如何在TextInput上提示错误

Question

我只想在用户输入时在TextInput上显示错误提示。 例如，如果输入长度小于8，我想在用户在Password is too short上键入时显示TextInput错误。

Answer 1

这是文本输入布局

xml布局文件中的

 <android.support.design.widget.TextInputLayout
                android:id="@+id/input_layout_password"
                android:layout_width="match_parent"
                android:layout_height="wrap_content">
                <EditText
                    android:id="@+id/textView_password"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:hint="@string/password"
                    android:inputType="textPassword" />
</android.support.design.widget.TextInputLayout>

你的活动应该是这样的。

passwordTIL = (TextInputLayout) findViewById(R.id.input_layout_password);
passwordET = (EditText) findViewById(R.id.textVIew_password);


passwordET.addTextChangedListener(new SigninTextWatcher(passwordET)

//you can use this for username too or to check if the email format is correct or not.

private class SigninTextWatcher implements TextWatcher {
        private View view;

        private SigninTextWatcher(View view) {
            this.view = view;
        }

        public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
        }

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

        public void afterTextChanged(Editable editable) {
            switch (view.getId()) {
                case R.id.textView_password:
                    validatePassword();
                    break;
            }
        }
    }


    private boolean validatePassword() {
        if (passwordET.getText().toString().trim().isEmpty()) {
            passwordTIL.setError("Empty error message");
            requestFocus(passwordET);
            return false;
        } else if(passwordET.getText().toString().length() < 6){
                passwordTIL.setError("Short password error message");
                requestFocus(passwordET);
                return false;
        }else {
                passwordTIL.setErrorEnabled(false);
            }
            return true;
        }

您也可以使用validatePassword（）函数来启用/禁用登录按钮

Answer 2

您可以使用附加到编辑文本的textChangedListener。 见简单示例：

Field1.addTextChangedListener(new TextWatcher() {

   @Override
   public void afterTextChanged(Editable s) {
    if(s.length() < 6)
       // show message too short
    }}

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

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

  });

Answer 3

使用

et_password.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {

        }

        @Override
        public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
            if(charSequence.length()<6){
                et_password.setError("The password must contain 6 characters");
            }

        }

        @Override
        public void afterTextChanged(Editable editable) {

        }
    });

Answer 4

将addTextChangedListener（）添加到您的editText。

    EditText password = (EditText) findViewById(R.id.password_et);

    password.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence charSequence, int i, int i2, int i3) {
        }

        @Override
        public void onTextChanged(CharSequence charSequence, int i, int i2, int i3) {
          if((charSequence.toString()).length < 6){
           Toast.makeText(this, "Password length less than 6", Toast.LENGTH_SHORT).show();
          }
        }

        @Override
        public void afterTextChanged(Editable editable) {

        }
});