简单的基于Android的网上学习系统的设计-2

       学生在“测试列表”页面可以看到所有已发布的测试和提交信息，这里同样是使用的一个ListView来进行显示，当点击里面的一个item后，就可以进入该测试。至于“已提交”和“未提交”的判断，我是先在服务端数据库里建了一个表(student_scores)，这个表主要用于存储学生的测试得分，然后，在进入“测试列表”页面时，我会根据用户名（username）去请求这个表中 该用户的 所有的测试提交信息，然后遍历提交信息，根据测试的id（testId）判断有没有提交某一个测试

       学生进入某一个测试后，系统先会判断该测试是否已经提交了，如果已经提交了，那么进入后显示的是考生的答题情况页面，如图1，如果没有提交过，那么就会判断是否已经过了截止日期，如果过了，那么就不能测试提交，没过的话就可以进行测试。当然，系统还会判断一下测试的类型，如果是考试，那么就会给出提示，让考生注意时间等，并且在确认考试后开始倒计时，测试页面如图2。

       学生的答题情况我是简单的先用一个List数组暂存，当提交测试时，直接将这里的数据封装传输。学生进行测试部分的代码如下：   

package com.sjhbysj.aixuexi.activities;
import java.io.Serializable;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.os.Messenger;
import android.view.KeyEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.LinearLayout;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;
import com.sjhbysj.aixuexi.R;
import com.sjhbysj.aixuexi.config.Constants;
import com.sjhbysj.aixuexi.domain.Question;
import com.sjhbysj.aixuexi.domain.StudentAnswer;
import com.sjhbysj.aixuexi.domain.StudentScore;
import com.sjhbysj.aixuexi.domain.Test;
import com.sjhbysj.aixuexi.service.TestService;
import com.sjhbysj.aixuexi.utils.MyXUtils;
import com.sjhbysj.aixuexi.view.CountDown;
import com.sjhbysj.aixuexi.view.CountDown.OnTimeCompleteListener;
public class StudentTestActivity extends Activity {
	private TextView tv_studenttest_type;
	private CountDown cd_studenttest_countdown;
	private TextView tv_studenttest_number;
	private TextView tv_studenttest_questiontype;
	private TextView tv_studenttest_grade;
	private TextView tv_studenttest_question;
	private RadioGroup rg_studenttest_select;
	private RadioButton rb_studenttest_A;
	private RadioButton rb_studenttest_B;
	private RadioButton rb_studenttest_C;
	private LinearLayout ll_studenttest_cb;
	private CheckBox cb_studenttest_A;
	private CheckBox cb_studenttest_B;
	private CheckBox cb_studenttest_C;
	private Button btn_studenttest_last;
	private TextView tv_studenttest_currentposition;
	private TextView tv_studenttest_totalnumber;
	private Button btn_studenttest_next;
	private Test test;
	private Question currentQuestion;  //当前显示的题目
	private int currentPosition = 0;
	private boolean isFirst = true;  //是否第一次答题
	private int score = 0;  //测试得分
	private ProgressDialog dialog;
	private Handler handler = new Handler(){
		public void handleMessage(android.os.Message msg) {
			switch (msg.what) {
			case Constants.REQUEST_QUESTION_SUCCESS:
				//获得了测试的 试题
				//清空 学生的作答 的集合
				TestService.studentAnswers.clear();
				if("考试".equals(test.getType())){
					//弹出提示框,准备倒计时
					showExamAlertDialog();
				}
				//显示第一题题目
				showQuestion(currentPosition);
				break;
			case Constants.CHECK_IN_TEST_SUCCESS:
				//交卷完成，跳转到 结果显示 的页面
				dialog.dismiss();
				Intent intent = new Intent(StudentTestActivity.this, TestResultActivity.class);
				intent.putExtra("score", score);
				startActivityForResult(intent, Constants.CHANGE_TEST);
				break;
			case Constants.INTERNET_ERROR:
				Toast.makeText(StudentTestActivity.this, "网络错误", 0).show();
				break;
			default:
				break;
			}
		}
	};
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_studenttest);
		initView();
		initData();
		initListener();
	}
	private void initListener() {
		// 上一题的点击按钮
		btn_studenttest_last.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				//判断是否在第一道题上
				if(currentPosition == 0){
					//不能再往上翻
					Toast.makeText(StudentTestActivity.this, "已经是第一题了", 0).show();
					return;
				}
				//显示上一题
				currentPosition--;
				showQuestion(currentPosition);
			}
		});
		// 下一题 或 提交测试（当处于最后一道题时） 的点击按钮
		btn_studenttest_next.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				//判断用户 有没有 去做这道题
				if(cb_studenttest_A.isChecked() || cb_studenttest_B.isChecked() || cb_studenttest_C.isChecked() ||
						rb_studenttest_A.isChecked() || rb_studenttest_B.isChecked() || rb_studenttest_C.isChecked()){
					//说明做了这道题，则判断要执行的操作
					if("提交测试".equals(btn_studenttest_next.getText().toString().trim())){
						//把 提交按钮 所在页面 的数据存入list集合
						dealStudentAnswer();
						//判断是否全部的题目都做完了
						if(TestService.studentAnswers.size() != TestService.questions.size()){
							//没有做完
							Toast.makeText(StudentTestActivity.this, "还有题目没有做哦", 0).show();
						}else{
							//做完了,提交试卷
							showloadingDialog("正在交卷");
							checkInTest();
						}
					}else if("下一题".equals(btn_studenttest_next.getText().toString().trim())){
						//将这道题做的答案存入list集合
						dealStudentAnswer();
						//显示下一题
						currentPosition++;
						showQuestion(currentPosition);
					}
				}else{
					//说明没有做这道题
					//判断操作
					if("提交测试".equals(btn_studenttest_next.getText().toString().trim())){
						//说明是在最后一道题上,但最后一道题没有写，所以提示用户要做 这道题
						Toast.makeText(StudentTestActivity.this, "还有题目没有做哦", 0).show();
					}else if("下一题".equals(btn_studenttest_next.getText().toString().trim())){
						// 不存数据，直接显示下一题
						currentPosition++;
						showQuestion(currentPosition);
					}
				}
			}
		});
		//倒计时结束的监听
		cd_studenttest_countdown.setOnTimeCompleteListener(new OnTimeCompleteListener() {
			@Override
			public void onTimeComplete() {
				showloadingDialog("考试结束，正在交卷");
				checkInTest();
			}
		});
	}
	
