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I have this custom camera activity in my app, which is working just fine, but when I press the home button while in camera activity, and then return to the app, it crashes, and the logcat says there was a null pointer exception at the surface view creation. This setup method is called on onResume:
public void setup()
{
preview = new CameraPreview(this);
((FrameLayout) findViewById(R.id.camera_preview)).addView(preview);
head=(ImageView)findViewById(R.id.head);
head.setX((float)(Shared.screenWidth/5*1.8));
head.setY((float)(Shared.screenHeight*0.03));
LayoutParams params = (LayoutParams) head.getLayoutParams();
params.width = (int)((Shared.screenWidth/5*3.2)-(head.getX()));
params.height=(int)((Shared.screenHeight/3.8)-(head.getY()));
head.setLayoutParams(params);
body=(ImageView)findViewById(R.id.body);
body.setX((float)(Shared.screenWidth/7));
body.setY((float)(Shared.screenHeight/3.8));
LayoutParams params2 = (LayoutParams) body.getLayoutParams();
params2.width = (int)((Shared.screenWidth/7*6)-(body.getX()));
params2.height=(int)((Shared.screenHeight)-(body.getY()));
body.setLayoutParams(params2);
go=(Button)findViewById(R.id.go);
again=(Button)findViewById(R.id.again);
stop=(ImageButton)findViewById(R.id.stop);
stop.setOnClickListener( new OnClickListener() {
public void onClick(View v) {
Intent i =new Intent(CamActivity.this,Main.class);
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);
}
});
btn = (ImageButton) findViewById(R.id.takePic);
btn.setOnClickListener( new OnClickListener() {
public void onClick(View v) {
preview.camera.takePicture(shutterCallback, rawCallback, jpegCallback);
btn.setVisibility(View.INVISIBLE);
btn.setEnabled(false);
go.setVisibility(View.VISIBLE);
go.setEnabled(true);
head.setVisibility(View.INVISIBLE);
body.setVisibility(View.INVISIBLE);
go.setOnClickListener( new OnClickListener() {
public void onClick(View v) {
Shared.bm=Bitmap.createScaledBitmap(bmp, Shared.screenWidth, Shared.screenHeight, true);
Intent i=new Intent(CamActivity.this,IKill.class);
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);
}
});
again.setVisibility(View.VISIBLE);
again.setEnabled(true);
again.setOnClickListener( new OnClickListener() {
public void onClick(View v) {
if (Build.VERSION.SDK_INT >= 11) {
recreate();
} else {
Intent intent = getIntent();
overridePendingTransition(0, 0);
intent.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
finish();
overridePendingTransition(0, 0);
startActivity(intent);
}
}
});
}
});
}
In addition, on my onCreate method I also have this:
requestWindowFeature(Window.FEATURE_NO_TITLE);
// hide status bar
final Window win = getWindow();
win.setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_camera);
and the logcat:
08-23 08:56:20.174: E/AndroidRuntime(835): FATAL EXCEPTION: main
08-23 08:56:20.174: E/AndroidRuntime(835): java.lang.NullPointerException
08-23 08:56:20.174: E/AndroidRuntime(835): at
com.example.i_kill.CameraPreview.surfaceCreated(CameraPreview.java:38)
08-23 08:56:20.174: E/AndroidRuntime(835): at
android.view.SurfaceView.updateWindow(SurfaceView.java:569)
08-23 08:56:20.174: E/AndroidRuntime(835): at
android.view.SurfaceView.access$000(SurfaceView.java:86)
08-23 08:56:20.174: E/AndroidRuntime(835): at
android.view.SurfaceView$3.onPreDraw(SurfaceView.java:174)
08-23 08:56:20.174: E/AndroidRuntime(835): at
android.view.ViewTreeObserver.dispatchOnPreDraw(ViewTreeObserver.java:680)
08-23 08:56:20.174: E/AndroidRuntime(835): at
android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1842)
08-23 08:56:20.174: E/AndroidRuntime(835): at
android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:989)
08-23 08:56:20.174: E/AndroidRuntime(835): at
android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4351)
08-23 08:56:20.174: E/AndroidRuntime(835): at
