WebView optimization and code refactoring

sakusaku3939 · sakusaku3939 · commit 50a00710ae66 · 2025-06-07T20:38:00.000+09:00
diff --git a/app/src/main/java/com/example/deeplviewer/activity/FloatingTextSelection.kt b/app/src/main/java/com/example/deeplviewer/activity/FloatingTextSelection.kt
@@ -9,8 +9,11 @@ import android.os.Handler
 import android.os.Looper
 import android.view.View
 import android.view.animation.AlphaAnimation
+import android.webkit.WebView
 import androidx.appcompat.app.AppCompatActivity
 import com.example.deeplviewer.R
+import com.example.deeplviewer.config.WebViewConfig
+import com.example.deeplviewer.helper.WebViewUrlHelper
 import com.example.deeplviewer.webview.MyWebViewClient
 import com.example.deeplviewer.webview.NestedScrollWebView
 import com.example.deeplviewer.webview.WebAppInterface
@@ -19,6 +22,9 @@ import com.google.android.material.bottomsheet.BottomSheetDialog
 
 
 class FloatingTextSelection : AppCompatActivity() {
+    private lateinit var webView: WebView
+    private lateinit var webViewClient: MyWebViewClient
+    private lateinit var layout: View
 
     private val startUrl by lazy {
         val urlParam = getSharedPreferences("config", Context.MODE_PRIVATE).getString(
@@ -66,6 +72,9 @@ class FloatingTextSelection : AppCompatActivity() {
         overridePendingTransition(0, 0)
     }
 
+    /**
+     * Launches the DeepL WebView in fullscreen mode with the selected text
+     */
     private fun launchFullscreen(initialText: String) {
         val intent = Intent(this, MainActivity::class.java)
         intent.putExtra("FLOATING_TEXT", initialText)
@@ -75,58 +84,85 @@ class FloatingTextSelection : AppCompatActivity() {
         finish()
     }
 
-    @SuppressLint("SetJavaScriptEnabled", "RestrictedApi", "VisibleForTests")
+    /**
+     * Launches a popup with the DeepL WebView and the selected text
+     */
     private fun launchPopup(initialText: String) {
-        val layout = layoutInflater.inflate(R.layout.popup_layout, null)
-        val webView = layout.findViewById<NestedScrollWebView>(R.id.webview)
+        initializeWebView()
+        setupWebViewClient()
 
-        webView.settings.javaScriptEnabled = true
-        webView.settings.domStorageEnabled = true
+        // Add JavaScript interface for communication
+        webView.addJavascriptInterface(WebAppInterface(this), "Android")
+
+        webViewClient.loadFinishedListener = {
+            setWebViewHeight()
+            showWebViewWithAnimation()
+        }
+
+        showBottomSheetDialog()
+
+        // Load the initial URL
+        val targetUrl = WebViewUrlHelper.buildUrl(startUrl, initialText)
+        webView.loadUrl(targetUrl)
+    }
+
+    /**
+     * Initializes the WebView
+     */
+    private fun initializeWebView() {
+        layout = layoutInflater.inflate(R.layout.popup_layout, null)
+        webView = layout.findViewById<NestedScrollWebView>(R.id.webview)
+
+        WebViewConfig.applyBasicSettings(webView)
+    }
 
-        val webViewClient = MyWebViewClient(this)
+    /**
+     * Sets up the WebViewClient
+     */
+    private fun setupWebViewClient() {
+        webViewClient = MyWebViewClient(this)
         webView.webViewClient = webViewClient
-        webView.addJavascriptInterface(WebAppInterface(this), "Android")
+    }
 
+    /**
+     * Shows the BottomSheetDialog with the WebView
+     */
+    @SuppressLint("RestrictedApi", "VisibleForTests")
+    private fun showBottomSheetDialog() {
         val dialog = BottomSheetDialog(this)
         dialog.setContentView(layout)
         dialog.setOnDismissListener { finish() }
         dialog.behavior.disableShapeAnimations()
         dialog.show()
+    }
 
