package com.wwwjjj.wangjian;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.RadioGroup;public class MainActivity extends Activity implements OnClickListener {private RadioGroup chufa;private RadioGroup kouhao;private EditText range;private EditText exp_num;private Button btn;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);chufa = (RadioGroup) findViewById(R.id.rg_chufa);kouhao = (RadioGroup) findViewById(R.id.rg_kuohao);range = (EditText) findViewById(R.id.et_range);exp_num = (EditText) findViewById(R.id.et_exp_num);btn = (Button) findViewById(R.id.btn_next);btn.setOnClickListener(this);}@Overridepublic void onClick(View arg0) {// TODO Auto-generated method stubint chufaId = chufa.getCheckedRadioButtonId();int kuohaoId = kouhao.getCheckedRadioButtonId();Boolean haveChufa = false, haveKuohao = false;if (chufaId == R.id.chuafa_yes)haveChufa = true;if (kuohaoId == R.id.kuohao_yes)haveKuohao = true;int r = Integer.valueOf(range.getText().toString());int en = Integer.valueOf(exp_num.getText().toString());Intent intent =new Intent(MainActivity.this,SolutionActivity.class);Bundle bundle=new Bundle();bundle.putBoolean("kuohao", haveKuohao);bundle.putBoolean("chufa", haveChufa);bundle.putInt("range", r);bundle.putInt("exp_num", en);intent.putExtras(bundle);startActivity(intent);}
}

package com.wwwjjj.wangjian;import java.math.BigDecimal;import android.app.Activity;
import android.os.Bundle;
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 SolutionActivity extends Activity implements OnClickListener{private TextView exp;private TextView tv_num;private EditText tv_ans;private Button okBtn;private Button nextBtn;private String expString;private Test test;private boolean haveChu;private boolean haveKuohao;private int range;private int exp_num;int chu=2,kuohao=2;double ans;private double result2;private double result;private Integer myans;private int count=1;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_solution);haveKuohao=getIntent().getBooleanExtra("kuohao", haveKuohao);haveChu=getIntent().getBooleanExtra("chufa", haveChu);if(haveChu)chu=1;if(haveKuohao)kuohao=1;range=getIntent().getIntExtra("range", range);exp_num=getIntent().getIntExtra("exp_num", exp_num);exp=(TextView)findViewById(R.id.tv_exp);tv_num=(TextView)findViewById(R.id.tv_num);tv_ans=(EditText)findViewById(R.id.et_ans);okBtn=(Button)findViewById(R.id.okBtn);nextBtn=(Button)findViewById(R.id.nextBtn);okBtn.setOnClickListener(this);nextBtn.setOnClickListener(this);//从java类中取出表达式到expString中tv_num.setText("第"+count+++"题：");test=new Test();expString= test.shu(chu,kuohao,range);//将表达式显示到exp （exp.setText(表达式)）exp.setText(expString+"=");result2 = test.computeWithStack(expString);BigDecimal bg2=new BigDecimal(result2);result=bg2.setScale(2,BigDecimal.ROUND_HALF_UP).doubleValue();}@Overridepublic void onClick(View v0) {// TODO Auto-generated method stubif(v0==okBtn){//从tv_ans中取出答案//判断答案是否正确//显示判断结果myans=Integer.valueOf(tv_ans.getText().toString());if(myans==result){Toast.makeText(SolutionActivity.this, "回答正确", 0).show();}else{Toast.makeText(SolutionActivity.this, "回答错误", 0).show();}}else if(v0==nextBtn){tv_ans.setText("");if(count>exp_num) finish();//从java类中取出表达式//将表达式显示到exp （exp.setText(表达式)）tv_num.setText("第"+count+++"题：");expString= test.shu(chu,kuohao,range);//将表达式显示到exp （exp.setText(表达式)）exp.setText(expString+"=");result2 = test.computeWithStack(expString);BigDecimal bg2=new BigDecimal(result2);result=bg2.setScale(2,BigDecimal.ROUND_HALF_UP).doubleValue();}}}

