更简单的是这样做:

int width = (int)(getResources().getDisplayMetrics().widthPixels*0.90);
int height = (int)(getResources().getDisplayMetrics().heightPixels*0.90);

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

到目前为止我能想到的最简单的方法

如果你的对话框是由垂直线性布局组成的，只需添加一个“高度填充”虚拟视图，它将占据屏幕的整个高度。

例如:

<?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:weightSum="1">

    <EditText
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:id="@+id/editSearch" />

    <ListView
       android:layout_width="match_parent"
       android:layout_height="match_parent"
       android:id="@+id/listView"/>


   <!-- this is a dummy view that will make sure the dialog is highest -->
   <View
       android:layout_width="match_parent"
       android:layout_height="match_parent"
       android:layout_weight="1"/>

</LinearLayout>

注意LinearLayout属性中的android:weightSum="1"和dummy View属性中的android:layout_weight="1"

尝试将你的自定义对话框布局包装成RelativeLayout而不是LinearLayout。这对我很管用。

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)
}

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);
}

***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
}