Android+文本的查找和替换+可以对文本进行查找替换撤销等，基本实现了PC端.txt查找替换功能

最近项目用到了类似PC端记事本查找替换功能，于是自己就写了一套算法，实现起来还是比较容易理解的。基于移动开发的文本查找替换功能，基本实现了PC段记事本查找替换的相关功能。基本功能包括，查找、替换、全部替换、撤销、上一条、下一条、颜色标记和位置定位等功能。

SpannableStringBuilder实现了CharSequence类，用来存储字符串。SpannableStringBuilder有一个setSpan（）函数，能给给存储的字符串添加各种各样的格式或者属性，，将原来的String以不同的样式显示出来，比如加上下划线、背景颜色、字体颜色、设置点击监听、设置超链接等。主要用到的就是设置背景颜色。有兴趣的同学可以自行了解一下。
 

查找算法

mBinding.tvSeek.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (TextUtils.isEmpty(mBinding.etName.getText().toString().trim())) {
                    showToast("输入查找内容");
                    return;
                }
                if (!mBinding.tvContent.getText().toString().contains(mBinding.etName.getText().toString())) {
                    showToast("查找内容不存在");
                    listFind = new ArrayList<>();
                    mBinding.tvNumber.setVisibility(View.INVISIBLE);
                    SpannableStringBuilder spannableStringBuilder = new SpannableStringBuilder(mBinding.tvContent.getText().toString());
                    BackgroundColorSpan colorSpan;
                    colorSpan = new BackgroundColorSpan(Color.parseColor("#ffffff"));
                    spannableStringBuilder.setSpan(colorSpan, 0, mBinding.tvContent.getText().toString().length() - 1, Spannable.SPAN_INCLUSIVE_INCLUSIVE);
                    mBinding.tvContent.setText(spannableStringBuilder);
                    return;
                }
                findKey = mBinding.etName.getText().toString();
                listReplace = new ArrayList<>();
                mBinding.tvContent.getText().toString().contains(mBinding.etName.getText().toString());
                getSubString(mBinding.tvContent.getText().toString(), findKey);
                SpannableStringBuilder spannableStringBuilder = new SpannableStringBuilder(mBinding.tvContent.getText().toString());
                if (listFind != null && listFind.size() != 0) {
                    for (int i = 0; i < listFind.size(); i++) {
                        BackgroundColorSpan colorSpan;
                        if (i == 0) {
                            colorSpan = new BackgroundColorSpan(Color.parseColor("#f50707"));
                        } else {
                            colorSpan = new BackgroundColorSpan(Color.parseColor("#AC00FF30"));
                        }
                        spannableStringBuilder.setSpan(colorSpan, listFind.get(i).getStart(), listFind.get(i).getEnd(), Spannable.SPAN_INCLUSIVE_INCLUSIVE);
                    }
                    mBinding.tvNumber.setVisibility(View.VISIBLE);
                    mBinding.tvNumber.setText("查找到" + listFind.size() + "条内容");
                } else {
                    BackgroundColorSpan colorSpan;
                    colorSpan = new BackgroundColorSpan(Color.parseColor("#212832"));
                    spannableStringBuilder.setSpan(colorSpan, 0, mBinding.tvContent.getText().length() - 1, Spannable.SPAN_INCLUSIVE_INCLUSIVE);
                    mBinding.tvNumber.setVisibility(View.INVISIBLE);
                }
                mBinding.tvContent.setText(spannableStringBuilder);

            }
        });

查找定位算法

mBinding.tvPrevious.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (listFind != null && listFind.size() != 0) {
                    if (select > 0) {
                        select = select - 1;
                    } else if (select == 0) {
                        select = listFind.size() - 1;
                    }
                } else {
                    return;
                }
                next();
            }
        });

private void next() {
        SpannableStringBuilder spannableStringBuilder = new SpannableStringBuilder(mBinding.tvContent.getText().toString());
        if (listFind != null && listFind.size() != 0) {
            for (int i = 0; i < listFind.size(); i++) {
                BackgroundColorSpan colorSpan = new BackgroundColorSpan(Color.parseColor("#AC00FF30"));
                spannableStringBuilder.setSpan(colorSpan, listFind.get(i).getStart(), listFind.get(i).getEnd(), Spannable.SPAN_INCLUSIVE_INCLUSIVE);
            }
        }
        if (listReplace != null && listReplace.size() != 0) {
            for (int i = 0; i < listReplace.size(); i++) {
                BackgroundColorSpan colorSpan = new BackgroundColorSpan(Color.parseColor("#f5e107"));
                spannableStringBuilder.setSpan(colorSpan, listReplace.get(i).getStart(), listReplace.get(i).getEnd(), Spannable.SPAN_INCLUSIVE_INCLUSIVE);
            }
        }
        BackgroundColorSpan colorSpan = new BackgroundColorSpan(Color.parseColor("#f50707"));
        spannableStringBuilder.setSpan(colorSpan, listFind.get(select).getStart(), listFind.get(select).getEnd(), Spannable.SPAN_INCLUSIVE_INCLUSIVE);

        mBinding.tvContent.setText(spannableStringBuilder);
        mBinding.tvContent.setSelection(listFind.get(select).getStart(), listFind.get(select).getEnd());

    }

替换算法

  mBinding.tvReplace.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (TextUtils.isEmpty(findKey)) {
                    showToast("输入查找内容");
                    return;
                }
                if (TextUtils.isEmpty(mBinding.etNames.getText().toString())) {
                    showToast("输入替换内容");
                    return;
                }
                replaceKey = mBinding.etNames.getText().toString();
                if (listFind != null && listFind.size() != 0) {
                    if (select <= listFind.size() - 1) {

                    } else {
                        select = 0;
                    }
                } else {
                    showToast("没找到要替换的内容");
                    return;
                }

                if (select < listFind.size()) {
                } else {
                    showToast("没找到要替换的内容");
                    return;
                }
                SpannableStringBuilder spannableStringBuilder = new SpannableStringBuilder(mBinding.tvContent.getText().toString());
                spannableStringBuilder.replace(listFind.get(select).getStart(), listFind.get(select).getEnd(), replaceKey);

                FindBean findBean = new FindBean();
                findBean.setStart(listFind.get(select).getStart());
                findBean.setEnd(listFind.get(select).getStart() + replaceKey.length());
                listReplace.add(findBean);
                listFind.remove(select);
                if (listFind != null && listFind.size() != 0) {
                    for (int i = 0; i < listFind.size(); i++) {
                        if (listFind.get(i).getStart() > findBean.getStart()) {
                            int sub1 = findBean.getEnd() - findBean.getStart();
                            int sub2 = listFind.get(i).getEnd() - listFind.get(i).getStart();
                            listFind.get(i).setStart(listFind.get(i).getStart() + sub1 - sub2);
                            listFind.get(i).setEnd(listFind.get(i).getEnd() + sub1 - sub2);
                        }
                    }
                }
                if (listReplace != null && listReplace.size() != 0) {
                    for (int i = 0; i < listReplace.size(); i++) {
                        if (listReplace.get(i).getStart() > findBean.getStart()) {
                            int sub1 = findBean.getEnd() - findBean.getStart();
                            listReplace.get(i).setStart(listReplace.get(i).getStart() + sub1 - findKey.length());
                            listReplace.get(i).setEnd(listReplace.get(i).getEnd() + sub1 - findKey.length());
                        }
                    }
                }


                for (int i = 0; i < listFind.size(); i++) {

                    BackgroundColorSpan colorSpan;
                    if (i == select) {
                        colorSpan = new BackgroundColorSpan(Color.parseColor("#f50707"));
                    } else {
                        colorSpan = new BackgroundColorSpan(Color.parseColor("#AC00FF30"));
                    }

                    spannableStringBuilder.setSpan(colorSpan, listFind.get(i).getStart(), listFind.get(i).getEnd(), Spannable.SPAN_INCLUSIVE_INCLUSIVE);


                }
                for (int i = 0; i < listReplace.size(); i++) {
                    BackgroundColorSpan colorSpan = new BackgroundColorSpan(Color.parseColor("#f5e107"));
                    spannableStringBuilder.setSpan(colorSpan, listReplace.get(i).getStart(), listReplace.get(i).getEnd(), Spannable.SPAN_INCLUSIVE_INCLUSIVE);
                }
                mBinding.tvContent.setText(spannableStringBuilder);
                mBinding.tvContent.setSelection(listFind.get(select).getStart(), listFind.get(select).getEnd());

            }
        });

撤销算法

mBinding.tvUndo.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (listReplace != null && listReplace.size() != 0) {
                    SpannableStringBuilder spannableStringBuilder = new SpannableStringBuilder(mBinding.tvContent.getText().toString());
                    spannableStringBuilder.replace(listReplace.get(listReplace.size() - 1).getStart(), listReplace.get(listReplace.size() - 1).getEnd(), findKey);
                    FindBean findBean = new FindBean();
                    findBean.setStart(listReplace.get(listReplace.size() - 1).getStart());
                    findBean.setEnd(listReplace.get(listReplace.size() - 1).getStart() + findKey.length());
                    listFind.add(findBean);
                    Collections.sort(listFind, new Comparator<FindBean>() {
                        @Override
                        public int compare(FindBean o1, FindBean o2) {
                            int diff = o1.getStart() - o2.getStart();
                            if (diff > 0) {
                                return 1;
                            } else if (diff < 0) {
                                return -1;
                            }
                            return 0; //相等为0
                        }
                    });
                    select = listFind.indexOf(findBean);
                    listReplace.remove(listReplace.size() - 1);
                    if (listFind != null && listFind.size() != 0) {
                        for (int i = 0; i < listFind.size(); i++) {
                            if (listFind.get(i).getStart() > findBean.getStart()) {
                                int sub1 = findBean.getEnd() - findBean.getStart();
                                listFind.get(i).setStart(listFind.get(i).getStart() + sub1 - replaceKey.length());
                                listFind.get(i).setEnd(listFind.get(i).getEnd() + sub1 - replaceKey.length());
                            }
                        }
                    }
                    if (listReplace != null && listReplace.size() != 0) {
                        for (int i = 0; i < listReplace.size(); i++) {
                            if (listReplace.get(i).getStart() > findBean.getStart()) {
                                int sub1 = findBean.getEnd() - findBean.getStart();
                                int sub2 = listReplace.get(i).getEnd() - listReplace.get(i).getStart();
                                listReplace.get(i).setStart(listReplace.get(i).getStart() + sub1 - sub2);
                                listReplace.get(i).setEnd(listReplace.get(i).getEnd() + sub1 - sub2);
                            }
                        }
                    }


                    for (int i = 0; i < listFind.size(); i++) {
                        BackgroundColorSpan colorSpan = new BackgroundColorSpan(Color.parseColor("#AC00FF30"));
                        spannableStringBuilder.setSpan(colorSpan, listFind.get(i).getStart(), listFind.get(i).getEnd(), Spannable.SPAN_INCLUSIVE_INCLUSIVE);
                    }
                    for (int i = 0; i < listReplace.size(); i++) {
                        BackgroundColorSpan colorSpan = new BackgroundColorSpan(Color.parseColor("#f5e107"));
                        spannableStringBuilder.setSpan(colorSpan, listReplace.get(i).getStart(), listReplace.get(i).getEnd(), Spannable.SPAN_INCLUSIVE_INCLUSIVE);
                    }
                    mBinding.tvContent.setText(spannableStringBuilder);
                    mBinding.tvContent.setSelection(listFind.get(select).getStart(), listFind.get(select).getEnd());
                } else {
                    showToast("撤销完毕");
                }
            }
        });

记录下标位置对象

public class FindBean {
    private int start;
    private int end;

    public int getStart() {
        return start;
    }

    public void setStart(int start) {
        this.start = start;
    }

    public int getEnd() {
        return end;
    }

    public void setEnd(int end) {
        this.end = end;
    }
}

了解具体做法可以产看demo：Android+文本的查找和替换+可以对文本进行查找替换撤销等，基本实现了PC端.txt查找替换功能-Android文档类资源-CSDN文库