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Merge pull request #452 from asmorkalov:android_tutorial_update

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pull/455/merge
Andrey Kamaev 12 years ago committed by OpenCV Buildbot
parent 4f4fe553bc c7e7b77093
commit bb25111d23
2 changed files with 153 additions and 214 deletions
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  1. 365
      doc/tutorials/introduction/android_binary_package/dev_with_OCV_on_Android.rst
  2. 2
      doc/tutorials/introduction/table_of_content_introduction/table_of_content_introduction.rst

365
doc/tutorials/introduction/android_binary_package/dev_with_OCV_on_Android.rst
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@ -78,39 +78,33 @@ See the "15-puzzle" OpenCV sample for details.
.. code-block:: java
:linenos:
public class MyActivity extends Activity implements HelperCallbackInterface
{
private BaseLoaderCallback mOpenCVCallBack = new BaseLoaderCallback(this) {
@Override
public void onManagerConnected(int status) {
switch (status) {
case LoaderCallbackInterface.SUCCESS:
{
Log.i(TAG, "OpenCV loaded successfully");
// Create and set View
mView = new puzzle15View(mAppContext);
setContentView(mView);
} break;
default:
{
super.onManagerConnected(status);
} break;
}
}
};
/** Call on every application resume **/
@Override
protected void onResume()
{
Log.i(TAG, "called onResume");
super.onResume();
Log.i(TAG, "Trying to load OpenCV library");
if (!OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_2, this, mOpenCVCallBack))
public class Sample1Java extends Activity implements CvCameraViewListener {
private BaseLoaderCallback mLoaderCallback = new BaseLoaderCallback(this) {
@Override
public void onManagerConnected(int status) {
switch (status) {
case LoaderCallbackInterface.SUCCESS:
{
Log.i(TAG, "OpenCV loaded successfully");
mOpenCvCameraView.enableView();
} break;
default:
{
super.onManagerConnected(status);
} break;
}
}
};
@Override
public void onResume()
{
Log.e(TAG, "Cannot connect to OpenCV Manager");
super.onResume();
OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_3, this, mLoaderCallback);
}
...
}
It this case application works with OpenCV Manager in asynchronous fashion. ``OnManagerConnected``
@ -297,220 +291,165 @@ application. It will be capable of accessing camera output, processing it and di
result.
#. Open Eclipse IDE, create a new clean workspace, create a new Android project
:menuselection:`File --> New --> Android Project`.
#. Set name, target, package and ``minSDKVersion`` accordingly.
#. Create a new class :menuselection:`File -> New -> Class`. Name it for example:
*HelloOpenCVView*.
.. image:: images/dev_OCV_new_class.png
:alt: Add a new class.
:align: center
:menuselection:`File --> New --> Android Project`
* It should extend ``SurfaceView`` class.
* It also should implement ``SurfaceHolder.Callback``, ``Runnable``.
#. Set name, target, package and ``minSDKVersion`` accordingly. The minimal SDK version for build
with OpenCV4Android SDK is 11. Minimal device API Level (for application manifest) is 8.
#. Edit ``HelloOpenCVView`` class.
#. Allow Eclipse to create default activity. Lets name the activity ``HelloOpenCvActivity``.
* Add an ``import`` line for ``android.content.context``.
#. Choose Blank Activity with full screen layout. Lets name the layout ``HelloOpenCvLayout``.
* Modify autogenerated stubs: ``HelloOpenCVView``, ``surfaceCreated``, ``surfaceDestroyed`` and
``surfaceChanged``.
.. code-block:: java
:linenos:
package com.hello.opencv.test;
import android.content.Context;
public class HelloOpenCVView extends SurfaceView implements Callback, Runnable {
public HelloOpenCVView(Context context) {
super(context);
getHolder().addCallback(this);
}
public void surfaceCreated(SurfaceHolder holder) {
(new Thread(this)).start();
}
#. Import OpenCV library project to your workspace.
public void surfaceDestroyed(SurfaceHolder holder) {
cameraRelease();
}
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
cameraSetup(width, height);
}
#. Reference OpenCV library within your project properties.
* Add ``cameraOpen``, ``cameraRelease`` and ``cameraSetup`` voids as shown below.
.. image:: images/dev_OCV_reference.png
:alt: Reference OpenCV library.