	private void checkInTest() {
		//计算得分
		for (Question question : TestService.questions) {
			for (StudentAnswer studentAnswer : TestService.studentAnswers) {
				if(studentAnswer.getQuestionId().equals(question.getQuestionId())){
					//找到了对应的题目
					//判断正误
					if(studentAnswer.getStudentAnswer().equals(question.getCorrectAnswer())){
						//答案正确
						//拿到该题的分数,并计算得分
						score += Integer.parseInt(question.getGrade());
					}
				}
			}
		}
		//封装数据
		StudentScore studentScore = new StudentScore(TestService.loginUser.getUserName(), test.getId(), score+"");
		//启动服务，提交
		Intent service = new Intent(StudentTestActivity.this, TestService.class);
		service.putExtra("operation", "checkInTest");
		service.putExtra("studentScore", (Serializable)studentScore);
		service.putExtra("messenger", new Messenger(handler));
		startService(service);
	}
	private void initData() {
		Intent intent = getIntent();
		test = (Test) intent.getSerializableExtra("test");
		//检查是否已经过了截止日期
		String currentTime = MyXUtils.getCurrentTime();
		//得到 yyyy-MM-dd HH:mm 型的时间
		currentTime = currentTime.substring(0, 16);
		//与 截止时间比较--可以先将里面的符号都给删掉，变为存数字的字符串，然后转化比较（ .replace("-", "").replace(" ", "").replace(":", "") ）
		//但实现发现，直接用原始字符串比较也可以得出正确结果
		if(currentTime.compareTo(test.getDeadline()) > 0){
			//说明已经过了截止时间
			AlertDialog.Builder builder = new AlertDialog.Builder(this);
			builder.setTitle("提示")
					.setMessage("该测试已经过了截止提交日期，无法答题")
					.setNeutralButton("确定", new DialogInterface.OnClickListener() {
						@Override
						public void onClick(DialogInterface dialog, int which) {
							finish();  //退出页面
						}
					});
			builder.show();
		}
		//显示信息
		//题目类型
		tv_studenttest_type.setText(test.getType());
		//倒计时
		if("作业".equals(test.getType())){
			//不显示倒计时控件
			cd_studenttest_countdown.setVisibility(View.GONE);
		}else if("考试".equals(test.getType())){
			//获得考试时间
			int examTime = Integer.parseInt(test.getExamTime());
			//将分钟转化为秒
			examTime = examTime*60;
			//初始化倒计时
			cd_studenttest_countdown.initTime(examTime);
		}
		//总题数
		tv_studenttest_totalnumber.setText(test.getQuestionCount());
		//启动服务，获取题目
		Intent service = new Intent(StudentTestActivity.this, TestService.class);
		service.putExtra("operation", "requestQuestion");
		service.putExtra("test", (Serializable)test);
		service.putExtra("messenger", new Messenger(handler));
		startService(service);
	}
	private void initView() {
		......  //控件的初始化
	}
	
