我是 Android 和 Kotlin 的新手。任何人都可以帮我在 webView 中加载 URL 吗？我只想在应用程序打开时加载 URL 并查看网页。原文由 Ayan Chakraborty 发布，翻译遵循 CC BY-SA 4.0 许可协议

如何使用 Android Kotlin 在 WebView 中加载 URL？

1.activity_main.xml

 <?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.kotlinwebview.MainActivity">

<WebView
    android:id="@+id/webview"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:ignore="MissingConstraints"
    tools:layout_editor_absoluteX="8dp"
    tools:layout_editor_absoluteY="8dp" />

</android.support.constraint.ConstraintLayout>

2.MainActivity.kt

 class MainActivity : AppCompatActivity() {

    private lateinit var webView: WebView

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        webView = findViewById(R.id.webview)
        webView.settings.setJavaScriptEnabled(true)

        webView.webViewClient = object : WebViewClient() {
            override fun shouldOverrideUrlLoading(view: WebView?, url: String?): Boolean {
                view?.loadUrl(url)
                return true
            }
        }
        webView.loadUrl("https://www.google.co.in/")
    }
}

原文由 Ramesh sambu 发布，翻译遵循 CC BY-SA 4.0 许可协议

这是在 android webView 中加载网站的完整工作代码。只需从 android studio 创建一个新项目并使用以下代码加载 web 视图。只需更改要在 Web 视图中加载它的 URL。

它将在 webview 中加载一个网站
它将检查互联网连接的可用性
如果没有互联网，请用户从小吃店消息中启用 WiFi
加载进度，直到网站加载
如果在加载网站时出现问题，则处理错误
处理后退按钮按压案例
使用 toast 处理退出应用程序确认

活动主.xml：

 <?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/rootView"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <WebView
        android:id="@+id/webView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/infoTV"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity.kt：

 import android.annotation.SuppressLint
import android.content.Context
import android.content.Intent
import android.graphics.Bitmap
import android.net.ConnectivityManager
import android.net.NetworkCapabilities
import android.os.Bundle
import android.os.Handler
import android.os.Looper
import android.provider.Settings
import android.util.Log
import android.view.KeyEvent
import android.webkit.WebResourceError
import android.webkit.WebResourceRequest
import android.webkit.WebView
import android.webkit.WebViewClient
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import com.google.android.material.snackbar.Snackbar
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {

    private var progress: Progress? = null
    private var isLoaded: Boolean = false
    private var doubleBackToExitPressedOnce = false
    private var webURL = "https://www.geeklabs.co.in/" // Change it with your URL

    @SuppressLint("SetJavaScriptEnabled")
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        webView.settings.javaScriptEnabled = true
        if (!isOnline()) {
            showToast(getString(R.string.no_internet))
            infoTV.text = getString(R.string.no_internet)
            showNoNetSnackBar()
            return
        }
    }

    override fun onResume() {
        if (isOnline() && !isLoaded) loadWebView()
        super.onResume()
    }

    private fun loadWebView() {
        infoTV.text = ""
        webView.loadUrl(webURL)
        webView.webViewClient = object : WebViewClient() {
            override fun shouldOverrideUrlLoading(view: WebView?, request: WebResourceRequest?): Boolean {
                val url = request?.url.toString()
                view?.loadUrl(url)
                return super.shouldOverrideUrlLoading(view, request)
            }

            override fun onPageStarted(view: WebView?, url: String?, favicon: Bitmap?) {
                setProgressDialogVisibility(true)
                super.onPageStarted(view, url, favicon)
            }

            override fun onPageFinished(view: WebView?, url: String?) {
                isLoaded = true
                setProgressDialogVisibility(false)
                super.onPageFinished(view, url)
            }

            override fun onReceivedError(view: WebView, request: WebResourceRequest, error: WebResourceError) {
                isLoaded = false
                val errorMessage = "Got Error! $error"
                showToast(errorMessage)
                infoTV.text = errorMessage
                setProgressDialogVisibility(false)
                super.onReceivedError(view, request, error)
            }
        }
    }

    override fun onKeyDown(keyCode: Int, event: KeyEvent): Boolean {
        if (event.action == KeyEvent.ACTION_DOWN) {
            if (keyCode == KeyEvent.KEYCODE_BACK) {
                if (webView.canGoBack()) {
                    webView.goBack()
                } else {
                    showToastToExit()
                }
                return true
            }
        }
        return super.onKeyDown(keyCode, event)
    }