:align: center
* Also, don't forget to add the public void ``run()`` as follows:
#. Edit your layout file as xml file and pass the following layout there:
.. code-block:: java
.. code-block:: xml
:linenos:
public void run() {
// TODO: loop { getFrame(), processFrame(), drawFrame() }
}
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:opencv="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent" >
public boolean cameraOpen() {
return false; //TODO: open camera
}
<org.opencv.android.JavaCameraView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:visibility="gone"
android:id="@+id/HelloOpenCvView"
opencv:show_fps="true"
opencv:camera_id="any" />
private void cameraRelease() {
// TODO release camera
}
private void cameraSetup(int width, int height) {
// TODO setup camera
}
</LinearLayout>
#. Create a new ``Activity`` :menuselection:`New -> Other -> Android -> Android Activity` and name
it, for example: *HelloOpenCVActivity*. For this activity define ``onCreate``, ``onResume`` and
``onPause`` voids.
#. Add the following permissions to the :file:`AndroidManifest.xml` file:
.. code-block:: java
.. code-block:: xml
:linenos:
public void onCreate (Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mView = new HelloOpenCVView(this);
setContentView (mView);
}
</application>
protected void onPause() {
super.onPause();
mView.cameraRelease();
}
<uses-permission android:name="android.permission.CAMERA"/>
protected void onResume() {
super.onResume();
if( !mView.cameraOpen() ) {
// MessageBox and exit app
AlertDialog ad = new AlertDialog.Builder(this).create();
ad.setCancelable(false); // This blocks the "BACK" button
ad.setMessage("Fatal error: can't open camera!");
ad.setButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
finish();
}
});
ad.show();
}
}
<uses-feature android:name="android.hardware.camera" android:required="false"/>
<uses-feature android:name="android.hardware.camera.autofocus" android:required="false"/>
<uses-feature android:name="android.hardware.camera.front" android:required="false"/>
<uses-feature android:name="android.hardware.camera.front.autofocus" android:required="false"/>
#. Add the following permissions to the :file:`AndroidManifest.xml` file:
#. Set application theme in AndroidManifest.xml to hide title and system buttons.
.. code-block:: xml
:linenos:
</application>
<application
android:icon="@drawable/icon"
android:label="@string/app_name"
android:theme="@android:style/Theme.NoTitleBar.Fullscreen" >
#. Add OpenCV library initialization to your activity. Fix errors by adding requited imports.
.. code-block:: java
:linenos:
private BaseLoaderCallback mLoaderCallback = new BaseLoaderCallback(this) {
@Override
public void onManagerConnected(int status) {
switch (status) {
case LoaderCallbackInterface.SUCCESS:
{
Log.i(TAG, "OpenCV loaded successfully");
mOpenCvCameraView.enableView();
} break;
default:
{
super.onManagerConnected(status);
} break;
}
}
};
<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />
<uses-feature android:name="android.hardware.camera.autofocus" />
#. Reference OpenCV library within your project properties.
.. image:: images/dev_OCV_reference.png
:alt: Reference OpenCV library.
:align: center
@Override
public void onResume()
{
super.onResume();
OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_3, this, mLoaderCallback);
}
#. We now need some code to handle the camera. Update the ``HelloOpenCVView`` class as follows:
#. Defines that your activity implements CvViewFrameListener interface and fix activity related
errors by defining missed methods. For this activity define ``onCreate``, ``onDestroy`` and
``onPause`` and implement them according code snippet bellow. Fix errors by adding requited
imports.
