Question

我正在尝试使用以下代码来捕获用户输入@symbol然后出现高光的情况无论在mPostTextView中的何处键入，tag_color中的后续文本。我还是Android开发的新手，所以我不确定为什么我得到以下错误消息，引用java.lang.IndexOutOfBoundsException：charAt：....如下所示这似乎与charAt（start）语句的长度有关。谁能阐明这一点？

 @Override
            public void onTextChanged(CharSequence charSequence, int start, int before, int count) {
                //@Mentions for tagging user
                if (charSequence.charAt(start) == '@') {
                    SpannableStringBuilder spannableStringBuilder = new SpannableStringBuilder(mPostToText.getText().toString());
                    ForegroundColorSpan foregroundSpan = new ForegroundColorSpan(ContextCompat.getColor(getContext(), R.color.tag_color));
                    spannableStringBuilder.setSpan(foregroundSpan, start, spannableStringBuilder.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
                    mPostToText.setText(spannableStringBuilder);

                }

这是来自日志

java.lang.IndexOutOfBoundsException: charAt: 22 >= length 22
    at android.text.SpannableStringBuilder.charAt(SpannableStringBuilder.java:119)
    at com.tradezapp.tradezapp.gui.activity.CreatePostActivity$CreatePostFragment$2$override.onTextChanged(CreatePostActivity.java:193)
    at com.tradezapp.tradezapp.gui.activity.CreatePostActivity$CreatePostFragment$2$override.access$dispatch(CreatePostActivity.java)
    at com.tradezapp.tradezapp.gui.activity.CreatePostActivity$CreatePostFragment$2.onTextChanged(CreatePostActivity.java)

Answer 1

尝试一下，还要检查charSequence的长度，

if (charSequence!=null && String.valueOf(charSequence.charAt(count-1)).equal("@")) {
....}

onTextChanged长度内的SpannableString不正确

1 个答案: