如何向LinearLayoutICS添加分隔线？

Question

背景

我正在尝试将 alternative "App Manager" app从ActionBarSherlock library切换到Google创建的support library，因为它获得了更多更新（不再开发ActionBarSherlock，链接{{3} }）我认为它应该涵盖很多功能。

问题

一切顺利（看起来似乎如此），除了ActionBarSherlock上一个名为ICSLinearLayout的类，我曾经用它来显示分频器，现在称为LinearLayoutICS。

它只是没有显示分隔符：

注意：在您询问“为什么不使用GridView？”之前，here原因，以及here's，以防我想要添加标题。

代码

代码与我用于ActionBarSherlock的代码大致相同：

rowLayout=new LinearLayoutICS(_context,null);
rowLayout.setMeasureWithLargestChildEnabled(true);
rowLayout.setShowDividers(LinearLayout.SHOW_DIVIDER_MIDDLE);
rowLayout.setDividerDrawable(_context.getResources().getDrawable(R.drawable.list_divider_holo_dark));
rowLayout.setOrientation(LinearLayout.HORIZONTAL);
... // add views, layout params, etc...

问题

如何使用此类以支持在支持库的所有受支持的OS版本上显示分隔符？

我写的代码出了什么问题？

Answer 1

好的，似乎setShowDividers和setDividerDrawable无法使用，因为LinearLayoutICS没有它们。

不仅如此，Lint并没有提醒我使用它。

所以，我最终得到的是复制LinearLayoutICS代码（来自here，希望它是最新版本）和一些原始的LinearLayout代码，以创建一些有用的东西。我希望它没有任何错误。

万岁开源......：）

可悲的是setMeasureWithLargestChildEnabled不适用于旧的API，所以我认为ActionBarSherlock的方式仍然更好，以防你想要使用它。

编辑： setMeasureWithLargestChildEnabled 方法不适用于ActionBarSherlock。

这是代码，适合那些希望使用的人。我希望下次更新库时，我会记得再次检查这个问题。

public class LinearLayoutICS extends LinearLayout
  {
  private Drawable mDivider;
  private int      mDividerWidth,mDividerHeight;
  private int      mShowDividers;
  private int      mDividerPadding;

  public LinearLayoutICS(final Context context,final AttributeSet attrs)
    {
    super(context,attrs);
    // the R is from "android.support.v7.appcompat.R" .
    final TypedArray a=context.obtainStyledAttributes(attrs,R.styleable.LinearLayoutICS);
    mDivider=a.getDrawable(R.styleable.LinearLayoutICS_divider);
    if(mDivider!=null)
      {
      mDividerWidth=mDivider.getIntrinsicWidth();
      mDividerHeight=mDivider.getIntrinsicHeight();
      }
    else mDividerHeight=mDividerWidth=0;
    mShowDividers=a.getInt(R.styleable.LinearLayoutICS_showDividers,SHOW_DIVIDER_NONE);
    mDividerPadding=a.getDimensionPixelSize(R.styleable.LinearLayoutICS_dividerPadding,0);
    a.recycle();
    setWillNotDraw(mDivider==null);
    }

  @Override
  protected void onDraw(final Canvas canvas)
    {
    if(getOrientation()==VERTICAL)
      drawDividersVertical(canvas);
    else drawDividersHorizontal(canvas);
    }

  @Override
  protected void measureChildWithMargins(final View child,final int parentWidthMeasureSpec,final int widthUsed,final int parentHeightMeasureSpec,final int heightUsed)
    {
    if(mDivider!=null)
      {
      final int childIndex=indexOfChild(child);
      final int count=getChildCount();
      final LayoutParams params=(LayoutParams)child.getLayoutParams();
      // To display the dividers in-between the child views, we modify their margins
      // to create space.
      if(getOrientation()==VERTICAL)
        {
        if(hasDividerBeforeChildAt(childIndex))
          params.topMargin=mDividerHeight;
        else if(childIndex==count-1&&hasDividerBeforeChildAt(count))
          params.bottomMargin=mDividerHeight;
        }
      else if(hasDividerBeforeChildAt(childIndex))
        params.leftMargin=mDividerWidth;
      else if(childIndex==count-1&&hasDividerBeforeChildAt(count))
        params.rightMargin=mDividerWidth;
      }
    super.measureChildWithMargins(child,parentWidthMeasureSpec,widthUsed,parentHeightMeasureSpec,heightUsed);
    }

