Android实现可点击展开的TextView

  /**
   * 添加监听
   * @param tv  要实现伸缩效果的 TextView
   * @param desc TextView 要展示的文字
   */
  public static void toggleEllipsize(final TextView tv,final String desc){
    if(desc == null){
      return;
    }

    //去除点击图片后的背景色（ SpannableString 在点击时会使背景变色 ，填上这句则可不变色 ）
    tv.setHighlightColor(Color.TRANSPARENT);

    //添加 TextView 的高度监听
    tv.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {

      @SuppressWarnings("deprecation")
      @SuppressLint("NewApi")
      @Override
      public void onGlobalLayout() {

        int paddingLeft = tv.getPaddingLeft();
        int paddingRight = tv.getPaddingRight();
        TextPaint paint = tv.getPaint();
        float moreText  = tv.getTextSize() * 3;
        float availableTextWidth = (tv.getWidth() - paddingLeft - paddingRight) * 2 - moreText;
        CharSequence ellipsizeStr = TextUtils.ellipsize(desc,paint,availableTextWidth,TextUtils.TruncateAt.END);

        // TextView 实际显示的文本长度 <应该显示文本的长度(收缩状态)
        if(ellipsizeStr.length()  应该显示文本的长度(展开状态)
        else{
          closeFun(tv, ellipsizeStr, desc);//显示展开状态的文本和图标
        }

        if(Build.VERSION.SDK_INT>=16){ 
          tv.getViewTreeObserver().removeOnGlobalLayoutListener(this); 
        }else{ 
          tv.getViewTreeObserver().removeGlobalOnLayoutListener(this); 
        }
      }
    });
  }

/**
 * ClickableImageSpan 继承自 ImageSpan，使其能响应点击事件，并图片垂直居中显示
 * @author lee
 *
 */
public abstract class ClickableImageSpan extends ImageSpan {

  public ClickableImageSpan(Drawable b) {
    super(b);
  }

  /** 图片垂直居中显示 */
  @Override
  public int getSize(Paint paint, CharSequence text, int start, int end, 
      Paint.FontMetricsInt fontMetricsInt) {

    Drawable drawable = getDrawable(); 
    Rect rect = drawable.getBounds(); 
    if (fontMetricsInt != null) { 
      Paint.FontMetricsInt fmPaint = paint.getFontMetricsInt(); 
      int fOntHeight= fmPaint.bottom - fmPaint.top; 
      int drHeight = rect.bottom - rect.top; 

      int top = drHeight / 2 - fontHeight / 4; 
      int bottom = drHeight / 2 + fontHeight / 4; 

      fontMetricsInt.ascent = -bottom; 
      fontMetricsInt.top = -bottom; 
      fontMetricsInt.bottom = top; 
      fontMetricsInt.descent = top; 
    } 
    return rect.right; 
  } 

  /** 图片垂直居中显示 */
  @Override 
  public void draw(Canvas canvas, CharSequence text, int start, int end, 
      float x, int top, int y, int bottom, Paint paint) {

    Drawable drawable = getDrawable(); 
    canvas.save(); 
    int transY = 0; 
    transY = ((bottom - top) - drawable.getBounds().bottom) / 2 + top; 
    canvas.translate(x, transY); 
    drawable.draw(canvas); 
    canvas.restore(); 
  }


  /** 添加点击事件 */
  public abstract void onClick(View view);
}

/**
 * ClickableMovementMethod 继承自 LinkMovementMethod，使其能响应 ClickableImageSpan
 * @author lee
 *
 */
public class ClickableMovementMethod extends LinkMovementMethod {

  private static ClickableMovementMethod sInstance;

  public static ClickableMovementMethod getInstance() {
    if (sInstance == null) {
      sInstance = new ClickableMovementMethod();
    }
    return sInstance;
  }


  public boolean onTouchEvent(TextView widget, Spannable buffer,
      MotionEvent event) {
    int action = event.getAction();

    if (action == MotionEvent.ACTION_UP ||
        action == MotionEvent.ACTION_DOWN) {
      int x = (int) event.getX();
      int y = (int) event.getY();

      x -= widget.getTotalPaddingLeft();
      y -= widget.getTotalPaddingTop();

      x += widget.getScrollX();
      y += widget.getScrollY();

