如果你正在使用约束布局，你可以在其中设置任何视图，以填充屏幕的百分比:

layout_constraintWidth_percent = " 0.8 "

例如，如果你在对话框中有一个ScrollView你想把它设置为屏幕高度的一个百分比。它是这样的:

<ScrollView
            android:id="@+id/scrollView"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            app:layout_constraintHeight_percent="0.8">

希望它能帮助到一些人!!

这里其他的答案都说得通，但它不符合费边的要求。这是我的一个解决办法。这可能不是完美的解决方案，但对我来说很管用。它显示了一个全屏的对话框，但你可以在顶部、底部、左边或右边指定一个填充。

首先把它放在res/values/styles.xml中:

<style name="CustomDialog" parent="@android:style/Theme.Dialog">
    <item name="android:windowIsTranslucent">true</item>
    <item name="android:windowBackground">@color/Black0Percent</item>
    <item name="android:paddingTop">20dp</item>
    <item name="android:windowContentOverlay">@null</item>
    <item name="android:windowNoTitle">true</item>
    <item name="android:backgroundDimEnabled">false</item>
    <item name="android:windowIsFloating">false</item>
</style>

正如你所看到的，我有android:paddingTop= 20dp基本上是你需要的。android:windowBackground = @color/Black0Percent只是在color.xml中声明的颜色代码

res /价值/ color.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
<color name="Black0Percent">#00000000</color>
</resources>

该颜色代码只是作为一个虚拟，以取代对话框的默认窗口背景与0%透明度的颜色。

接下来构建自定义对话框布局res/layout/dialog.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/dialoglayout"
    android:layout_width="match_parent"
    android:background="@drawable/DesiredImageBackground"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <EditText
        android:id="@+id/edittext1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:singleLine="true"
        android:textSize="18dp" />

    <Button
        android:id="@+id/button1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Dummy Button"
        android:textSize="18dp" />

</LinearLayout>

最后这是我们的对话框，它设置了使用dialog.xml的自定义视图:

Dialog customDialog;
LayoutInflater inflater = (LayoutInflater) getLayoutInflater();
View customView = inflater.inflate(R.layout.dialog, null);
// Build the dialog
customDialog = new Dialog(this, R.style.CustomDialog);
customDialog.setContentView(customView);
customDialog.show();

结论:我试图在名为CustomDialog的styles.xml中覆盖对话框的主题。它覆盖了对话框窗口布局，让我有机会设置填充和改变背景的不透明度。这可能不是完美的解决方案，但我希望它能帮助你…:)

public static WindowManager.LayoutParams setDialogLayoutParams(Activity activity, Dialog dialog)
    {
        try 
        {
            Display display = activity.getWindowManager().getDefaultDisplay();
            Point screenSize = new Point();
            display.getSize(screenSize);
            int width = screenSize.x;

            WindowManager.LayoutParams layoutParams = new WindowManager.LayoutParams();
            layoutParams.copyFrom(dialog.getWindow().getAttributes());
            layoutParams.width = (int) (width - (width * 0.07) ); 
            layoutParams.height = WindowManager.LayoutParams.WRAP_CONTENT;
            return layoutParams;
        } 
        catch (Exception e)
        {
            e.printStackTrace();
            return null;
        }
    }

***In Kotlin You can Code like This : -*** 

fun customDialog(activity: Activity?, layout: Int): Dialog {
    val dialog = Dialog(activity!!)
    try {
        dialog.requestWindowFeature(Window.FEATURE_NO_TITLE)
        dialog.setCancelable(false)
        dialog.setContentView(layout)
        dialog.window!!.setBackgroundDrawable(ColorDrawable(Color.TRANSPARENT))
        dialog.window!!.setLayout(ConstraintLayout.LayoutParams.MATCH_PARENT, ConstraintLayout.LayoutParams.WRAP_CONTENT);
        dialog.show()
    } catch (e: Exception) {

    }
    return dialog
}

    final AlertDialog alertDialog;

    LayoutInflater li = LayoutInflater.from(mActivity);
    final View promptsView = li.inflate(R.layout.layout_dialog_select_time, null);

    RecyclerView recyclerViewTime;
    RippleButton buttonDone;

    AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(mActivity);
    alertDialogBuilder.setView(promptsView);

    // create alert dialog
    alertDialog = alertDialogBuilder.create();

    /**
     * setting up window design
     */
    alertDialog.requestWindowFeature(Window.FEATURE_NO_TITLE);


    alertDialog.show();

    DisplayMetrics metrics = new DisplayMetrics(); //get metrics of screen
    mActivity.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

    alertDialog.getWindow().setLayout(width, height); //set layout
    recyclerViewTime = promptsView.findViewById(R.id.recyclerViewTime);


    DialogSelectTimeAdapter dialogSelectTimeAdapter = new DialogSelectTimeAdapter(this);
    RecyclerView.LayoutManager linearLayoutManager = new LinearLayoutManager(this);
    recyclerViewTime.setLayoutManager(linearLayoutManager);
    recyclerViewTime.setAdapter(dialogSelectTimeAdapter);

    buttonDone = promptsView.findViewById(R.id.buttonDone);
    buttonDone.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            alertDialog.dismiss();

        }
    });

部分基于阿南德的回答。这对我来说很管用:

override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
    val fragmentActivity = requireActivity()
    val v = View.inflate(context, R.layout.fragment_about_dialog, null)
    val dialog = Dialog(fragmentActivity)
    dialog.requestWindowFeature(Window.FEATURE_NO_TITLE)
    dialog.setContentView(v)

    val wm = fragmentActivity.getSystemService(Context.WINDOW_SERVICE) as WindowManager 

    val display = if (VERSION.SDK_INT >= VERSION_CODES.R) {
        fragmentActivity.display
    } else {
        wm.defaultDisplay // deprecated in API 30
    }

    val size = Point()
    display?.getSize(size)

    val width = size.x - 50
    val height = size.y - 50
    val lp = WindowManager.LayoutParams()
    lp.copyFrom(dialog.window?.attributes)
    lp.width = width
    lp.height = height
    dialog.show()
    dialog.window?.attributes = lp
    
    return dialog
}

对于对话框布局使用constraintLayout:

<androidx.constraintlayout.widget.ConstraintLayout 
        android:id="@+id/dialogLayout"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
    ...
</androidx.constraintlayout.widget.ConstraintLayout>

结果:

这在改变屏幕方向时工作得很好。