设计一个简易的有道词典

1.实现有道词典需要拖拽一个EditText,一个Button,以及一个TextView。其具体代码如下：

activity类的代码：

 1 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     xmlns:tools="http://schemas.android.com/tools"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:background="@drawable/mainbg"
 6     android:paddingBottom="@dimen/activity_vertical_margin"
 7     android:paddingLeft="@dimen/activity_horizontal_margin"
 8     android:paddingRight="@dimen/activity_horizontal_margin"
 9     android:paddingTop="@dimen/activity_vertical_margin"
10     tools:context=".MainActivity" >
11
12     <EditText
13         android:id="@+id/etWord"
14         android:layout_width="wrap_content"
15         android:layout_height="wrap_content"
16         android:layout_alignParentLeft="true"
17         android:layout_alignParentTop="true"
18         android:layout_marginTop="31dp"
19         android:background="@android:drawable/edit_text"
20         android:ems="10"
21         android:hint="@string/searchHint"
22         android:singleLine="true"
23         android:textColor="#552006"
24         android:textColorHint="#782f10" >
25
26         <requestFocus />
27     </EditText>
28
29     <Button
30         android:id="@+id/btnSearch"
31         android:layout_width="wrap_content"
32         android:layout_height="wrap_content"
33         android:layout_alignBaseline="@+id/etWord"
34         android:layout_alignBottom="@+id/etWord"
35         android:layout_marginLeft="16dp"
36         android:layout_toRightOf="@+id/etWord"
37         android:background="@drawable/ibsearchword"
38         android:onClick="searchWord"
39         android:text="@string/serachWord" />
40
41     <TextView
42         android:id="@+id/tvSearchResult"
43         android:layout_width="match_parent"
44         android:layout_height="match_parent"
45         android:layout_alignLeft="@+id/etWord"
46         android:layout_below="@+id/etWord"
47         android:layout_marginTop="22dp"
48         android:textSize="25sp"
49         android:background="@drawable/bg_roundcorner"
50         android:textAppearance="?android:attr/textAppearanceMedium" />
51
52 </RelativeLayout>

2.MainActivity类的代码：

 1 package com.example.happydictionary;
 2
 3 import android.app.Activity;
 4 import android.os.Bundle;
 5 import android.text.TextUtils;
 6 import android.view.Menu;
 7 import android.view.View;
 8 import android.widget.EditText;
 9 import android.widget.TextView;
10
11 import com.example.happydictionary.dao.WordDao;
12
13 public class MainActivity extends Activity {
14     private WordDao wordDao;
15     private EditText etWord;
16     private TextView tvResult;
17
18     @Override
19     protected void onCreate(Bundle savedInstanceState) {
20         super.onCreate(savedInstanceState);
21         setContentView(R.layout.activity_main);
22
23         initViews();
24     }
25
26     private void initViews() {
27         etWord = (EditText) findViewById(R.id.etWord);
28         tvResult = (TextView) findViewById(R.id.tvSearchResult);
29     }
30
31     @Override
32     public boolean onCreateOptionsMenu(Menu menu) {
33         // Inflate the menu; this adds items to the action bar if it is present.
34         getMenuInflater().inflate(R.menu.main, menu);
35         return true;
36     }
37
38     public void searchWord(View view) {
39         String english = etWord.getText().toString();
40         wordDao = new WordDao(this);
41         if (TextUtils.isEmpty(english)) {
42             tvResult.setText("请输入您想查询的单词");
43         } else {
44             String chinese = wordDao.getChinese(english);
45             tvResult.setText(chinese);
46         }
47     }
48
49 }

