从而导致错误