{"id":382,"date":"2011-03-30T20:35:00","date_gmt":"2011-03-30T20:35:00","guid":{"rendered":"http:\/\/www.javacodegeeks.com\/2012\/10\/android-http-camera-live-preview-tutorial.html"},"modified":"2012-10-21T19:39:12","modified_gmt":"2012-10-21T19:39:12","slug":"android-http-camera-live-preview","status":"publish","type":"post","link":"https:\/\/www.javacodegeeks.com\/2011\/03\/android-http-camera-live-preview.html","title":{"rendered":"Android HTTP Camera Live Preview Tutorial"},"content":{"rendered":"
The Android SDK includes a Camera<\/a> class that is used to set image capture settings, start\/stop preview, snap pictures, and retrieve frames for encoding for video. It is a handy abstraction of the real hardware device. However, the SDK doesn’t provide any camera emulation, something that makes testing camera enabled applications quite difficult. In this tutorial, I am going to show you how to use a web camera in order to obtain a live camera preview. <\/p>\n
\nWhat we are essentially going to do is setup a web camera to publish static images in a predefined URL and then grab these images from our application and present them as motion pictures. Note that this tutorial was inspired by a post named \u201cLive Camera Previews in Android\u201d<\/a>.<\/p>\n

Let’s start by creating an Eclipse project under the name \u201cAndroidHttpCameraProject\u201d and an Activity named \u201cMyCamAppActivity\u201d. As a first step, I am going to show you how to use the SDK camera. You can find many resources on how to manipulate the camera, one of them being the CameraPreview<\/a> class that is included in the SDK’s samples. In short, we are going to extend the SurfaceView<\/a> class and provide our implementation using the device’s camera. Then, we use the setContentView<\/a> method of our Activity<\/a> in order to set the activity content to that specific View<\/a>. Let’s see what the two classes look like:<\/p>\n

MyCamAppActivity<\/strong><\/p>\n

package com.javacodegeeks.android.camera;\r\n\r\nimport android.app.Activity;\r\nimport android.os.Bundle;\r\nimport android.view.SurfaceView;\r\nimport android.view.Window;\r\n\r\npublic class MyCamAppActivity extends Activity {\r\n    \r\n    private SurfaceView cameraPreview;\r\n\r\n    @Override\r\n    public void onCreate(Bundle savedInstanceState) {\r\n        \r\n        super.onCreate(savedInstanceState);\r\n        requestWindowFeature(Window.FEATURE_NO_TITLE);\r\n        \r\n        cameraPreview = new CameraPreview(this);\r\n        \r\n        setContentView(cameraPreview);\r\n        \r\n    }\r\n    \r\n}\r\n<\/pre>\n
CameraPreview<\/strong><\/p>\n
package com.javacodegeeks.android.camera;\r\n\r\nimport android.content.Context;\r\nimport android.hardware.Camera;\r\nimport android.util.Log;\r\nimport android.view.SurfaceHolder;\r\nimport android.view.SurfaceView;\r\n\r\npublic class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {\r\n\r\n    private SurfaceHolder holder;\r\n    private Camera camera;\r\n\r\n    public CameraPreview(Context context) {\r\n        super(context);\r\n        holder = getHolder();\r\n        holder.addCallback(this);\r\n        holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);\r\n    }\r\n\r\n    @Override\r\n    public void surfaceChanged(SurfaceHolder holder2, int format, int w, int h) {\r\n        Camera.Parameters parameters = camera.getParameters();\r\n        parameters.setPreviewSize(w, h);\r\n        camera.setParameters(parameters);\r\n        camera.startPreview();\r\n    }\r\n\r\n    @Override\r\n    public void surfaceCreated(SurfaceHolder holder1) {\r\n        try {\r\n            camera = Camera.open();\r\n            camera.setPreviewDisplay(holder1);\r\n        } \r\n        catch (Exception e) {\r\n            Log.i(\"Exception surfaceCreated()\", \"e=\" + e);\r\n            camera.release();\r\n            camera = null;\r\n        }\r\n\r\n    }\r\n\r\n    @Override\r\n    public void surfaceDestroyed(SurfaceHolder arg0) {\r\n        camera.stopPreview();\r\n        camera.release();\r\n        camera = null;\r\n    }\r\n    \r\n}\r\n<\/pre>\n
In our \u201cCameraPreview\u201d class, we implement the SurfaceHolder.Callback<\/a> interface so that we receive information about changes to the underlying surface. The methods that have to be implemented are the following:<\/p>\n