RadioPreference.java

package me.barrasso.android.volume.ui;

import android.app.Service;
import android.content.Context;
import android.content.SharedPreferences;
import android.content.res.TypedArray;
import android.os.Parcel;
import android.os.Parcelable;
import android.preference.TwoStatePreference;
import android.util.AttributeSet;
import android.view.View;
import android.view.accessibility.AccessibilityEvent;
import android.view.accessibility.AccessibilityManager;
import android.widget.Checkable;

public class RadioPreference extends TwoStatePreference {

    private CharSequence mSummaryOn;
    private CharSequence mSummaryOff;
    private boolean mSendAccessibilityEventViewClickedType;
    private AccessibilityManager mAccessibilityManager;
    private boolean mChecked;

    private boolean mDisableDependentsState;

    public RadioPreference(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        mAccessibilityManager = (AccessibilityManager) getContext().getSystemService(Service.ACCESSIBILITY_SERVICE);
    }

    public RadioPreference(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public RadioPreference(Context context) {
        this(context, null);
    }

    @Override
    public boolean isPersistent() {
        return false;
    }

    @Override
    protected void onBindView(View view) {
        super.onBindView(view);
        View checkboxView = view.findViewById(android.R.id.checkbox);
        if (checkboxView != null && checkboxView instanceof Checkable) {
            ((Checkable) checkboxView).setChecked(mChecked);
            if (mSendAccessibilityEventViewClickedType &&
                    mAccessibilityManager.isEnabled() &&
                    checkboxView.isEnabled())
            {
                mSendAccessibilityEventViewClickedType = false;
                int eventType = AccessibilityEvent.TYPE_VIEW_CLICKED;
                checkboxView.sendAccessibilityEventUnchecked(AccessibilityEvent.obtain(eventType));
            }
        }
    }

    @Override
    protected void onClick() {
        super.onClick();
        boolean newValue = !isChecked();
        mSendAccessibilityEventViewClickedType = true;

        if (!callChangeListener(newValue)) {
            return;
        }
        setChecked(newValue);

    }

    /**
     * Sets the checked state and saves it to the {@link SharedPreferences}.
     *
     * @param checked
     *            The checked state.
     */
    @Override
    public void setChecked(boolean checked) {
        if (mChecked != checked) {
            mChecked = checked;
            persistBoolean(checked);
            notifyDependencyChange(shouldDisableDependents());
            notifyChanged();
        }
    }

    /**
     * Returns the checked state.
     *
     * @return The checked state.
     */
    @Override
    public boolean isChecked() {
        return mChecked;
    }

    @Override
    public boolean shouldDisableDependents() {
        boolean shouldDisable = mDisableDependentsState ? mChecked : !mChecked;
        return shouldDisable || super.shouldDisableDependents();
    }

    /**
     * Sets the summary to be shown when checked.
     *
     * @param summary
     *            The summary to be shown when checked.
     */
    @Override
    public void setSummaryOn(CharSequence summary) {
        mSummaryOn = summary;
        if (isChecked()) {
            notifyChanged();
        }
    }

    /**
     * @see #setSummaryOn(CharSequence)
     * @param summaryResId
     *            The summary as a resource.
     */
    @Override
    public void setSummaryOn(int summaryResId) {
        setSummaryOn(getContext().getString(summaryResId));
    }

    /**
     * Returns the summary to be shown when checked.
     *
     * @return The summary.
     */
    @Override
    public CharSequence getSummaryOn() {
        return mSummaryOn;
    }

    /**
     * Sets the summary to be shown when unchecked.
     *
     * @param summary
     *            The summary to be shown when unchecked.
     */
    @Override
    public void setSummaryOff(CharSequence summary) {
        mSummaryOff = summary;
        if (!isChecked()) {
            notifyChanged();
        }
    }

    /**
     * @see #setSummaryOff(CharSequence)
     * @param summaryResId
     *            The summary as a resource.
     */
    @Override
    public void setSummaryOff(int summaryResId) {
        setSummaryOff(getContext().getString(summaryResId));
    }

    /**
     * Returns the summary to be shown when unchecked.
     *
     * @return The summary.
     */
    @Override
    public CharSequence getSummaryOff() {
        return mSummaryOff;
    }

    /**
     * Returns whether dependents are disabled when this preference is on (
     * {@code true}) or when this preference is off ({@code false}).
     *
     * @return Whether dependents are disabled when this preference is on (
     *         {@code true}) or when this preference is off ({@code false}).
     */
    @Override
    public boolean getDisableDependentsState() {
        return mDisableDependentsState;
    }

    /**
     * Sets whether dependents are disabled when this preference is on (
     * {@code true}) or when this preference is off ({@code false}).
     *
     * @param disableDependentsState
     *            The preference state that should disable dependents.
     */
    @Override
    public void setDisableDependentsState(boolean disableDependentsState) {
        mDisableDependentsState = disableDependentsState;
    }

    @Override
    protected Object onGetDefaultValue(TypedArray a, int index) {
        return a.getBoolean(index, false);
    }

    @Override
    protected void onSetInitialValue(boolean restoreValue, Object defaultValue) {
        setChecked(restoreValue ? getPersistedBoolean(mChecked)
                : (Boolean) defaultValue);
    }

    @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.checked = isChecked();
        return myState;
    }

    @Override
    protected void onRestoreInstanceState(Parcelable state) {
        if (state == null || !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());
        setChecked(myState.checked);
    }

    private static class SavedState extends BaseSavedState {
        boolean checked;

        public SavedState(Parcel source) {
            super(source);
            checked = source.readInt() == 1;
        }

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

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

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

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