Prevent crash on devices with bad webview

app/build.gradle

@@ -93,6 +93,7 @@ dependencies {
     implementation "androidx.fragment:fragment:1.3.0-rc01"
     implementation "androidx.preference:preference:1.1.1"
     implementation "androidx.recyclerview:recyclerview:1.2.0-beta01"
+    implementation 'androidx.webkit:webkit:1.4.0'
     implementation 'com.google.android.material:material:1.3.0-beta01'
     implementation 'com.getkeepsafe.relinker:relinker:1.4.1'
     implementation 'com.getkeepsafe.taptargetview:taptargetview:1.13.0'

app/src/main/java/com/hippo/ehviewer/preference/SignInRequiredPreference.java

@@ -28,6 +28,7 @@ import com.hippo.ehviewer.client.EhCookieStore;
 import com.hippo.ehviewer.client.EhUrl;
 import com.hippo.ehviewer.ui.SettingsActivity;
 import com.hippo.ehviewer.ui.scene.BaseScene;
+import com.hippo.util.WebViewUtil;
 
 import okhttp3.HttpUrl;
 
@@ -58,6 +59,10 @@ public class SignInRequiredPreference extends Preference implements Preference.O
 
     @Override
     public boolean onPreferenceClick(Preference preference) {
+        if (!WebViewUtil.available(getContext())) {
+            mActivity.showTip(R.string.error_no_webview, BaseScene.LENGTH_SHORT);
+            return true;
+        }
         EhCookieStore store = EhApplication.getEhCookieStore(getContext());
         HttpUrl e = HttpUrl.get(EhUrl.HOST_E);
         HttpUrl ex = HttpUrl.get(EhUrl.HOST_EX);

app/src/main/java/com/hippo/ehviewer/ui/scene/SignInScene.java

@@ -45,6 +45,7 @@ import com.hippo.ehviewer.ui.MainActivity;
 import com.hippo.scene.Announcer;
 import com.hippo.scene.SceneFragment;
 import com.hippo.util.ExceptionUtils;
+import com.hippo.util.WebViewUtil;
 import com.hippo.yorozuya.AssertUtils;
 import com.hippo.yorozuya.IntIdGenerator;
 import com.hippo.yorozuya.ViewUtils;
@@ -225,6 +226,10 @@ public final class SignInScene extends SolidScene implements EditText.OnEditorAc
         } else if (mSignIn == v) {
             signIn();
         } else if (mSignInViaWebView == v) {
+            if (!WebViewUtil.available(getContext())) {
+                showTip(R.string.error_no_webview, BaseScene.LENGTH_SHORT);
+                return;
+            }
             startScene(new Announcer(WebViewSignInScene.class).setRequestCode(this, REQUEST_CODE_WEBVIEW));
         } else if (mSignInViaCookies == v) {
             startScene(new Announcer(CookieSignInScene.class).setRequestCode(this, REQUEST_CODE_COOKIE));

app/src/main/java/com/hippo/util/WebViewUtil.java

@@ -0,0 +1,25 @@
+package com.hippo.util;
+
+import android.content.Context;
+import android.content.pm.PackageInfo;
+import android.os.Build;
+import android.util.Log;
+
+import androidx.webkit.WebViewCompat;
+
+public class WebViewUtil {
+    private static final String TAG = "WebViewUtil";
+
+    public static boolean available(Context context) {
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {
+            return false;
+        }
+        PackageInfo webViewPackageInfo = WebViewCompat.getCurrentWebViewPackage(context);
+        if (webViewPackageInfo == null) {
+            Log.d(TAG, "WebView not available");
+            return false;
+        }
+        Log.d(TAG, "WebView version: " + webViewPackageInfo.versionName);
+        return true;
+    }
+}

app/src/main/res/values/strings.xml

@@ -809,4 +809,5 @@
     <string name="settings_advanced_clear_memory_cache_done">Memory cache cleaning completed</string>
     <string name="action_add_tag">Add tag</string>
     <string name="action_add_tag_tip">Enter new tags, separated with comma</string>
+    <string name="error_no_webview">WebView is not available.</string>
 </resources>