java - 无法解决 makeText 方法

Question

我是开发新手，我买了一本书，《Big Nerd Ranch Android 编程指南》。我完成了第 2 章，这个应用程序一切正常，它向我展示了如何制作。现在我试图完成最后的挑战，但行不通。它给了我一个我根本没有改变的东西的错误，并且它昨天起作用了。该挑战要求我添加一个“上一个”按钮。

“无法解决方法‘makeText(anonymous android.view.View.OnClickListener, int, int)’

错误位于我尝试创建 Toast 的最底部。

package com.example.lthol.geoquiz;

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

public class QuizActivity extends AppCompatActivity {

    private Button mTrueButton;
    private Button mFalseButton;
    private Button mNextButton;
    private Button mPrevButton;
    private TextView mQuestionTextView;

    private Question[] mQuestionBank = new Question[] {
            new Question(R.string.question_australia, true),
            new Question(R.string.question_oceans, true),
            new Question(R.string.question_mideast, false),
            new Question(R.string.question_africa, false),
            new Question(R.string.question_americas, true),
            new Question(R.string.question_asia, true),
    };

    private int mCurrentIndex = 0;

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

        mQuestionTextView = (TextView) findViewById(R.id.question_text_view);

        mTrueButton = (Button) findViewById(R.id.true_button);
        mTrueButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                checkAnswer(true);
            }
        });

        mFalseButton = (Button) findViewById(R.id.false_button);
        mFalseButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                checkAnswer(false);
            }
        });

        mNextButton = (Button) findViewById(R.id.next_button);
        mNextButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mCurrentIndex = (mCurrentIndex + 1) % mQuestionBank.length;
                updateQuestion();

        mPrevButton = (Button) findViewById(R.id.prev_button);
        mPrevButton.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        mCurrentIndex = (mCurrentIndex - 1) % mQuestionBank.length;
                        updateQuestion();

            }
        });

        updateQuestion();
    }

    private void updateQuestion() {
        int question = mQuestionBank[mCurrentIndex].getTextResId();
        mQuestionTextView.setText(question);
    }

    private void checkAnswer(boolean userPressedTrue) {
        boolean answerIsTrue = mQuestionBank[mCurrentIndex].isAnswerTrue();

        int messageResId = 0;

        if (userPressedTrue == answerIsTrue) {
            messageResId = R.string.correct_toast;
        } else {
            messageResId = R.string.incorrect_toast;
        }

        Toast.makeText(this, messageResId, Toast.LENGTH_SHORT)
                .show();
    }
}

Answer 1

mPrevButton onClick 监听器实际上包含在 mNextButton 实现中。您需要关闭支架以使它们分开。