      Layout layout = widget.getLayout();
      int line = layout.getLineForVertical(y);
      int off = layout.getOffsetForHorizontal(line, x);

      ClickableSpan[] link = buffer.getSpans(off, off, ClickableSpan.class);

      /** 修改位置【1】 START **/
      ClickableImageSpan[] imageSpans = buffer.getSpans(off, off, ClickableImageSpan.class);
      /******  END  ******/

      if (link.length != 0) {
        if (action == MotionEvent.ACTION_UP) {
          link[0].onClick(widget);
        } else if (action == MotionEvent.ACTION_DOWN) {
          Selection.setSelection(buffer,
              buffer.getSpanStart(link[0]),
              buffer.getSpanEnd(link[0]));
        }

        return true;
      } 
      /** 修改位置【2】START **/
      else if (imageSpans.length != 0) {
        if (action == MotionEvent.ACTION_UP) {
          imageSpans[0].onClick(widget);
        } else if (action == MotionEvent.ACTION_DOWN) {
          Selection.setSelection(buffer,
              buffer.getSpanStart(imageSpans[0]),
              buffer.getSpanEnd(imageSpans[0]));
        }

        return true;
      } 
      /******  END   ******/

      else {
        Selection.removeSelection(buffer);
      }
    }

    return false;
  }
}

  // 显示收缩状态的文本，设置点击图标，并添加点击事件
  private static void openFun(final TextView tv,final CharSequence ellipsizeStr,final String desc){
    CharSequence temp = ellipsizeStr+".";
    SpannableStringBuilder ssb = new SpannableStringBuilder(temp);
    Drawable dd = tv.getResources().getDrawable(R.drawable.ic_expand);
    dd.setBounds(0, 0, dd.getIntrinsicWidth(), dd.getIntrinsicHeight());
    ClickableImageSpan is = new ClickableImageSpan(dd) {
      @Override
      public void onClick(View view) {
        closeFun(tv,ellipsizeStr,desc);
      }

    };
    ssb.setSpan(is, temp.length()-1, temp.length(), Spannable.SPAN_INCLUSIVE_EXCLUSIVE);
    tv.setText(ssb);
    tv.setMovementMethod(ClickableMovementMethod.getInstance());
  }

  // 显示展开状态的文本，设置点击图标，并添加点击事件
  private static void closeFun(final TextView tv,final CharSequence ellipsizeStr,final String desc) {
    SpannableStringBuilder ssb = new SpannableStringBuilder(desc);
    Drawable dd = tv.getResources().getDrawable(R.drawable.ic_normal);
    dd.setBounds(0, 0, dd.getIntrinsicWidth(), dd.getIntrinsicHeight());
    ClickableImageSpan is = new ClickableImageSpan(dd) {
      @Override
      public void onClick(View view) {
        openFun(tv,ellipsizeStr,desc);
      }
    };
    ssb.setSpan(is, desc.length()-1, desc.length(), Spannable.SPAN_INCLUSIVE_EXCLUSIVE);
    tv.setText(ssb);
    tv.setMovementMethod(ClickableMovementMethod.getInstance());
  }

public class MainActivity extends Activity {
  private TextView mTv;
  private String str = "我有一只小毛驴,我从来也不骑~ "
      + "有一天我心血来潮骑它去赶集,我手里拿着小皮鞭,我心里正得意~ "
      + "不知怎么哗啦啦啦啦,我摔了一身泥~";

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    mTv = (TextView) findViewById(R.id.tv_test);
    //调用 toggleEllipsize 方法来设置 mTv
    Utils.toggleEllipsize(mTv,str);
  }

}