android--自己定义ProgressDialog显示位置(其他Dialog子类都能够设置)

1、普通情况下，系统默认的Dialog显示位置为屏幕居中：

	pbDialog = new ProgressDialog(MainActivity.this);
	pbDialog.setMessage("请稍等，载入中");
	pbDialog.show();

	pbDialog = new ProgressDialog(MainActivity.this);
	pbDialog.setMessage("请稍等，载入中");

	WindowManager.LayoutParams params = pbDialog.getWindow().getAttributes();
	pbDialog.getWindow().setGravity(Gravity.BOTTOM);
	pbDialog.show();

	pbDialog = new ProgressDialog(MainActivity.this);
	pbDialog.setMessage("请稍等，载入中");

	WindowManager.LayoutParams params = pbDialog.getWindow().getAttributes();
	pbDialog.getWindow().setGravity(Gravity.BOTTOM);
	params.y = 100;
	pbDialog.getWindow().setAttributes(params);
	pbDialog.show();