Android example source code file (YesNoPreference.java)

This example Android source code file (YesNoPreference.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

android, attributeset, basesavedstate, boolean, content, creator, dialogpreference, object, os, override, parcelable, preferences, savedstate, util, utilities, yesnopreference

The YesNoPreference.java Android example source code

/*
 * Copyright (C) 2007 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 com.android.internal.preference;

import android.content.Context;
import android.content.res.TypedArray;
import android.os.Parcel;
import android.os.Parcelable;
import android.preference.DialogPreference;
import android.util.AttributeSet;

/**
 * The {@link YesNoPreference} is a preference to show a dialog with Yes and No
 * buttons.
 * <p>
 * This preference will store a boolean into the SharedPreferences.
 */
public class YesNoPreference extends DialogPreference {
    private boolean mWasPositiveResult;
    
    public YesNoPreference(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    public YesNoPreference(Context context, AttributeSet attrs) {
        this(context, attrs, com.android.internal.R.attr.yesNoPreferenceStyle);
    }
    
    public YesNoPreference(Context context) {
        this(context, null);
    }

    @Override
    protected void onDialogClosed(boolean positiveResult) {
        super.onDialogClosed(positiveResult);

        if (callChangeListener(positiveResult)) {
            setValue(positiveResult);
        }
    }

    /**
     * Sets the value of this preference, and saves it to the persistent store
     * if required.
     * 
     * @param value The value of the preference.
     */
    public void setValue(boolean value) {
        mWasPositiveResult = value;
        
        persistBoolean(value);
        
        notifyDependencyChange(!value);
    }
    
    /**
     * Gets the value of this preference.
     * 
     * @return The value of the preference.
     */
    public boolean getValue() {
        return mWasPositiveResult;
    }
    
    @Override
    protected Object onGetDefaultValue(TypedArray a, int index) {
        return a.getBoolean(index, false);
    }

    @Override
    protected void onSetInitialValue(boolean restorePersistedValue, Object defaultValue) {
        setValue(restorePersistedValue ? getPersistedBoolean(mWasPositiveResult) :
            (Boolean) defaultValue);
    }

    @Override
    public boolean shouldDisableDependents() {
        return !mWasPositiveResult || super.shouldDisableDependents();
    }
    
    @Override
    protected Parcelable onSaveInstanceState() {
        final Parcelable superState = super.onSaveInstanceState();
        if (isPersistent()) {
            // No need to save instance state since it's persistent
            return superState;
        }
        
        final SavedState myState = new SavedState(superState);
        myState.wasPositiveResult = getValue();
        return myState;
    }

    @Override
    protected void onRestoreInstanceState(Parcelable state) {
        if (!state.getClass().equals(SavedState.class)) {
            // Didn't save state for us in onSaveInstanceState
            super.onRestoreInstanceState(state);
            return;
        }
         
        SavedState myState = (SavedState) state;
        super.onRestoreInstanceState(myState.getSuperState());
        setValue(myState.wasPositiveResult);
    }
    
    private static class SavedState extends BaseSavedState {
        boolean wasPositiveResult;
        
        public SavedState(Parcel source) {
            super(source);
            wasPositiveResult = source.readInt() == 1;
        }

        @Override
        public void writeToParcel(Parcel dest, int flags) {
            super.writeToParcel(dest, flags);
            dest.writeInt(wasPositiveResult ? 1 : 0);
        }

        public SavedState(Parcelable superState) {
            super(superState);
        }

        public static final Parcelable.Creator<SavedState> CREATOR =
                new Parcelable.Creator<SavedState>() {
            public SavedState createFromParcel(Parcel in) {
                return new SavedState(in);
            }

            public SavedState[] newArray(int size) {
                return new SavedState[size];
            }
        };
    }
    
}