CompoundButtonContract.java

/*
 * Copyright (C) 2017 Simple Finance Technology Ltd.
 *
 * 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.banksimple.view;

import android.support.annotation.IdRes;
import android.util.SparseArray;
import android.widget.CompoundButton;

/**
 * Manager for multiple compound buttons (e.g. {@link android.widget.RadioButton}).
 * <p/>
 * When a managed button is checked, all others will be unchecked.
 */
public class CompoundButtonContract {
    private static final int NONE = -1;

    private SparseArray<CompoundButton> mItems;

    @IdRes
    private int mCheckedId = NONE;

    public CompoundButtonContract(CompoundButton... views) {
        SparseArray<CompoundButton> items = new SparseArray<>(views.length);
        for (CompoundButton v : views) {
            items.put(v.getId(), v);

            // Listen for changes to the checked state of this button
            v.setOnCheckedChangeListener(mOnCheckedChangeListener);
        }
        mItems = items;
    }

    public void check(@IdRes int resId) {
        CompoundButton button = mItems.get(resId);
        if (button != null) {
            button.setChecked(true);
        }
    }

    public void clear() {
        CompoundButton button = mItems.get(mCheckedId);
        if (button != null) {
            button.setChecked(false);
        }
        mCheckedId = NONE;
    }

    @IdRes
    public int getCheckedId() {
        return mCheckedId;
    }

    private final CompoundButton.OnCheckedChangeListener mOnCheckedChangeListener =
            new CompoundButton.OnCheckedChangeListener() {
                public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                    if (!isChecked) {
                        return; // We only care about newly checked buttons
                    }

                    // Uncheck the currently checked button
                    CompoundButton checked = mItems.get(mCheckedId);
                    if (checked != null) {
                        checked.setChecked(false);
                    }

                    // Cache the ID of the newly checked button
                    mCheckedId = buttonView.getId();
                }
            };
}