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。

你必须在显示之前设置对话框的高度和宽度(dialog.show())

所以，像这样做:

dialog.getWindow().setLayout(width, height);

//then

dialog.show()

得到这段代码，我做了一些改变:

dialog.getWindow().setLayout((int)(MapGeaGtaxiActivity.this.getWindow().peekDecorView().getWidth()*0.9),(int) (MapGeaGtaxiActivity.this.getWindow().peekDecorView().getHeight()*0.9));

但是，当设备改变位置时，对话框的大小也会改变。当度量发生变化时，您可能需要自己处理。 peekDecorView，暗示在活动中的布局是正确初始化的，否则你可以使用

DisplayMetrics metrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metrics);
int height = metrics.heightPixels;
int wwidth = metrics.widthPixels;

为了得到屏幕大小

我的答案是基于koma的，但它不需要覆盖onStart，但只需要onCreateView，当你创建新的片段时，默认情况下几乎总是被覆盖。

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View v = inflater.inflate(R.layout.your_fragment_layout, container);

    Rect displayRectangle = new Rect();
    Window window = getDialog().getWindow();
    window.getDecorView().getWindowVisibleDisplayFrame(displayRectangle);

    v.setMinimumWidth((int)(displayRectangle.width() * 0.9f));
    v.setMinimumHeight((int)(displayRectangle.height() * 0.9f));

    return v;
}

我在Android 5.0.1上进行了测试。

在对话框窗口上指定FILL_PARENT，就像其他人建议的那样，对我来说并不管用(在Android 4.0.4上)，因为它只是拉伸了黑色对话框背景来填充整个屏幕。

正常工作的方法是使用最小显示值，但在代码中指定它，以便对话框占用屏幕的90%。

So:

Activity activity = ...;
AlertDialog dialog = ...;

// retrieve display dimensions
Rect displayRectangle = new Rect();
Window window = activity.getWindow();
window.getDecorView().getWindowVisibleDisplayFrame(displayRectangle);

// inflate and adjust layout
LayoutInflater inflater = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View layout = inflater.inflate(R.layout.your_dialog_layout, null);
layout.setMinimumWidth((int)(displayRectangle.width() * 0.9f));
layout.setMinimumHeight((int)(displayRectangle.height() * 0.9f));

dialog.setView(layout);

一般来说，在大多数情况下，只调整宽度就足够了。

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)
}

    ...
    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