实际90%计算解:

@Override public void onStart() {
   Dialog dialog = getDialog();
   if (dialog != null) {
     dialog.getWindow()
        .setLayout((int) (getScreenWidth(getActivity()) * .9), ViewGroup.LayoutParams.MATCH_PARENT);
   }
}

其中getScreenWidth(Activity Activity)定义如下(最好放在Utils类中):

public static int getScreenWidth(Activity activity) {
   Point size = new Point();
   activity.getWindowManager().getDefaultDisplay().getSize(size);
   return size.x;
}

    ...
    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
    Dialog d = builder.create(); //create Dialog
    d.show(); //first show

    DisplayMetrics metrics = new DisplayMetrics(); //get metrics of screen
    getActivity().getWindowManager().getDefaultDisplay().getMetrics(metrics);
    int height = (int) (metrics.heightPixels*0.9); //set height to 90% of total
    int width = (int) (metrics.widthPixels*0.9); //set width to 90% of total

    d.getWindow().setLayout(width, height); //set layout

在自定义视图xml中设置android:minWidth和android:minHeight。这可以强制警告不只是包装内容大小。 使用这样的视图应该做到:

<LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:minWidth="300dp" 
  android:minHeight="400dp">
  <ImageView
   android:layout_width="fill_parent"
   android:layout_height="fill_parent"
   android:background="@drawable/icon"/>
</LinearLayout>

您需要使用样式@style.xml，例如CustomDialog来显示可自定义的对话框。

<style name="CustomDialog" parent="@android:style/Theme.DeviceDefault.Light.Dialog">
    <item name="android:windowIsTranslucent">true</item>
    <item name="android:windowBackground">@color/colorWhite</item>
    <item name="android:editTextColor">@color/colorBlack</item>
    <item name="android:windowContentOverlay">@null</item>
    <item name="android:windowNoTitle">true</item>
    <item name="android:backgroundDimEnabled">true</item>
    <item name="android:windowIsFloating">true</item>
    <item name="android:windowSoftInputMode">stateUnspecified|adjustPan</item>
</style>

在activity。java中使用这种样式

Dialog dialog = new Dialog(Activity.this, R.style.CustomDialog);
dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
dialog.setContentView(R.layout.custom_dialog);

你的custom_dialog.xml应该在你的布局目录中

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingLeft="10dp"
    android:paddingRight="10dp">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text=""
        android:textSize="20dp"
        android:id="@+id/tittle_text_view"
        android:textColor="@color/colorBlack"
        android:layout_marginTop="20dp"
        android:layout_marginLeft="10dp"/>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:layout_marginLeft="20dp"
        android:layout_marginBottom="10dp"
        android:layout_marginTop="20dp"
        android:layout_marginRight="20dp">

        <EditText
            android:id="@+id/edit_text_first"
            android:layout_width="50dp"
            android:layout_height="match_parent"
            android:hint="0"
            android:inputType="number" />

        <TextView
            android:id="@+id/text_view_first"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_marginLeft="5dp"
            android:gravity="center"/>

        <EditText
            android:id="@+id/edit_text_second"
            android:layout_width="50dp"
            android:layout_height="match_parent"
            android:hint="0"
            android:layout_marginLeft="5dp"
            android:inputType="number" />

        <TextView
            android:id="@+id/text_view_second"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_marginLeft="5dp"
            android:gravity="center"/>

    </LinearLayout>

</LinearLayout>

dialog.getWindow().setLayout(WindowManager.LayoutParams.MATCH_PARENT,WindowManager.LayoutParams.WRAP_CONTENT);

根据Android平台开发人员Dianne Hackborn在这个讨论组的帖子，对话框将窗口的顶层布局宽度和高度设置为WRAP_CONTENT。要使对话框更大，可以将这些参数设置为MATCH_PARENT。

演示代码:

    AlertDialog.Builder adb = new AlertDialog.Builder(this);
    Dialog d = adb.setView(new View(this)).create();
    // (That new View is just there to have something inside the dialog that can grow big enough to cover the whole screen.)

    WindowManager.LayoutParams lp = new WindowManager.LayoutParams();
    lp.copyFrom(d.getWindow().getAttributes());
    lp.width = WindowManager.LayoutParams.MATCH_PARENT;
    lp.height = WindowManager.LayoutParams.MATCH_PARENT;
    d.show();
    d.getWindow().setAttributes(lp);

注意，属性是在对话框显示之后设置的。系统对设置时间很挑剔。(我猜布局引擎必须在对话框第一次显示时设置它们。)

最好通过扩展Theme来实现这一点。对话，那么您就不必玩什么时候调用setAttributes的猜谜游戏了。(尽管让对话框自动采用适当的明暗主题或蜂巢Holo主题需要更多的工作。这可以根据http://developer.android.com/guide/topics/ui/themes.html#SelectATheme来做)