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)

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);
}

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)
}

    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();

        }
    });

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()

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。