Question

上面的代码执行没有任何问题。但是当我添加“mQuestionTextView.setText（question）;”应用程序在启动时崩溃。我猜，从语法上讲，指令是正确的。需要帮助

public class MainActivity extends ActionBarActivity {
private TextView mQuestionTextView;
private TrueFalse[] mQuestionBank = {
        new TrueFalse(R.string.question_africa,false),
        new TrueFalse(R.string.question_americas,true),
        new TrueFalse(R.string.question_asia,true),
        new TrueFalse(R.string.question_mideast,false),
        new TrueFalse(R.string.question_oceans,true)
};
private int mCurrentIndex = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mQuestionTextView = (TextView) findViewById(R.id.question_tv);
    int question = mQuestionBank[mCurrentIndex].getQuestion();
    mQuestionTextView.setText(question);

    ...}

activity_main.XML文件：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:gravity="center"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.geopquiz1.MainActivity$PlaceholderFragment" >

<TextView
    android:id="@+id/question_tv"
    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:onClick="true_onClick" 
        android:id = "@+id/true_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/true_button_text"/>
    <Button 
        android:onClick="false_onClick"
        android:id = "@+id/false_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/false_button_text"/>
   <Button
       android:id="@+id/next_button"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:text="@string/next_btn_text"/>
</LinearLayout>

</LinearLayout>

TrueFalse.java文件：

package com.example.geopquiz1;

public class TrueFalse {
private int mQuestion;
private Boolean mTrueQuestion;
public TrueFalse(int question,Boolean trueQuestion){
    mQuestion = question;
    trueQuestion = mTrueQuestion;
}
public int getQuestion() {
    return mQuestion;
}
public void setQuestion(int question) {
    mQuestion = question;
}
public Boolean isTrueQuestion() {
    return mTrueQuestion;
}
public void setTrueQuestion(Boolean trueQuestion) {
    mTrueQuestion = trueQuestion;
}
}

Answer 1

我能理解的是问题是int值。但TextView.setText()只接受字符串值。所以你必须尝试这样

mQuestionTextView.setText(question+"");

Answer 2

在调用setText(..)方法时，只有在传递任何整数时才必须传递String值，它将检查R.java中的值。

所以在调用setText时将该整数转换为String，那么你的问题就会得到解决。

等

textview.setText(5+"");

这样写，在oncreate中初始化数组。

    private TrueFalse[] mQuestionBank;
    private int mCurrentIndex = 0;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

mQuestionBank = {
            new TrueFalse(R.string.question_africa,false),
            new TrueFalse(R.string.question_americas,true),
            new TrueFalse(R.string.question_asia,true),
            new TrueFalse(R.string.question_mideast,false),
            new TrueFalse(R.string.question_oceans,true)
    };

为什么此View.setText函数调用无法正常工作

2 个答案: