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1，EditText获取焦点并显示软键盘

 /**     * EditText获取焦点并显示软键盘     */    public static void showSoftInputFromWindow(Activity activity, EditText editText) {        InputMethodManager imm = (InputMethodManager) activity.getSystemService(Context.INPUT_METHOD_SERVICE);        //获取软键盘焦点        editText.setFocusable(true);        editText.setFocusableInTouchMode(true);        editText.requestFocus();        //editText光标在末尾位置        editText.setSelection(editText.getText().length());        //显示软键盘        if (imm != null && editText != null) {            editText.postDelayed(new Runnable() {                @Override                public void run() {                    imm.showSoftInput(editText, 0);                }            }, 200);        }    }

2，Textview字间距

//xml布局设置android:letterSpacing="0.1"

3，EditText输入监听判断不大于

//设置价钱文本框输入监听事件binding.editMoney.addTextChangedListener(textWatcher); TextWatcher textWatcher = new TextWatcher() {        private CharSequence temp;//用于记录当前正在输入文本的个数        // 输入文本之前的状态        @Override        public void beforeTextChanged(CharSequence s, int start, int count, int after) {        }        // 输入文本中的状态        @Override        public void onTextChanged(CharSequence s, int start, int before, int count) {            temp = s;        }        // 输入文本之后的状态        @Override        public void afterTextChanged(Editable s) {            int editStart = binding.editMoney.getSelectionStart();// 光标开始位置            int editEnd = binding.editMoney.getSelectionEnd();// 光标结束位置            if (!TextUtils.isEmpty(temp.toString())){                if (Double.parseDouble(temp.toString()) > 9999999.99) {                    s.delete(editStart - 1, editEnd);//                    money = String.format("%.2f", Double.parseDouble(s.toString()));//                    Log.i("TAG", "money: " + money);                    binding.editMoney.setText(s.toString());                    binding.editMoney.setSelection(s.length());                }            }            Log.i("TAG", "现在的值: " + s.toString());        }    };   

4，处理倒计时

Handler handler = new Handler();private int time = 5;//倒计时五秒//onCreate调用handler.postDelayed(runnable, 0);//处理倒计时private final Runnable runnable = new Runnable() {    @SuppressLint("SetTextI18n")    public void run() {        binding.tvFinishTime.setText(String.format("确认（ %ss ）", time));        handler.postDelayed(this, 1000);        if (time == 0) {            //倒计时完成 执行操作            handler.removeCallbacks(runnable);        }        time--;//会在这里在减去1    }};

5，银行卡号，四位数间距

String splitStr= “8888888888888888”.replaceAll("\\d{4}(?!$)", "$0  ");

6，银行卡号，中间几位加密代替

String CardNo = "0624144312248830";//16String card = CardNo.substring(0,6) + "******" + CardNo.substring(12,CardNo.length());//card输出结果：062414********8830

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