3.WordDao类的代码：

 1 package com.example.happydictionary.dao;
 2
 3 import android.content.Context;
 4 import android.database.Cursor;
 5 import android.database.sqlite.SQLiteDatabase;
 6
 7 import com.example.happydictionary.db.DBHelper;
 8
 9 public class WordDao {
10      private DBHelper dbHelper;
11      private SQLiteDatabase sqLiteDatabase;
12      public WordDao(Context context){
13          dbHelper=new DBHelper(context);
14      }
15      public String getChinese(String english){
16          sqLiteDatabase=dbHelper.openDatabase();
17          String sql="select chinese from t_words where english=?";
18          Cursor cursor=sqLiteDatabase.rawQuery(sql, new String[]{english});
19          String chinese="查无该词";
20          if(cursor.moveToFirst()){
21              chinese=cursor.getString(cursor.getColumnIndex("chinese"));
22          }
23          return chinese;
24      }
25 }

4.DBHelper类的代码：

 1 package com.example.happydictionary.db;
 2
 3 import java.io.File;
 4 import java.io.FileNotFoundException;
 5 import java.io.FileOutputStream;
 6 import java.io.IOException;
 7 import java.io.InputStream;
 8
 9 import com.example.happydictionary.R;
10 import com.example.happydictionary.R.raw;
11
12 import android.content.Context;
13 import android.database.sqlite.SQLiteDatabase;
14 import android.os.Environment;
15 import android.util.Log;
16
17 /**
18  * 实现将数据库文件从raw目录拷贝到手机里存放数据库的位置
19  *
20  * @author cabbage
21  */
22 public class DBHelper {
23     private final int BUFFER_SIZE = 400000;
24     public static final String DB_NAME = "idiom.db"; // 保存的数据库文件名
25     public static final String PACKAGE_NAME = "com.example.happydictionary";// 应用的包名
26     public static final String DB_PATH = "/data"
27             + Environment.getDataDirectory().getAbsolutePath() + "/"
28             + PACKAGE_NAME + "/databases";
29     /*// SDCard 定义数据库的存放路径
30     private final String DATABASE_PATH = android.os.Environment
31             .getExternalStorageDirectory().getAbsolutePath() + "/dictionary";*/
32
33     private Context context;
34
35     public DBHelper(Context context) {
36         this.context = context;
37     }
38
39     public SQLiteDatabase openDatabase() {
40         try {
41             File myDataPath = new File(DB_PATH);
42             if (!myDataPath.exists()) {
43                 myDataPath.mkdirs();// 如果没有这个目录则创建
44             }
45             String dbfile = myDataPath + "/" + DB_NAME;
46             if (!(new File(dbfile).exists())) {// 判断数据库文件是否存在，若不存在则执行导入，否则直接打开数据库
47                 InputStream is = context.getResources().openRawResource(
48                         R.raw.dictionary); // 欲导入的数据库
49                 FileOutputStream fos = new FileOutputStream(dbfile);
50                 byte[] buffer = new byte[BUFFER_SIZE];
51                 int count = 0;
52                 while ((count = is.read(buffer)) > 0) {
53                     fos.write(buffer, 0, count);
54                 }
55                 fos.close();
56                 is.close();
57             }
58             SQLiteDatabase db = SQLiteDatabase.openOrCreateDatabase(dbfile,
59                     null);
60             return db;
61         } catch (FileNotFoundException e) {
62             Log.e("Database", "File not found");
63             e.printStackTrace();
64         } catch (IOException e) {
65             Log.e("Database", "IO exception");
66             e.printStackTrace();
67         }
68         return null;
69     }
70 }

5.Word类的代码：

 1 package com.example.happydictionary.entity;
 2
 3 public class Word {
 4     private String english;
 5     private String chinese;
 6
 7     public String getEnglish() {
 8         return english;
 9     }
10
11     public void setEnglish(String english) {
12         this.english = english;
13     }
14
15     public String getChinese() {
16         return chinese;
17     }
18
19     public void setChinese(String chinese) {
20         this.chinese = chinese;
21     }
22
23 }

6.DBHelperTest类的代码：

 1 package com.example.happydictionary.test;
 2
 3 import com.example.happydictionary.db.DBHelper;
 4
 5 import android.test.AndroidTestCase;
 6
 7 public class DBHelperTest extends AndroidTestCase {
 8      public void testCreateDB(){
 9          DBHelper dbHelper=new DBHelper(getContext());
10          dbHelper.openDatabase();
11      }
12 }