package com.wwwjjj.wangjian;//import java.awt.SystemColor;
import java.util.HashMap;
import java.util.Map;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.regex.Pattern;public class Test {public double computeWithStack(String computeExpr) {//把表达式用运算符、括号分割成一段一段的，并且分割后的结果包含分隔符StringTokenizer tokenizer = new StringTokenizer(computeExpr, "+-*/()", true);Stack<Double> numStack = new Stack<Double>(); //用来存放数字的栈 Stack<Operator> operStack = new Stack<Operator>(); //存放操作符的栈 Map<String, Operator> computeOper = this.getComputeOper(); //获取运算操作符 String currentEle; //当前元素 while (tokenizer.hasMoreTokens()) { currentEle = tokenizer.nextToken().trim(); //去掉前后的空格 if (!"".equals(currentEle)) { //只处理非空字符 if (this.isNum(currentEle)) { //为数字时则加入到数字栈中 numStack.push(Double.valueOf(currentEle)); } else { //操作符 Operator currentOper = computeOper.get(currentEle);//获取当前运算操作符 if (currentOper != null) { //不为空时则为运算操作符 while (!operStack.empty() && operStack.peek().priority() >= currentOper.priority()) { compute(numStack, operStack); } //计算完后把当前操作符加入到操作栈中 operStack.push(currentOper); } else {//括号 if ("(".equals(currentEle)) { //左括号时加入括号操作符到栈顶 operStack.push(Operator.BRACKETS); } else { //右括号时, 把左括号跟右括号之间剩余的运算符都执行了。 while (!operStack.peek().equals(Operator.BRACKETS)) { compute(numStack, operStack); } operStack.pop();//移除栈顶的左括号 } } } } } // 经过上面代码的遍历后最后的应该是nums里面剩两个数或三个数，operators里面剩一个或两个运算操作符 while (!operStack.empty()) { compute(numStack, operStack); } return numStack.pop(); } /** * 判断一个字符串是否是数字类型 * @param str * @return */ private boolean isNum(String str) { String numRegex = "^\\d+(\\.\\d+)?$"; //数字的正则表达式 return Pattern.matches(numRegex, str); } /** * 获取运算操作符 * @return */ private Map<String, Operator> getComputeOper() { return new HashMap<String, Operator>() { // 运算符 private static final long serialVersionUID = 7706718608122369958L; { put("+", Operator.PLUS); put("-", Operator.MINUS); put("*", Operator.MULTIPLY); put("/", Operator.DIVIDE); } }; } private void compute(Stack<Double> numStack, Stack<Operator> operStack) { Double num2 = numStack.pop(); // 弹出数字栈最顶上的数字作为运算的第二个数字 Double num1 = numStack.pop(); // 弹出数字栈最顶上的数字作为运算的第一个数字 Double computeResult = operStack.pop().compute( num1, num2); // 弹出操作栈最顶上的运算符进行计算 numStack.push(computeResult); // 把计算结果重新放到队列的末端 } /** * 运算符 */ private enum Operator { /** * 加 */ PLUS { @Override public int priority() { return 1; } @Override public double compute(double num1, double num2) { return num1 + num2; } }, /** * 减 */ MINUS { @Override public int priority() { return 1; } @Override public double compute(double num1, double num2) { return num1 - num2; } }, /** * 乘 */ MULTIPLY { @Override public int priority() { return 2; } @Override public double compute(double num1, double num2) { return num1 * num2; } }, /** * 除 */ DIVIDE { @Override public int priority() { return 2; } @Override public double compute(double num1, double num2) { return num1 / num2; } }, /** * 括号 */ BRACKETS { @Override public int priority() { return 0; } @Override public double compute(double num1, double