Allow apps to be installed after download is completed.

Show an install button after the download is complete so the user can
click it to initiate an install. This is in preference to popping up
install manager activities on their behalf, because they may have queued
up several apps to update.

app/src/main/java/org/fdroid/fdroid/views/apps/AppListItemController.java

@@ -2,6 +2,7 @@ package org.fdroid.fdroid.views.apps;
 
 import android.annotation.TargetApi;
 import android.app.Activity;
+import android.app.PendingIntent;
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
@@ -32,15 +33,21 @@ import org.fdroid.fdroid.Utils;
 import org.fdroid.fdroid.data.Apk;
 import org.fdroid.fdroid.data.ApkProvider;
 import org.fdroid.fdroid.data.App;
+import org.fdroid.fdroid.installer.ApkCache;
 import org.fdroid.fdroid.installer.InstallManagerService;
 import org.fdroid.fdroid.installer.Installer;
+import org.fdroid.fdroid.installer.InstallerFactory;
 import org.fdroid.fdroid.net.Downloader;
 import org.fdroid.fdroid.net.DownloaderService;
 
+import java.io.File;
+
 // TODO: Support cancelling of downloads by tapping the install button a second time.
 // TODO: Support installing of an app once downloaded by tapping the install button a second time.
 public class AppListItemController extends RecyclerView.ViewHolder {
 
+    private static final String TAG = "AppListItemController";
+
     private final Activity activity;
 
     private final ImageView installButton;
@@ -138,6 +145,15 @@ public class AppListItemController extends RecyclerView.ViewHolder {
 
     }
 
+    private boolean isReadyToInstall(@NonNull App app) {
+        for (AppUpdateStatusManager.AppUpdateStatus appStatus : AppUpdateStatusManager.getInstance(activity).getByPackageName(app.packageName)) {
+            if (appStatus.status == AppUpdateStatusManager.Status.ReadyToInstall) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     /**
      * The install button is shown when an app:
      *  * Is compatible with the users device.
@@ -151,16 +167,9 @@ public class AppListItemController extends RecyclerView.ViewHolder {
             return;
         }
 
-        boolean readyToInstall = false;
+        if (isReadyToInstall(app)) {
-        for (AppUpdateStatusManager.AppUpdateStatus appStatus : AppUpdateStatusManager.getInstance(activity).getByPackageName(app.packageName)) {
-            if (appStatus.status == AppUpdateStatusManager.Status.ReadyToInstall) {
-                readyToInstall = true;
-                break;
-            }
-        }
-
-        if (readyToInstall) {
             installButton.setImageDrawable(ContextCompat.getDrawable(activity, R.drawable.ic_download_complete));
+            installButton.setVisibility(View.VISIBLE);
             // TODO: If in the downloading phase, then need to reflect that instead of this "download complete" icon.
         } else {
             boolean installable = app.canAndWantToUpdate(activity) || !app.isInstalled();
@@ -246,7 +255,36 @@ public class AppListItemController extends RecyclerView.ViewHolder {
                 return;
             }
 
-            InstallManagerService.queue(activity, currentApp, ApkProvider.Helper.findApkFromAnyRepo(activity, currentApp.packageName, currentApp.suggestedVersionCode));
+            final Apk suggestedApk = ApkProvider.Helper.findApkFromAnyRepo(activity, currentApp.packageName, currentApp.suggestedVersionCode);
+
+            if (isReadyToInstall(currentApp)) {
+                File apkFilePath = ApkCache.getApkDownloadPath(activity, Uri.parse(suggestedApk.getUrl()));
+                Utils.debugLog(TAG, "skip download, we have already downloaded " + suggestedApk.getUrl() + " to " + apkFilePath);
+
+                // TODO: This seems like a bit of a hack. Is there a better way to do this by changing
+                // the Installer API so that we can ask it to install without having to get it to fire
+                // off an intent which we then listen for and action?
+                final LocalBroadcastManager broadcastManager = LocalBroadcastManager.getInstance(activity);
+                final BroadcastReceiver receiver = new BroadcastReceiver() {
+                    @Override
+                    public void onReceive(Context context, Intent intent) {
+                        broadcastManager.unregisterReceiver(this);
+
+                        if (Installer.ACTION_INSTALL_USER_INTERACTION.equals(intent.getAction())) {
+                            PendingIntent pendingIntent = intent.getParcelableExtra(Installer.EXTRA_USER_INTERACTION_PI);
+                            try {
+                                pendingIntent.send();
+                            } catch (PendingIntent.CanceledException ignored) { }
+                        }
+                    }
+                };
+
+                broadcastManager.registerReceiver(receiver, Installer.getInstallIntentFilter(Uri.parse(suggestedApk.getUrl())));
+                Installer installer = InstallerFactory.create(activity, suggestedApk);
+                installer.installPackage(Uri.parse(apkFilePath.toURI().toString()), Uri.parse(suggestedApk.getUrl()));
+            } else {
+                InstallManagerService.queue(activity, currentApp, suggestedApk);
+            }
         }
     };
 }