Add in-app download and silent install for GitHub updates

- ApkInstaller.downloadAndInstall downloads APK by URL with a progress dialog
- Reuses existing PackageInstaller silent-install pipeline via shared File path
- Update dialogs now download in-app instead of opening a browser
- Add UpdateDownloading string

Verified: TMessagesProj compileReleaseJavaWithJavac succeeds.

TMessagesProj/src/main/java/org/telegram/ui/Components/BlockingUpdateView.java

@@ -149,8 +149,12 @@ public class BlockingUpdateView extends FrameLayout implements NotificationCente
                     showProgress(true);
                 }
             } else if (appUpdate.url != null) {
+                if (getContext() instanceof Activity activity) {
+                    ApkInstaller.downloadAndInstall(activity, appUpdate.url, appUpdate.version);
+                } else {
                     Browser.openUrl(getContext(), appUpdate.url);
                 }
+            }
         });
 
         acceptTextView = new TextView(context);

TMessagesProj/src/main/java/org/telegram/ui/Components/UpdateAppAlertDialog.java

@@ -4,6 +4,7 @@ import android.animation.Animator;
 import android.animation.AnimatorListenerAdapter;
 import android.animation.AnimatorSet;
 import android.animation.ObjectAnimator;
+import android.app.Activity;
 import android.content.Context;
 import android.graphics.Canvas;
 import android.graphics.Color;
@@ -38,6 +39,8 @@ import org.telegram.ui.ActionBar.Theme;
 import org.telegram.ui.Components.spoilers.SpoilersTextView;
 import org.telegram.ui.Stories.recorder.ButtonWithCounterView;
 
+import tw.nekomimi.nekogram.helpers.ApkInstaller;
+
 public class UpdateAppAlertDialog extends BottomSheet {
 
     private TLRPC.TL_help_appUpdate appUpdate;
@@ -297,9 +300,13 @@ public class UpdateAppAlertDialog extends BottomSheet {
         doneButton.setOnClickListener(v -> {
             if (update.document instanceof TLRPC.TL_document) {
                 FileLoader.getInstance(accountNum).loadFile(appUpdate.document, "update", FileLoader.PRIORITY_NORMAL, 1);
+            } else if (appUpdate.url != null) {
+                if (getContext() instanceof Activity activity) {
+                    ApkInstaller.downloadAndInstall(activity, appUpdate.url, appUpdate.version);
                 } else {
                     Browser.openUrl(context, appUpdate.url);
                 }
+            }
             dismiss();
         });
         container.addView(doneButton, LayoutHelper.createFrame(LayoutHelper.MATCH_PARENT, 48, Gravity.FILL_HORIZONTAL | Gravity.BOTTOM, 20, 0, 20, 48 + 4 + 8));

TMessagesProj/src/main/java/tw/nekomimi/nekogram/helpers/ApkInstaller.java

@@ -34,6 +34,7 @@ import org.telegram.messenger.R;
 import org.telegram.messenger.UserConfig;
 import org.telegram.messenger.Utilities;
 import org.telegram.messenger.XiaomiUtilities;
+import org.telegram.messenger.browser.Browser;
 import org.telegram.tgnet.TLRPC;
 import org.telegram.ui.ActionBar.AlertDialog;
 import org.telegram.ui.ActionBar.Theme;
@@ -44,9 +45,12 @@ import org.telegram.ui.LaunchActivity;
 
