在Android Kotlin中使用WebView和数据库的解决方法如下:
implementation 'androidx.webkit:webkit:1.4.0'
implementation 'androidx.room:room-runtime:2.3.0'
kapt 'androidx.room:room-compiler:2.3.0'
import android.annotation.SuppressLint
import android.os.Bundle
import android.webkit.WebChromeClient
import android.webkit.WebView
import android.webkit.WebViewClient
import androidx.appcompat.app.AppCompatActivity
class WebViewActivity : AppCompatActivity() {
private lateinit var webView: WebView
@SuppressLint("SetJavaScriptEnabled")
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
webView = WebView(this)
setContentView(webView)
webView.settings.javaScriptEnabled = true
webView.webChromeClient = WebChromeClient()
webView.webViewClient = WebViewClient()
}
override fun onBackPressed() {
if (webView.canGoBack()) {
webView.goBack()
} else {
super.onBackPressed()
}
}
}
import androidx.room.Entity
import androidx.room.PrimaryKey
@Entity(tableName = "web_pages")
data class WebPage(
@PrimaryKey val id: Int,
val title: String,
val url: String
)
import androidx.room.Dao
import androidx.room.Insert
import androidx.room.OnConflictStrategy
import androidx.room.Query
@Dao
interface WebPageDao {
@Query("SELECT * FROM web_pages")
fun getAllWebPages(): List
@Insert(onConflict = OnConflictStrategy.REPLACE)
fun insertWebPage(webPage: WebPage)
@Query("DELETE FROM web_pages WHERE id = :id")
fun deleteWebPage(id: Int)
}
import android.content.Context
import androidx.room.Database
import androidx.room.Room
import androidx.room.RoomDatabase
@Database(entities = [WebPage::class], version = 1)
abstract class WebPageDatabase : RoomDatabase() {
abstract fun webPageDao(): WebPageDao
companion object {
@Volatile
private var INSTANCE: WebPageDatabase? = null
fun getDatabase(context: Context): WebPageDatabase {
val tempInstance = INSTANCE
if (tempInstance != null) {
return tempInstance
}
synchronized(this) {
val instance = Room.databaseBuilder(
context.applicationContext,
WebPageDatabase::class.java,
"web_page_database"
).build()
INSTANCE = instance
return instance
}
}
}
}
import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
class WebViewActivity : AppCompatActivity() {
private lateinit var webView: WebView
private lateinit var webPageDao: WebPageDao
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
webView = WebView(this)
setContentView(webView)
val database = WebPageDatabase.getDatabase(this)
webPageDao = database.webPageDao()
}
private fun saveWebPage(title: String, url: String) {
val webPage = WebPage(1, title, url)
webPageDao.insertWebPage(webPage)
}
private fun deleteWebPage(id: Int) {
webPageDao.deleteWebPage(id)
}
}
这样,你就可以在WebViewActivity中使用WebView和数据库了。你可以调用saveWebPage方法将网页保存到数据库中,调用deleteWebPage方法从数据库中删除网页。当然,你可以根据自己的需求对代码进行修改和扩展。