android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
08-23 08:56:20.174: E/AndroidRuntime(835): at
android.view.Choreographer.doCallbacks(Choreographer.java:562)
08-23 08:56:20.174: E/AndroidRuntime(835): at
android.view.Choreographer.doFrame(Choreographer.java:532)
08-23 08:56:20.174: E/AndroidRuntime(835): at
android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
08-23 08:56:20.174: E/AndroidRuntime(835): at
android.os.Handler.handleCallback(Handler.java:725)
08-23 08:56:20.174: E/AndroidRuntime(835): at
android.os.Handler.dispatchMessage(Handler.java:92)
08-23 08:56:20.174: E/AndroidRuntime(835): at android.os.Looper.loop(Looper.java:137)
08-23 08:56:20.174: E/AndroidRuntime(835): at
android.app.ActivityThread.main(ActivityThread.java:5041)
08-23 08:56:20.174: E/AndroidRuntime(835): at
java.lang.reflect.Method.invokeNative(Native Method)
08-23 08:56:20.174: E/AndroidRuntime(835): at
java.lang.reflect.Method.invoke(Method.java:511)
08-23 08:56:20.174: E/AndroidRuntime(835): at
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
08-23 08:56:20.174: E/AndroidRuntime(835): at
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
08-23 08:56:20.174: E/AndroidRuntime(835): at dalvik.system.NativeStart.main(Native
Method)
08-23 08:56:26.065: E/Trace(909): error opening trace file: No such file or directory
and here's the entire class: package com.example.i_kill;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.hardware.Camera;
import android.hardware.Camera.PictureCallback;
import android.hardware.Camera.ShutterCallback;
import android.os.Build;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup.LayoutParams;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.ImageButton;
import android.widget.ImageView;
public class CamActivity extends Activity {
public static final int MEDIA_TYPE_IMAGE = 1;
public static String TAG="MainActivity";
private static Camera camera;
private CameraPreview preview;
private ImageView head,body;
private ImageButton btn, stop;
private Button again,go;
private Bitmap bmp;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
// hide status bar
final Window win = getWindow();
win.setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_camera);
}
public void setup()
{
preview = new CameraPreview(this);
((FrameLayout) findViewById(R.id.camera_preview)).addView(preview);
head=(ImageView)findViewById(R.id.head);
head.setX((float)(Shared.screenWidth/5*1.8));
head.setY((float)(Shared.screenHeight*0.03));
LayoutParams params = (LayoutParams) head.getLayoutParams();
params.width = (int)((Shared.screenWidth/5*3.2)-(head.getX()));
params.height=(int)((Shared.screenHeight/3.8)-(head.getY()));
head.setLayoutParams(params);
body=(ImageView)findViewById(R.id.body);
body.setX((float)(Shared.screenWidth/7));
body.setY((float)(Shared.screenHeight/3.8));
LayoutParams params2 = (LayoutParams) body.getLayoutParams();
params2.width = (int)((Shared.screenWidth/7*6)-(body.getX()));
params2.height=(int)((Shared.screenHeight)-(body.getY()));
body.setLayoutParams(params2);
go=(Button)findViewById(R.id.go);
again=(Button)findViewById(R.id.again);
stop=(ImageButton)findViewById(R.id.stop);
stop.setOnClickListener( new OnClickListener() {
public void onClick(View v) {
Intent i =new Intent(CamActivity.this,Main.class);
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);
}
});
btn = (ImageButton) findViewById(R.id.takePic);
btn.setOnClickListener( new OnClickListener() {
public void onClick(View v) {
preview.camera.takePicture(shutterCallback, rawCallback, jpegCallback);
btn.setVisibility(View.INVISIBLE);
btn.setEnabled(false);
go.setVisibility(View.VISIBLE);
go.setEnabled(true);
head.setVisibility(View.INVISIBLE);
body.setVisibility(View.INVISIBLE);
go.setOnClickListener( new OnClickListener() {
public void onClick(View v) {
Shared.bm=Bitmap.createScaledBitmap(bmp, Shared.screenWidth, Shared.screenHeight, true);
Intent i=new Intent(CamActivity.this,IKill.class);
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);
}
});
again.setVisibility(View.VISIBLE);
again.setEnabled(true);
again.setOnClickListener( new OnClickListener() {
public void onClick(View v) {
if (Build.VERSION.SDK_INT >= 11) {
recreate();
} else {
Intent intent = getIntent();
overridePendingTransition(0, 0);
intent.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
finish();
overridePendingTransition(0, 0);
startActivity(intent);
}
}
});
}
});
}
ShutterCallback shutterCallback = new ShutterCallback() {
public void onShutter() {
Log.d(TAG, "onShutter'd");
}
};
PictureCallback rawCallback = new PictureCallback() {
public void onPictureTaken(byte[] data, Camera camera) {
Log.d(TAG, "onPictureTaken - raw");
}
};
/** Handles data for jpeg picture */
PictureCallback jpegCallback = new PictureCallback() {
public void onPictureTaken(byte[] data, Camera camera) {
bmp=BitmapFactory.decodeByteArray(data, 0, data.length );
System.out.println(bmp.getHeight());
System.out.println(bmp.getWidth());
};
};
public void onPause(){
super.onPause();
if(camera!=null){
camera.stopPreview();
camera.setPreviewCallback(null);
camera.release();
camera = null;
}
}
public void onResume()
{
super.onResume();
setup();
}
}
and camera preview class:
package com.example.i_kill;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.List;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.hardware.Camera;
import android.hardware.Camera.PreviewCallback;
import android.hardware.Camera.Size;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
private SurfaceHolder holder;
public Camera camera;
public static String TAG="CameraPreview";
public CameraPreview(Context context) {
super(context);
holder=getHolder();
holder.addCallback(this);
holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, now tell the camera where to draw the preview.
camera = getCameraInstance();
try {
camera.setPreviewDisplay(holder);
camera.setPreviewCallback(new PreviewCallback() {
public void onPreviewFrame(byte[] data, Camera arg1) {
FileOutputStream outStream = null;
try {
outStream = new FileOutputStream(String.format("/sdcard/%d.jpg", System.currentTimeMillis()));
outStream.write(data);
outStream.close();
Log.d(TAG, "onPreviewFrame - wrote bytes: " + data.length);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
}
CameraPreview.this.invalidate();
}
});
} catch (IOException e) {
e.printStackTrace();
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
if(camera!=null){
camera.stopPreview();
camera.setPreviewCallback(null);
camera.release();
camera = null;
}
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
Camera.Parameters parameters = camera.getParameters();
List<Size> previewSizes = parameters.getSupportedPreviewSizes();
Size bestSize = null;
int bestDiff = 0;
int diff = 0;
for (Size size : previewSizes) {
diff = Math.abs(h - size.height) + Math.abs(w - size.width);
if (bestSize == null || diff < bestDiff) {
bestSize = size;
bestDiff = diff;
}
parameters.setPreviewSize(bestSize.width, bestSize.height);
camera.setParameters(parameters);
}
//start preview of camera
camera.startPreview();
}
@Override
public void draw(Canvas canvas) {
super.draw(canvas);
Paint p= new Paint(Color.RED);
Log.d(TAG,"draw");
canvas.drawText("PREVIEW", canvas.getWidth()/2, canvas.getHeight()/2, p );
}
private Camera getCameraInstance(){
Camera c = null;
try {
c = Camera.open(); // attempt to get a Camera instance
}
catch (Exception e){
// Camera is not available (in use or does not exist)
}
return c; // returns null if camera is unavailable
}
}
Thanks for your help :)
557
I solved it by calling setContentView on resume. Thank you all!
100
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