added ViewIdGenerator

Author: codeanticode

core/src/processing/android/PermissionRequestor.java

@@ -5,6 +5,7 @@
 import android.support.v4.app.ActivityCompat;
 import android.support.v4.os.ResultReceiver;
 
+// A simple utility activity to request permissions in a service.
 public class PermissionRequestor extends Activity {
   public static final String KEY_RESULT_RECEIVER = "resultReceiver";
   public static final String KEY_PERMISSIONS = "permissions";

core/src/processing/android/ViewIdGenerator.java

@@ -0,0 +1,32 @@
+package processing.android;
+
+import java.util.concurrent.atomic.AtomicInteger;
+import android.annotation.SuppressLint;
+import android.os.Build;
+import android.view.View;
+
+// An utility class to generate unique View ID's. Needed until minimum API level
+// in raised to 17, where we can just use View.generateViewId().
+// Largely based on fantouch code at http://stackoverflow.com/a/21000252
+public class ViewIdGenerator {
+  // Start at 15,000,000, taking into account the comment from Singed
+  // http://stackoverflow.com/a/39307421
+  private static final AtomicInteger nextId = new AtomicInteger(15000000);
+
+  @SuppressLint("NewApi")
+  public static int getUniqueId() {
+    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN_MR1) {
+      for (;;) {
+        final int result = nextId.get();
+        // aapt-generated IDs have the high byte nonzero; clamp to the range under that.
+        int newValue = result + 1;
+        if (newValue > 0x00FFFFFF) newValue = 1; // Roll over to 1, not 0.
+        if (nextId.compareAndSet(result, newValue)) {
+          return result;
+        }
+      }
+    } else {
+      return View.generateViewId();
+    }
+  }
+}

templates/FragmentActivity.java.tmpl

@@ -1,12 +1,12 @@
 package @@package_name@@;
 
 import android.os.Bundle;
-import android.view.View;
 import android.view.ViewGroup;
 import android.widget.FrameLayout;
 import android.support.v7.app.AppCompatActivity;
 
 import processing.android.PFragment;
+import processing.android.ViewIdGenerator;
 import processing.core.PApplet;
 
 public class MainActivity extends AppCompatActivity {
@@ -16,7 +16,7 @@ public class MainActivity extends AppCompatActivity {
   protected void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     FrameLayout frame = new FrameLayout(this);
-    frame.setId(View.generateViewId());
+    frame.setId(ViewIdGenerator.getUniqueId());
     setContentView(frame, new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 
                                                      ViewGroup.LayoutParams.MATCH_PARENT));