java - 如何修复 "Error: ' ;' expected"或 "Error: ' )' expected"以及 boolean 值中的错误

Question

我正在尝试为 ExpenseName 和 ExpenseCost Edittext 创建验证，以便如果没有用户输入，它将提醒用户输入一些数据，并且 boolean 值中的“文本”也有错误，因为它是红色的。我从另一个 .java 复制了代码，所以我很确定它工作得很好

package com.example.back4app.userregistrationexample.Classes;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

import com.example.back4app.userregistrationexample.R;

public class ExpenseActivity extends AppCompatActivity {

private EditText ExpenseName;
private EditText ExpenseCost;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_expense);

    ExpenseName = (EditText) findViewById(R.id.txt_expensename);
    ExpenseCost = (EditText) findViewById(R.id.txt_expensecost);

    final Button btn_addexpense = findViewById(R.id.btn_addexpense);
        btn_addexpense.setOnClickListener(new View.OnClickListener()); {
            @Override
            public void onClick(View v) {
                //Validating the log in data
                boolean validationError = false;

                StringBuilder validationErrorMessage = new StringBuilder("Please, insert ");
                if (isEmpty(ExpenseCost)) {
                    validationError = true;
                    validationErrorMessage.append("the cost of the expense");
                }
                if (isEmpty(ExpenseName)) {
                    if (validationError) {
                        validationErrorMessage.append(" and ");
                    }
                    validationError = true;
                    validationErrorMessage.append("the name of the expense");
                }
            }
        }

    private boolean isEmpty(EditText text) {
        if (text.getText().toString().trim().length() > 0) {
            return false;
        } else {
            return true;
        }
    }
}
}

我尝试将“(”和“)”放在“文本”之外，但它仍然是红色，我还尝试将“isEmpty”更改为任何其他名称，因为它可能正在另一个.java上读取，但仍然发生同样的事情。另外，我尝试重建项目和清理项目，但没有任何效果，我还尝试使缓存无效/重新启动，因为我读到有人说 Android 出现这样的错误并不罕见。我的代码有问题吗？

编辑:

好的。所以我关闭了 OnClickListener 但现在更多“错误:';'”出现“expected”并且“OnClickListener”是抽象的；无法实例化”

Answer 1

您没有在发布的代码中关闭 onCreate 或 setOnClickListener。

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_expense);

    ExpenseName = (EditText) findViewById(R.id.txt_expensename);
    ExpenseCost = (EditText) findViewById(R.id.txt_expensecost);

    final Button btn_addexpense = findViewById(R.id.btn_addexpense);
    btn_addexpense.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
                //Validating the log in data
                boolean validationError = false;

               StringBuilder validationErrorMessage = new StringBuilder("Please, insert ");
                if (isEmpty(ExpenseCost)) {
                    validationError = true;
                    validationErrorMessage.append("the cost of the expense");
                }
                if (isEmpty(ExpenseName)) {
                    if (validationError) {
                        validationErrorMessage.append(" and ");
                    }
                    validationError = true;
                    validationErrorMessage.append("the name of the expense");
                }
        }
    }); // here
}

private boolean isEmpty(EditText text) {
    if (text.getText().toString().trim().length() > 0) {
        return false;
    } else {
        return true;
    }
}