安卓编程，存储数据，特别是结果比较规则的数据，使用数据库来存储是比较合适的，常用的数据库有原生的sqlite和第三方GreenDao。
下面以一个存储录音的信息为例，展示两种数据库的用法。
sqlite
- 录音信息Bean:RecorderInfo
public class RecorderInfo{
private Long id;
private String name;
private String dater;
private String type;
private String length;
private String size;
private String r1;
public RecorderInfo() {
}
public Long getId() {
return this.id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return this.name;
}
public void setName(String name) {
this.name = name;
}
public String getDater() {
return this.dater;
}
public void setDater(String dater) {
this.dater = dater;
}
public String getType() {
return this.type;
}
public void setType(String type) {
this.type = type;
}
public String getLength() {
return this.length;
}
public void setLength(String length) {
this.length = length;
}
public String getSize() {
return this.size;
}
public void setSize(String size) {
this.size = size;
}
public String getR1() {
return this.r1;
}
public void setR1(String r1) {
this.r1 = r1;
}
- 创建数据库的版本、表、字段：DBConstant
public class DBConstant {
public static final String DATABASE_NAME = "db";
public static final int DB_VERSION = 1;
public static final String TABLE_NAME = "recorder_info";
public static final String COLUMN_ID = "recorder_id";
public static final String COLUMN_RECORDER_DATE = "recorder_date";
public static final String COLUMN_RECORDER_TYPE = "recorder_type";
public static final String COLUMN_RECORDER_TITLE = "recorder_title";
public static final String COLUMN_RECORDER_DURATION = "recorder_duration";
public static final String COLUMN_RECORDER_SIZE = "recorder_size";
public static final String COLUMN_R1 = "r1";
}
- 创建数据库的管理工具类：DBHelper
import android.content.ContentValues;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
import com.xxxx.soundrecorder.base.DBConstant;
public class DBHelper extends SQLiteOpenHelper {
private static final String TAG=DBHelper.class.getSimpleName();
public DBHelper(Context context) {
super(context, DBConstant.DATABASE_NAME, null, DBConstant.DB_VERSION);
}
public DBHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
super(context, name, factory, version);
}
@Override
public void onCreate(SQLiteDatabase db) {
createCityInfoTab(db);
//模拟插入数据
insertDefault(db)
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
/**
* 创建录音信息表
*
* @param db
*/
private void createCityInfoTab(SQLiteDatabase db) {
Log.d(TAG,"创建录音信息表");
String strSQL = "create table "
+ DBConstant.TABLE_NAME
+ "(" + DBConstant.COLUMN_ID + " integer primary key autoincrement,"
+ DBConstant.COLUMN_RECORDER_DATA + " varchar(150), "
+ DBConstant.COLUMN_RECORDER_TITLE + " varchar(10), "
+ DBConstant.COLUMN_RECORDER_TYPE + " varchar(100), "
+ DBConstant.COLUMN_RECORDER_SIZE + " varchar(100), "
+ DBConstant.COLUMN_RECORDER_DURATION+ " varchar(100), "
+ DBConstant.COLUMN_R1 + " varchar(50))";
db.execSQL(strSQL);
}
private void insertDefault(SQLiteDatabase db){
ContentValues values = new ContentValues();
values.put(DBConstant.COLUMN_RECORDER_DATE, "2018/5/5");
values.put(DBConstant.COLUMN_RECORDER_TITLE, "recorder12515");
values.put(DBConstant.COLUMN_RECORDER_TYPE, "3gp");
values.put(DBConstant.COLUMN_RECORDER_DURATION, "12");
db.insert(DBConstant.TABLE_NAME, null, values);
}
}
- 数据的操作工具：DBUtil
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.util.Log;
import com.xxxx.soundrecorder.base.DBConstant;
import com.xxxx.soundrecorder.bean.RecorderInfo;
import java.util.ArrayList;
import java.util.List;
public class DBUtil {
private final String TAG = DBUtil.class.getSimpleName();
private DBHelper dbHelper = null;
private static DBUtil instance = null;
public static synchronized DBUtil getInstance(Context context) {
if (instance == null) {
instance = new DBUtil(context);
}
return instance;
}
private DBUtil(Context context) {
dbHelper = new DBHelper(context);
}
/**
* 查询所有录音
*
* @return 所有数据
*/
public List queryAllRecords() {
List cityInfoModels = new ArrayList<>();
SQLiteDatabase db = null;
Cursor cursor = null;
try {
db = dbHelper.getReadableDatabase();
cursor = db.query(DBConstant.TABLE_NAME, new String[]{"*"}, null, null, null, null, null);
if (cursor != null) {
