Merge pull request #1209 from bowwran/master

#5 #20 第五次实验

students/net1814080903140/DBHelper.java

@@ -0,0 +1,23 @@
+package edu.hzuapps.androidlabs.net1814080903140;
+
+import android.content.Context;
+import android.database.sqlite.SQLiteDatabase;
+import android.database.sqlite.SQLiteOpenHelper;
+
+public class DBHelper extends SQLiteOpenHelper{
+
+    public DBHelper(Context context){
+        super(context,"forecast.db",null,1);
+    }
+    @Override
+    public void onCreate(SQLiteDatabase db) {
+//        创建表的操作
+        String sql = "create table info(_id integer primary key autoincrement,city varchar(20) unique not null,content text not null)";
+        db.execSQL(sql);
+    }
+
+    @Override
+    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
+
+    }
+}

students/net1814080903140/DBManager.java

@@ -0,0 +1,82 @@
+package edu.hzuapps.androidlabs.net1814080903140;
+import android.content.ContentValues;
+import android.content.Context;
+import android.database.Cursor;
+import android.database.sqlite.SQLiteDatabase;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class DBManager {
+    public static SQLiteDatabase database;
+    /* 初始化数据库信息*/
+    public static void initDB(Context context){
+        DBHelper dbHelper = new DBHelper(context);
+        database = dbHelper.getWritableDatabase();
+    }
+    /* 查找数据库当中城市列表*/
+    public static List<String>queryAllCityName(){
+        Cursor cursor = database.query("info", null, null, null, null, null,null);
+        List<String>cityList = new ArrayList<>();
+        while (cursor.moveToNext()) {
+            String city = cursor.getString(cursor.getColumnIndex("city"));
+            cityList.add(city);
+        }
+        return cityList;
+    }
+    /* 根据城市名称，替换信息内容*/
+    public static int updateInfoByCity(String city,String content){
+        ContentValues values = new ContentValues();
+        values.put("content",content);
+        return database.update("info",values,"city=?",new String[]{city});
+    }
+    /* 新增一条城市记录*/
+    public static long addCityInfo(String city,String content){
+        ContentValues values = new ContentValues();
+        values.put("city",city);
+        values.put("content",content);
+        return database.insert("info",null,values);
+    }
+    /* 根据城市名，查询数据库当中的内容*/
+    public static String queryInfoByCity(String city){
+        Cursor cursor = database.query("info", null, "city=?", new String[]{city}, null, null, null);
+        if (cursor.getCount()>0) {
+            cursor.moveToFirst();
+            String content = cursor.getString(cursor.getColumnIndex("content"));
+            return content;
+        }
+        return null;
+    }
+
+    /* 存储城市天气要求最多存储5个城市的信息，一旦超过5个城市就不能存储了，获取目前已经存储的数量*/
+    public static int getCityCount(){
+        Cursor cursor = database.query("info", null, null, null, null, null, null);
+        int count = cursor.getCount();
+        return count;
+    }
+
+    /* 查询数据库当中的全部信息*/
+    public static List<DatabaseBean>queryAllInfo(){
+        Cursor cursor = database.query("info", null, null, null, null, null, null);
+        List<DatabaseBean>list = new ArrayList<>();
+        while (cursor.moveToNext()) {
+            int id = cursor.getInt(cursor.getColumnIndex("_id"));
+            String city = cursor.getString(cursor.getColumnIndex("city"));
+            String content = cursor.getString(cursor.getColumnIndex("content"));
+            DatabaseBean bean = new DatabaseBean(id, city, content);
+            list.add(bean);
+        }
+        return list;
+    }
+
+    /* 根据城市名称，删除这个城市在数据库当中的数据*/
+    public static int deleteInfoByCity(String city){
+        return database.delete("info","city=?",new String[]{city});
+    }
+
+    /* 删除表当中所有的数据信息*/
+    public static void deleteAllInfo(){
+        String sql = "delete from info";
+        database.execSQL(sql);
+    }
+}

students/net1814080903140/DatabaseBean.java

@@ -0,0 +1,40 @@
+package edu.hzuapps.androidlabs.net1814080903140;
+
+public class DatabaseBean {
+    private int _id;
+    private String city;
+    private String content;
+
+    public DatabaseBean() {
+    }
+
+    public DatabaseBean(int _id, String city, String content) {
+        this._id = _id;
+        this.city = city;
+        this.content = content;
+    }
+
+    public int get_id() {
+        return _id;
+    }
+
+    public void set_id(int _id) {
+        this._id = _id;
+    }
+
+    public String getCity() {
+        return city;
+    }
+
+    public void setCity(String city) {
+        this.city = city;
+    }
+
+    public String getContent() {
+        return content;
+    }
+
+    public void setContent(String content) {
+        this.content = content;
+    }
+}