Android TextView实现多文本折叠、展开效果

<linearlayout
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:orientation="vertical">

 <com.wiggins.expandable.widget.morelinetextview
  android:id="@+id/tv_more_line_short"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:background="@color/white"
  android:padding="@dimen/padding_small"
  app:clickall="true"
  app:textcolor="@color/red" />

 <view style="@style/spaceline" />

 <com.wiggins.expandable.widget.expandable.expandabletextview
  android:id="@+id/tv_expandable_short"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:background="@color/white"
  android:ellipsize="end"
  android:padding="@dimen/padding_small"
  android:textcolor="@color/blue"
  app:allclickable="false"
  app:contenttextcolor="@color/blue"
  app:isdisplayicon="false"
  app:maxcollapsedlines="4" />

 <view style="@style/spaceline" />

 <com.wiggins.expandable.widget.morelinetextview
  android:id="@+id/tv_more_line_long"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:background="@color/white"
  android:padding="@dimen/padding_small"
  app:clickall="true"
  app:textcolor="@color/red" />

 <view style="@style/spaceline" />

 <com.wiggins.expandable.widget.expandable.expandabletextview
  android:id="@+id/tv_expandable_long"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:background="@color/white"
  android:ellipsize="end"
  android:padding="@dimen/padding_small"
  android:textcolor="@color/blue"
  app:allclickable="false"
  app:contenttextcolor="@color/blue"
  app:isdisplayicon="false"
  app:maxcollapsedlines="4" />
</linearlayout>

private void initdata() {
 mtvmorelineshort.settext(constant.content1);
 mtvexpandableshort.settext(constant.content2);
 mtvmorelinelong.settext(constant.content3);
 mtvexpandablelong.settext(constant.content4);
}

<declare-styleable name="moretextstyle">
 <!--内容大小-->
 <attr name="textsize" format="dimension" />
 <!--内容颜色-->
 <attr name="textcolor" format="color" />
 <!--内容默认最大行数-->
 <attr name="maxline" format="integer" />
 <!--展开/收起图标-->
 <attr name="expandicon" format="reference" />
 <!--展开/收起动画执行时间-->
 <attr name="durationmillis" format="integer" />
 <!--可点击区域，默认展开/收起区域可点击-->
 <attr name="clickall" format="boolean" />
</declare-styleable>

@override
protected void onmeasure(int widthmeasurespec, int heightmeasurespec) {
 super.onmeasure(widthmeasurespec, heightmeasurespec);
 // 如果没有变化，测量并返回
 if (!mrelayout || getvisibility() == view.gone) {
  super.onmeasure(widthmeasurespec, heightmeasurespec);
  return;
 }
 mrelayout = false;

 super.onmeasure(widthmeasurespec, heightmeasurespec);

 // 内容区域初始显示行高
 mtvcontent.setheight(mtvcontent.getlineheight() * (mmaxline > mtvcontent.getlinecount() ? mtvcontent.getlinecount() : mmaxline));
 mllexpand.post(new runnable() {

  @override
  public void run() {
   // 是否显示折叠效果
   mllexpand.setvisibility(mtvcontent.getlinecount() > mmaxline ? view.visible : view.gone);
  }
 });
}

/**
 * @description 设置显示内容
 */
public void settext(string str) {
 mrelayout = true;
 mtvcontent.settext(str);
 setvisibility(textutils.isempty(str) ? view.gone : view.visible);
}

@override
public void onclick(view v) {
 if (mtvcontent.getlinecount() <= mmaxline) {
  return;
 }
 isexpand = !isexpand;
 mtvcontent.clearanimation();
 final int deltavalue;
 final int startvalue = mtvcontent.getheight();
 if (isexpand) {
  deltavalue = mtvcontent.getlineheight() * mtvcontent.getlinecount() - startvalue;//计算要展开高度
  rotateanimation animation = new rotateanimation(0, 180, animation.relative_to_self, 0.5f, animation.relative_to_self, 0.5f);
  animation.setduration(mdurationmillis);
  animation.setfillafter(true);
  mivexpand.startanimation(animation);
  mtvexpand.settext(getcontext().getstring(r.string.collapse));
 } else {
  deltavalue = mtvcontent.getlineheight() * mmaxline - startvalue;//为负值，收缩的高度
  rotateanimation animation = new rotateanimation(180, 0, animation.relative_to_self, 0.5f, animation.relative_to_self, 0.5f);
  animation.setduration(mdurationmillis);
  animation.setfillafter(true);
  mivexpand.startanimation(animation);
  mtvexpand.settext(getcontext().getstring(r.string.expand));
 }
 animation animation = new animation() {
  protected void applytransformation(float interpolatedtime, transformation t) {
   //interpolatedtime:为当前动画帧对应的相对时间，值总在0-1之间,原始长度+高度差*（从0到1的渐变）即表现为动画效果
   mtvcontent.setheight((int) (startvalue + deltavalue * interpolatedtime));
  }
 };
 animation.setduration(mdurationmillis);
 mtvcontent.startanimation(animation);
}