  void drawDividersVertical(final Canvas canvas)
    {
    final int count=getChildCount();
    for(int i=0;i<count;i++)
      {
      final View child=getChildAt(i);
      if(child!=null&&child.getVisibility()!=GONE&&hasDividerBeforeChildAt(i))
        {
        final LayoutParams lp=(LayoutParams)child.getLayoutParams();
        drawHorizontalDivider(canvas,child.getTop()-lp.topMargin);
        }
      }
    if(hasDividerBeforeChildAt(count))
      {
      final View child=getChildAt(count-1);
      int bottom=0;
      if(child==null)
        bottom=getHeight()-getPaddingBottom()-mDividerHeight;
      else bottom=child.getBottom();
      drawHorizontalDivider(canvas,bottom);
      }
    }

  void drawDividersHorizontal(final Canvas canvas)
    {
    final int count=getChildCount();
    for(int i=0;i<count;i++)
      {
      final View child=getChildAt(i);
      if(child!=null&&child.getVisibility()!=GONE&&hasDividerBeforeChildAt(i))
        {
        final LayoutParams lp=(LayoutParams)child.getLayoutParams();
        drawVerticalDivider(canvas,child.getLeft()-lp.leftMargin);
        }
      }
    if(hasDividerBeforeChildAt(count))
      {
      final View child=getChildAt(count-1);
      int right=0;
      if(child==null)
        right=getWidth()-getPaddingRight()-mDividerWidth;
      else right=child.getRight();
      drawVerticalDivider(canvas,right);
      }
    }

  void drawHorizontalDivider(final Canvas canvas,final int top)
    {
    mDivider.setBounds(getPaddingLeft()+mDividerPadding,top,getWidth()-getPaddingRight()-mDividerPadding,top+mDividerHeight);
    mDivider.draw(canvas);
    }

  void drawVerticalDivider(final Canvas canvas,final int left)
    {
    mDivider.setBounds(left,getPaddingTop()+mDividerPadding,left+mDividerWidth,getHeight()-getPaddingBottom()-mDividerPadding);
    mDivider.draw(canvas);
    }

  /**
   * Determines where to position dividers between children.
   *
   * @param childIndex Index of child to check for preceding divider
   * @return true if there should be a divider before the child at childIndex
   * @hide Pending API consideration. Currently only used internally by the system.
   */
  protected boolean hasDividerBeforeChildAt(final int childIndex)
    {
    if(childIndex==0)
      return (mShowDividers&SHOW_DIVIDER_BEGINNING)!=0;
    else if(childIndex==getChildCount())
      return (mShowDividers&SHOW_DIVIDER_END)!=0;
    else if((mShowDividers&SHOW_DIVIDER_MIDDLE)!=0)
      {
      boolean hasVisibleViewBefore=false;
      for(int i=childIndex-1;i>=0;i--)
        if(getChildAt(i).getVisibility()!=GONE)
          {
          hasVisibleViewBefore=true;
          break;
          }
      return hasVisibleViewBefore;
      }
    return false;
    }

  @Override
  public int getDividerPadding()
    {
    return mDividerPadding;
    }

  @Override
  public void setDividerPadding(final int dividerPadding)
    {
    mDividerPadding=dividerPadding;
    }

  @Override
  public void setShowDividers(final int showDividers)
    {
    if(mShowDividers!=showDividers)
      requestLayout();
    mShowDividers=showDividers;
    }

  @Override
  public void setDividerDrawable(final Drawable divider)
    {
    if(divider==mDivider)
      return;
    mDivider=divider;
    if(divider!=null)
      {
      mDividerWidth=divider.getIntrinsicWidth();
      mDividerHeight=divider.getIntrinsicHeight();
      }
    else
      {
      mDividerWidth=0;
      mDividerHeight=0;
      }
    setWillNotDraw(divider==null);
    requestLayout();
    }

  @Override
  public Drawable getDividerDrawable()
    {
    return mDivider;
    }
  }