num2) { return 0; } }; /** * 对应的优先级 * @return */ public abstract int priority(); /** * 计算两个数对应的运算结果 * @param num1 第一个运算数 * @param num2 第二个运算数 * @return */ public abstract double compute(double num1, double num2); } //符号函数 //------------------------------------------------------------- static String fuhao(int chu) { String fu; int num_3; if (chu == 1) { num_3 = ((int)(Math.random() * 100)) % 4; if (num_3 == 0) fu = "+"; else if (num_3 == 1) fu = "-"; else if (num_3 == 2) fu = "*"; else fu = "/"; return fu; } else { num_3 = ((int)(Math.random()*20)) % 2; if (num_3 == 0) fu = "+"; else fu = "-"; return fu; } } //分数函数 //------------------------------------------------------------- static String fenshu() { int a1 = 0, b1 = 0, a2 = 0, b2 = 0; a1 = ((int)(Math.random()*(97))); b1 = ((int)(Math.random()*100 - a1)) + a1 + 1; a2 = ((int)(Math.random()* (97))); b2 = ((int)(Math.random()* (100 - a2))) + a2 + 1; String first_a1, second_b1; String first_a2, second_b2; first_a1 = String.valueOf(a1); second_b1 = String.valueOf(b1); first_a2 = String.valueOf(a2); second_b2 = String.valueOf(b2); String all1 = ""; //随机产生四则运算符 int fu = 0; fu = ((int)(Math.random()*100)) % 2; if (fu == 0) { all1 = "(" + first_a1 + "/" + second_b1 + ")" + "+" + "(" + first_a2 + "/" + second_b2 + ")" ; } else if (fu == 1) { all1 = "(" + first_a1 + "/" + second_b1 + ")" + "-" + "(" + first_a2 + "/" + second_b2 + ")" ; } else if (fu == 2) { all1 = "(" + first_a1 + "/" + second_b1 + ")" + "*" + "(" + first_a2 + "/" + second_b2 + ")" ; } else { all1 = "(" + first_a1 + "/" + second_b1 + ")" + "/" + "(" + first_a2 + "/" + second_b2 + ")" ; } return all1; } /*private static String to_String(int b1) { // TODO Auto-generated method stub return null; }*/ //运算函数 //------------------------------------------------------------- String shu(int chu, int kuohao, int range) { int num_1, num_2; int geshu; int calculate_kuohao=3; String str_first, str_second; String all = ""; int ch1; geshu = ((int)(Math.random()*(4)) + 2); for (int i = 1; i <= geshu; i++) { num_1 = ((int)(Math.random()* (range))) + 1; str_first = String.valueOf(num_1); num_2 = ((int)(Math.random()*(range))) + 1; str_second = String.valueOf(num_2); if ((kuohao == 1)&&(calculate_kuohao!=0)) { ch1 = ((int)(Math.random()*(4))) + 1; switch (ch1){ case 1: { if (all == "") { all = str_first + fuhao(chu) + str_second; } else { all = str_first + fuhao(chu) + all; } }break; case 2: { if (all == "") { all = str_second + fuhao(chu) + str_first; } else { all = all + fuhao(chu) + str_first; } }break; case 3: { if (all == "") { all = "(" + str_first + fuhao(chu) + str_second + ")"; } else { all = "(" + str_first + fuhao(chu) + all + ")"; } calculate_kuohao = calculate_kuohao - 1; }break; case 4: { if (all == ""){ all = "(" + str_second + fuhao(chu) + str_first + ")"; } else { all = "(" + all + fuhao(chu) + str_first + ")"; } calculate_kuohao = calculate_kuohao - 1; }break; } } else { ch1 = ((int)(Math.random()*(2))) + 1; switch (ch1){ case 1: { if (all == "") { all = str_first + fuhao(chu) + str_second; } else { all = str_first + fuhao(chu) + all; } }break; case 2: { if (all == "") { all = str_second + fuhao(chu) + str_first; } else { all = all + fuhao(chu) + str_first; } }break; } } } return all ; } }