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使用 Room 实现
效果图示例：
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定义数据实体类：
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| @Entity(tableName = "Account")
data class AccountBean(
@PrimaryKey(autoGenerate = true) var accountId: Int = 0,
@ColumnInfo(name = "_loginAccount") var loginAccount: String,
@ColumnInfo(name = "_loginPassword") var loginPassword: String,
@ColumnInfo(name = "_loginIpAddress") var loginIpAddress:String
)
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定义数据库访问对象：
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| @Dao
interface AccountDao {
@Insert
fun insertAccount(accountBean: AccountBean)
@Query("select * from Account")
fun loadAccountList():List<AccountBean>
@Query("select * from Account where _loginAccount == :loginAccount")
fun findAccountByLoginAccount(loginAccount:String):AccountBean?
@Update
fun updateAccountBean(accountBean: AccountBean)
@Delete
fun deleteAccount(accountBean: AccountBean)
}
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创建 Database：
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|
@Database(entities = [AccountBean::class], version = 2)
abstract class AccountDatabase : RoomDatabase() {
abstract val accountDao:AccountDao
companion object{
val accountDb : AccountDatabase by lazy(mode = LazyThreadSafetyMode.SYNCHRONIZED) {
Room.databaseBuilder(MyApplication.applicationContext(),AccountDatabase::class.java,"account.db")
.addMigrations(MIGRATION_1_2)
.build()
}
}
}
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数据库升级：
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| val MIGRATION_1_2 = object : Migration(1, 2) {
override fun migrate(database: SupportSQLiteDatabase) {
database.execSQL("ALTER TABLE Account ADD COLUMN _loginIpAddress TEXT NOT NULL DEFAULT ''")
}
}
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Activity：
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| class AccountActivity : BaseActivity<ActivityAccountBinding>() {
private val TAG = "TAG_AccountActivity"
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
initView()
}
private fun initView() {
mViewBinding.btnSave.setOnClickListener {
thread {
val account =
AccountDatabase.accountDb.accountDao.findAccountByLoginAccount(getLoginAccount())
account?.let {
Log.d(TAG, "账号：${getLoginAccount()} 已经存在了")
if (it.loginPassword == getLoginPassword()) {
Log.d(TAG, "密码相同不用操作")
} else {
Log.d(TAG, "密码不同更新密码")
it.loginPassword = getLoginPassword()
AccountDatabase.accountDb.accountDao.updateAccountBean(it)
}
} ?: let {
Log.d(TAG, "账号：${getLoginAccount()} 不存在")
val accounBean = AccountBean(
loginAccount = getLoginAccount(),
loginPassword = getLoginPassword(),
loginIpAddress = "..."
)
AccountDatabase.accountDb.accountDao.insertAccount(accounBean)
Log.d(TAG, "账号：${getLoginAccount()} 已保存")
}
}
}
mViewBinding.btnQuery.setOnClickListener {
thread {
val list = AccountDatabase.accountDb.accountDao.loadAccountList()
list.let {
runOnUiThread {
mViewBinding.tvLoginResult.text = ""
for (i in it.indices) {
mViewBinding.tvLoginResult.append(" id：${it[i].accountId}")
mViewBinding.tvLoginResult.append(" 账号：${it[i].loginAccount}")
mViewBinding.tvLoginResult.append(" 密码：${it[i].loginPassword}\n")
}
}
}
}
}
mViewBinding.btnDelete.setOnClickListener {
thread {
val list = AccountDatabase.accountDb.accountDao.loadAccountList()
list.let {
for (i in it.indices) {
AccountDatabase.accountDb.accountDao.deleteAccount(it[i])
}
}
}
}
}
private fun getLoginPassword(): String {
return mViewBinding.etLoginPassword.text.toString()
}
private fun getLoginAccount(): String {
return mViewBinding.etLoginAccount.text.toString()
}
override fun getViewBinding(): ActivityAccountBinding {
return ActivityAccountBinding.inflate(layoutInflater)
}
companion object {
fun actionStart(context: Context) {
val intent = Intent(context, AccountActivity::class.java)
context.startActivity(intent)
}
}
}
|
activity_account.xml1
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| <?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto">
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/et_login_account"
android:hint="请输入登录账号"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"/>
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/et_login_password"
android:hint="请输入登录密码"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@id/et_login_account" />
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/btn_save"
android:text="保存"
app:layout_constraintTop_toBottomOf="@id/et_login_password"
app:layout_constraintStart_toStartOf="parent"/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/btn_query"
android:text="查询"
app:layout_constraintTop_toBottomOf="@id/btn_save"
app:layout_constraintStart_toStartOf="parent"/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/btn_delete"
android:text="删除"
app:layout_constraintTop_toBottomOf="@id/btn_query"
app:layout_constraintStart_toStartOf="parent"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/tv_login_result"
app:layout_constraintTop_toBottomOf="@id/btn_delete"
app:layout_constraintStart_toStartOf="parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>
|
备注
参考资料：
《Android Jetpack开发 原理解析与应用实战》
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