	private void dealStudentAnswer() {
		String sAnswer = "";
		boolean updateList = false;  //是否更新了 学生作答的 list集合
		if("多选题".equals(currentQuestion.getType())){
			//拼接答案
			if(cb_studenttest_A.isChecked()){
				//选项A被选中了
				sAnswer += "A:";
			}
			if(cb_studenttest_B.isChecked()){
				//选项B被选中了
				sAnswer += "B:";
			}
			if(cb_studenttest_C.isChecked()){
				//选项C被选中了
				sAnswer += "C:";
			}
		}else{
			//为 单选 或者 判断
			int id = rg_studenttest_select.getCheckedRadioButtonId();
			if(id == R.id.rb_studenttest_A){
				sAnswer = "A:";
			}
			if(id == R.id.rb_studenttest_B){
				sAnswer = "B:";
			}
			if(id == R.id.rb_studenttest_C){
				sAnswer = "C:";
			}
		}
		//判断答案正误
		String isCorrect = "F";
		if(sAnswer.equals(currentQuestion.getCorrectAnswer())){
			isCorrect = "T";
		}
		//封装数据
		StudentAnswer stuAnswer = new StudentAnswer(TestService.loginUser.getUserName(), currentQuestion.getQuestionId(), test.getId(), sAnswer, isCorrect);
		if(isFirst){
			//说明为第一次做题---直接将数据加入集合
			TestService.studentAnswers.add(stuAnswer);
			isFirst = false;
		}else{
			//说明已经做了题目，即集合里有数据了，可以遍历集合。当集合为空时，不会执行遍历函数
			StudentAnswer studentAnswer = new StudentAnswer();
			//遍历 学生已作答的list集合 ，看这道题之前有没有写过---如果写过，则更新数据
			for (int i = 0; i < TestService.studentAnswers.size(); i++) {
				studentAnswer = TestService.studentAnswers.get(i);
				if(studentAnswer.getQuestionId().equals(currentQuestion.getQuestionId())){
					//说明本题已经作答了---更新数据
					TestService.studentAnswers.set(i, stuAnswer);
					updateList = true;  //更新了集合，即这道题之前写过，不再另外添加到list集合里
					break;  //已得到了结果，可直接跳出循环
				}
			}
			if(!updateList){
				//说明 遍历完整个 学生作答的list集合 也没有找到当前显示的题目---即这道题还没有做过，那么直接加入到list集合
				TestService.studentAnswers.add(stuAnswer);
				updateList = false;  //恢复标志
			}
		}
	}
	
