如何在安卓中创建问答应用？
安卓 是一个 操作系统是为基本上为手机打造的。它基于 Linux Kernel 等开源 软件，由 谷歌 开发。安卓现在在学生中非常受欢迎，学生们现在选择安卓作为他们的项目。对于初学者来说，构建婴儿安卓应用来学习安卓非常重要。在本文中，让我们使用 Java 在安卓系统中创建一个简单的问答应用。一个简单的测验应用程序，包含一组精选的问题及其答案，并检查用户给出的答案的正确性。它使用动态编程浏览问题。
接近
第一步:创建新项目
- 点击左侧最左上角的文件选项。
- 然后点击新建，打开一个新建项目，并命名该项目。
- 现在选择语言为 Java 的空活动。
- 将其命名为 QuizApp 。
第二步:用 activity_main.xml 设计 UI
在 activity_main.xml 文件中添加以下代码。这里的父布局是一个线性布局，其方向设置为垂直。里面有一个 ImageView ，一个 TextView ，两个按钮，两个image button。按钮和图像按钮位于水平方向的子线性布局中。图像视图用于显示图像，文本视图用于显示问题，按钮用于指示真/假，图像按钮用于导航到下一个/上一个问题。
*在* 可绘制文件夹中添加图像:****
以下是本项目中使用的所有可绘制文件的链接。
*activity_main.xml* 文件的完整代码如下。
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<!--Using linear layout with vertical orientation and center gravity -->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:background="#FFFFFF"
android:layout_height="match_parent"
android:orientation="vertical"
android:gravity="center"
tools:context=".MainActivity">
<!--ImageView used for showing pictures along with questions-->
<ImageView
android:id="@+id/myimage"
android:layout_width="wrap_content"
android:src="@drawable/f1"
android:layout_height="wrap_content"/>
<!--TextView used for showing questions on screen-->
<TextView
android:id="@+id/answer_text_view"
android:text="@string/a"
android:textColor="@android:color/black"
android:textSize="30sp"
android:padding="10dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<!--Using another LinearLayout for showing buttons
in horizontal orientation-->
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<!--TrueButton-->
<Button
android:id="@+id/true_button"
android:layout_marginRight="20dp"
android:backgroundTint="#5BD91B"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="20sp"
android:text="@string/true_text" />
<!--FalseButton-->
<Button
android:id="@+id/false_button"
android:layout_marginLeft="20dp"
android:layout_width="wrap_content"
android:backgroundTint="#E33328"
android:layout_height="wrap_content"
android:textSize="20sp"
android:text="@string/false_text" />
</LinearLayout>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<!--PreviousButton-->
<ImageButton
android:id="@+id/prev_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/baseline_keyboard_arrow_left_black_18dp"
android:backgroundTint="#DFD2D1"
android:text="@string/prev_text" />
<!--NextButton-->
<ImageButton
android:id="@+id/next_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:backgroundTint="#DFD2D1"
android:src="@drawable/baseline_keyboard_arrow_right_black_18dp"
android:text="@string/next_text" />
</LinearLayout>
</LinearLayout>
*在 activity_main.xml 中添加这段代码后，UI 看起来像:*
*第三步:与 Question.java 合作*
要创建新的 Java 类右键单击一个 Java 文件或文件夹，选择新建> Java 类。
现在在Question.java中添加以下代码。这里使用 getters 和 setters 方法来检索和设置数据。方法 是一个答案真() 返回答案真就像在问题构造函数中已经传递的一样。
Question.java
package org.geeksforgeeks.quizapp;
public class Question
{
// answerResId will store question
private int answerResId;
// answerTrue will store correct answer
// of the question provided
private boolean answerTrue;
public Question(int answerResId, boolean answerTrue)
{
// setting the values through
// arguments passed in constructor
this.answerResId = answerResId;
this.answerTrue = answerTrue;
}
// returning the question passed
public int getAnswerResId()
{
return answerResId;
}
// setting the question passed
public void setAnswerResId(int answerResId)
{
this.answerResId = answerResId;
}
// returning the correct answer
// of question
public boolean isAnswerTrue()
{
return answerTrue;
}
// setting the correct
// ans of question
public void setAnswerTrue(boolean answerTrue)
{
this.answerTrue = answerTrue;
}
}
*第 4 步:使用 strings.xml 文件*
在 strings.xml 文件中，我们必须提供题库。人们可以在这个文件中添加许多问题。
strings.xml
<resources>
<!--All the string resources come here including Questions and title -->
<string name="app_name">GFG | HOW WELL DO YOU KNOW SIMRAN?</string>
<string name="correct"><b>CORRECTNESS IS</b> \n
<b>%1$d</b> OUT OF 6</string>
<string name="true_text">true</string>
<string name="false_text">false</string>
<string name="correct_answer">That\'s correct</string>
<string name="wrong_answer">That\'s incorrect</string>
<string name="a">Simran loves Chocolates.</string>
<string name="b">Simran Knows Following Skills:\n \t
<b>Ballet</b>\n \t
<b>HipHop</b></string>
<string name="c">Do You Think Simran Believes In:\n \t
<b>Luck!!!</b></string>
<string name="d">Do You Think Simran Wants To Visit <b>Italy</b></string>
<string name="e">Simran Loves Loyalty.</string>
<string name="f">Simran Sleeps Less</string>
