Android自定义进度条ProgressDialog

进度条布局xml：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:gravity="center">

    <ImageView
            android:id="@+id/progress_image"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:contentDescription="@null"
            android:background="@anim/progress_indeterminate_horizontal"/>
    <TextView
            android:id="@+id/progress_textview"
            android:text="@string/loading"
            android:textColor="#ffffff"
            android:textSize="17sp"
            android:gravity="center"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>

</LinearLayout>

/**
 * 自定义进度条
 * Created by Lezg on 2014/5/2.
 */
public class MyProgressDialog extends Dialog{

    private static MyProgressDialog myProgressDialog = null;

    private MyProgressDialog(Context context, int theme){
        super(context, theme);
    }

    public static MyProgressDialog createDialog(Context context){
        myProgressDialog = new MyProgressDialog(context, R.style.customProgressDialog);
        myProgressDialog.setContentView(R.layout.progress_dialog);
        myProgressDialog.getWindow().getAttributes().gravity = Gravity.CENTER;
        return myProgressDialog;
    }

    public void onWindowFocusChanged(boolean hasFocus){
        if(myProgressDialog == null){
            return;
        }
        ImageView imageView = (ImageView)myProgressDialog.findViewById(R.id.progress_image);
        AnimationDrawable ad = (AnimationDrawable)imageView.getBackground();
        if(ad != null){
            ad.start();
        }
    }

   /* public MyProgressDialog setMessage(String msg){
        TextView tvMsg = (TextView)myProgressDialog.findViewById(R.id.progress_textview);
        if(tvMsg != null){
            tvMsg.setText(msg);
        }
        return myProgressDialog;
    }*/
}