if (dialog == null) {

    dialog = new Dialog(context, R.style.theme_from_bottom);

    View view = View.inflate(context, R.layout.udialog, null);

    ImageView closeView = view.findViewById(R.id.user_contract_close_view);

    Button button = view.findViewById(R.id.user_contract_im_view);

    dialog.setContentView(view);

    dialog.setCancelable(false);

    //设置自适应的方法：

    WindowManager.LayoutParams dialogParams = contactDialog.getWindow().getAttributes();

    dialogParams.width = WindowManager.LayoutParams.MATCH_PARENT;

    dialogParams.height = WindowManager.LayoutParams.WRAP_CONTENT;

    //设置底部显示

    dialogParams.gravity = Gravity.BOTTOM;

    contactDialog.getWindow().setAttributes(dialogParams);

    //设置窗口大小的方法：

    int with = (int) (context.getResources().getDisplayMetrics().widthPixels * 0.6)

    int height = (int) (context.getResources().getDisplayMetrics().heightPixels * 0.4);

    //对话框重置属性

    contactDialog.getWindow().setAttributes(dialogParams);

}

 <style name="theme_from_bottom" parent="@android:style/Theme.Dialog">

        <item name="android:windowFrame">@null</item>

        <item name="android:windowNoTitle">true</item>

        <item name="android:windowIsFloating">true</item>

        <item name="android:windowIsTranslucent">true</item>

        <item name="android:windowAnimationStyle">@style/dialog_bottom</item>

        <item name="android:backgroundDimEnabled">true</item>

        <item name="android:windowBackground">@android:color/transparent</item>

    </style>

    <style name="dialog_bottom" parent="@android:style/Animation.Dialog">

        <item name="android:windowFrame">@null</item>

        <item name="android:windowIsFloating">true</item>

        <item name="android:windowIsTranslucent">false</item>

        <item name="android:windowNoTitle">true</item>

        <item name="android:backgroundDimEnabled">false</item>

        <item name="android:windowEnterAnimation">@anim/dialog_bottom_in</item>

        <item name="android:windowExitAnimation">@anim/dialog_bottom_out</item>

    </style>　

动画

dialog_bottom_in

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android" >
    <translate
        android:duration="300"
        android:fromYDelta="100%p"
        android:toYDelta="0"
     />
    <alpha 
       android:interpolator="@android:anim/accelerate_interpolator"
       android:fromAlpha="0.0" android:toAlpha="1.0"
       android:duration="300" />
</set>

dialog_bottom_out

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android" >
    <translate
        android:duration="300"
        android:fromYDelta="0"
        android:toYDelta="100%p" />
    <alpha 
       android:interpolator="@android:anim/accelerate_interpolator"
       android:fromAlpha="1.0" android:toAlpha="0.0"
       android:duration="300" />
</set>