点击显示题目即可在指定范围内随机出算数题目，适合初学者上手，易懂，另外，我没有把每一种运算的可能性都写出来，只写了部分的，不过两个数，三个数和四个数运算的可能性我都写了1-2中，你们可以比划模仿去写出其他的运算可能性，也很容易的，下面上代码！
xml布局
<?xml version="1.0" encoding="utf-8"?>
<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:layout_height="match_parent"
tools:context=".MainActivity"
android:orientation="vertical"
>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="自动出题APP"
android:textSize="35sp"
android:textColor="#FF5722"
android:gravity="center"
android:layout_marginTop="20dp"
/>
<TextView
android:layout_marginTop="100dp"
android:id="@+id/tv_math"
android:layout_width="match_parent"
android:layout_height="100dp"
android:textSize="40sp"
android:gravity="center_horizontal"
/>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#E91E63"
/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<Button
android:layout_marginTop="20dp"
android:layout_marginLeft="10dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="显示题目"
android:textSize="30sp"
android:id="@+id/btn_question"
/>
<Button
android:background="#05FC2E"
android:layout_marginLeft="100dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="显示答案"
android:id="@+id/btn_answers"
android:textSize="30sp"
android:layout_marginTop="20dp"
/>
</LinearLayout>
</LinearLayout>
Java代码文件
package com.example.dysuanshuti;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private TextView tv_math;
private Button btn_question;
private Button btn_answers;
@ Override
protected void onCreate (Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main) ;
initView();
}
private void initView(){
tv_math = (TextView) findViewById(R.id.tv_math) ;
btn_question = (Button) findViewById(R.id.btn_question);
btn_answers = (Button) findViewById(R.id.btn_answers);
btn_question.setOnClickListener(MainActivity.this );
btn_answers.setOnClickListener(MainActivity.this ) ;
}
public void onClick(View v) {
switch (v.getId()) {
case R.id.btn_question:
question();
break;
}
}
private void question() {
java.util.Random random = new java.util.Random();
//先指定随机生成几组数字(2~4)；
int temp = random.nextInt(3) + 2;
//随机生成(0~3)四个数字分别对应：+，-，×，÷
//如果随机到四组数字，则会有三个运算符
int signal = random.nextInt(4);//第一个运算符
int signal1 = random.nextInt(4);//第二个运算符
int signal2 = random.nextInt(4);//第三个运算符
//指随机生成的每组数字的数值(1~11)
final int num1 = random.nextInt(11) + 1;
final int num2 = random.nextInt(11) + 1;
final int num3 = random.nextInt(11) + 1;
final int num4 = random.nextInt(11) + 1;
switch (temp) {
case 2://2组数字
switch (signal) {
case 0:// +
tv_math.setText(num1 + "+" + num2 + "=?");
btn_answers.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
tv_math.setText(num1 + "+" + num2 + "=" + (num1 + num2));
}
});
break;
case 1:// -
tv_math.setText(num1 + "-" + num2 + "=?");
btn_answers.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
tv_math.setText(num1 + "-" + num2 + "=" + (num1 - num2));
}
});
break;
case 2:// ×
tv_math.setText(num1 + "*" + num2 + "=?");
btn_answers.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
tv_math.setText(num1 + "*" + num2 + "=" + (num1 * num2));
}
});
break;
case 3:// ÷
tv_math.setText(num1 + "/" + num2 + "=?");
btn_answers.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
tv_math.setText(num1 + "/" + num2 + "=" + (num1 / num2));
}
});
break;
}
break;
case 3://3组数字
switch (signal) {//第一个运算符
case 0:// +
switch (signal1) {//第二个运算符
case 0:// +
tv_math.setText(num1 + "+" + num2 + "+" + num3 + "=?");
btn_answers.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
tv_math.setText(num1 + "+" + num2 + "+" + num3 + "=" + (num1 + num2 + num3));
}
});
break;
case 2:// *
switch (signal1) {//第二个运算符
case 1:// -
tv_math.setText(num1 + "*" + num2 + "-" + num3 + "=?");
btn_answers.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
tv_math.setText(num1 + "*" + num2 + "-" + num3 + "=" + (num1 * num2 - num3));
}
});
break;
}
break;
case 4://4组数字
switch (signal) {//第一个运算符
case 0:// +
switch (signal1) {//第二个运算符
case 0:// +
switch (signal2) {//第三个运算符
case 0:// +
tv_math.setText(num1 + "+" + num2 + "+" + num3 + "+" + num4 + "=?");
btn_answers.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
tv_math.setText(num1 + "+" + num2 + "+" + num3 + "+" + num4 + "=" + (num1 + num2 + num3 + num4));
}
});
break;
case 1:// -
switch (signal1) {//第二个运算符
case 3:// /
switch (signal2) {//第三个运算符
case 2:// *
tv_math.setText(num1 + "-" + num2 + "/" + num3 + "*" + num4 + "=?");
btn_answers.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
tv_math.setText(num1 + "-" + num2 + "/" + num3 + "*" + num4 + "=" + (num1 - num2 / num3 * num4));
}
});
}
}
break;
}
break;
}
}
}
}
}
}
}