-        webViewClient.loadFinishedListener = {
-            // wait a bit, cause the WebView will change it's height multiple times caused by some lazy-loaded elements
-            Handler(Looper.getMainLooper()).postDelayed({
-                // Get the screen height and set the WebView height to 70% of the screen height
-                val displayMetrics = resources.displayMetrics
-                val screenHeight = displayMetrics.heightPixels
-                val webViewHeight = (screenHeight * 0.7).toInt()
-
-                val layoutParams = webView.layoutParams
-                layoutParams.height = webViewHeight
-                webView.layoutParams = layoutParams
-
-                webView.measure(
-                    View.MeasureSpec.makeMeasureSpec(webView.width, View.MeasureSpec.EXACTLY),
-                    View.MeasureSpec.makeMeasureSpec(webViewHeight, View.MeasureSpec.EXACTLY)
-                )
-                webView.layout(0, 0, webView.width, webViewHeight)
-
-                // Fade in the WebView and hide the shimmer effect
-                val animation = AlphaAnimation(0.0F, 1.0F)
-                animation.duration = 250
-                webView.visibility = View.VISIBLE
-                webView.startAnimation(animation)
-                layout.findViewById<ShimmerFrameLayout>(R.id.shimmer_view_container).hideShimmer()
-            }, 750)
-        }
-
-        webView.loadUrl(
-            startUrl + Uri.encode(
-                initialText.replace(
-                    "/",
-                    "\\/"
-                )
-            )
+    /**
+     * Sets the height of the WebView to 70% of the screen height
+     */
+    private fun setWebViewHeight() {
+        val displayMetrics = resources.displayMetrics
+        val screenHeight = displayMetrics.heightPixels
+        val webViewHeight = (screenHeight * 0.7).toInt()
+
+        val layoutParams = webView.layoutParams
+        layoutParams.height = webViewHeight
+        webView.layoutParams = layoutParams
+
+        webView.measure(
+            View.MeasureSpec.makeMeasureSpec(webView.width, View.MeasureSpec.EXACTLY),
+            View.MeasureSpec.makeMeasureSpec(webViewHeight, View.MeasureSpec.EXACTLY)
         )
+        webView.layout(0, 0, webView.width, webViewHeight)
+    }
+
+    /**
+     * Shows the WebView with a fade-in animation
+     */
+    private fun showWebViewWithAnimation() {
+        val animation = AlphaAnimation(0.0F, 1.0F)
+        animation.duration = 250
+        webView.visibility = View.VISIBLE
+        webView.startAnimation(animation)
+        layout.findViewById<ShimmerFrameLayout>(R.id.shimmer_view_container).hideShimmer()
     }
 }
diff --git a/app/src/main/java/com/example/deeplviewer/activity/MainActivity.kt b/app/src/main/java/com/example/deeplviewer/activity/MainActivity.kt
@@ -1,24 +1,27 @@
 package com.example.deeplviewer.activity
 
-import android.annotation.SuppressLint
 import android.content.Context
 import android.content.Intent
 import android.net.Uri
 import android.os.Bundle
+import android.util.Log
 import android.view.animation.AlphaAnimation
-import android.webkit.WebSettings
 import android.webkit.WebView
 import android.widget.ImageButton
 import androidx.appcompat.app.AppCompatActivity
 import com.example.deeplviewer.helper.CookieManagerHelper
 import com.example.deeplviewer.webview.MyWebViewClient
 import com.example.deeplviewer.R
+import com.example.deeplviewer.config.WebViewConfig
+import com.example.deeplviewer.helper.WebViewUrlHelper
 import com.example.deeplviewer.webview.WebAppInterface
 
 class MainActivity : AppCompatActivity() {
+    private lateinit var webView: WebView
     private lateinit var webViewClient: MyWebViewClient
+
     private val startUrl by lazy {
-        return@lazy ORIGIN_URL + getSharedPreferences("config", Context.MODE_PRIVATE).getString(
+        ORIGIN_URL + getSharedPreferences("config", Context.MODE_PRIVATE).getString(
             "urlParam",
             DEFAULT_PARAM
         )
@@ -32,56 +35,109 @@ class MainActivity : AppCompatActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
-        createWebView(intent, savedInstanceState)
 
-        findViewById<ImageButton>(R.id.settingButton).setOnClickListener {
-            val intent = Intent(this, SettingsActivity::class.java)
-            startActivity(intent)
-        }
+        initializeWebView()
+        createWebView(intent, savedInstanceState)
+        setupSettingsButton()
     }
 
     override fun onNewIntent(intent: Intent?) {
         super.onNewIntent(intent)
         createWebView(intent)
     }
 
-    @SuppressLint("SetJavaScriptEnabled", "AddJavascriptInterface")
+    override fun onSaveInstanceState(outState: Bundle) {
+        super.onSaveInstanceState(outState)
+        saveWebViewState(outState)
+    }
+
+    override fun onDestroy() {
+        if (::webView.isInitialized) {
+            // Remove the WebView from its parent view and destroy it
+            (webView.parent as? android.view.ViewGroup)?.removeView(webView)
+            webView.destroy()
+        }
+        super.onDestroy()
+    }
+
+    /**
+     * Creates and configures the WebView with the provided intent or saved instance state
+     */
     private fun createWebView(intent: Intent?, savedInstanceState: Bundle? = null) {
-        val floatingText = intent?.getStringExtra("FLOATING_TEXT")
-        val shareText = intent?.getStringExtra(Intent.EXTRA_TEXT)
-        val savedText = savedInstanceState?.getString("SavedText")
-        val receivedText = savedText ?: (floatingText ?: (shareText ?: ""))
+        val receivedText = extractReceivedText(intent, savedInstanceState)
 
