兩種思路實(shí)現(xiàn)sqlite字節(jié)數(shù)組的存放操作：
- 將字節(jié)數(shù)組轉(zhuǎn)為string類型存放，這種方式比較容易理解
Base64.encodeToString(rawData, Base64.DEFAULT) byte[]轉(zhuǎn)為string
Base64.decode(printData.getBytes(), Base64.DEFAULT) string轉(zhuǎn)為byte[]
- 指定字段的數(shù)據(jù)類型為blob
BLOB - The value is a blob of data, stored exactly as it was input.（BLOB數(shù)據(jù)不做任何轉(zhuǎn)換，以輸入形式存儲(chǔ)。）
需要注意的是，移動(dòng)端數(shù)據(jù)庫的設(shè)計(jì)，比較好的實(shí)現(xiàn)方式是優(yōu)先可讀性
在實(shí)際的項(xiàng)目中遇到的是java對(duì)象的序列化和保存，第一反應(yīng)就是先序列化成字節(jié)流，然后保存該字節(jié)流。調(diào)試過程中發(fā)現(xiàn)數(shù)據(jù)庫完全不可讀，很是耽誤事。最后決定將對(duì)象轉(zhuǎn)成json字符串，保存字符串就好多了。
一個(gè)android順序安裝APK管理器的設(shè)計(jì)與實(shí)現(xiàn)
class PackageInstallDatabaseHelper(context: Context?, name: String,
factory: SQLiteDatabase.CursorFactory?,
version: Int) :
SQLiteOpenHelper(context, name, factory, version) {
private lateinit var database: SQLiteDatabase
fun initHelp() {
database = writableDatabase
}
fun createOneInstallTask(pkg: PackageInformation?) {
if (pkg == null) {
return
}
val installedVid = PackageUtil.getVersion(pkg.packageName)
if (TextUtils.isEmpty(pkg.packageName)
|| pkg.version < installedVid
|| TextUtils.isEmpty(pkg.filePath)) {
installedListener?.installedResult(pkg, false)
LogUtil.d(TAG, "添加一個(gè)安裝任務(wù)失敗，已安裝版本$installedVid;pdk$pkg")
return
}
LogUtil.d(TAG, "添加一個(gè)安裝任務(wù)$pkg")
var alreadyInTask = false
// 如果已經(jīng)存在記錄，就修改記錄，否則添加一條記錄
val sql = "select * from package_version where packageName = ?"
val cursor = database.rawQuery(sql, arrayOf(pkg.packageName))
while (cursor.moveToNext()) {
val vid = cursor.getInt(cursor.getColumnIndex("vid"))
if (vid == pkg.version) {
alreadyInTask = true
}
}
cursor?.close()
// 插入任務(wù)隊(duì)列中
if (alreadyInTask) {
LogUtil.e(TAG, "安裝任務(wù)已存在，同一個(gè)版本應(yīng)只安裝一次?。?！調(diào)整安裝狀態(tài)與path，$pkg")
val sql = "update package_version set path = ?, installResult = 0 where packageName = ? and vid = ?"
database.execSQL(sql, arrayOf(pkg.filePath, pkg.packageName, pkg.version.toString()))
} else {
LogUtil.d(TAG, "從未安裝過，$pkg")
val sql = "insert into package_version(packageName, vid, path) values(?,?,?)"
database.execSQL(sql, arrayOf(pkg.packageName, pkg.version.toString(), pkg.filePath))
}
}
fun isInstallingOrWaiting(pkg: PackageInformation?): Boolean {
if (pkg == null)
return false
val installedVid = PackageUtil.getVersion(pkg.packageName)
if (TextUtils.isEmpty(pkg.packageName) || pkg.version < installedVid) {
LogUtil.d(TAG, "檢測(cè)一個(gè)安裝任務(wù)失敗已安裝版本$installedVid;pdk$pkg")
return false
}
val sql = "select * from package_version where packageName = ? and vid = ? and installResult = 0"
val cursor = database.rawQuery(sql, arrayOf(pkg.packageName, pkg.version.toString()))
val b = cursor.moveToNext()
cursor?.close()
LogUtil.d(TAG, "檢測(cè)一個(gè)安裝任務(wù)$b,$pkg")
return b
}
fun getInstalledTime(pkgName: String?): String? {
if (TextUtils.isEmpty(pkgName)) {
LogUtil.d(TAG, "獲取安裝時(shí)間失敗$pkgName")
return null
}
var installTime: String? = null
// 查詢本機(jī)已安裝的apk對(duì)應(yīng)的版本號(hào)
val vid = PackageUtil.getVersion(pkgName)
val sql = "select * from package_version where packageName = ? and vid = ? and installResult = 1 limit 1"
val cursor = database.rawQuery(sql, arrayOf(pkgName, vid.toString()))
while (cursor.moveToNext()) {
installTime = cursor.getString(cursor.getColumnIndex("installTime"))
}
cursor?.close()
LogUtil.d(TAG, "獲取安裝時(shí)間" + installTime)
return installTime
}
private fun getTaskFromQueue(): PackageInformation? {
var result: PackageInformation? = null
val sql = "select * from package_version where installResult = 0 limit 1"
val cursor = database.rawQuery(sql, null)
while (cursor.moveToNext()) {
val packageName = cursor.getString(cursor.getColumnIndex("packageName"));
val vid = cursor.getInt(cursor.getColumnIndex("vid"));
val path = cursor.getString(cursor.getColumnIndex("path"))
result = PackageInformation(packageName, vid, path)
}
cursor?.close()
return result
}
private fun saveLogTaskExecuted(pck: PackageInformation) {
var installResult = "2"
val vid = PackageUtil.getVersion(pck.packageName)
if (vid >= pck.version) {
installResult = "1"
}
val installTime = (System.currentTimeMillis() / 1000).toString()
val sql = "update package_version set installResult = ?, installTime = ? where packageName = ? and vid = ?"
database.execSQL(sql, arrayOf(installResult, installTime, pck.packageName, pck.version.toString()))
}
override fun onOpen(db: SQLiteDatabase?) {
db?.execSQL(CREATE_TABLE_STR)
super.onOpen(db)
}
override fun onCreate(db: SQLiteDatabase?) {
db?.execSQL(CREATE_TABLE_STR)
}
override fun onUpgrade(db: SQLiteDatabase?, oldVersion: Int, newVersion: Int) {
// 把舊數(shù)據(jù)庫里的數(shù)據(jù)遷移到新數(shù)據(jù)庫里
// 本身就是第一版，不存在舊版本
}
companion object {
// installResult 0未安裝，1安裝成功，2安裝失敗
private val CREATE_TABLE_STR = // "DROP TABLE IF EXISTS package_version;" +
"CREATE TABLE IF NOT EXISTS package_version(" +
"id integer primary key autoincrement, " +
"packageName text, " +
"vid integer integer default 0, " +
"path text," +
"installResult integer default 0, " +
"installTime text)"
}
}
