SwitchPreference Listener with Custom Layout

问题

I'm trying to use a SwitchPreference in my Settings page, but i can't get the listener to work. I am using a custom widget layout in order to style the switch, as I cannot find how to use themes to achieve this. In my settings.xml i have the following:

<SwitchPreference
            android:key="uitestmode"
            android:summary="Enable to display test data in fragments"
            android:title="UI Test Mode"
            android:widgetLayout="@layout/widget_custom_switch_on_off" >
</SwitchPreference>

and my SettingsFragment looks like:

SwitchPreference uiTestModePref = (SwitchPreference) findPreference("uitestmode");
uiTestModePref.setOnPreferenceChangeListener(new OnPreferenceChangeListener() {

    @Override
    public boolean onPreferenceChange(Preference preference, Object newValue) {
        Log.d(preference.getKey(), newValue.toString());
        return false;
    }
});

and my custom layout for my switch:

<?xml version="1.0" encoding="utf-8"?>
<Switch xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/custom_switch_item"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:gravity="center_vertical"
    android:textColor="@android:color/white"
    android:textIsSelectable="false"
    android:textSize="18sp"
    android:textOn="On"
    android:textOff="Off"
    android:textStyle="bold"
    android:thumb="@drawable/carcast_switch_inner_holo_dark"
    android:track="@drawable/carcast_switch_track_holo_dark" />

The problem I have is that when I click the switch, the listener is not called. Does anybody know why and how to fix it?

回答1:

I ran into the same issue, my solution is similar to the followings:

In your custom switch layout, add following code. This "uncovers" the preference, and makes the whole block clickable. That's why the listener is not triggered at all.

android:clickable="false" android:focusable="false"

Extend "SwitchPreference", and in "onBindView" class, get states from SharedPreferences, and handle switch states change there.

public class MySwitchPreference extends SwitchPreference {

    public MySwitchPreference(Context context) {
        super(context, null);
    }

    public MySwitchPreference(Context context, AttributeSet attrs) {
        super(context, attrs);
    }
    public MySwitchPreference(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    protected void onBindView(View view) {
        // Clean listener before invoke SwitchPreference.onBindView
        ViewGroup viewGroup= (ViewGroup)view;
        clearListenerInViewGroup(viewGroup);
        super.onBindView(view);

        final Switch mySwitch = (Switch) view.findViewById(R.id.custom_switch_item);
        Boolean initVal = this.getPersistedBoolean(false);
        if (initVal) {
            mySwitch.setChecked(true);
        }
        this.setOnPreferenceChangeListener(new OnPreferenceChangeListener() {
            @Override
            public boolean onPreferenceChange(Preference preference, Object newValue) {
                //Do your things here, toggling the switch and so on
                return true;
            }
        });
    }

    private void clearListenerInViewGroup(ViewGroup viewGroup) {
        if (null == viewGroup) {
            return;
        }

        int count = viewGroup.getChildCount();
        for(int n = 0; n < count; ++n) {
            View childView = viewGroup.getChildAt(n);
            if(childView instanceof Switch) {
                final Switch switchView = (Switch) childView;
                switchView.setOnCheckedChangeListener(null);
                return;
            } else if (childView instanceof ViewGroup){
                ViewGroup childGroup = (ViewGroup)childView;
                clearListenerInViewGroup(childGroup);
            }
        }
    }
}

Hopefully this can help you. I was not able to find any solution for my case until I figured it out this way.

回答2:

Solution – based on @RickCase answer, but works with both Switch and SwitchCompat.

来源：https://stackoverflow.com/questions/24655834/switchpreference-listener-with-custom-layout

标签

android

preferencefragment

android-switch