***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
}

这里有一个简短的答案，对我来说是有效的(在API 8和API 19上测试)。

Dialog mDialog;
View   mDialogView;
...
// Get height
int height = mDialog.getWindow()
.getWindowManager().getDefaultDisplay()
.getHeight();

// Set your desired padding (here 90%)
int padding = height - (int)(height*0.9f);

// Apply it to the Dialog
mDialogView.setPadding(
// padding left
0,
// padding top (90%)
padding, 
// padding right
0, 
// padding bottom (90%)
padding);

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)
}

实际90%计算解:

@Override public void onStart() {
   Dialog dialog = getDialog();
   if (dialog != null) {
     dialog.getWindow()
        .setLayout((int) (getScreenWidth(getActivity()) * .9), ViewGroup.LayoutParams.MATCH_PARENT);
   }
}

其中getScreenWidth(Activity Activity)定义如下(最好放在Utils类中):

public static int getScreenWidth(Activity activity) {
   Point size = new Point();
   activity.getWindowManager().getDefaultDisplay().getSize(size);
   return size.x;
}

dialog.getWindow().setLayout(WindowManager.LayoutParams.MATCH_PARENT,WindowManager.LayoutParams.WRAP_CONTENT);

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()