xref: /frameworks/support/v7/gridlayout/src/android/support/v7/widget/ViewGroup.java

/*
 * Copyright (C) 2012 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.support.v7.widget;

import android.content.Context;
import android.os.Build;
import android.util.AttributeSet;
import android.view.View;

/**
 * Custom ViewGroup providing some services to the support implementation of GridLayout.
 *
 */
abstract class ViewGroup extends android.view.ViewGroup {

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

    protected static final int MEASURED_STATE_TOO_SMALL = 0x01000000;

    /**
     * Bits of {@link #getMeasuredWidthAndState()} and
     * {@link #getMeasuredWidthAndState()} that provide the additional state bits.
     */
    protected static final int MEASURED_STATE_MASK = 0xff000000;

    /**
     * Utility to reconcile a desired size and state, with constraints imposed
     * by a MeasureSpec.  Will take the desired size, unless a different size
     * is imposed by the constraints.  The returned value is a compound integer,
     * with the resolved size in the {@link #MEASURED_SIZE_MASK} bits and
     * optionally the bit {@link #MEASURED_STATE_TOO_SMALL} set if the resulting
     * size is smaller than the size the view wants to be.
     *
     * @param size How big the view wants to be
     * @param measureSpec Constraints imposed by the parent
     * @return Size information bit mask as defined by
     * {@link #MEASURED_SIZE_MASK} and {@link #MEASURED_STATE_TOO_SMALL}.
     */
    public static int resolveSizeAndState(int size, int measureSpec, int childMeasuredState) {
        if (Build.VERSION.SDK_INT >= 11) {
            return View.resolveSizeAndState(size, measureSpec, childMeasuredState);
        }
        int result = size;
        int specMode = MeasureSpec.getMode(measureSpec);
        int specSize =  MeasureSpec.getSize(measureSpec);
        switch (specMode) {
        case MeasureSpec.UNSPECIFIED:
            result = size;
            break;
        case MeasureSpec.AT_MOST:
            if (specSize < size) {
                result = specSize | MEASURED_STATE_TOO_SMALL;
            } else {
                result = size;
            }
            break;
        case MeasureSpec.EXACTLY:
            result = specSize;
            break;
        }
        return result | (childMeasuredState&MEASURED_STATE_MASK);
    }

    protected static boolean isLayoutRtl(View view) {
        return false;
    }
}