Added 'T' as a shortcut to toggle debug method tracing using android.os.Debug and traceview for analysis. The traces are written to /sdcard, which means the SD Card must not be mounted as a volume by USB at the time. Tracing can slow down decoding by a factor of 5 or more but gives very useful insights into where the time is going.

git-svn-id: https://zxing.googlecode.com/svn/trunk@358 59b500cc-1b3d-0410-9834-0bbf25fbcc57

android-m3/res/values/ids.xml

@@ -23,6 +23,7 @@
   <item type="id" name="set_decode_all_mode"/>
   <item type="id" name="set_decode_1D_mode"/>
   <item type="id" name="set_decode_QR_mode"/>
+  <item type="id" name="toggle_tracing"/>
   <item type="id" name="decode_started"/>
   <item type="id" name="decode_succeeded"/>
   <item type="id" name="decode_failed"/>

android-m3/src/com/google/zxing/client/android/BarcodeReaderCaptureActivity.java

@@ -110,6 +110,8 @@ public final class BarcodeReaderCaptureActivity extends Activity {
       cameraThread.setDecodeQRMode();
     } else if (keyCode == KeyEvent.KEYCODE_S) {
       cameraManager.setUsePreviewForDecode(false);
+    } else if (keyCode == KeyEvent.KEYCODE_T) {
+      cameraThread.toggleTracing();
     } else if (keyCode == KeyEvent.KEYCODE_U) {
       cameraThread.setDecode1DMode();
     } else {

android-m3/src/com/google/zxing/client/android/CameraThread.java

@@ -144,6 +144,11 @@ final class CameraThread extends Thread {
     message.sendToTarget();
   }
 
+  public void toggleTracing() {
+    Message message = Message.obtain(decodeThread.handler, R.id.toggle_tracing);
+    message.sendToTarget();
+  }
+
   /**
    * Start a decode if possible, but not now if the DecodeThread is in the middle of saving.
    */

android-m3/src/com/google/zxing/client/android/DecodeThread.java

@@ -18,6 +18,7 @@ package com.google.zxing.client.android;
 
 import android.app.Application;
 import android.graphics.Bitmap;
+import android.os.Debug;
 import android.os.Handler;
 import android.os.Looper;
 import android.os.Message;
@@ -51,10 +52,14 @@ final class DecodeThread extends Thread {
   private final CameraManager cameraManager;
   private Hashtable<DecodeHintType, Object> hints;
   private Handler cameraThreadHandler;
+  private int methodTraceCount;
+  private boolean tracing;
 
   DecodeThread(BarcodeReaderCaptureActivity activity, CameraManager cameraManager) {
     this.activity = activity;
     this.cameraManager = cameraManager;
+    methodTraceCount = 0;
+    tracing = false;
   }
 
   @Override
@@ -81,6 +86,9 @@ final class DecodeThread extends Thread {
           case R.id.set_decode_QR_mode:
             setDecodeQRMode();
             break;
+          case R.id.toggle_tracing:
+            tracing = !tracing;
+            break;
         }
       }
     };
@@ -123,19 +131,32 @@ final class DecodeThread extends Thread {
     Message restart = Message.obtain(cameraThreadHandler, R.id.decode_started);
     restart.sendToTarget();
 
-    Result rawResult;
+    if (tracing) {
+      Debug.startMethodTracing("/sdcard/ZXingDecodeThread" + methodTraceCount);
+      methodTraceCount++;
+    }
+    boolean success;
+    Result rawResult = null;
     try {
       MonochromeBitmapSource source = new RGBMonochromeBitmapSource(bitmap);
       rawResult = new MultiFormatReader().decode(source, hints);
+      success = true;
     } catch (ReaderException e) {
-      Message failure = Message.obtain(cameraThreadHandler, R.id.decode_failed);
-      failure.sendToTarget();
-      return;
+      success = false;
+    }
+    if (tracing) {
+      Debug.stopMethodTracing();
     }
     Date endDate = new Date();
-    Message success = Message.obtain(cameraThreadHandler, R.id.decode_succeeded, rawResult);
-    success.arg1 = (int) (endDate.getTime() - startDate.getTime());
-    success.sendToTarget();
+
+    if (success) {
+      Message message = Message.obtain(cameraThreadHandler, R.id.decode_succeeded, rawResult);
+      message.arg1 = (int) (endDate.getTime() - startDate.getTime());
+      message.sendToTarget();
+    } else {
+      Message message = Message.obtain(cameraThreadHandler, R.id.decode_failed);
+      message.sendToTarget();
+    }
   }
 
   /**

android-m3/strings.xml.template

@@ -22,7 +22,7 @@
   <string name="menu_about">About...</string>
   <string name="menu_help">Help...</string>
   <string name="msg_about">ZXing Barcode Reader v@VERSION@\nhttp://code.google.com/p/zxing</string>
-  <string name="msg_help">A: Decode all barcodes\nC: Capture and save a JPEG\nP: Use the preview image for decoding\nQ: Decode only QR Codes\nS: Use a still image for decoding\nU: Decode only UPC/1D barcodes</string>
+  <string name="msg_help">A: Decode all barcodes\nC: Capture and save a JPEG\nP: Use the preview image for decoding\nQ: Decode only QR Codes\nS: Use a still image for decoding\nT: Toggle debug method tracing\nU: Decode only UPC/1D barcodes</string>
   <string name="title_about">About</string>
   <string name="title_add_contact">Add Contact?</string>
   <string name="title_barcode_detected">Barcode Detected</string>