while (cursor.moveToNext()) {
long id = cursor.getInt(cursor.getColumnIndex(DBConstant.COLUMN_ID));
String fileData = cursor.getString(cursor.getColumnIndex(DBConstant.COLUMN_RECORDER_DATE));
String fileDate = cursor.getString(cursor.getColumnIndex(DBConstant.COLUMN_RECORDER_TITLE));
String fileType = cursor.getString(cursor.getColumnIndex(DBConstant.COLUMN_RECORDER_TYPE));
String fileSize = cursor.getString(cursor.getColumnIndex(DBConstant.COLUMN_RECORDER_SIZE));
String fileLength = cursor.getString(cursor.getColumnIndex(DBConstant.COLUMN_RECORDER_DURATION));
String r1 = cursor.getString(cursor.getColumnIndex(DBConstant.COLUMN_R1));
RecorderInfo recorderInfo = new RecorderInfo();
recorderInfo.setId(id);
recorderInfo.setName(fileData);
recorderInfo.setDater(fileDate);
recorderInfo.setSize(fileSize);
recorderInfo.setType(fileType);
recorderInfo.setLength(fileLength);
recorderInfo.setR1(r1);
cityInfoModels.add(recorderInfo);
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (cursor != null) {
cursor.close();
}
if (db != null) {
db.close();
}
}
return cityInfoModels;
}
/**
* 插入录音
*
* @param recorderInfo 录音
* @return 操作成功与否
*/
public synchronized boolean insertRecord(RecorderInfo recorderInfo) {
boolean isSuccess = false;
if (recorderInfo == null) {
return isSuccess;
}
SQLiteDatabase db = null;
try {
db = dbHelper.getWritableDatabase();
//开启事务
db.beginTransaction();
ContentValues values = new ContentValues();
values.put(DBConstant.COLUMN_RECORDER_DATE, recorderInfo.getName());
values.put(DBConstant.COLUMN_RECORDER_TITLE, recorderInfo.getDater());
values.put(DBConstant.COLUMN_RECORDER_TYPE, recorderInfo.getType());
values.put(DBConstant.COLUMN_RECORDER_SIZE, recorderInfo.getSize());
values.put(DBConstant.COLUMN_RECORDER_DURATION, recorderInfo.getLength());
long no = db.insert(DBConstant.TABLE_NAME, null, values);
if (no > 0) {
isSuccess = true;
}
db.setTransactionSuccessful();
} catch (Exception e) {
e.printStackTrace();
} finally {
if (db != null) {
db.endTransaction();
db.close();
}
}
return isSuccess;
}
/**
* 根据录音ID,删除文件
*
* @param id 录音ID
* @return 操作成功与否
*/
public synchronized boolean deleteRecord(int id) {
boolean isSuccess = false;
SQLiteDatabase db = null;
try {
db = dbHelper.getWritableDatabase();
db.beginTransaction();
int no = db.delete(DBConstant.TABLE_NAME, " " + DBConstant.COLUMN_ID + "=? ", new String[]{id + ""});
if (no > 0) {
isSuccess = true;
}
db.setTransactionSuccessful();
} catch (Exception e) {
Log.e(TAG, e.getMessage());
} finally {
if (db != null) {
db.endTransaction();
db.close();
}
}
return isSuccess;
}
/**
* 根据录音名称，删除文件
*
* @param fileName 录音名称
* @return 操作成功与否
*/
public synchronized boolean deleteRecordByName(String fileName) {
Log.i(TAG, "deleteRecorderByName=" + fileName);
boolean isSuccess = false;
SQLiteDatabase db = null;
try {
db = dbHelper.getWritableDatabase();
db.beginTransaction();
int no = db.delete(DBConstant.TABLE_NAME, " " + DBConstant.COLUMN_RECORDER_DATE + "=? ", new String[]{fileName + ""});
if (no > 0) {
isSuccess = true;
}
db.setTransactionSuccessful();
} catch (Exception e) {
Log.e(TAG, e.getMessage());
} finally {
if (db != null) {
db.endTransaction();
db.close();
}
}
return isSuccess;
}
/**
* 根据录音ID,更新录音名称
*
* @param id 录音ID
* @param newFileName 录音名称
* @returnid 操作成功与否
*/
public synchronized boolean updateRecordById(long id, String newFileName) {
Log.i(TAG, "deleteRecorderByName=" + id + ",newFileName=" + newFileName);
boolean isSuccess = false;
SQLiteDatabase db = null;
try {
db = dbHelper.getWritableDatabase();
db.beginTransaction();
ContentValues values = new ContentValues();
values.put(DBConstant.COLUMN_RECORDER_DATE, newFileName);
// db.update("tablename", values, "name=?", new String[]{"xiadong"});
//db.update("tablename",values,"name=? AND age=?",new Object{"xiadong", 20});
db.update(DBConstant.TABLE_NAME, values, DBConstant.COLUMN_ID + "=?", new String[]{id + ""});
isSuccess = true;
db.setTransactionSuccessful();
} catch (Exception e) {
Log.e(TAG, e.getMessage());
} finally {
if (db != null) {
db.endTransaction();
db.close();
}
}
return isSuccess;
}
}
好了。上面就是sqlite的基本用法。greendao的有时间整理在写....