.. code-block:: java
:linenos:
private VideoCapture mCamera;
public boolean cameraOpen() {
synchronized (this) {
cameraRelease();
mCamera = new VideoCapture(Highgui.CV_CAP_ANDROID);
if (!mCamera.isOpened()) {
mCamera.release();
mCamera = null;
Log.e("HelloOpenCVView", "Failed to open native camera");
return false;
}
}
return true;
}
private CameraBridgeViewBase mOpenCvCameraView;
public void cameraRelease() {
synchronized(this) {
if (mCamera != null) {
mCamera.release();
mCamera = null;
}
}
}
@Override
public void onCreate(Bundle savedInstanceState) {
Log.i(TAG, "called onCreate");
super.onCreate(savedInstanceState);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
setContentView(R.layout.HelloOpenCvLayout);
mOpenCvCameraView = (CameraBridgeViewBase) findViewById(R.id.HelloOpenCvView);
mOpenCvCameraView.setVisibility(SurfaceView.VISIBLE);
mOpenCvCameraView.setCvCameraViewListener(this);
}
private void cameraSetup(int width, int height) {
synchronized (this) {
if (mCamera != null && mCamera.isOpened()) {
List<Size> sizes = mCamera.getSupportedPreviewSizes();
int mFrameWidth = width;
int mFrameHeight = height;
{ // selecting optimal camera preview size
double minDiff = Double.MAX_VALUE;
for (Size size : sizes) {
if (Math.abs(size.height - height) < minDiff) {
mFrameWidth = (int) size.width;
mFrameHeight = (int) size.height;
minDiff = Math.abs(size.height - height);
}
}
}
mCamera.set(Highgui.CV_CAP_PROP_FRAME_WIDTH, mFrameWidth);
mCamera.set(Highgui.CV_CAP_PROP_FRAME_HEIGHT, mFrameHeight);
}
}
}
@Override
public void onPause()
{
super.onPause();
if (mOpenCvCameraView != null)
mOpenCvCameraView.disableView();
}
#. The last step would be to update the ``run()`` void in ``HelloOpenCVView`` class as follows:
public void onDestroy() {
super.onDestroy();
if (mOpenCvCameraView != null)
mOpenCvCameraView.disableView();
}
.. code-block:: java
:linenos:
public void onCameraViewStarted(int width, int height) {
}
public void run() {
while (true) {
Bitmap bmp = null;
synchronized (this) {
if (mCamera == null)
break;
if (!mCamera.grab())
break;
bmp = processFrame(mCamera);
}
if (bmp != null) {
Canvas canvas = getHolder().lockCanvas();
if (canvas != null) {
canvas.drawBitmap(bmp, (canvas.getWidth() - bmp.getWidth()) / 2,
(canvas.getHeight() - bmp.getHeight()) / 2, null);
getHolder().unlockCanvasAndPost(canvas);
}
bmp.recycle();
}
}
}
public void onCameraViewStopped() {
}
protected Bitmap processFrame(VideoCapture capture) {
Mat mRgba = new Mat();
capture.retrieve(mRgba, Highgui.CV_CAP_ANDROID_COLOR_FRAME_RGBA);
//process mRgba
Bitmap bmp = Bitmap.createBitmap(mRgba.cols(), mRgba.rows(), Bitmap.Config.ARGB_8888);
try {
Utils.matToBitmap(mRgba, bmp);
} catch(Exception e) {
Log.e("processFrame", "Utils.matToBitmap() throws an exception: " + e.getMessage());
bmp.recycle();
bmp = null;
}
return bmp;
}
public Mat onCameraFrame(Mat inputFrame) {
return inputFrame;
}
#. Run your application on device or emulator.
Lets discuss some most important steps. Every Android application with UI must implement Activity
and View. By the first steps we create blank activity and default view layout. The simplest
OpenCV-centric application must implement OpenCV initialization, create its own view to show
preview from camera and implements ``CvViewFrameListener`` interface to get frames from camera and
process it.
First of all we create our application view using xml layout. Our layout consists of the only
one full screen component of class ``org.opencv.android.JavaCameraView``. This class is
implemented inside OpenCV library. It is inherited from ``CameraBridgeViewBase``, that extends
``SurfaceView`` and uses standard Android camera API. Alternatively you can use
``org.opencv.android.NativeCameraView`` class, that implements the same interface, but uses
``VideoCapture`` class as camera access back-end. ``opencv:show_fps="true"`` and
``opencv:camera_id="any"`` options enable FPS message and allow to use any camera on device.
Application tries to use back camera first.
After creating layout we need to implement ``Activity`` class. OpenCV initialization process has
been already discussed above. In this sample we use asynchronous initialization. Implementation of
``CvCameraViewListener`` interface allows you to add processing steps after frame grabbing from
camera and before its rendering on screen. The most important function is ``onCameraFrame``. It is
callback function and it is called on retrieving frame from camera. The callback input is frame
from camera. RGBA format is used by default. You can change this behavior by ``SetCaptureFormat``
method of ``View`` class. ``Highgui.CV_CAP_ANDROID_COLOR_FRAME_RGBA`` and
``Highgui.CV_CAP_ANDROID_GREY_FRAME`` are supported. It expects that function returns RGBA frame
that will be drawn on the screen.

2
doc/tutorials/introduction/table_of_content_introduction/table_of_content_introduction.rst
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@ -137,7 +137,7 @@ Here you can read tutorials about how to set up your computer to work with the O
================ =================================================
|AndroidLogo| **Title:** :ref:`dev_with_OCV_on_Android`
*Compatibility:* > OpenCV 2.4.2
*Compatibility:* > OpenCV 2.4.3
*Author:* |Author_VsevolodG|

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