Factor out geodata and direction handler

A recurrent problem is that the geodata and direction listeners must be
started on the UI thread. To ensure that this is indeed always the case,
operations on the geodata object should be performed through this type.

1 files changed, 122 insertions, 0 deletions

diff --git a/main/src/cgeo/geocaching/utils/GeoDirHandler.java b/main/src/cgeo/geocaching/utils/GeoDirHandler.java
new file mode 100644
index 0000000..2700348
--- /dev/null
+++ b/main/src/cgeo/geocaching/utils/GeoDirHandler.java
@@ -0,0 +1,122 @@
+package cgeo.geocaching.utils;
+
+import android.os.Handler;
+import android.os.Message;
+
+import cgeo.geocaching.IGeoData;
+import cgeo.geocaching.Settings;
+import cgeo.geocaching.cgeoapplication;
+import cgeo.geocaching.utils.IObserver;
+
+/**
+ * GeoData and Direction handler. Manipulating geodata and direction information
+ * through a GeoDirHandler ensures that all listeners are registered from a
+ * {@link android.os.Looper} thread.
+ */
+public class GeoDirHandler extends Handler implements IObserver<Object> {
+
+    private static final int OBSERVABLE = 1 << 1;
+    private static final int START_GEO = 1 << 2;
+    private static final int START_DIR = 1 << 3;
+    private static final int STOP_GEO = 1 << 4;
+    private static final int STOP_DIR = 1 << 5;
+
+    private static final cgeoapplication app = cgeoapplication.getInstance();
+
+    @Override
+    final public void handleMessage(final Message message) {
+        if ((message.what & START_GEO) != 0) {
+            app.addGeoObserver(this);
+        }
+
+        if ((message.what & START_DIR) != 0) {
+            app.addDirectionObserver(this);
+        }
+
+        if ((message.what & STOP_GEO) != 0) {
+            app.deleteGeoObserver(this);
+        }
+
+        if ((message.what & STOP_DIR) != 0) {
+            app.deleteDirectionObserver(this);
+        }
+
+        if ((message.what & OBSERVABLE) != 0) {
+            if (message.obj instanceof IGeoData) {
+                updateGeoData((IGeoData) message.obj);
+            } else {
+                updateDirection((Float) message.obj);
+            }
+        }
+    }
+
+    @Override
+    final public void update(final Object o) {
+        obtainMessage(0, o).sendToTarget();
+    }
+
+    /**
+     * Update method called when new IGeoData is available.
+     *
+     * @param data the new data
+     */
+    protected void updateGeoData(final IGeoData data) {
+        // Override this in children
+    }
+
+    /**
+     * Update method called when new direction data is available.
+     *
+     * @param direction the new direction
+     */
+    protected void updateDirection(final float direction) {
+        // Override this in children
+    }
+
+    /**
+     * Register the current GeoDirHandler for GeoData information.
+     */
+    public void startGeo() {
+        sendEmptyMessage(START_GEO);
+    }
+
+    /**
+     * Register the current GeoDirHandler for direction information if the preferences
+     * allow it.
+     */
+    public void startDir() {
+        if (Settings.isUseCompass()) {
+            sendEmptyMessage(START_DIR);
+        }
+    }
+
+    /**
+     * Register the current GeoDirHandler for GeoData and direction information (if the
+     * preferences allow it).
+     */
+    public void startGeoAndDir() {
+        sendEmptyMessage(START_GEO | (Settings.isUseCompass() ? START_DIR : 0));
+    }
+
+    /**
+     * Unregister the current GeoDirHandler for GeoData information.
+     */
+    public void stopGeo() {
+        sendEmptyMessage(STOP_GEO);
+    }
+
+    /**
+     * Unregister the current GeoDirHandler for direction information.
+     */
+    public void stopDir() {
+        sendEmptyMessage(STOP_DIR);
+    }
+
+    /**
+     * Unregister the current GeoDirHandler for GeoData and direction information.
+     */
+    public void stopGeoAndDir() {
+        sendEmptyMessage(STOP_GEO | STOP_DIR);
+    }
+}
+