    private fun showToastToExit() {
        when {
            doubleBackToExitPressedOnce -> {
                onBackPressed()
            }
            else -> {
                doubleBackToExitPressedOnce = true
                showToast(getString(R.string.back_again_to_exit))
                Handler(Looper.myLooper()!!).postDelayed({ doubleBackToExitPressedOnce = false }, 2000)
            }
        }
    }

    private fun setProgressDialogVisibility(visible: Boolean) {
        if (visible) progress = Progress(this, R.string.please_wait, cancelable = true)
        progress?.apply { if (visible) show() else dismiss() }
    }

    private fun isOnline(): Boolean {
        val connectivityManager =
                getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
        val capabilities =
                connectivityManager.getNetworkCapabilities(connectivityManager.activeNetwork)
        if (capabilities != null) {
            when {
                capabilities.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR) -> {
                    Log.i("Internet", "NetworkCapabilities.TRANSPORT_CELLULAR")
                    return true
                }
                capabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI) -> {
                    Log.i("Internet", "NetworkCapabilities.TRANSPORT_WIFI")
                    return true
                }
                capabilities.hasTransport(NetworkCapabilities.TRANSPORT_ETHERNET) -> {
                    Log.i("Internet", "NetworkCapabilities.TRANSPORT_ETHERNET")
                    return true
                }
            }
        }
        return false
    }

    private fun showToast(message: String) {
        Toast.makeText(this, message, Toast.LENGTH_SHORT).show()
    }

    private fun showNoNetSnackBar() {
        val snack = Snackbar.make(rootView, getString(R.string.no_internet), Snackbar.LENGTH_INDEFINITE)
        snack.setAction(getString(R.string.settings)) {
            startActivity(Intent(Settings.ACTION_WIFI_SETTINGS))
        }
        snack.show()
    }
}

进度.kt：

 import android.app.AlertDialog
import android.app.Dialog
import android.content.Context
import android.view.LayoutInflater
import android.view.View
import android.widget.TextView
import androidx.annotation.StringRes

class Progress constructor(
    context: Context?,
    @StringRes private val titleRes: Int,
    cancelable: Boolean = false
) {

    private var view: View? = null
    private var builder: AlertDialog.Builder
    private var dialog: Dialog

    init {
        view = LayoutInflater.from(context).inflate(R.layout.progress, null)
        view?.findViewById<TextView>(R.id.text)?.setText(titleRes)
        builder = AlertDialog.Builder(context)
        builder.setView(view)
        dialog = builder.create()
        dialog.setCancelable(cancelable)
    }

    fun setProgressMessage(@StringRes titleRes: Int) {
        view?.findViewById<TextView>(R.id.text)?.setText(titleRes)
    }

    fun show() {
        dialog.show()
    }

    fun dismiss() {
        if (dialog.isShowing) {
            dialog.dismiss()
        }
    }

    fun setProgressDialogVisibility(isVisible: Boolean) {

    }
}

pregress.xml：

 <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/linearLayout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:gravity="center_vertical">

    <ProgressBar
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="16dp" />

    <TextView
        android:id="@+id/text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="@style/TextAppearance.AppCompat.SearchResult.Subtitle"
        tools:text="Loading" />

</LinearLayout>

清单.xml：

 <?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.geeklabs.webviewkotlin">

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

    <application
        android:allowBackup="true"
        android:fullBackupContent="false"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

字符串.xml：

 <resources>
    <string name="app_name">WebViewKotlin</string>
    <string name="please_wait">Please wait&#8230;</string>
    <string name="no_internet">No internet connection!</string>
    <string name="settings">Settings</string>
    <string name="back_again_to_exit">Please click BACK again to exit</string>
</resources>

构建.gradle：

 apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'

android {
    compileSdkVersion 30
    buildToolsVersion "30.0.0"

    defaultConfig {
        applicationId "com.geeklabs.webviewkotlin"
        minSdkVersion 23
        targetSdkVersion 30
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: "libs", include: ["*.jar"])
    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
    implementation 'androidx.core:core-ktx:1.3.1'
    implementation 'androidx.appcompat:appcompat:1.1.0'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    implementation 'com.google.android.material:material:1.1.0'
    testImplementation 'junit:junit:4.13'
    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'

}

这是 Git hub 中的完整工作代码。单击此处导航到 Git Hub

原文由 Shailendra Madda 发布，翻译遵循 CC BY-SA 4.0 许可协议

如何使用 Android Kotlin 在 WebView 中加载 URL？

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如何在Android POS机上实现H5项目脱机断网功能？

uniapp+安卓 预览本地doc等文件，大家都是怎么解决的？

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请问下，Android SDK 和 Android SDK Platform 的区别是什么？

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