Question

我尝试了以下代码，但android不允许我这样做，因为我进入了一个无限循环。

mEditText = (EditText) getActivity().findViewById(R.id.input_content);
mEditText.addTextChangedListener(new TextWatcher(){
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count,
                    int after) {}

            @Override
            public void onTextChanged(CharSequence s, int start, int before,
                    int count) {

            }

            @Override
            public void afterTextChanged(Editable s) {
                   //I want to format the already existing text in s in a certain way as      the user is typing
                   mEditText.setText(s.toString() + " \n");
            }       
        });

请任何想法都会非常有帮助。感谢

Answer 1

3种可能的解决方案：

检查字符串中的回车状态

像这样：

mEditText = (EditText) getActivity().findViewById(R.id.input_content);
mEditText.addTextChangedListener(new TextWatcher()
{
    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {}

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {}

    @Override
    public void afterTextChanged(Editable s)
    {
        //I want to format the already existing text in s in a certain way as      the user is typing
        if (s.toString().charAt(s.length() - 1 ) != '\n')
        {
            mEditText.setText(s.toString() + " \n");
        }
    }
});

根据输入字符串中的内容

在beforeTextChanged

像这样：

mEditText = (EditText) getActivity().findViewById(R.id.input_content);
mEditText.addTextChangedListener(new TextWatcher()
{
    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after)
    {
        //I want to format the already existing text in s in a certain way as      the user is typing
        mEditText.setText(s.toString() + " \n");
    }

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {}

    @Override
    public void afterTextChanged(Editable s) {}
});

暂时取消听众

像这样：

final TextWatcher tw = new TextWatcher()
{
    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {}

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {}

    @Override
    public void afterTextChanged(Editable s)
    {
        //I want to format the already existing text in s in a certain way as      the user is typing
        mEditText.removeTextChangedListener(tw);
        mEditText.setText(s.toString() + " \n");
        mEditText.addTextChangedListener(tw);
    }
});

mEditText = (EditText) getActivity().findViewById(R.id.input_content);
mEditText.addTextChangedListener(tw);

Answer 2

您最有可能进入无限循环，因为您正在更改public void afterTextChanged(Editable s)中的文本，然后再次调用该方法。
最好的解决方案是改变其他方法中的文本，或者改变可编辑的焦点。有关详细信息，请参阅View.OnFocusChangeListener。

以下是一个例子：

textView.setOnFocusChangeListener(new OnFocusChangeListener() {          
    public void onFocusChange(View v, boolean hasFocus) {
        if(!hasFocus) {
            textView.setText(s.toString() + " \n");
        }
    }
});

如何在TextView上监听并对android中的同一TextView进行更改

2 个答案: