enable sending installed APKs via NFC/Android Beam on AppDetails

If you are viewing the AppDetails screen for an installed app, this code
configures Android Beam to send the APK for that installed app if the you
initiate via NFC.

Also move the SDK checks into each method so that they are easier to use
without doing the wrong thing.

src/org/fdroid/fdroid/AppDetails.java

@@ -34,11 +34,13 @@ import android.app.AlertDialog;
 import android.app.ListActivity;
 import android.app.ProgressDialog;
 import android.net.Uri;
+import android.nfc.NfcAdapter;
 import android.os.Build;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.Message;
 import android.preference.PreferenceManager;
+import android.content.pm.ApplicationInfo;
 import android.content.pm.PackageManager;
 import android.content.pm.PackageInfo;
 import android.content.pm.Signature;
@@ -624,11 +626,14 @@ public class AppDetails extends ListActivity {
         adapter.notifyDataSetChanged();
 
         TextView tv = (TextView) findViewById(R.id.status);
-        if (!app.isInstalled())
-            tv.setText(getString(R.string.details_notinstalled));
-        else
+        if (app.isInstalled()) {
             tv.setText(getString(R.string.details_installed,
                     app.installedVersionName));
+            NfcBeamManager.setAndroidBeam(this, app.id);
+        } else {
+            tv.setText(getString(R.string.details_notinstalled));
+            NfcBeamManager.disableAndroidBeam(this);
+        }
 
         tv = (TextView) infoView.findViewById(R.id.signature);
         if (pref_expert && mInstalledSignature != null) {
@@ -1101,5 +1106,4 @@ public class AppDetails extends ListActivity {
             break;
         }
     }
-
 }

src/org/fdroid/fdroid/FDroid.java

@@ -129,9 +129,8 @@ public class FDroid extends FragmentActivity {
     @Override
     protected void onResume() {
         super.onResume();
-        // RepoDetailsActivity sets a different beam, so reset here
-        if (Build.VERSION.SDK_INT >= 16)
-            setupAndroidBeam();
+        // AppDetails and RepoDetailsActivity set different NFC actions, so reset here
+        NfcBeamManager.setAndroidBeam(this, getApplication().getPackageName());
     }
 
     @Override
@@ -422,23 +421,4 @@ public class FDroid extends FragmentActivity {
 
     }
 
-    @TargetApi(16)
-    private void setupAndroidBeam() {
-        PackageManager pm = getPackageManager();
-        NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
-        if (nfcAdapter != null) {
-            ApplicationInfo appInfo;
-            try {
-                appInfo = pm.getApplicationInfo("org.fdroid.fdroid",
-                        PackageManager.GET_META_DATA);
-                // TODO can we send the repo here also, as a file?
-                Uri uris[] = {
-                        Uri.parse("file://" + appInfo.publicSourceDir),
-                };
-                nfcAdapter.setBeamPushUris(uris, this);
-            } catch (NameNotFoundException e1) {
-                e1.printStackTrace();
-            }
-        }
-    }
 }

src/org/fdroid/fdroid/NfcBeamManager.java

@@ -0,0 +1,43 @@
+
+package org.fdroid.fdroid;
+
+import android.annotation.TargetApi;
+import android.app.Activity;
+import android.content.pm.ApplicationInfo;
+import android.content.pm.PackageManager;
+import android.content.pm.PackageManager.NameNotFoundException;
+import android.net.Uri;
+import android.nfc.NfcAdapter;
+import android.os.Build;
+
+@TargetApi(16)
+public class NfcBeamManager {
+
+    static void setAndroidBeam(Activity activity, String packageName) {
+        if (Build.VERSION.SDK_INT < 16)
+            return;
+        PackageManager pm = activity.getPackageManager();
+        NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(activity);
+        if (nfcAdapter != null) {
+            ApplicationInfo appInfo;
+            try {
+                appInfo = pm.getApplicationInfo(packageName, PackageManager.GET_META_DATA);
+                Uri uris[] = {
+                        Uri.parse("file://" + appInfo.publicSourceDir),
+                };
+                nfcAdapter.setBeamPushUris(uris, activity);
+            } catch (NameNotFoundException e) {
+                e.printStackTrace();
+            }
+        }
+    }
+
+    static void disableAndroidBeam(Activity activity) {
+        if (Build.VERSION.SDK_INT < 16)
+            return;
+        NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(activity);
+        if (nfcAdapter != null)
+            nfcAdapter.setBeamPushUris(null, activity);
+    }
+
+}

src/org/fdroid/fdroid/views/RepoDetailsActivity.java

@@ -69,14 +69,12 @@ public class RepoDetailsActivity extends FragmentActivity {
         setTitle(repo.getName());
 
         wifiManager = (WifiManager) getSystemService(WIFI_SERVICE);
-
-        // required NFC support starts in android-14
-        if (Build.VERSION.SDK_INT >= 14)
-            setNfc();
     }
 
     @TargetApi(14)
     private void setNfc() {
+        if (Build.VERSION.SDK_INT < 14)
+            return;
         NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
         if (nfcAdapter == null) {
             return;
@@ -97,8 +95,9 @@ public class RepoDetailsActivity extends FragmentActivity {
     public void onResume() {
         Log.i(TAG, "onResume");
         super.onResume();
-        if (Build.VERSION.SDK_INT >= 9)
-            processIntent(getIntent());
+        // FDroid.java and AppDetails set different NFC actions, so reset here
+        setNfc();
+        processIntent(getIntent());
     }
 
     @Override
@@ -112,6 +111,8 @@ public class RepoDetailsActivity extends FragmentActivity {
 
     @TargetApi(9)
     void processIntent(Intent i) {
+        if (Build.VERSION.SDK_INT < 9)
+            return;
         if (NfcAdapter.ACTION_NDEF_DISCOVERED.equals(i.getAction())) {
             Log.i(TAG, "ACTION_NDEF_DISCOVERED");
             Parcelable[] rawMsgs =