<declare-styleable name="expandabletextview">
 <!--内容默认最大行数，超过隐藏-->
 <attr name="maxcollapsedlines" format="integer" />
 <!--展开/收起动画执行时间-->
 <attr name="animduration" format="integer" />
 <!--展开图片-->
 <attr name="expanddrawable" format="reference" />
 <!--收起图片-->
 <attr name="collapsedrawable" format="reference" />
 <!--内容颜色-->
 <attr name="contenttextcolor" format="color" />
 <!--内容大小-->
 <attr name="contenttextsize" format="dimension" />
 <!--收起/展开颜色-->
 <attr name="collapseexpandtextcolor" format="color" />
 <!--收起/展开大小-->
 <attr name="collapseexpandtextsize" format="dimension" />
 <!--收起文字-->
 <attr name="textcollapse" format="string" />
 <!--展开文字-->
 <attr name="textexpand" format="string" />
 <!--可点击区域，默认展开/收起区域可点击-->
 <attr name="allclickable" format="boolean" />
 <!--是否显示展开/收起图标，默认显示-->
 <attr name="isdisplayicon" format="boolean" />
 <!--收起/展开位置，默认左边-->
 <attr name="collapseexpandgrarity">
  <flag name="left" value="3" />
  <flag name="right" value="5" />
 </attr>
 <!--收起/展开图标位置，默认右边-->
 <attr name="drawablegrarity">
  <flag name="left" value="3" />
  <flag name="right" value="5" />
 </attr>
</declare-styleable>

@override
protected void onmeasure(int widthmeasurespec, int heightmeasurespec) {
 // 如果没有变化，测量并返回
 if (!mrelayout || getvisibility() == view.gone) {
  super.onmeasure(widthmeasurespec, heightmeasurespec);
  return;
 }
 mrelayout = false;

 // setup with optimistic case
 // i.e. everything fits. no button needed
 mllexpand.setvisibility(view.gone);
 mtvcontent.setmaxlines(integer.max_value);

 // measure
 super.onmeasure(widthmeasurespec, heightmeasurespec);

 //如果内容真实行数小于等于最大行数，不处理
 if (mtvcontent.getlinecount() <= mmaxcollapsedlines) {
  return;
 }
 // 获取内容tv真实高度（含padding）
 mtextheightwithmaxlines = getrealtextviewheight(mtvcontent);

 // 如果是收起状态，重新设置最大行数
 if (mcollapsed) {
  mtvcontent.setmaxlines(mmaxcollapsedlines);
 }
 mllexpand.setvisibility(view.visible);

 // re-measure with new setup
 super.onmeasure(widthmeasurespec, heightmeasurespec);

 if (mcollapsed) {
  // gets the margin between the textview's bottom and the viewgroup's bottom
  mtvcontent.post(new runnable() {
   @override
   public void run() {
    mmarginbetweentxtandbottom = getheight() - mtvcontent.getheight();
   }
  });
  // 保存这个容器的测量高度
  mcollapsedheight = getmeasuredheight();
 }
}

/**
 * @description 设置显示内容
 */
public void settext(charsequence text) {
 mrelayout = true;
 mtvcontent.settext(text);
 setvisibility(textutils.isempty(text) ? view.gone : view.visible);
}

@override
public void onclick(view view) {
 if (mllexpand.getvisibility() != view.visible) {
  return;
 }

 mcollapsed = !mcollapsed;
 // 修改收起/展开图标、文字
 setdrawbleandtext();
 // 保存位置状态
 if (mcollapsedstatus != null) {
  mcollapsedstatus.put(mposition, mcollapsed);
 }

 // 执行展开/收起动画
 manimating = true;
 valueanimator valueanimator;
 if (mcollapsed) {
  valueanimator = new valueanimator().ofint(getheight(), mcollapsedheight);
 } else {
  mcollapsedheight = getheight();
  valueanimator = new valueanimator().ofint(getheight(), getheight() + mtextheightwithmaxlines - mtvcontent.getheight());
 }

 valueanimator.addupdatelistener(new valueanimator.animatorupdatelistener() {

  @override
  public void onanimationupdate(valueanimator valueanimator) {
   int animatedvalue = (int) valueanimator.getanimatedvalue();
   mtvcontent.setmaxheight(animatedvalue - mmarginbetweentxtandbottom);
   getlayoutparams().height = animatedvalue;
   requestlayout();
  }
 });

 valueanimator.addlistener(new animator.animatorlistener() {

  @override
  public void onanimationstart(animator animator) {

  }

  @override
  public void onanimationend(animator animator) {
   // 动画结束后发送结束的信号，清除动画标志
   manimating = false;
   // 通知监听
   if (mlistener != null) {
    mlistener.onexpandstatechanged(mtvcontent, !mcollapsed);
   }
  }

  @override
  public void onanimationcancel(animator animator) {

  }

  @override
  public void onanimationrepeat(animator animator) {

  }
 });

 valueanimator.setduration(manimationduration);
 valueanimator.start();
}