我正在构建消息应用程序，我的消息和号码显示在列表视图中，但我不确定如何将列表视图数据传递给SQLite数据库？这是我的列表视图代码看起来像但不确定如何将数据传递到数据库。
package com.example.sunny.messager;
import java.util.ArrayList;
import android.net.Uri;
import android.os.Bundle;
import android.app.Activity;
import android.database.Cursor;
import android.view.Menu;
import android.widget.ArrayAdapter;
import android.widget.ListView;
public class ListActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list);
ListView lv=(ListView)findViewById(R.id.SmsList);
if(fetchInbox()!=null){
ArrayAdapter<String> adapter=new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1,fetchInbox());
lv.setAdapter(adapter);
}
}
public ArrayList<String> fetchInbox(){
ArrayList<String> sms=new ArrayList<String>();
Uri uriSms=Uri.parse("content://sms/");
Cursor cursor=getContentResolver().query(uriSms, new String[]{"_id","address","date","body"}, null, null, null);
cursor.moveToFirst();
while(cursor.moveToNext()){
String address=cursor.getString(1);
String body=cursor.getString(3);
sms.add("Number: " +address+"\n Message: " +body);
}
return sms;
}
}
答案 0 :(得分：0)
您需要使用这些类SQLiteDatabase和SQLiteOpenHelper。
现在让我们首先在表结构部分启动代码 - 在Android中创建表。我们将创建一个文件名SMSData.java，此文件中的代码将如下所示
package com.example.sqlitedb;
public class SMSData {
// Labels table name
public static final String TABLE = "SMSData";
// Labels Table Columns names
public static final String KEY_ID = "id";
public static final String KEY_number = "number";
public static final String KEY_message= "message";
// property help us to keep data
public int SMSData_ID;
public int number;
public String message;
}
我们将创建一个类并将其命名为DBHelper.java，此文件中的代码将如下所示，以便逐行理解代码我将代码放在注释中。
package com.example.sqlitedb;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DBHelper extends SQLiteOpenHelper {
//version number to upgrade database version
//each time if you Add, Edit table, you need to change the
//version number.
private static final int DATABASE_VERSION = 4;
// Database Name
private static final String DATABASE_NAME = "crud.db";
public DBHelper(Context context ) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
//All necessary tables you like to create will create here
String CREATE_TABLE_SMSDATA= "CREATE TABLE " + SMSData.TABLE + "("
+ SMSData.KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT ,"
+ SMSData.KEY_number+ " INTEGER, "
+ SMSData.KEY_message+ " TEXT )";
db.execSQL(CREATE_TABLE_SMSDATA);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed, all data will be gone!!!
db.execSQL("DROP TABLE IF EXISTS " + SMSData.TABLE);
// Create tables again
onCreate(db);
}
}
通过以上2个步骤，将在应用程序启动时创建SMSData表，现在我们可以编写CRUD函数了！创建SMSDataRepo.java，此类的目的是在SMSData表上执行CRUD。此文件中的代码如下所示。
package com.example.sqlitedb;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import java.util.ArrayList;
import java.util.HashMap;
public class SMSDataRepo {
private DBHelper dbHelper;
public SMSDataRepo(Context context) {
dbHelper = new DBHelper(context);
}
public int insert(SMSData sMSData) {
//Open connection to write data
SQLiteDatabase db = dbHelper.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(SMSData.KEY_number, sMSData.number);
values.put(SMSData.KEY_message,sMSData.message);
// Inserting Row
long SMSData_Id = db.insert(SMSData.TABLE, null, values);
db.close(); // Closing database connection
return (int) SMSData_Id;
}
public void delete(int SMSData_Id) {
SQLiteDatabase db = dbHelper.getWritableDatabase();
// It's a good practice to use parameter ?, instead of concatenate string
db.delete(SMSData.TABLE, SMSData.KEY_ID + "= ?", new String[] { String.valueOf(SMSData_Id) });
db.close(); // Closing database connection
}
public void update(SMSData sMSData) {
SQLiteDatabase db = dbHelper.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(SMSData.KEY_number, sMSData.number);
values.put(SMSData.KEY_message,sMSData.message);
// It's a good practice to use parameter ?, instead of concatenate string
db.update(SMSData.TABLE, values, SMSData.KEY_ID + "= ?", new String[] { String.valueOf(SMSData.SMSData_ID) });
db.close(); // Closing database connection
}
public ArrayList<HashMap<String, String>> getSMSDataList() {
//Open connection to read only
SQLiteDatabase db = dbHelper.getReadableDatabase();
String selectQuery = "SELECT " +
SMSData.KEY_ID + "," +
SMSData.KEY_number+
SMSData.KEY_message+ "," +
" FROM " + SMSData.TABLE;
//SMSData sMSData= new SMSData();
ArrayList<HashMap<String, String>> sMSDataList = new ArrayList<HashMap<String, String>>();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
HashMap<String, String> sMSData= new HashMap<String, String>();
sMSData.put("number", cursor.getString(cursor.getColumnIndex(SMSData.KEY_number)));
sMSData.put("message", cursor.getString(cursor.getColumnIndex(SMSData.KEY_message)));
sMSDataList.add(sMSData);
} while (cursor.moveToNext());
}
cursor.close();
db.close();
return sMSDataList;
}
public SMSData getSMSDataById(int Id){
SQLiteDatabase db = dbHelper.getReadableDatabase();
String selectQuery = "SELECT " +
SMSData.KEY_ID + "," +
SMSData.KEY_number + "," +
SMSData.KEY_message +
" FROM " + SMSData.TABLE
+ " WHERE " +
SMSData.KEY_ID + "=?";// It's a good practice to use parameter ?, instead of concatenate string
int iCount =0;
SMSData sMSData= new SMSData();
Cursor cursor = db.rawQuery(selectQuery, new String[] { String.valueOf(Id) } );
if (cursor.moveToFirst()) {
do {
sMSData.SMSData_ID =cursor.getInt(cursor.getColumnIndex(SMSData.KEY_ID));
sMSData.number=cursor.getInt(cursor.getColumnIndex(SMSData.KEY_number));
sMSData.message=cursor.getString(cursor.getColumnIndex(SMSData.KEY_message));
} while (cursor.moveToNext());
}
cursor.close();
db.close();
return sMSData;
}
}