android-EditText长度过滤器无法正常工作

首先，我必须说，我在这里读过类似的问题和答案，所以这个问题基本上是和其他许多问题的重复，但是这些问题的答案并不是我想要的那样

问题：

以编程方式在我的EditText上设置长度筛选器，如下所示：

editText.setFilters(new InputFilter[]{new LengthFilter(10)} );

它所做的唯一一件事就是在EditText中隐藏超出限制的文本。它仍然在建议框中显示长（无限）文本，我必须删除（退格）每个字母，然后才能删除编辑文本中显示的内容

建议的解决方案：

将InputType设置为

textFilter

通过编程，我做到了这一点：

editText.setInputType( InputType.TYPE_TEXT_VARIATION_FILTER );

它隐藏了建议，但无限文本仍然存在，我仍然必须使用退格删除不应该存在的字母

将InputType设置为

textNoSuggestions | textVisiblePassword

我通过编程实现了这一点（必须添加

TYPE\u CLASS\u TEXT

，否则它将无法工作）：

这一个确实有效，但问题是它停止了“手势输入”，并将字体更改为单空格

更好的解决方案？

---

如您所见，如果没有其他问题，这两种方法实际上无法工作。有没有其他我错过的方法。如果我想保持手势输入和建议，我应该只使用

文本观察程序吗？
我最终使用了文本观察程序。我不确定这是否是最好的方法，但它确实可以提供建议，并且不会关闭手势输入或更改字体样式。下面是我是如何做到的（我对android很陌生，所以如果这需要改进，请随时告诉我）

我在评论中添加了一个例子来澄清发生了什么

使这些全局变量：

private boolean mWatcherIsBlocked = false;
private String mBeforeChange;
private String mFilteredString; 
private int mCursorPosition = 0;

然后创建TextWatcher并将其添加到EditText中

final int maxLength = 10; // desired length limit

/** 
 * lets say our EditText is showing "abcdefgh". We select "cdef" from it and 
 * paste a new text "ijklmnop" in the middle. What we should get according to
 * our maxLength is this: 
 * (1) "ab" (0th up to the letter from before_change_text we were selecting) + 
 * (2) "ijklmn" (part of the text we pasted minus the number of letters the whole 
 *      after_change_text goes over the 10 letter limit) + 
 * (3) "gh" (last part of before_change_text that wasn't selected)
 * 
 * so the new text has to be "abijkmngh"
 */

TextWatcher textWatcher = new TextWatcher() {
    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
        // get before_change_text if textWatcher isn't blocked
        if (!mWatcherIsBlocked) mBeforeChange = s.toString();
    }
    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        if (!mWatcherIsBlocked){
            // get after_change_text if textWatcher isn't blocked
            String after = s.toString();
            // if after_change_text's length is bigger than the limit 
            if (after.length() > maxLength) {
                // see how much it goes over the limit
                int over = after.length() - maxLength;
                // add parts (1) and (2) like our example above
                String st = mBeforeChange.substring(0, start) + // (1)
                            after.substring(start, start + count - over); // (2)
                // get where the cursor position should be after pasting (
                // = after the last letter we could paste = length of (1) + (2) )
                mCursorPosition = st.length();
                // now add part (3) of our text to the first two
                st += mBeforeChange.substring(
                          mBeforeChange.length() - (maxLength - st.length()), 
                          mBeforeChange.length());
                // now assign this new text to a global variable
                mFilteredString = st;
            } else { 
                // if after_change_text hasn't gone over the limit assign it 
                // directly to our global variable
                mFilteredString = s.toString();
            }
        }
    }
    @Override
    public void afterTextChanged(Editable s) {
        // if filtered text is not the same as unfiltered text 
        // or textWatcher is not blocked
        if (!mFilteredString.equals(s.toString()) && !mWatcherIsBlocked) {
            // block textWatcher to avoid infinite loops created by setText 
            // (this might not work as I well as I think!)
            mWatcherIsBlocked = true;
            // set new text to our EditText
            editText.setText(mFilteredString);
            // set its cursor position 
            editText.setSelection(mCursorPosition);
            // unblock the textWatcher
            mWatcherIsBlocked = false;
        }
    }
};

// add the TextWatcher to our EditText
editText.addTextChangedListener(textWatcher);

final int maxLength = 10; // desired length limit

/** 
 * lets say our EditText is showing "abcdefgh". We select "cdef" from it and 
 * paste a new text "ijklmnop" in the middle. What we should get according to
 * our maxLength is this: 
 * (1) "ab" (0th up to the letter from before_change_text we were selecting) + 
 * (2) "ijklmn" (part of the text we pasted minus the number of letters the whole 
 *      after_change_text goes over the 10 letter limit) + 
 * (3) "gh" (last part of before_change_text that wasn't selected)
 * 
 * so the new text has to be "abijkmngh"
 */

TextWatcher textWatcher = new TextWatcher() {
    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
        // get before_change_text if textWatcher isn't blocked
        if (!mWatcherIsBlocked) mBeforeChange = s.toString();
    }
    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        if (!mWatcherIsBlocked){
            // get after_change_text if textWatcher isn't blocked
            String after = s.toString();
            // if after_change_text's length is bigger than the limit 
            if (after.length() > maxLength) {
                // see how much it goes over the limit
                int over = after.length() - maxLength;
                // add parts (1) and (2) like our example above
                String st = mBeforeChange.substring(0, start) + // (1)
                            after.substring(start, start + count - over); // (2)
                // get where the cursor position should be after pasting (
                // = after the last letter we could paste = length of (1) + (2) )
                mCursorPosition = st.length();
                // now add part (3) of our text to the first two
                st += mBeforeChange.substring(
                          mBeforeChange.length() - (maxLength - st.length()), 
                          mBeforeChange.length());
                // now assign this new text to a global variable
                mFilteredString = st;
            } else { 
                // if after_change_text hasn't gone over the limit assign it 
                // directly to our global variable
                mFilteredString = s.toString();
            }
        }
    }
    @Override
    public void afterTextChanged(Editable s) {
        // if filtered text is not the same as unfiltered text 
        // or textWatcher is not blocked
        if (!mFilteredString.equals(s.toString()) && !mWatcherIsBlocked) {
            // block textWatcher to avoid infinite loops created by setText 
            // (this might not work as I well as I think!)
            mWatcherIsBlocked = true;
            // set new text to our EditText
            editText.setText(mFilteredString);
            // set its cursor position 
            editText.setSelection(mCursorPosition);
            // unblock the textWatcher
            mWatcherIsBlocked = false;
        }
    }
};

// add the TextWatcher to our EditText
editText.addTextChangedListener(textWatcher);