	private void showQuestion(int position) {
		//拿到对应的题目
		currentQuestion = TestService.questions.get(position);
		//显示题目内容
		tv_studenttest_number.setText(currentQuestion.getNumber());
		tv_studenttest_questiontype.setText(currentQuestion.getType());
		tv_studenttest_grade.setText("(分值：" + currentQuestion.getGrade() + ")");
		tv_studenttest_question.setText(currentQuestion.getQuestion());
		//清空选择--避免其余题目的选择的干扰
		rg_studenttest_select.clearCheck();
		cb_studenttest_A.setChecked(false);
		cb_studenttest_B.setChecked(false);
		cb_studenttest_C.setChecked(false);
		if("单选题".equals(currentQuestion.getType())){
			//则显示单选框--即多选框隐藏
			rg_studenttest_select.setVisibility(View.VISIBLE);
			ll_studenttest_cb.setVisibility(View.GONE);
			rb_studenttest_C.setVisibility(View.VISIBLE);  //防止前面有判断题
			//显示选项内容
			rb_studenttest_A.setText("A:" + currentQuestion.getAnswer_1());
			rb_studenttest_B.setText("B:" + currentQuestion.getAnswer_2());
			rb_studenttest_C.setText("C:" + currentQuestion.getAnswer_3());
		}else if("多选题".equals(currentQuestion.getType())){
			//则显示多选框--即隐藏单选框
			rg_studenttest_select.setVisibility(View.GONE);
			ll_studenttest_cb.setVisibility(View.VISIBLE);
			//显示选项内容
			cb_studenttest_A.setText("A:" + currentQuestion.getAnswer_1());
			cb_studenttest_B.setText("B:" + currentQuestion.getAnswer_2());
			cb_studenttest_C.setText("C:" + currentQuestion.getAnswer_3());
		}else if("判断题".equals(currentQuestion.getType())){
			//则显示单选框--即多选框隐藏
			rg_studenttest_select.setVisibility(View.VISIBLE);
			ll_studenttest_cb.setVisibility(View.GONE);
			//且只显示两个选项
			rb_studenttest_C.setVisibility(View.GONE);
			//显示选项内容
			rb_studenttest_A.setText("A:" + currentQuestion.getAnswer_1());
			rb_studenttest_B.setText("B:" + currentQuestion.getAnswer_2());
		}
		//如果学生 选择了答案，再回过头来看时，要显示他选择的答案
		//遍历学生 作答答案 的list集合，看是否 做过 当前显示的题目---因为学生 作答的list集合的数据的位置 并不是和 题目集合 一一对应的，可能他中间会先跳过某道题，所以要遍历查找
		for (StudentAnswer studentAnswer : TestService.studentAnswers) {
			if(studentAnswer.getQuestionId().equals(currentQuestion.getQuestionId())){
				//说明本题已经作答了---显示作答的答案
				if("多选题".equals(currentQuestion.getType())){
					//切割答案
					String[] stuAnswers = studentAnswer.getStudentAnswer().split(":");
					for (int i = 0; i < stuAnswers.length; i++) {
						if("A".equals(stuAnswers[i])){
							cb_studenttest_A.setChecked(true);
						}
						if("B".equals(stuAnswers[i])){
							cb_studenttest_B.setChecked(true);
						}
						if("C".equals(stuAnswers[i])){
							cb_studenttest_C.setChecked(true);
						}
					}
				}else{
					//说明为 单选 或判断
					if("A:".equals(studentAnswer.getStudentAnswer())){
						rb_studenttest_A.setChecked(true);
					}
					if("B:".equals(studentAnswer.getStudentAnswer())){
						rb_studenttest_B.setChecked(true);
					}
					if("C:".equals(studentAnswer.getStudentAnswer())){
						rb_studenttest_C.setChecked(true);
					}
				}
				break;  //已经查找到了结果，不需要再循环了
			}
		}
		//显示当前位置
		int cp = position+1; //因为position是从0开始算的,所以+
		tv_studenttest_currentposition.setText(cp+"");
		//判断该题是否是最后一道题
		if(position == TestService.questions.size()-1){
			//说明是最后一道题---显示为 提交测试
			btn_studenttest_next.setText("提交测试");
		}else{
			btn_studenttest_next.setText("下一题");  //当从最后一题往前翻时，也要变化 显示
		}
	}
	
	private void showExamAlertDialog() {
		AlertDialog.Builder builder = new AlertDialog.Builder(StudentTestActivity.this);
		builder.setTitle("提示")
				.setMessage("该测试类型为 考试。请注意：\n1.开始后将启动倒计时,请把握好考试时间。\n2.考试只有一次机会，中途退出将自动提交答卷，请保证手机电量充足，网络畅通。")
				.setPositiveButton("开始考试", new DialogInterface.OnClickListener() {
					@Override
					public void onClick(DialogInterface dialog, int which) {
						cd_studenttest_countdown.reStart();
					}
				}).setNegativeButton("不考了", new DialogInterface.OnClickListener() {
					@Override
					public void onClick(DialogInterface dialog, int which) {
						// 直接返回上一个页面
						setResult(Constants.CHANGE_TEST);
						finish();
					}
				});
		builder.show();
	}
	
	private void showloadingDialog(String message) {
		dialog = new ProgressDialog(this);
		dialog.setMessage(message);
		dialog.setCanceledOnTouchOutside(false);  //设置点击对话框之外的地方不会取消对话框 
		dialog.show();
	}
	@Override
	protected void onActivityResult(int requestCode, int resultCode, Intent data) {
		super.onActivityResult(requestCode, resultCode, data);
		if(resultCode == Constants.CHANGE_TEST){
			//从结果页面跳转回来，则自动返回至测试列表页面
			setResult(Constants.CHANGE_TEST);
			finish();
		}
	}
	@Override
	public boolean onKeyUp(int keyCode, KeyEvent event) {
		if(keyCode == KeyEvent.KEYCODE_BACK){
			if("考试".equals(test.getType())){
				AlertDialog.Builder builder = new AlertDialog.Builder(this);
				builder.setTitle("提示")
						.setMessage("退出后将会自动交卷，确定退出吗。")
						.setPositiveButton("确定", new DialogInterface.OnClickListener() {
							@Override
							public void onClick(DialogInterface dialog, int which) {
								//交卷
								showloadingDialog("正在交卷");
								checkInTest();
							}
						}).setNegativeButton("取消", null);
				builder.show();
			}else{
				//不是考试，则可以直接退出
				finish();
			}
			return true;
		}
		return super.onKeyUp(keyCode, event);
	}
}