定义style

<style name="LoadProgress" parent="@android:style/Theme.Dialog">
        <item name="android:windowFrame">@null</item>
        <item name="android:windowContentOverlay">@null</item>
        <item name="android:windowIsFloating">true</item>
        <item name="android:windowIsTranslucent">true</item>
        <item name="android:windowNoTitle">true</item>
        <item name="android:backgroundDimEnabled">true</item>
        <item name="android:background">#00000000</item>
        <item name="android:windowBackground">@android:color/transparent</item>
        <!--<item name="android:windowAnimationStyle">@style/ActionSheetAnimation</item>  -->
    </style>

创建Dialog

Dialog  protocolDialog = new Dialog(context, R.style.LoadProgress);
        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        LinearLayout layout = (LinearLayout) inflater.inflate(
                R.layout.dialog_loadprogress, null);
        protocolDialog.setCanceledOnTouchOutside(false);

        protocolDialog.setContentView(layout);
        protocolDialog.setOnKeyListener(new DialogInterface.OnKeyListener() {
            @Override
            public boolean onKey(DialogInterface dialog, int keyCode, KeyEvent event) {
                if (keyCode == KeyEvent.KEYCODE_SEARCH) {
                    return true;
                } else {
                    return true; //默认返回 false，这里false不能屏蔽返回键，改成true就可以了
                }
            }

        });

布局文件dialog_loadprogress,

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_gravity="center"
        android:orientation="vertical"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center" >
        <ProgressBar
        android:background="@android:color/transparent"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:indeterminate="false"
       />
</LinearLayout>

调用

 public void show() {
        if (protocolDialog != null && !protocolDialog.isShowing() && context != null && !context.isFinishing()) {
            protocolDialog.show();
        }
    }

    public void close() {
        if (protocolDialog != null) {
            if (protocolDialog.isShowing()) {
                protocolDialog.dismiss();
            }
        }