androidx.recyclerview.widget.RecyclerView.LayoutParams Java Examples

/**
 * 对适配器中的itemView任何View(含itemView本身)
 * 进入relayout
 * @param customLayoutParams 自定义的布局参数
 * @param assignTagId 指定的要给View标识为是否已经relayout了
 * @param anyView 要relayout的任何View
 * @param isTheAdapteItemView 是否为适配器的itemView本身
 * @return true:relayout了; false:未进行relayout或者已经relayout过了
 */
protected boolean relayoutAnyView(@Nullable ViewGroup.LayoutParams customLayoutParams, @IdRes int assignTagId, View anyView,boolean isTheAdapteItemView) {
    if (anyView == null) {
        return false;//代表本次不去relayout了
    }
    Object relayoutTag = anyView.getTag(assignTagId);
    if (relayoutTag != null) {//已经relayout了当前的view,则不进行relayout了
        return false;//代表本次不去relayout了
    }
    // Q:2019/10/24 ??要回调开始relayout了吗？A:还是回调吧，如果有额外的处理,则给机会处理，然后最后统一setLayoutParams
    startRelayoutAnyView(isTheAdapteItemView,anyView);
    anyView.setTag(assignTagId, "relayouted");
    if (customLayoutParams != null) {
        anyView.setLayoutParams(customLayoutParams);
    }
    return true;//代表本次relayout了
}
 

@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int viewType) {
  LinearLayout container =
      (LinearLayout)
          LayoutInflater.from(viewGroup.getContext())
              .inflate(R.layout.mtrl_calendar_month_labeled, viewGroup, false);

  if (MaterialDatePicker.isFullscreen(viewGroup.getContext())) {
    container.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, itemHeight));
    return new ViewHolder(container, /* showLabel= */ true);
  } else {
    return new ViewHolder(container, /* showLabel= */ false);
  }
}
 

/**
 * added by fee 2019-07-11:
 * <P>注：该方法主要是用来relayout适配的itemView布局,依赖的前提条件为外部指定了itemView的宽、高</P>
 * 为了满足某些场景下，需要通过外部来重新指定item view的宽、高，则在{convert(xx,xx)}
 * 需要重新设置item view的布局参数
 * @param assignTagId 所指定的给 theItemView setTag()用于标记已经relayout过的
 * @param theItemView 当前的item 视图
 * @return true:重置了itemview布局
 */
protected boolean relayoutTheItemView(@IdRes int assignTagId, View theItemView) {
    if (theAssignItemHeight == 0 && theAssignItemWidth == 0) {
        return false;
    }
    if (theItemView == null) {
        return false;
    }
    Object relayoutTag = theItemView.getTag(assignTagId);
    if (relayoutTag != null) {//已经relayout了当前的item view,则不进行relayout了
        return false;
    }
    startRelayoutItemView(theItemView);//这里回调出去主要是为了如果有额外的处理,则给机会处理，然后最后统一setLayoutParams
    ViewGroup.LayoutParams vlp = theItemView.getLayoutParams();
    if (vlp == null) {
        vlp = new ViewGroup.LayoutParams(WRAP_CONTENT, WRAP_CONTENT);
    }
    if (theAssignItemWidth > 0) {//一般宽较容易确定
        vlp.width = theAssignItemWidth;
    }
    if (theAssignUiDesignWidthRatio != 0 && theAssignUiDesignHeightRatio != 0 && theAssignItemWidth > 0) {
        //h实 = w实 * h设计高占比 /w设计宽占比：即等比缩放itemView宽高
        theAssignItemHeight = theAssignItemWidth * theAssignUiDesignHeightRatio / theAssignUiDesignWidthRatio;
    }
    if (theAssignItemHeight > 0) {
        vlp.height = theAssignItemHeight;
    }
    theItemView.setTag(assignTagId, "relayouted");
    theItemView.setLayoutParams(vlp);
    return true;
}
 

protected boolean relayoutTheItemView(ViewGroup.LayoutParams customLayoutParams, @IdRes int assignTagId, View theItemView) {
    if (customLayoutParams == null || theItemView == null) {
        return false;
    }
    Object relayoutTag = theItemView.getTag(assignTagId);
    if (relayoutTag != null) {//已经relayout了当前的item view,则不进行relayout了
        return false;
    }
    startRelayoutItemView(theItemView);
    theItemView.setTag(assignTagId,"relayouted");
    theItemView.setLayoutParams(customLayoutParams);
    return true;
}
 

@Override
public LayoutParams generateDefaultLayoutParams() {
  return getOrientation() == OrientationHelper.VERTICAL
      ? new RecyclerView.LayoutParams(MATCH_PARENT, WRAP_CONTENT)
      : new RecyclerView.LayoutParams(WRAP_CONTENT, MATCH_PARENT);
}
 

public int getWidth(View itemView) {
    return itemView.getMeasuredWidth() + itemView.getPaddingRight() + ((LayoutParams) itemView.getLayoutParams()).rightMargin;
}
 

/**
 * When set to true, the item will layout using all span area. That means, if orientation
 * is vertical, the view will have full width; if orientation is horizontal, the view will
 * have full height.
 * if the hold view use StaggeredGridLayoutManager they should using all span area
 *
 * @param holder True if this item should traverse all spans.
 */
protected void setFullSpan(RecyclerView.ViewHolder holder) {
    if (holder.itemView.getLayoutParams() instanceof StaggeredGridLayoutManager.LayoutParams) {
        StaggeredGridLayoutManager.LayoutParams params = (StaggeredGridLayoutManager.LayoutParams) holder
                .itemView.getLayoutParams();
        params.setFullSpan(true);
    }
}