Added Choreographer alternative for ancient devices

src/main/java/org/quantumbadger/redreader/views/RRAnimation.java

@@ -17,11 +17,9 @@
 
 package org.quantumbadger.redreader.views;
 
-import android.view.Choreographer;
+public abstract class RRAnimation implements RRChoreographer.Callback {
 
-public abstract class RRAnimation implements Choreographer.FrameCallback {
-
-	private static final Choreographer CHOREOGRAPHER = Choreographer.getInstance();
+	private static final RRChoreographer CHOREOGRAPHER = RRChoreographer.getInstance();
 
 	private long mFirstFrameNanos = -1;
 

src/main/java/org/quantumbadger/redreader/views/RRChoreographer.java

@@ -0,0 +1,44 @@
+/*******************************************************************************
+ * This file is part of RedReader.
+ *
+ * RedReader is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * RedReader is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with RedReader.  If not, see <http://www.gnu.org/licenses/>.
+ ******************************************************************************/
+
+package org.quantumbadger.redreader.views;
+
+import android.os.Build;
+import android.support.annotation.NonNull;
+import android.util.Log;
+import org.quantumbadger.redreader.common.AndroidApi;
+
+public abstract class RRChoreographer {
+
+	public interface Callback {
+		void doFrame(long frameTimeNanos);
+	}
+
+	@NonNull
+	public static RRChoreographer getInstance() {
+
+		if(AndroidApi.isGreaterThanOrEqualTo(Build.VERSION_CODES.JELLY_BEAN)) {
+			Log.i("RRChoreographer", "Using modern Choreographer");
+			return RRChoreographerModern.INSTANCE;
+		} else {
+			Log.i("RRChoreographer", "Using legacy Choreographer");
+			return RRChoreographerLegacy.INSTANCE;
+		}
+	}
+
+	public abstract void postFrameCallback(@NonNull final Callback callback);
+}

src/main/java/org/quantumbadger/redreader/views/RRChoreographerLegacy.java

@@ -0,0 +1,57 @@
+/*******************************************************************************
+ * This file is part of RedReader.
+ *
+ * RedReader is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * RedReader is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with RedReader.  If not, see <http://www.gnu.org/licenses/>.
+ ******************************************************************************/
+
+package org.quantumbadger.redreader.views;
+
+import android.support.annotation.NonNull;
+import org.quantumbadger.redreader.common.AndroidApi;
+
+public class RRChoreographerLegacy extends RRChoreographer implements Runnable {
+
+	static final RRChoreographerLegacy INSTANCE = new RRChoreographerLegacy();
+
+	private final Callback[] mCallbacks = new Callback[128];
+	private int mCallbackCount = 0;
+	private boolean mPosted = false;
+
+	private RRChoreographerLegacy() {}
+
+	@Override
+	public void postFrameCallback(@NonNull final Callback callback) {
+		mCallbacks[mCallbackCount] = callback;
+		mCallbackCount++;
+
+		if(!mPosted) {
+			AndroidApi.UI_THREAD_HANDLER.postDelayed(this, 1000 / 60);
+			mPosted = true;
+		}
+	}
+
+	@Override
+	public void run() {
+
+		final long frameTimeNanos = System.nanoTime();
+
+		final int callbackCount = mCallbackCount;
+		mPosted = false;
+		mCallbackCount = 0;
+
+		for(int i = 0; i < callbackCount; i++) {
+			mCallbacks[i].doFrame(frameTimeNanos);
+		}
+	}
+}

src/main/java/org/quantumbadger/redreader/views/RRChoreographerModern.java

@@ -0,0 +1,62 @@
+/*******************************************************************************
+ * This file is part of RedReader.
+ *
+ * RedReader is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * RedReader is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with RedReader.  If not, see <http://www.gnu.org/licenses/>.
+ ******************************************************************************/
+
+package org.quantumbadger.redreader.views;
+
+import android.annotation.TargetApi;
+import android.os.Build;
+import android.support.annotation.NonNull;
+import android.view.Choreographer;
+
+@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
+public class RRChoreographerModern extends RRChoreographer implements Choreographer.FrameCallback {
+
+	static final RRChoreographerModern INSTANCE = new RRChoreographerModern();
+
+	private static final Choreographer CHOREOGRAPHER = Choreographer.getInstance();
+
+	private final Callback[] mCallbacks = new Callback[128];
+	private int mCallbackCount = 0;
+	private boolean mPosted = false;
+
+	private RRChoreographerModern() {}
+
+	@Override
+	public void postFrameCallback(@NonNull final Callback callback) {
+		mCallbacks[mCallbackCount] = callback;
+		mCallbackCount++;
+
+		if(!mPosted) {
+			CHOREOGRAPHER.postFrameCallback(this);
+			mPosted = true;
+		}
+	}
+
+	@Override
+	public void doFrame(final long frameTimeNanos) {
+
+		final int callbackCount = mCallbackCount;
+		mPosted = false;
+		mCallbackCount = 0;
+
+		for(int i = 0; i < callbackCount; i++) {
+			mCallbacks[i].doFrame(frameTimeNanos);
+		}
+
+
+	}
+}