如果你使用对话片段，你可以用onResume方法。 这是Xamarin Android的代码，但我认为它很容易理解

public override void OnResume() 
{
    base.OnResume();
    var metrics = Resources.DisplayMetrics;

    double width = metrics.WidthPixels * 0.9;
    double height = metrics.HeightPixels * 0.6;

    this.Dialog.Window.SetLayout((int)width, (int)height);
    this.Dialog.Window.SetGravity(Android.Views.GravityFlags.Center);
}

让你的对话成为一种活动。3个步骤

步骤1: 将其中一个放在styles.xml中

风格: 我喜欢这个，因为你可以将父主题更改为你的主题的名称，你将在你的应用程序的其余部分使用。

<style name="DialogTheme" parent="Theme.AppCompat.Light.NoActionBar">
    <item name="android:windowIsTranslucent">true</item>
    <item name="android:windowBackground">@color/transparent</item>
    <item name="android:windowIsFloating">true</item>
    <item name="android:windowMinWidthMajor">90%</item>
    <item name="android:windowMinWidthMinor">90%</item>
</style>

方式二:

<style name="DialogTheme" parent="Theme.AppCompat.Dialog">
    <item name="android:windowMinWidthMajor">90%</item>
    <item name="android:windowMinWidthMinor">90%</item>
</style>

步骤2: 然后把它放在AndroidManifest.xml中

<activity
    android:name="com.example.YourApp.DialogActivity"
    android:theme="@style/DialogTheme" />

步骤3: 确保你的主布局宽度fill_parent或match_parent在activity_dialog.xml中

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    tools:context=".DialogActivity">

</androidx.constraintlayout.widget.ConstraintLayout>

上面的许多答案都很好，但没有一个对我完全有效。所以我结合@nmr的答案得到了这个。

final Dialog d = new Dialog(getActivity());
        //  d.getWindow().setBackgroundDrawable(R.color.action_bar_bg);
        d.requestWindowFeature(Window.FEATURE_NO_TITLE);
        d.setContentView(R.layout.dialog_box_shipment_detail);

        WindowManager wm = (WindowManager) getActivity().getSystemService(Context.WINDOW_SERVICE); // for activity use context instead of getActivity()
        Display display = wm.getDefaultDisplay(); // getting the screen size of device
        Point size = new Point();
        display.getSize(size);
        int width = size.x - 20;  // Set your heights
        int height = size.y - 80; // set your widths

        WindowManager.LayoutParams lp = new WindowManager.LayoutParams();
        lp.copyFrom(d.getWindow().getAttributes());

        lp.width = width;
        lp.height = height;

        d.getWindow().setAttributes(lp);
        d.show();

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;
        }
    }

我发现了一个非常简单易行的解决办法

    fun showDialog(){
    val dialog = Dialog(this@DialogActivity)
    dialog.requestWindowFeature(Window.FEATURE_NO_TITLE)
    dialog.setCancelable(false)
    dialog.setContentView(R.layout.custom_dialog)
    val txtTitle = dialog.findViewById<TextView>(R.id.txtTitle)
    val btn  = dialog.findViewById<Button>(R.id.button)

    btn.setOnClickListener {
        Toast.makeText(this,"test",Toast.LENGTH_SHORT).show()
    }
    txtTitle.setText("ali")
    dialog.show()

    val window = dialog.window
    window?.setLayout(WindowManager.LayoutParams.MATCH_PARENT,WindowManager.LayoutParams.WRAP_CONTENT)
}

下面是我的自定义对话框宽度的变体:

DisplayMetrics displaymetrics = new DisplayMetrics();
mActivity.getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
int width = (int) (displaymetrics.widthPixels * (ThemeHelper.isPortrait(mContext) ? 0.95 : 0.65));

WindowManager.LayoutParams params = getWindow().getAttributes();
params.width = width;
getWindow().setAttributes(params);

因此，根据设备方向(ThemeHelper.isPortrait(mContext))对话框的宽度将是95%(纵向模式)或65%(横向模式)。这比作者要求的要多一点，但对某些人来说可能有用。

你需要创建一个从Dialog扩展而来的类，并把这段代码放到你的onCreate(Bundle savedInstanceState)方法中。

对于对话框的高度，代码应该类似于此。