Alertdialog.Builder setview: Call requires API level 21

Question

I am trying to get a radius NumberPicker running in a class that extends DialogPreference, and I am having a lot of trouble getting setView() to work. Let's start with some code:

public class RadiusPickerPreference extends DialogPreference{
    public RadiusPickerPreference(Context context, AttributeSet attrs) {
        super(context, attrs);
    }
    @Override
    protected void onPrepareDialogBuilder(android.app.AlertDialog.Builder builder) {
        builder.setTitle(R.string.set_radius_dialog_fragment_title);
        builder.setView(R.layout.dialog_radius_picker);
        builder.setPositiveButton(android.R.string.ok, null);
        builder.setNegativeButton(android.R.string.cancel, null);
    }
}

This gives me an error on builder.setView saying "Call requires API 21 (current min is 15)." I want to support devices with APIs 15+, so changing this is not an option. Now, if I try to override

protected void onPrepareDialogBuilder(android.support.v7.app.AlertDialog.Builder builder)

instead, it says "Method does not override method from its superclass."

Question is, how can I set the view? It doesn't necessarily have to be in onPrepareDialogBuilder(), as long as it supports API 15+. Thanks!

PS: Let me know if you need more code. To get it displayed in XML, just add this to a <PreferenceScreen>:

<com.example.project.RadiusPickerPreference
    android:id="@+id/radPickerPref"
    android:key="@string/pref_key_default_radius"
    android:title="@string/pref_title_default_radius"/>

Answer 1

What you're trying to do here is call a function that was added in API 21 instead of the one added in API 1. As per the documentation, you want setView(View view) instead of setView(int layoutResId). To get a View from a layout, you need a LayoutInflater. To get an instance of LayoutInflater, you will need a context object. When you create your dialog, I would recommend storing your Context as a variable in the class for future use. Then, in onPrepareDialogBuilder, you can use (as per the docs):

LayoutInflater inflater = (LayoutInflater)context.getSystemService (Context.LAYOUT_INFLATER_SERVICE)

Now, you can use inflater to get a View from your layout and set your dialog's View as follows:

 View v = inflater.inflate(R.layout.dialog_radius_picker, null);

So, your code could look like:

@Override
protected void onPrepareDialogBuilder(android.app.AlertDialog.Builder builder) {
    LayoutInflater inflater = (LayoutInflater)context.getSystemService (Context.LAYOUT_INFLATER_SERVICE);
    builder.setTitle(R.string.set_radius_dialog_fragment_title);
    View v = inflater.inflate(R.layout.dialog_radius_picker, null);
    builder.setView(v);
    builder.setPositiveButton(android.R.string.ok, null);
    builder.setNegativeButton(android.R.string.cancel, null);
}

Hopefully that helps!