ComponentStatePreference.java

package org.getlantern.firetweet.preference;

import android.annotation.SuppressLint;
import android.content.ComponentName;
import android.content.Context;
import android.content.pm.PackageManager;
import android.content.res.TypedArray;
import android.preference.CheckBoxPreference;
import android.preference.PreferenceManager;
import android.support.annotation.NonNull;
import android.util.AttributeSet;

public class ComponentStatePreference extends CheckBoxPreference {

    private final PackageManager mPackageManager;
    private final ComponentName mComponentName;

    public ComponentStatePreference(final Context context) {
        this(context, null);
    }

    public ComponentStatePreference(final Context context, final AttributeSet attrs) {
        this(context, attrs, android.R.attr.checkBoxPreferenceStyle);
    }

    public ComponentStatePreference(final Context context, final AttributeSet attrs, final int defStyle) {
        super(context, attrs, defStyle);
        mPackageManager = context.getPackageManager();
        mComponentName = getComponentName(context, attrs);
        setDefaultValue(isComponentEnabled());
    }

    @Override
    public boolean shouldDisableDependents() {
        final boolean disableDependentsState = getDisableDependentsState();
        final boolean value = isComponentEnabled();
        return disableDependentsState ? value : !value;
    }

    @Override
    protected Object onGetDefaultValue(final TypedArray a, final int index) {
        return isComponentEnabled();
    }

    @Override
    protected void onSetInitialValue(final boolean restoreValue, final Object defaultValue) {
        setChecked(getPersistedBoolean(true));
    }

    protected ComponentName getComponentName(Context context, AttributeSet attrs) {
        final TypedArray a = context.obtainStyledAttributes(attrs, new int[]{android.R.attr.name});
        final String name = a.getString(0);
        a.recycle();
        if (name == null) throw new NullPointerException();
        return new ComponentName(context.getPackageName(), name);
    }

    protected boolean isComponentAvailable() {
        return true;
    }

    @Override
    protected boolean shouldPersist() {
        return true;
    }

    @Override
    protected void notifyHierarchyChanged() {
        super.notifyHierarchyChanged();
        updateEnableState();
    }

    @Override
    protected void onAttachedToHierarchy(@NonNull final PreferenceManager preferenceManager) {
        super.onAttachedToHierarchy(preferenceManager);
        updateEnableState();
    }

    @Override
    protected boolean persistBoolean(final boolean value) {
        final int newState = value ? PackageManager.COMPONENT_ENABLED_STATE_ENABLED
                : PackageManager.COMPONENT_ENABLED_STATE_DISABLED;
        mPackageManager.setComponentEnabledSetting(mComponentName, newState, PackageManager.DONT_KILL_APP);
        return true;
    }

    @Override
    protected boolean getPersistedBoolean(final boolean defaultReturnValue) {
        return isComponentEnabled();
    }

    @SuppressLint("InlinedApi")
    private boolean isComponentEnabled() {
        try {
            final int state = mPackageManager.getComponentEnabledSetting(mComponentName);
            return state != PackageManager.COMPONENT_ENABLED_STATE_DISABLED
                    && state != PackageManager.COMPONENT_ENABLED_STATE_DISABLED_USER
                    && state != PackageManager.COMPONENT_ENABLED_STATE_DISABLED_UNTIL_USED;
        } catch (NullPointerException e) {
            // Seems this will thrown on older devices
            return false;
        }
    }

    private void updateEnableState() {
        setEnabled(isComponentAvailable());
    }

}