core/java/android/preference/SwitchPreference.java

/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.preference;

import android.annotation.StringRes;
import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.view.View;
import android.widget.Checkable;
import android.widget.CompoundButton;
import android.widget.Switch;

/**
 * A {@link Preference} that provides a two-state toggleable option.
 * <p>
 * This preference will store a boolean into the SharedPreferences.
 *
 * @attr ref android.R.styleable#SwitchPreference_summaryOff
 * @attr ref android.R.styleable#SwitchPreference_summaryOn
 * @attr ref android.R.styleable#SwitchPreference_switchTextOff
 * @attr ref android.R.styleable#SwitchPreference_switchTextOn
 * @attr ref android.R.styleable#SwitchPreference_disableDependentsState
 */
public class SwitchPreference extends TwoStatePreference {
    private final Listener mListener = new Listener();

    // Switch text for on and off states
    private CharSequence mSwitchOn;
    private CharSequence mSwitchOff;

    private class Listener implements CompoundButton.OnCheckedChangeListener {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            if (!callChangeListener(isChecked)) {
                // Listener didn't like it, change it back.
                // CompoundButton will make sure we don't recurse.
                buttonView.setChecked(!isChecked);
                return;
            }

            SwitchPreference.this.setChecked(isChecked);
        }
    }

    /**
     * Construct a new SwitchPreference with the given style options.
     *
     * @param context The Context that will style this preference
     * @param attrs Style attributes that differ from the default
     * @param defStyleAttr An attribute in the current theme that contains a
     *        reference to a style resource that supplies default values for
     *        the view. Can be 0 to not look for defaults.
     * @param defStyleRes A resource identifier of a style resource that
     *        supplies default values for the view, used only if
     *        defStyleAttr is 0 or can not be found in the theme. Can be 0
     *        to not look for defaults.
     */
    public SwitchPreference(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);

        TypedArray a = context.obtainStyledAttributes(attrs,
                com.android.internal.R.styleable.SwitchPreference, defStyleAttr, defStyleRes);
        setSummaryOn(a.getString(com.android.internal.R.styleable.SwitchPreference_summaryOn));
        setSummaryOff(a.getString(com.android.internal.R.styleable.SwitchPreference_summaryOff));
        setSwitchTextOn(a.getString(
                com.android.internal.R.styleable.SwitchPreference_switchTextOn));
        setSwitchTextOff(a.getString(
                com.android.internal.R.styleable.SwitchPreference_switchTextOff));
        setDisableDependentsState(a.getBoolean(
                com.android.internal.R.styleable.SwitchPreference_disableDependentsState, false));
        a.recycle();
    }

    /**
     * Construct a new SwitchPreference with the given style options.
     *
     * @param context The Context that will style this preference
     * @param attrs Style attributes that differ from the default
     * @param defStyleAttr An attribute in the current theme that contains a
     *        reference to a style resource that supplies default values for
     *        the view. Can be 0 to not look for defaults.
     */
    public SwitchPreference(Context context, AttributeSet attrs, int defStyleAttr) {
        this(context, attrs, defStyleAttr, 0);
    }

    /**
     * Construct a new SwitchPreference with the given style options.
     *
     * @param context The Context that will style this preference
     * @param attrs Style attributes that differ from the default
     */
    public SwitchPreference(Context context, AttributeSet attrs) {
        this(context, attrs, com.android.internal.R.attr.switchPreferenceStyle);
    }

    /**
     * Construct a new SwitchPreference with default style options.
     *
     * @param context The Context that will style this preference
     */
    public SwitchPreference(Context context) {
        this(context, null);
    }

    @Override
    protected void onBindView(View view) {
        super.onBindView(view);

        View checkableView = view.findViewById(com.android.internal.R.id.switch_widget);
        if (checkableView != null && checkableView instanceof Checkable) {
            if (checkableView instanceof Switch) {
                final Switch switchView = (Switch) checkableView;
                switchView.setOnCheckedChangeListener(null);
            }

            ((Checkable) checkableView).setChecked(mChecked);

            if (checkableView instanceof Switch) {
                final Switch switchView = (Switch) checkableView;
                switchView.setTextOn(mSwitchOn);
                switchView.setTextOff(mSwitchOff);
                switchView.setOnCheckedChangeListener(mListener);
            }
        }

        syncSummaryView(view);
    }

    /**
     * Set the text displayed on the switch widget in the on state.
     * This should be a very short string; one word if possible.
     *
     * @param onText Text to display in the on state
     */
    public void setSwitchTextOn(CharSequence onText) {
        mSwitchOn = onText;
        notifyChanged();
    }

    /**
     * Set the text displayed on the switch widget in the off state.
     * This should be a very short string; one word if possible.
     *
     * @param offText Text to display in the off state
     */
    public void setSwitchTextOff(CharSequence offText) {
        mSwitchOff = offText;
        notifyChanged();
    }

    /**
     * Set the text displayed on the switch widget in the on state.
     * This should be a very short string; one word if possible.
     *
     * @param resId The text as a string resource ID
     */
    public void setSwitchTextOn(@StringRes int resId) {
        setSwitchTextOn(getContext().getString(resId));
    }

    /**
     * Set the text displayed on the switch widget in the off state.
     * This should be a very short string; one word if possible.
     *
     * @param resId The text as a string resource ID
     */
    public void setSwitchTextOff(@StringRes int resId) {
        setSwitchTextOff(getContext().getString(resId));
    }

    /**
     * @return The text that will be displayed on the switch widget in the on state
     */
    public CharSequence getSwitchTextOn() {
        return mSwitchOn;
    }

    /**
     * @return The text that will be displayed on the switch widget in the off state
     */
    public CharSequence getSwitchTextOff() {
        return mSwitchOff;
    }
}