检测ListView中的TextView是否为椭圆化

Question

我有一个自定义适配器,在ListView中呈现一些项目.如果项目的文本是椭圆形的,我需要在ListView的项目上显示一个图标,如果有足够的空间让文本完成,我需要隐藏它.我可以访问我的适配器的getView方法中的按钮(我设置文本),但是在设置文本时不会立即添加省略号.

有什么方法可以做到这一点吗？

这是我的TextView标记:

<TextView android:layout_width="fill_parent"
          android:layout_height="wrap_content"
          android:ellipsize="end"
          android:singleLine="true"
          android:id="@+id/list_item_description"/>

Answer 1

public int getEllipsisCount(int line):

返回要椭圆化的字符数,如果不进行省略则返回0.

所以,只需致电:

if(textview1.getLayout().getEllipsisCount() > 0) {
   // Do anything here..
}

由于在设置布局之前无法调用getLayout(),因此请使用ViewTreeObserver查找加载textview的时间:

ViewTreeObserver vto = textview.getViewTreeObserver();
vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
    @Override
    public void onGlobalLayout() {
       Layout l = textview.getLayout();
       if ( l != null){
          int lines = l.getLineCount();
          if ( lines > 0)
              if ( l.getEllipsisCount(lines-1) > 0)
                Log.d(TAG, "Text is ellipsized");
       }  
    }
});

最后,当你需要它时,不要忘记删除removeOnGlobalLayoutListener.

Answer 2

棘手的部分是你正在使用的视图getView有时会被布局,有时不会,所以你必须处理这两种情况.

如果尚未布局,则设置视图树观察器以检查省略号.在循环视图的情况下,布局已经存在,您可以在设置文本后立即检查省略号.

public View getView(int position, View convertView, ViewGroup parent) {
  final ViewHolder vh;
  if (convertView == null) {
    vh = new ViewHolder();
    ... // create/inflate view and populate the ViewHolder
  }
  vh = (ViewHolder) convertView.getTag();

  // Set the actual content of the TextView
  vh.textView.setText(...);

  // Hide the (potentially recycled) expand button until ellipsizing checked
  vh.expandBtn.setVisibility(GONE);

  Layout layout = vh.textView.getLayout();
  if (layout != null) {
    // The TextView has already been laid out
    // We can check whether it's ellipsized immediately
    if (layout.getEllipsisCount(layout.getLineCount()-1) > 0) {
      // Text is ellipsized in re-used view, show 'Expand' button
      vh.expandBtn.setVisibility(VISIBLE);
    }
  } else {
    // The TextView hasn't been laid out, so we need to set an observer
    // The observer fires once layout's done, when we can check the ellipsizing
    ViewTreeObserver vto = vh.textView.getViewTreeObserver();
    vto.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
      @Override
      public void onGlobalLayout() {
        Layout layout = vh.textView.getLayout();
        if (layout.getEllipsisCount(layout.getLineCount()-1) > 0) {
          // Text is ellipsized in newly created view, show 'Expand' button
          vh.expandBtn.setVisibility(VISIBLE);
        }

        // Remove the now unnecessary observer
        // It wouldn't fire again for reused views anyways
        ViewTreeObserver obs = vh.textView.getViewTreeObserver();
        obs.removeGlobalOnLayoutListener(this);
      }
    });

  return convertView;
}

Answer 3

您可以将文本设置为标记。在您的代码中添加此内容可能会有所帮助......

    android:ellipsize="marquee"
    android:focusable="true"
    android:focusableInTouchMode="true"
    android:scrollHorizontally="true"
    android:freezesText="true"
    android:marqueeRepeatLimit="marquee_forever"

您还可以为您的代码添加水平滚动视图......

    <HorizontalScrollView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" >

        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="vertical" >

            <TextView
                android:id="@+id/list_item_description"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_gravity="center_vertical"
                android:layout_weight="1"
                android:ellipsize="end"
                android:gravity="center_vertical"
                android:singleLine="true"
                android:textAppearance="?android:attr/textAppearanceSmall" />
        </LinearLayout>
    </HorizontalScrollView>