Android仿微信@好友功能 输入@跳转、删除整块

public class MsgEditText extends AppCompatEditText {
 public MsgEditText(Context context) {
  super(context);
 }
 public MsgEditText(Context context, AttributeSet attrs) {
  super(context, attrs);
 }
 public MsgEditText(Context context, AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
 }
}

 private void generateOneSpan(Spannable spannableString, UnSpanText unSpanText) {
  //生成一个TextView
  View spanView = getSpanView(getContext(),  unSpanText.showText.toString(), getMeasuredWidth());
  //再将TextView转换为一个图片
  BitmapDrawable bitmpaDrawable = (BitmapDrawable) UIUtils.convertViewToDrawable(spanView);
  bitmpaDrawable.setBounds(0, 0, bitmpaDrawable.getIntrinsicWidth(), bitmpaDrawable.getIntrinsicHeight());
  //最后将这个图片放到Span里，
  MyImageSpan what = new MyImageSpan(bitmpaDrawable, unSpanText.showText.toString(),unSpanText.returnText);
  final int start = unSpanText.start;
  final int end = unSpanText.end;
  spannableString.setSpan(what, start, end, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
  //设置一个Span
  spannableString.setSpan(touchableSpan, start, end, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
 }

//这个是需要成块删除的内容
 private class MyTextSpan extends MetricAffectingSpan {
  private String showText;
  private long userId;
  //userId是为了适应需求，如果不需要请自行去掉
  public MyTextSpan(String showText, long userId) {
   this.showText = showText;
   this.userId = userId;
  }
  public String getShowText() {
   return showText;
  }
  public long getUserId() {
   return userId;
  }
  @Override
  public void updateMeasureState(TextPaint p) {
  }
  @Override
  public void updateDrawState(TextPaint tp) {
  }
 }
 //这个是非整块删除的内容，当然你如果想也是可以删除的
 private class UnSpanText {
  int start;
  int end;
  String returnText;
  UnSpanText(int start, int end, String returnText) {
   this.start = start;
   this.end = end;
   this.returnText = returnText;
  }
 }

//外部调用一个增加Span的方法
 public void addSpan(String showText, String returnText, long userId) {
  getText().append(showText);
  SpannableString spannableString = new SpannableString(getText());
  makeSpan(spannableString, new UnSpanText(spannableString.length() - showText.length(), spannableString.length(), showText, returnText), userId);
  setText(spannableString);
  setSelection(spannableString.length());
 }
 //生成一个需要整体删除的Span
 private void makeSpan(Spannable sps, UnSpanText unSpanText, long userId) {
  MyTextSpan what = new MyTextSpan(unSpanText.returnText, userId);
  int start = unSpanText.start;
  int end = unSpanText.end;
  sps.setSpan(what, start, end, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
 }

 @Override
 protected void onTextChanged(CharSequence text, int start, int lengthBefore, int lengthAfter) {
  super.onTextChanged(text, start, lengthBefore, lengthAfter);
  //向前删除一个字符，@后的内容必须大于一个字符，可以在后面加一个空格
  if (lengthBefore == 1 && lengthAfter == 0) {
   MyTextSpan[] spans = getText().getSpans(0, getText().length(), MyTextSpan.class);
   for (MyTextSpan myImageSpan : spans) {
    if (getText().getSpanEnd(myImageSpan) == start && !text.toString().endsWith(myImageSpan.getShowText())) {
     getText().delete(getText().getSpanStart(myImageSpan), getText().getSpanEnd(myImageSpan));
     break;
    }
   }
  }
 }

 //获取用户Id列表,这只是个参考，可根据需求修改
 public String getUserIdString() {
  MyTextSpan[] spans = getText().getSpans(0, getText().length(), MyTextSpan.class);
  StringBuilder builder = new StringBuilder();
  for (MyTextSpan myTextSpan : spans) {
   String realText = getText().toString().substring(getText().getSpanStart(myTextSpan), getText().getSpanEnd(myTextSpan));
   String showText = myTextSpan.getShowText();
   if (realText.equals(showText)) {
    builder.append(myTextSpan.getUserId()).append(",");
   }
  }
  if (!TextUtils.isEmpty(builder.toString())) {
   builder.deleteCharAt(builder.length() - 1);
  }
  return builder.toString();
 }