Question

对不起，这个长锅，但我需要帮助。我是Android World的新手，并且遵循Chris Stewart（The Big Nerd Ranch）的“Android Development”一书。一切顺利，但现在我卡住了。当我运行我的应用程序时，它崩溃了这行代码

String text = Integer.toString(Integer.toString(question));

根据书，它显示了问题文本。我也将代码更改为此，但它显示为0。

package com.example.subrose.geoquiz;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
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 TextView mQuestionTextView;
    private Question[] mQuestionBank = new Question[]{
            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);
        int question = mQuestionBank[mCurrentIndex].getTextResId();
     mQuestionTextView.setText(question);

    mTrueButton = (Button)findViewById(R.id.true_button);

    mTrueButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Toast.makeText(QuizActivity.this, R.string.correct_toast, Toast.LENGTH_SHORT).show();
        }
    });

    mFalseButton = (Button)findViewById(R.id.false_button);

    mFalseButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Toast.makeText(QuizActivity.this, R.string.incorrect_toast, Toast.LENGTH_SHORT).show();
        }
    });
}
}

任何解决方案。提前致谢。这是我的完整代码。

QuizActivity.java

public class Question {

private int mTextResId;
private boolean mAnswerTrue;

public Question(int mTextResId, boolean mAnswerTrue)
{
    mTextResId = mTextResId;
    mAnswerTrue = mAnswerTrue;
}

public int getTextResId() {
    return mTextResId;
}

public void setTextResId(int textResId) {
    mTextResId = textResId;
}

public boolean isAnswerTrue() {
    return mAnswerTrue;
}

public void setAnswerTrue(boolean answerTrue) {
    mAnswerTrue = answerTrue;
}

}

Question.java

<resources>
<string name="app_name">GeoQuiz</string>
<string name="true_button">True</string>
<string name="false_button">False</string>
<string name="next_button">Next</string>
<string name="correct_toast">Correct!</string>
<string name="incorrect_toast">Incorrect!</string>
<string name="action_settings">Settings</string>
<string name="question_oceans">The Pacific Ocean is larger than the Atlantic Ocean.</string>
<string name="question_mideast">The Suez Canal connects the Red Sea and the Indian Ocean.</string>
<string name="question_africa">The source of the Nile River is in Egypt.</string>
<string name="question_americas">The Amazon River is the longest river in the Americas.</string>
<string name="question_asia">Lake Baikal is the world\'s oldest and deepest freshwater lake.</string>
</resources>

的strings.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:orientation="vertical" >

<TextView
    android:id="@+id/question_text_view"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:padding="24dp" />

<LinearLayout
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="horizontal">

    <Button
        android:id="@+id/true_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/true_button"/>

    <Button
        android:id="@+id/false_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/false_button"/>

</LinearLayout>

<Button
    android:id="@+id/next_button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/next_button"/>

</LinearLayout>

activity_quiz.xml

ref

Answer 1

您无法在settext中设置整数，因此请从

更改代码

mQuestionTextView.setText(question);替换为

mQuestionTextView.setText(String.valueOf(question));

Answer 2

int question = mQuestionBank[mCurrentIndex].getTextResId();

mQuestionTextView.setText(question);

在TextView中设置整数，你有以下可能性：

将其替换为：

mQuestionTextView.setText(String.format(Locale.US, "%d", question));

或

mQuestionTextView.setText(question+"");

或

mQuestionTextView.setText(String.valueOf(question));

Answer 3

构造函数中的主要问题。将其更改如下。

public Question(int mTextResId, boolean mAnswerTrue)
 {
   this.mTextResId = mTextResId;
    this.mAnswerTrue = mAnswerTrue;
 }

您应该在数据阴影中使用this。当前值未分配给实例变量，因为您只使用了本地变量。这就是他们返回默认值的原因。按上述方式进行。

除了setText()有几个变体，如果您使用资源ID，您可以直接使用setText(int id)。阅读setText varients。

Answer 4

为什么不检查使用：

mQuestionTextView.setText(getString(mQuestionBank[mCurrentIndex].getTextResId()));

无论如何，我没有在您的代码中看到任何错误，无法在您的视图中设置文字。

TextView不显示文本

4 个答案: