四则运算-安卓版

1.Exp.java    产生运算式计算

package com.example.cal;

import android.util.Log;

public class Exp {// 产生表达式及结果
	private int item_num = 0;// 0:两项，1：三项
	private int sign_num = 0;// 0+,1-,2*,3/
	private int sign_num_1 = 0;// 0+,1-,2*,3/ 三项的时候需要两个运算符
	private int kuohao = 0;// 0不产生括号，1产生括号
	private int kuohao_weizhi = 0;// 0表示前2项有括号，1表示后2项有括号

	private int result;// 结果

	private StringBuilder exp=new StringBuilder();// 式子

	enum Sign {
		add, subtract, multiply, divide
	}

	Exp() {
		while(true){
			if(createExp()==true)
			{
				break;
			}
		}
	}

	public StringBuilder getExp() {
		return exp;
	}

	public void setExp(StringBuilder exp) {
		this.exp = exp;
	}

	public void setResult(int result) {
		this.result = result;
	}

	private boolean createExp() {
		item_num = (int) (Math.random() * 2);
		sign_num = (int) (Math.random() * 4);
		int a = (int) (Math.random() * 100);// 随机生成0-100以内的数
		int b = (int) (Math.random() * 100);
		int c = (int) (Math.random() * 100);
		kuohao = (int) (Math.random() * 2);
		Log.e("jhd", item_num+"");
		Log.e("jhd", sign_num+"");
		Log.e("jhd", kuohao+"");
		Log.e("jhd", a+"");
		Log.e("jhd", b+"");
		Log.e("jhd", c+"");
		if (item_num == 0) {// 产生2项的情况
			String temp = "";
			switch (sign_num) {
			case 0:// +
				temp = a + "+" + b;
				result = a + b;
				break;
			case 1:// -
				temp = a + "-" + b;
				result = a - b;
				break;
			case 2:// *
				temp = a + "*" + b;
				result = a * b;
				break;
			case 3:// /
				temp = a + "÷" + b;
				if (a % b != 0) {// 不整除旧返回false
					return false;

				}
				result = a / b;
				break;
			}
			exp.append(temp);
		}
		if (item_num == 1) {// 式子为三项时

			sign_num_1 = (int) (Math.random() * 4);// 随机产生一个运算符
			if (kuohao == 0) {// 不产生括号
				// 比较优先级
				String temp;
				if (sign_num <= 1 && sign_num_1 > 1) {// 先计算后两项

					if (calculate(b, sign_num_1, c) == null) {
						return false;
					}
					result = calculate(a, sign_num, calculate(b, sign_num_1, c));
					exp.append(a + getSign(sign_num) + b + getSign(sign_num_1)
							+ c);
				} else {// 计算前两项
					if (calculate(a, sign_num, b) == null) {
						return false;
					}
					if (calculate(calculate(a, sign_num, b), sign_num_1, c) == null) {
						return false;
					}
					result = calculate(calculate(a, sign_num, b), sign_num_1, c);
					exp.append(a + getSign(sign_num) + b + getSign(sign_num_1)
							+ c);
				}
			}
			else{
				return false;
			}
			

		}
		
		return true;

	}

	public Integer calculate(int a, int sign, int b) {
		Integer temp = null;
		switch (sign) {
		case 0:
			temp = a + b;

			break;
		case 1:
			temp = a - b;
			break;
		case 2:
			temp = a * b;
			break;
		case 3:
			if (a % b != 0) {// 保证能整除
				return null;
			}
			temp = a / b;
			break;
		}
		return temp;
	}

	private String getSign(int sign) {
		String temp = null;
		switch (sign) {
		case 0:
			temp = "+";

			break;
		case 1:
			temp = "-";

			break;
		case 2:
			temp = "*";

			break;
		case 4:
			temp = "/";

			break;
		}
		return temp;
	}

	public int getResult() {// 得到产生表达式的结果
		return result;
	}

	/*public String getExpression() {// 得到产生的表达式
		//if(get)
	}*/

}

2.ExpActivity,java

package com.example.cal;

import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class ExpActivity extends Activity implements OnClickListener {

	private CreateExp expclass;
	private TextView tv_exp;
	private EditText et_result;
	private Button next;
	private Button exit;
	private TextView all;
	private TextView completed;
	private TextView wrong;

	private int index = 0;// 当前题目位置
	private int wrong_num = 0;// 答错题目数量

	private List<Exp> list;// 题目数组，所有题目

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_exp);
		expclass = new CreateExp();// 随机产生一个2-3项四则运算式子，及式子的结果
		// ---初始控件
		intViews();

		int num = getIntent().getIntExtra("num", 0);
		if (num != 0) {
			list = new ArrayList<Exp>();
			for (int i = 0; i < num; i++) {
				list.add(new Exp());
			}
			tv_exp.setText(list.get(index).getExp());//
			all.setText("共计："+num);
			completed.setText("已答："+(index));
			wrong.setText("答错：");
		}

	}

	private void intViews() {
		// TODO Auto-generated method stub
		tv_exp = (TextView) findViewById(R.id.tv_exp);
		et_result = (EditText) findViewById(R.id.et_result);
		next = (Button) findViewById(R.id.next_btn);
		exit = (Button) findViewById(R.id.exit_btn);
		all = (TextView) findViewById(R.id.all);
		completed = (TextView) findViewById(R.id.completed);
		wrong = (TextView) findViewById(R.id.wrong);

		next.setOnClickListener(new OnClickListener() {// 点击下一题时，判断上一道是否正确，并且显示下一道

			@Override
			public void onClick(View arg0) {
				// TODO Auto-generated method stub
				if(et_result.getText().toString()==""){
					Toast.makeText(getApplicationContext(), "答案不能为空！",
							Toast.LENGTH_SHORT).show();
				}
				int result = Integer.valueOf(et_result.getText().toString());
				if (index >= list.size()) {
					Toast.makeText(getApplicationContext(), "题目已经答完！",
							Toast.LENGTH_SHORT).show();
					return;
				}
				
				if (result != list.get(index).getResult()) {
					wrong_num++;
					wrong.setText("答错："+wrong_num);
					Log.d("jhd", "已答错数目：" + wrong_num);
				}
				index++;
				completed.setText("已答："+(index));
				if(index==list.size())
				{
					Toast.makeText(getApplicationContext(), "题目已经答完！",
							Toast.LENGTH_SHORT).show();
					return;
				}
				
				tv_exp.setText(list.get(index).getExp());
				et_result.setText("");
			}
		});

		exit.setOnClickListener(new OnClickListener() {

			@Override
			public void onClick(View arg0) {
				// TODO Auto-generated method stub
				finish();
			}
		});
	}

	@Override
	public void onClick(View arg0) {
		// TODO Auto-generated method stub

	}

}

3.InputAvctivity.java 

package com.example.cal;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class InputActivity extends Activity implements OnClickListener{

	private EditText et_num;
	private Button btn;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_input);
		et_num=(EditText)findViewById(R.id.et_num);
		btn=(Button)findViewById(R.id.num_btn);
		btn.setOnClickListener(this);
		
	}

	@Override
	public void onClick(View arg0) {
		// TODO Auto-generated method stub
		if(et_num!=null){
			int n=Integer.valueOf(et_num.getText().toString());
			Intent intent=new Intent(InputActivity.this,ExpActivity.class);
			if(n==0){
				Toast.makeText(getApplicationContext(), "请输入大于0的整数！", Toast.LENGTH_SHORT).show();
			}
			intent.putExtra("num", n);
			startActivity(intent);
		}
	}


}

4.MainActivuty.java 

package com.example.cal;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity implements OnClickListener {

	private Button enterBtn;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		enterBtn=(Button)findViewById(R.id.enter_btn);
		enterBtn.setOnClickListener(this);
	}
	@Override
	public void onClick(View arg0) {
		// TODO Auto-generated method stub
		Intent intent=new Intent(MainActivity.this,InputActivity.class);
		startActivity(intent);
	}

	
}

5.界面  .xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    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.cal.MainActivity"
    android:orientation="vertical" >

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="100dp"
        android:text="欢迎进入四则运算" 
        android:textSize="30dp"
        android:gravity="center"
        />
    <Button 
        android:id="@+id/enter_btn"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="进入"
        />

</LinearLayout>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    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.cal.InputActivity" 
    android:orientation="vertical">
	<LinearLayout 
	    android:layout_width="fill_parent"
		android:layout_height="50dp"	
		android:orientation="horizontal"    
	    >
	    <EditText
	        android:id="@+id/et_num"
	        android:layout_width="0dp"
	        android:layout_height="fill_parent"
	        android:hint="输入算式数："
	        android:digits="0123456789"
	       	android:layout_weight="3"
	        />
	    <Button 
	        android:id="@+id/num_btn"
	        android:layout_width="0dp"
	        android:layout_height="fill_parent"
	        android:text="确认"
	        android:layout_weight="1"
	        />
	</LinearLayout>
</LinearLayout>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    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.cal.ExpActivity" >

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="30dp"
        android:text="运算式："
        android:textSize="20dp" />

    <TextView
        android:id="@+id/tv_exp"
        android:layout_width="fill_parent"
        android:layout_height="30dp"
        android:text="111"
        android:background="@android:color/white"
        android:textSize="20dp" />

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="30dp"
        android:text="请输入运算结果："
        android:textSize="20dp" />

    <EditText
        android:layout_marginTop="5dp"
        android:id="@+id/et_result"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:digits="-0123456789"
        android:textSize="20dp" />

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

        <Button
            android:id="@+id/next_btn"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="下一题" />
        <Button
            android:id="@+id/exit_btn"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="退出" />
    </LinearLayout>
    
    <LinearLayout 
        android:layout_marginTop="15dp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <TextView 
            android:id="@+id/all"
            android:gravity="center_horizontal"
            android:layout_width="0dp"
            android:text="共计："
            android:layout_weight="1"
            android:layout_height="wrap_content"/>
        <TextView 
             android:id="@+id/completed"
            android:gravity="center_horizontal"
            android:text="已答："
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_height="wrap_content"/>
        <TextView  
            android:id="@+id/wrong"
            android:gravity="center_horizontal"
            android:text="答错："
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_height="wrap_content"/>
    </LinearLayout>

</LinearLayout>

介绍：

随机产生最多三位数，随机产生运算符，用户可选择出题数目，系统随机产生算式，用户回答，系统可判断正误。

结对的小伙伴博客：http://www.cnblogs.com/fooreveryu/