<string name="next_text">next</string>
<string name="prev_text">previous</string>
</resources>
*第五步:与 MainActivity.java 合作*
*onCreate()* 方法在 app 启动时首先被调用。问题[] 数组用问题标识和正确答案进行实例化。setOnClickListener()方法在每次点击按钮/ImageButton 时都会被调用，因此当用户点击一个按钮时，它会通过 getId() 方法检查其 Id ，并按照我们的逻辑执行动作。updateQuestion()通过 TextView 的 settext() 方法更新问题，并通过跟踪问题编号来更改图像。check answer()方法点击按钮检查原答案，并使用 Toast 相应显示文本。
MainActivity.java
package org.geeksforgeeks.quizapp;
import android.annotation.SuppressLint;
import android.os.Build;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;
public class MainActivity extends AppCompatActivity
implements View.OnClickListener {
// setting up things
private Button falseButton;
private Button trueButton;
private ImageButton nextButton;
private ImageButton prevButton;
private ImageView Image;
private TextView questionTextView;
private int correct = 0;
// to keep current question track
private int currentQuestionIndex = 0;
private Question[] questionBank = new Question[] {
// array of objects of class Question
// providing questions from string
// resource and the correct ans
new Question(R.string.a, true),
new Question(R.string.b, false),
new Question(R.string.c, true),
new Question(R.string.d, true),
new Question(R.string.e, true),
new Question(R.string.f, false),
};
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// setting up the buttons
// associated with id
falseButton = findViewById(R.id.false_button);
trueButton = findViewById(R.id.true_button);
nextButton = findViewById(R.id.next_button);
prevButton = findViewById(R.id.prev_button);
// register our buttons to listen to
// click events
questionTextView
= findViewById(R.id.answer_text_view);
Image = findViewById(R.id.myimage);
falseButton.setOnClickListener(this);
trueButton.setOnClickListener(this);
nextButton.setOnClickListener(this);
prevButton.setOnClickListener(this);
}
@SuppressLint("SetTextI18n")
@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
@Override
public void onClick(View v)
{
// checking which button is
// clicked by user
// in this case user choose false
switch (v.getId()) {
case R.id.false_button:
checkAnswer(false);
break;
case R.id.true_button:
checkAnswer(true);
break;
case R.id.next_button:
// go to next question
// limiting question bank range
if (currentQuestionIndex < 7) {
currentQuestionIndex
= currentQuestionIndex + 1;
// we are safe now!
// last question reached
// making buttons
// invisible
if (currentQuestionIndex == 6) {
questionTextView.setText(getString(
R.string.correct, correct));
nextButton.setVisibility(
View.INVISIBLE);
prevButton.setVisibility(
View.INVISIBLE);
trueButton.setVisibility(
View.INVISIBLE);
falseButton.setVisibility(
View.INVISIBLE);
if (correct > 3)
questionTextView.setText(
"CORRECTNESS IS " + correct
+ " "
+ "OUT OF 6");
// showing correctness
else
Image.setImageResource(
R.drawable.resu);
// if correctness<3 showing sad emoji
}
else {
updateQuestion();
}
}
break;
case R.id.prev_button:
if (currentQuestionIndex > 0) {
currentQuestionIndex
= (currentQuestionIndex - 1)
% questionBank.length;
updateQuestion();
}
}
}
@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
private void updateQuestion()
{
Log.d("Current",
"onClick: " + currentQuestionIndex);
questionTextView.setText(
questionBank[currentQuestionIndex]
.getAnswerResId());
// setting the textview with new question
switch (currentQuestionIndex) {
case 1:
// setting up image for each
// question
Image.setImageResource(R.drawable.f2);
break;
case 2:
Image.setImageResource(R.drawable.f3);
break;
case 3:
Image.setImageResource(R.drawable.f4);
break;
case 4:
Image.setImageResource(R.drawable.f5);
break;
case 5:
Image.setImageResource(R.drawable.f6);
break;
case 6:
Image.setImageResource(R.drawable.f7);
break;
case 7:
Image.setImageResource(R.drawable.f1);
break;
}
}
private void checkAnswer(boolean userChooseCorrect)
{
boolean answerIsTrue
= questionBank[currentQuestionIndex]
.isAnswerTrue();
// getting correct ans of current question
int toastMessageId;
// if ans matches with the
// button clicked
if (userChooseCorrect == answerIsTrue) {
toastMessageId = R.string.correct_answer;
correct++;
}
else {
// showing toast
// message correct
toastMessageId = R.string.wrong_answer;
}
Toast
.makeText(MainActivity.this, toastMessageId,
Toast.LENGTH_SHORT)
.show();
}
}
*输出:在仿真器上运行*
https://media.geeksforgeeks.org/wp-content/uploads/20200823112349/Quiz-app.mp4
在安卓中完成小考应用项目–
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