限制用户输入在编辑文本1十进制值 [英] Limiting a user to enter 1 decimal value in Edit Text

问题描述

要求是从数字/十进制编辑文本字段中输入不超过1个十进制值来限制用户。话虽如此，我也需要限制的号码输入到6最大数字。例如。 999999.9

The requirement is to limit user from not entering more than 1 decimal value in a numeric/decimal edit text field. That said, I also need to limit the number entry to 6 Max digits. eg. 999999.9

如果用户输入的数字孤独 - 那么我应该能够限制用户6位数最高，但应允许。和十进制数（如果由用户输入的）。

If a user enters numeric alone - then I should be able to limit the user to 6 digits Max, but should allow "." and decimal number(if entered by the user).

我不知道，如何做到这一点。任何帮助和参考将有很大的帮助。

I am not sure, how to do this. Any help and reference will be of great help.

推荐答案

也许有些实施与此类似？我是pretty的确保它可以被优化了很多！

Maybe some implementation similar to this? I'm pretty sure it can be optimized a lot!

EditText et;
.....
// force number input type on edittext
et.setRawInputType(InputType.TYPE_CLASS_NUMBER | InputType.TYPE_NUMBER_FLAG_DECIMAL);
et.addTextChangedListener(new CustomTextWatcher(et));

其中：

class CustomTextWatcher implements TextWatcher {
    private NumberFormat nf = NumberFormat.getNumberInstance();
    private EditText et;
    private String tmp = "";
    private int moveCaretTo;
    private static final int INTEGER_CONSTRAINT = 6;
    private static final int FRACTION_CONSTRAINT = 1;
    private static final int MAX_LENGTH = INTEGER_CONSTRAINT + FRACTION_CONSTRAINT + 1;

    public CustomTextWatcher(EditText et) {
        this.et = et;
        nf.setMaximumIntegerDigits(INTEGER_CONSTRAINT);
        nf.setMaximumFractionDigits(FRACTION_CONSTRAINT);
        nf.setGroupingUsed(false);
    }

    public int countOccurrences(String str, char c) {
        int count = 0;
        for (int i = 0; i < str.length(); i++) {
            if (str.charAt(i) == c) {
                count++;
            }
        }
        return count;
    }

    @Override
    public void afterTextChanged(Editable s) {
        et.removeTextChangedListener(this); // remove to prevent stackoverflow
        String ss = s.toString();
        int len = ss.length();
        int dots = countOccurrences(ss, '.');
        boolean shouldParse = dots <= 1 && (dots == 0 ? len != (INTEGER_CONSTRAINT + 1) : len < (MAX_LENGTH + 1));
        if (shouldParse) {
            if (len > 1 && ss.lastIndexOf(".") != len - 1) {
                try {
                    Double d = Double.parseDouble(ss);
                    if (d != null) {
                        et.setText(nf.format(d));
                    }
                } catch (NumberFormatException e) {
                }
            }
        } else {
            et.setText(tmp);
        }
        et.addTextChangedListener(this); // reset listener

        //tried to fix caret positioning after key type:
        if (et.getText().toString().length() > 0) {
            if (dots == 0 && len >= INTEGER_CONSTRAINT && moveCaretTo > INTEGER_CONSTRAINT) {
                moveCaretTo = INTEGER_CONSTRAINT;
            } else if (dots > 0 && len >= (MAX_LENGTH) && moveCaretTo > (MAX_LENGTH)) {
                moveCaretTo = MAX_LENGTH;
            }
            try {
                et.setSelection(et.getText().toString().length());
                // et.setSelection(moveCaretTo); <- almost had it :))
            } catch (Exception e) {
            }
        }
    }

    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
        moveCaretTo = et.getSelectionEnd();
        tmp = s.toString();
    }

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        int length = et.getText().toString().length();
        if (length > 0) {
            moveCaretTo = start + count - before;
        }
    }
}

不是100％，但可以作为一个基础使用，并建立在它之上;）

Not 100% but you can use as a base and build on top of it ;)

编辑：试图抛光设置文本更改后的插入位置，但它比我估计的，并回复到设定插入符的每个字符输入后，到底有多难。我离开了code，我开始对插入符号也许你可以改善呢？

tried to polishing setting the caret position after text changed but it was more difficult than I estimated and reverted to setting the caret at the end after each char input. I left the code I started on for the caret maybe you can improve it?

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