title: what theme to use for the AlertDialog to adjust the color automatically with day/night theme
body: <p>if the app called <code>AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES);</code>  it is expect to show dark theme,  and if not the app is with light theme.</p>
  
  <p>Having <code>AlertDialog.Builder(this)</code>,  and would like to apply one theme so that in MODE_NIGHT  it shows the dialog with dark theme,  other wise  the dialog shows with the light theme,  something like below (but this <code>android.R.style.Theme_Material_Dialog</code> will causes the dialog to be always in dark theme)</p>
  
  <pre><code>AlertDialog.Builder(this, android.R.style.Theme_Material_Dialog)
  </code></pre>
  
  <p>Is there one theme for the AlertDialog? or it has to define two themes and check the mode and then to code with the theme respectively?</p>