CheckableImageButton.java

package com.circlegate.liban.view;

import android.content.Context;
import android.os.Build.VERSION;
import android.os.Build.VERSION_CODES;
import android.os.Parcel;
import android.os.Parcelable;
import android.util.AttributeSet;
import android.view.accessibility.AccessibilityEvent;
import android.view.accessibility.AccessibilityNodeInfo;
import android.widget.CheckBox;
import android.widget.Checkable;
import android.widget.ImageButton;

public class CheckableImageButton extends ImageButton implements Checkable {
    private static final int[] CHECKED_STATE_SET = { android.R.attr.state_checked };

    private boolean mChecked;
    private boolean mBroadcasting;
    private OnCheckedChangeListener mOnCheckedChangeListener;

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

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

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

    //
    // GETTERS
    //

    @Override
    public boolean isChecked() {
        return mChecked;
    }


    //
    // SETTERS
    //

    @Override
    public void setChecked(boolean checked) {
        if (this.mChecked != checked) {
            mChecked = checked;
            refreshDrawableState();

            // Avoid infinite recursions if setChecked() is called from a listener
            if (mBroadcasting) {
                return;
            }

            mBroadcasting = true;
            if (mOnCheckedChangeListener != null) {
                mOnCheckedChangeListener.onCheckedChanged(this, mChecked);
            }

            mBroadcasting = false;
        }
    }

    @Override
    public void toggle() {
        setChecked(!mChecked);
    }

    @Override
    public boolean performClick() {
        toggle();
        return super.performClick();
    }


    //
    // CALLBACKS
    //

    /**
     * Register a callback to be invoked when the checked state of this button changes.
     *
     * @param listener
     *            the callback to call on checked state change
     */
    public void setOnCheckedChangeListener(OnCheckedChangeListener listener) {
        mOnCheckedChangeListener = listener;
    }

    /**
     * Interface definition for a callback.
     */
    public static interface OnCheckedChangeListener {
        /**
         * Called when the checked state of a button has changed.
         *
         * @param button
         *            The button view whose state has changed.
         * @param isChecked
         *            The new checked state of button.
         */
        void onCheckedChanged(CheckableImageButton button, boolean isChecked);
    }

    @Override
    public int[] onCreateDrawableState(int extraSpace) {
        final int[] drawableState = super.onCreateDrawableState(extraSpace + 1);
        if (isChecked()) {
            mergeDrawableStates(drawableState, CHECKED_STATE_SET);
        }
        return drawableState;
    }

    @Override
    protected void drawableStateChanged() {
        super.drawableStateChanged();
        invalidate();
    }

    @Override
    public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
        super.onInitializeAccessibilityEvent(event);
        event.setChecked(isChecked());
        event.setClassName(CheckBox.class.getName());
    }

    @Override
    public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
        super.onInitializeAccessibilityNodeInfo(info);
        if (VERSION.SDK_INT >= VERSION_CODES.ICE_CREAM_SANDWICH) {
            info.setCheckable(true);
            info.setChecked(isChecked());
            info.setClassName(CheckBox.class.getName());
        }
    }


    //
    // SAVED STATE
    //

    public static class SavedState extends BaseSavedState {
        boolean checked;

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

        private SavedState(Parcel in) {
            super(in);
            checked = (Boolean) in.readValue(null);
        }

        @Override
        public void writeToParcel(Parcel out, int flags) {
            super.writeToParcel(out, flags);
            out.writeValue(checked);
        }

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

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

    @Override
    public Parcelable onSaveInstanceState() {
        Parcelable superState = super.onSaveInstanceState();
        SavedState ss = new SavedState(superState);
        ss.checked = isChecked();
        return ss;
    }

    @Override
    public void onRestoreInstanceState(Parcelable state) {
        SavedState ss = (SavedState) state;
        super.onRestoreInstanceState(ss.getSuperState());
        setChecked(ss.checked);
        requestLayout();
    }
}