Android 新 class TextWatcher 无法从 mainActivity 中转换值

Question

我有关于 android 应用程序开发的问题，我有一个 class 到 TextWatcher。但textWatcher不能使用getSelectionStart()、getSelectionEnd()、length()、findViewById(mInputLayout)、setText(s)和setSelection(tempSelection)的方法。并且 mainActivity 无法将值转换为 customTextWatcher。你能帮帮我吗

public class customTextWatcher implements TextWatcher {
    CharSequence temp;
    int editStart;
    int editEnd;

    String mEditText; //EditText
   String mInputLayout; //Input Layout
    int tempLength; // Set the EditText length to limit it
    //private String activity; // Set the Activity of the class to use this class
    String errorText; // When out of boundary with EditText , it will show the errorText

    // Constructor for this Class,
    // Get the params from main Class
    public customTextWatcher(String mEditText, String mInputLayout, int tempLength, String errorText) {
        this.mEditText = mEditText;
        this.mInputLayout = mInputLayout;
        this.tempLength = tempLength;
        //this.activity = activity;
        this.errorText = errorText;
    }

    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {}

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

    @Override
    public void afterTextChanged(Editable s) {
        // String selectedText = mEditText.getText().substring(editStart, editEnd);
        editStart = mEditText.getSelectionStart();
        editEnd = mEditText.getSelectionEnd();

        if (tempLength.length() > 10) {
            TextInputLayout til = (TextInputLayout)findViewById(mInputLayout);
            til.setErrorEnabled(true);
            til.setError(errorText);

            s.delete(editStart - 1, editEnd);
            int tempSelection = editStart;
            mEditText.setText(s);
            mEditText.setSelection(tempSelection);
        }
    }
}






mEditTextLastName = (EditText) findViewById(R.id.input_lastName);
        mEditTextFirstName = (EditText) findViewById(R.id.input_firstName);
        mEditTextHomeAddress = (EditText) findViewById(R.id.input_homeAddress);
        mEditTextCountry = (EditText) findViewById(R.id.input_country);
        mEditTextPhoneCode = (EditText) findViewById(R.id.input_PhoneCode);
        mEditTextMobile = (EditText) findViewById(R.id.input_mobile);
        mEditTextOtherPhone = (EditText) findViewById(R.id.input_otherPhone);
        mEditTextEmail = (EditText) findViewById(R.id.input_email);
        mEditTextPassword = (EditText) findViewById(R.id.input_password);
        mEditTextReComfirmPassword = (EditText) findViewById(R.id.input_reConfirmPassword);
        mEditTextWechat = (EditText) findViewById(R.id.input_wechat);
/**
 * mTextInputLayout  findById of layout TextInputLayout
 */
        mTextInputLayout_LastName = (TextInputLayout) findViewById(R.id.lastNameLayout);
        mTextInputLayout_FistName = (TextInputLayout) findViewById(R.id.firstNameLayout);
        mTextInputLayout_HomeAddress = (TextInputLayout) findViewById(R.id.homeAddressLayout);
        mTextInputLayout_Country = (TextInputLayout) findViewById(R.id.countryLayout);
        mTextInputLayout_PhoneCode = (TextInputLayout) findViewById(R.id.phoneCodeLayout);
        mTextInputLayout_Mobile = (TextInputLayout) findViewById(R.id.mobileLayout);
        mTextInputLayout_OtherPhone = (TextInputLayout) findViewById(R.id.otherPhoneLayout);
        mTextInputLayout_Email = (TextInputLayout) findViewById(R.id.emailAddressLayout);
        mTextInputLayout_Password = (TextInputLayout) findViewById(R.id.passwordLayout);
        mTextInputLayout_ReComfirmPassword = (TextInputLayout) findViewById(R.id.reConfirmPasswordLayout);
        mTextInputLayout_Wechat = (TextInputLayout) findViewById(R.id.wechatLayout);


        mEditTextLastName.addTextChangedListener(new customTextWatcher(mEditTextLastNam,mTextInputLayout_LastName,20,"error : Can't over 20's character!"));

Answer 1

那是因为您将 TextWatcher 移到了单独的 class 中。如果您的 TextWatcher 在 Activity 内部 class，您可以访问那个 Activity（上下文）。一种解决方案是在您的 TextWatcher 中定义回调接口并在 Activity 中实现它。通过这样做，您将能够将 Activity 设置为 TextWatcher 的回调并访问 Activity 的方法。

Android 新 class TextWatcher 无法从 mainActivity 中转换值

Android new class TextWatcher cannot tran value from mainActivity

java

android

android-textwatcher