 import java.io.File;
 import java.io.FileInputStream;
+import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.net.HttpURLConnection;
+import java.net.URL;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 
@@ -107,6 +111,113 @@ public final class ApkInstaller {
         if (apk == null) {
             return;
         }
+        showInstallDialog(context, apk);
+    }
+
+    // Downloads an APK from a direct URL (e.g. a GitHub release asset) with a
+    // progress dialog, then performs the same silent install as the Telegram
+    // document update flow.
+    public static void downloadAndInstall(Activity context, String url, String version) {
+        if (context == null || TextUtils.isEmpty(url)) {
+            return;
+        }
+        // Not a direct apk link (e.g. a release page) — just open it.
+        if (!url.toLowerCase().endsWith(".apk")) {
+            Browser.openUrl(context, url);
+            return;
+        }
+        if (dialog != null && dialog.isShowing()) {
+            return;
+        }
+        var progressDialog = new AlertDialog(context, AlertDialog.ALERT_TYPE_LOADING);
+        progressDialog.setMessage(LocaleController.getString(R.string.UpdateDownloading));
+        progressDialog.setCanCancel(false);
+        progressDialog.show();
+        dialog = progressDialog;
+
+        Utilities.globalQueue.postRunnable(() -> {
+            File apk = downloadApk(context, url, version, progress -> AndroidUtilities.runOnUIThread(() -> {
+                if (dialog != null && dialog.isShowing()) {
+                    dialog.setProgress(progress);
+                }
+            }));
+            AndroidUtilities.runOnUIThread(() -> {
+                if (dialog != null) {
+                    dialog.dismiss();
+                    dialog = null;
+                }
+                if (apk == null) {
+                    AlertsCreator.createSimpleAlert(context, LocaleController.getString(R.string.ErrorOccurred)).show();
+                    return;
+                }
+                showInstallDialog(context, apk);
+            });
+        });
+    }
+
+    // @WorkerThread @Nullable
+    private static File downloadApk(Activity context, String url, String version, Utilities.Callback<Integer> onProgress) {
+        HttpURLConnection connection = null;
+        try {
+            File dir = FileLoader.getDirectory(FileLoader.MEDIA_DIR_CACHE);
+            String name = "update-" + (TextUtils.isEmpty(version) ? "latest" : version.replaceAll("[^A-Za-z0-9._-]", "_")) + ".apk";
+            File apk = new File(dir, name);
+            if (apk.exists()) {
+                //noinspection ResultOfMethodCallIgnored
+                apk.delete();
+            }
+
+            URL downloadUrl = new URL(url);
+            connection = (HttpURLConnection) downloadUrl.openConnection();
+            connection.setInstanceFollowRedirects(true);
+            connection.setConnectTimeout(15000);
+            connection.setReadTimeout(30000);
+            connection.setRequestProperty("User-Agent", ApplicationLoader.getApplicationId());
+
+            int code = connection.getResponseCode();
+            if (code != HttpURLConnection.HTTP_OK) {
+                FileLog.e("ApkInstaller: download failed, HTTP " + code);
+                return null;
+            }
+
+            long total = connection.getContentLength();
+            long downloaded = 0;
+            int lastReported = -1;
+            try (InputStream in = connection.getInputStream();
+                 OutputStream out = new FileOutputStream(apk)) {
+                byte[] buffer = new byte[8192];
+                int read;
+                while ((read = in.read(buffer)) >= 0) {
+                    out.write(buffer, 0, read);
+                    downloaded += read;
+                    if (total > 0 && onProgress != null) {
+                        int progress = (int) (downloaded * 100 / total);
+                        if (progress != lastReported) {
+                            lastReported = progress;
+                            onProgress.run(progress);
+                        }
+                    }
+                }
+            }
+            return apk;
+        } catch (Exception e) {
+            FileLog.e(e);
+            return null;
+        } finally {
+            if (connection != null) {
+                connection.disconnect();
+            }
+        }
+    }
+
+    private static void showInstallDialog(Activity context, File apk) {
+        if (context == null || apk == null || !apk.exists()) {
+            return;
+        }
+        if (hasBrokenPackageInstaller(context)) {
+            AndroidUtilities.openForView(apk, "install.apk", "application/vnd.android.package-archive", context, null, false);
+            return;
+        }
         if (dialog != null && dialog.isShowing()) {
             return;
         }

TMessagesProj/src/main/res/values/strings_neko.xml

@@ -149,6 +149,7 @@
     <string name="ShareNekogram">Share FoxiGram...</string>
     <string name="NekogramVersion">FoxiGram %1$s\nBased on Telegram %2$s\nDesigned by %3$s</string>
     <string name="UpdateInstalling">Installing update...</string>
+    <string name="UpdateDownloading">Downloading update...</string>
     <string name="UpdateInstallingNotification">A notification will be shown when the update completes.</string>
     <string name="UpdateInstallingRelaunch">The app will relaunch when the update completes.</string>
     <string name="UpdateInstalledNotification">Update installation finished, tap to launch the app.</string>