-        val webView: WebView = findViewById(R.id.webview)
+        setupWebViewClient()
+        setupCookies()
+
+        // Add JavaScript interface for communication
+        webView.addJavascriptInterface(WebAppInterface(this), "Android")
+
+        // Load the initial URL
+        val targetUrl = WebViewUrlHelper.buildUrl(startUrl, receivedText)
+        webView.loadUrl(targetUrl)
+    }
+
+    /**
+     * Initializes the WebView
+     */
+    private fun initializeWebView() {
+        webView = findViewById(R.id.webview)
+        webView.alpha = 0.0F
+        WebViewConfig.applyBasicSettings(webView)
+        WebViewConfig.applyOptimizedSettings(webView)
+    }
+
+    /**
+     * Extracts the text from the intent or saved instance state
+     */
+    private fun extractReceivedText(intent: Intent?, savedInstanceState: Bundle?): String {
+        return savedInstanceState?.getString("SavedText")
+            ?: intent?.getStringExtra("FLOATING_TEXT")
+            ?: intent?.getStringExtra(Intent.EXTRA_TEXT)
+            ?: ""
+    }
+
+    /**
+     * Sets up the WebViewClient to handle page loading and animations
+     */
+    private fun setupWebViewClient() {
         webViewClient = MyWebViewClient(this)
         webViewClient.loadFinishedListener = {
-            val animation = AlphaAnimation(0.0F, 1.0F)
-            animation.duration = 100
+            val animation = AlphaAnimation(0.0F, 1.0F).apply { duration = 100 }
             webView.startAnimation(animation)
             webView.alpha = 1.0F
         }
+        webView.webViewClient = webViewClient
+    }
 
-        CookieManagerHelper().migrateCookie(this)
-        CookieManagerHelper().addPrivacyCookie()
-
-        webView.settings.javaScriptEnabled = true
-        webView.settings.domStorageEnabled = true
-        webView.settings.cacheMode = WebSettings.LOAD_CACHE_ELSE_NETWORK
+    /**
+     * Sets up cookies for the WebView
+     */
+    private fun setupCookies() {
+        try {
+            CookieManagerHelper().apply {
+                migrateCookie(this@MainActivity)
+                addPrivacyCookie()
+            }
+        } catch (e: Exception) {
+            Log.w("MainActivity", "Cookie setup failed", e)
+        }
+    }
 
-        webView.webViewClient = webViewClient
-        webView.addJavascriptInterface(WebAppInterface(this), "Android")
-        webView.loadUrl(
-            startUrl + Uri.encode(
-                receivedText.replace(
-                    "/",
-                    "\\/"
-                )
-            )
-        )
+    /**
+     * Sets up the settings button to open the SettingsActivity
+     */
+    private fun setupSettingsButton() {
+        findViewById<ImageButton>(R.id.settingButton).setOnClickListener {
+            val intent = Intent(this, SettingsActivity::class.java)
+            startActivity(intent)
+        }
     }
 
-    override fun onSaveInstanceState(outState: Bundle) {
-        super.onSaveInstanceState(outState)
+    /**
+     * Saves the current state of the WebView to the outState bundle
+     */
+    private fun saveWebViewState(outState: Bundle) {
         val webView: WebView = findViewById(R.id.webview)
         val url = webView.url ?: ""
 
@@ -95,6 +151,10 @@ class MainActivity : AppCompatActivity() {
             outState.putString("SavedText", inputText)
         }
 
-        CookieManagerHelper().saveCookies(this, webView)
+        try {
+            CookieManagerHelper().saveCookies(this, webView)
+        } catch (e: Exception) {
+            Log.w("MainActivity", "Cookie save failed", e)
+        }
     }
-}
+}
diff --git a/app/src/main/java/com/example/deeplviewer/config/WebViewConfig.kt b/app/src/main/java/com/example/deeplviewer/config/WebViewConfig.kt
@@ -0,0 +1,41 @@
+package com.example.deeplviewer.config
+
+import android.annotation.SuppressLint
+import android.webkit.WebSettings
+import android.webkit.WebView
+
+object WebViewConfig {
+    @SuppressLint("SetJavaScriptEnabled")
+    fun applyBasicSettings(webView: WebView) {
+        webView.settings.apply {
+            javaScriptEnabled = true
+            domStorageEnabled = true
+
+            // cache settings
+            cacheMode = WebSettings.LOAD_DEFAULT
+        }
+    }
+
+    @SuppressLint("SetJavaScriptEnabled")
+    fun applyOptimizedSettings(webView: WebView) {
+        webView.settings.apply {
+            // security settings
+            allowFileAccess = false
+            allowContentAccess = false
+            setGeolocationEnabled(false)
+
+            if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M) {
+                // off screen pre-rasterization (API 23+)
+                offscreenPreRaster = true
+            }
+
+            if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
+                // safe browsing (API 26+)
+                safeBrowsingEnabled = true
+            }
+
+            // mixed content mode
+            mixedContentMode = WebSettings.MIXED_CONTENT_COMPATIBILITY_MODE
+        }
+    }
+}
diff --git a/app/src/main/java/com/example/deeplviewer/helper/WebViewUrlHelper.kt b/app/src/main/java/com/example/deeplviewer/helper/WebViewUrlHelper.kt
