I'm interested as well how that could work. I'm also looking for a way
to use the Preview app inside my application but don't know how to use
it inside my XML file.
On 6 Jul., 18:22, Bobalot <[EMAIL PROTECTED]> wrote:
> hi, im trying to make a simple camera app, by extending the
> CameraPreview class in the api demos, anyway im trying to cast the
> preview onto a surfaceview that i have defined in my layout xml file.
> but everytime i do this i get a null pointer exception, and i cant for
> the life of me figure out how to make this work.
>
> if anyone has any info or sample code i would be very gratefull.
> this is what i have so far, the Preview class is what i took from the
> CameraPreview.java
>
> ------------------------------------------------------------------------------------------------
> package bob.CameraAlbum;
>
> import android.app.Activity;
> import android.content.Context;
> import android.graphics.Canvas;
> import android.hardware.CameraDevice;
> import android.os.Bundle;
> import android.view.SurfaceHolder;
> import android.view.SurfaceView;
> import android.widget.TabHost;
> import android.widget.TabHost.TabSpec;
>
> public class Camera extends Activity {
> private TabHost myTabHost;
> private Preview mPreview;
>
> @Override
> protected void onCreate(Bundle icicle) {
> super.onCreate(icicle);
> //SurfaceHolder mHolder;
> // Hide the window title.
> // requestWindowFeature(Window.FEATURE_NO_TITLE);
>
> setContentView(R.layout.tabs);
> mPreview = new Preview(this);
>
> this.myTabHost = (TabHost)this.findViewById(R.id.tabhost);
> this.myTabHost.setup();
>
> TabSpec ts1 = myTabHost.newTabSpec("TAB1");
> ts1.setIndicator("Take Photo",
> getResources().getDrawable(R.drawable.cameraphoto));
> ts1.setContent(R.id.grid_set_menu_page1);
> this.myTabHost.addTab(ts1);
>
> TabSpec ts2 = myTabHost.newTabSpec("TAB2");
> ts2.setIndicator("Album",
> getResources().getDrawable(R.drawable.driveharddisk));
> ts2.setContent(R.id.grid_set_menu_page2);
> this.myTabHost.addTab(ts2);
>
> TabSpec ts3 = myTabHost.newTabSpec("TAB3");
> ts3.setIndicator("Upload",
> getResources().getDrawable(R.drawable.networkwireless));
> ts3.setContent(R.id.grid_set_menu_page3);
> this.myTabHost.addTab(ts3);
>
> this.myTabHost.setCurrentTab(0);
>
> //mPreview = (Preview) findViewById(R.id.photo_surface);
>
> }
>
> @Override
> protected void onResume() {
> // Because the CameraDevice object is not a shared resource,
> // it's very important to release it when the activity is paused.
> super.onResume();
> mPreview.resume();
>
> }
>
> @Override
> protected void onPause() {
> // Start Preview again when we resume.
> super.onPause();
> mPreview.pause();
>
> }
> }
>
> class Preview extends SurfaceView implements SurfaceHolder.Callback {
> SurfaceHolder mHolder;
> private PreviewThread mPreviewThread;
> private boolean mHasSurface;
> SurfaceView Sview;
> Preview(Context context) {
> super(context);
>
> // Install a SurfaceHolder.Callback so we get notified when
> the
> // underlying surface is created and destroyed.
> Sview=(SurfaceView) findViewById(R.id.photo_surface);
> mHolder = Sview.getHolder();
>
> mHolder.addCallback(this);
> mHasSurface = false;
>
> // In this example, we hardcode the size of the preview. In a
> real
> // application this should be more dynamic. This guarantees
> that
> // the uderlying surface will never change size.
> mHolder.setFixedSize(320, 240);
> }
>
> public void resume() {
> // We do the actual acquisition in a separate thread. Create
> it now.
> if (mPreviewThread == null) {
> mPreviewThread = new PreviewThread();
> // If we already have a surface, just start the thread now
> too.
> if (mHasSurface == true) {
> mPreviewThread.start();
> }
> }
> }
>
> public void pause() {
> // Stop Preview.
> if (mPreviewThread != null) {
> mPreviewThread.requestExitAndWait();
> mPreviewThread = null;
> }
> }
>
> public void surfaceCreated(SurfaceHolder holder) {
> // The Surface has been created, start our main acquisition
> thread.
> mHasSurface = true;
> if (mPreviewThread != null) {
> mPreviewThread.start();
> }
> }
>
> public void surfaceDestroyed(SurfaceHolder holder) {
> // Surface will be destroyed when we return. Stop the preview.
> mHasSurface = false;
> pause();
> }
>
> public void surfaceChanged(SurfaceHolder holder, int format, int
> w, int h) {
> // Surface size or format has changed. This should not happen
> in this
> // example.
> }
>
> //
> ----------------------------------------------------------------------
>
> class PreviewThread extends Thread {
> private boolean mDone;
>
> PreviewThread() {
> super();
> mDone = false;
> }
>
> @Override
> public void run() {
> // We first open the CameraDevice and configure it.
> CameraDevice camera = CameraDevice.open();
> if (camera != null) {
> CameraDevice.CaptureParams param = new
> CameraDevice.CaptureParams();
> param.type = 1; // preview
> param.srcWidth = 1280;
> param.srcHeight = 960;
> param.leftPixel = 0;
> param.topPixel = 0;
> param.outputWidth = 320;
> param.outputHeight = 240;
> param.dataFormat = 2; // RGB_565
> camera.setCaptureParams(param);
> }
>
> // This is our main acquisition thread's loop, we go until
> // asked to quit.
> SurfaceHolder holder = mHolder;
> while (!mDone) {
> // Lock the surface, this returns a Canvas that can
> // be used to render into.
> Canvas canvas = holder.lockCanvas();
>
> // Capture directly into the Surface
> if (camera != null) {
> camera.capture(canvas);
> }
>
> // And finally unlock and post the surface.
> holder.unlockCanvasAndPost(canvas);
> }
>
> // Make sure to release the CameraDevice
> if (camera != null) {
> camera.close();
> }
> }
>
> public void requestExitAndWait() {
> // don't call this from PreviewThread thread or it a
> guaranteed
> // deadlock!
> mDone = true;
> try {
> join();
> } catch (InterruptedException ex) { }
> }
> }
>
> }
>
> -------------------------------------------------------------------------------------
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