CenterLayout.java

/*
 * Copyright (C) 2013 YIXIA.COM
 *
 * 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 io.vov.vitamio.widget;

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.widget.RemoteViews.RemoteView;

@RemoteView
public class CenterLayout extends ViewGroup {
  private int mPaddingLeft = 0;
  private int mPaddingRight = 0;
  private int mPaddingTop = 0;
  private int mPaddingBottom = 0;
  private int mWidth, mHeight;

  public CenterLayout(Context context) {
    super(context);
  }

  public CenterLayout(Context context, AttributeSet attrs) {
    super(context, attrs);
  }

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

  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    int count = getChildCount();

    int maxHeight = 0;
    int maxWidth = 0;

    measureChildren(widthMeasureSpec, heightMeasureSpec);

    for (int i = 0; i < count; i++) {
      View child = getChildAt(i);
      if (child.getVisibility() != GONE) {
        int childRight;
        int childBottom;

        CenterLayout.LayoutParams lp = (CenterLayout.LayoutParams) child.getLayoutParams();

        childRight = lp.x + child.getMeasuredWidth();
        childBottom = lp.y + child.getMeasuredHeight();

        maxWidth = Math.max(maxWidth, childRight);
        maxHeight = Math.max(maxHeight, childBottom);
      }
    }

    maxWidth += mPaddingLeft + mPaddingRight;
    maxHeight += mPaddingTop + mPaddingBottom;

    maxHeight = Math.max(maxHeight, getSuggestedMinimumHeight());
    maxWidth = Math.max(maxWidth, getSuggestedMinimumWidth());

    setMeasuredDimension(resolveSize(maxWidth, widthMeasureSpec), resolveSize(maxHeight, heightMeasureSpec));
  }

  @Override
  protected void onLayout(boolean changed, int l, int t, int r, int b) {
    int count = getChildCount();
    mWidth = getMeasuredWidth();
    mHeight = getMeasuredHeight();
    for (int i = 0; i < count; i++) {
      View child = getChildAt(i);
      if (child.getVisibility() != GONE) {
        CenterLayout.LayoutParams lp = (CenterLayout.LayoutParams) child.getLayoutParams();
        int childLeft = mPaddingLeft + lp.x;
        if (lp.width > 0)
          childLeft += (int) ((mWidth - lp.width) / 2.0);
        else
          childLeft += (int) ((mWidth - child.getMeasuredWidth()) / 2.0);
        int childTop = mPaddingTop + lp.y;
        if (lp.height > 0)
          childTop += (int) ((mHeight - lp.height) / 2.0);
        else
          childTop += (int) ((mHeight - child.getMeasuredHeight()) / 2.0);
        child.layout(childLeft, childTop, childLeft + child.getMeasuredWidth(), childTop + child.getMeasuredHeight());
      }
    }
  }

  @Override
  protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
    return p instanceof CenterLayout.LayoutParams;
  }

  @Override
  protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) {
    return new LayoutParams(p);
  }

  public static class LayoutParams extends ViewGroup.LayoutParams {
    public int x;
    public int y;

    public LayoutParams(int width, int height, int x, int y) {
      super(width, height);
      this.x = x;
      this.y = y;
    }

    public LayoutParams(ViewGroup.LayoutParams source) {
      super(source);
    }
  }
}