我有一个自定义相机应用程序，一切正常。但是每当应用程序被暂停时（当调用onPause或onDestroyed时）相机被释放，之后当调用onResume并且点击捕获按钮是拍摄图像时，我的应用程序崩溃。我该怎么解决这个问题？请帮助我，提前致谢
CameraActivity代码
package com.example.skmishra.plates.Activities;
import android.app.ActionBar;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.hardware.Camera;
import android.hardware.SensorManager;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.util.Log;
import android.view.MotionEvent;
import android.view.OrientationEventListener;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.ZoomControls;
import com.example.skmishra.plates.Asyncs.CameraAsync;
import com.example.skmishra.plates.CameraHandler;
import com.example.skmishra.plates.Library.Fonts;
import com.example.skmishra.plates.R;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FilenameFilter;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.SortedSet;
import java.util.TreeSet;
/**
* Created by skmishra on 12/28/2015.
*/
public class camera extends Activity {
private static final int RESULT_LOAD_IMAGE = 200 ;
private Camera mCamera=null;
private CameraHandler surface_view;
public static final int MEDIA_TYPE_IMAGE = 1;
public static final int MEDIA_TYPE_VIDEO = 2;
public static final String TAG = "Aloo";
int toRotate = 90;
public int currentCameraID = 0;
OrientationEventListener myOrientationEventListener;
private ZoomControls zoomControls;
private double mDist;
Boolean imageSwitchClicked = false;
Boolean mShowFlash = false;
ImageView mSwitch_cam;
ImageView mFlashBut;
FrameLayout preview;
CameraAsync mCamAsync;
ImageView imageGallery;
TextView raleway;
TextView headerCameraText;
Fonts mFonts;
int permCode=4;
Camera.Parameters params;
String recievedType=null;
@Override
protected void onCreate(Bundle savedInstanceState) {
Log.e("I Called Thus "," cda");
mCamAsync=new CameraAsync(this);
mCamAsync.execute();
super.onCreate(savedInstanceState);
setContentView(R.layout.camera);
imageGallery = (ImageView) findViewById(R.id.select_gallery);
mFonts = new Fonts();
preview = (FrameLayout) findViewById(R.id.camera_preview);
mFlashBut = (ImageView) findViewById(R.id.flash);
mSwitch_cam = (ImageView) findViewById(R.id.white_switch);
raleway = (TextView) findViewById(R.id.textView2);
headerCameraText = (TextView) findViewById(R.id.imageHead);
// mFonts.setRalewayBold(this, headerCameraText);
Intent gets = getIntent();
recievedType = gets.getExtras().getString("recievedCameraPurpose");
handleHeaderText(recievedType);
mFonts.setRalewayBold(this, raleway);
myOrientationEventListener
= new OrientationEventListener(this, SensorManager.SENSOR_DELAY_NORMAL) {
@Override
public void onOrientationChanged(int arg0) {
int rotation = arg0;
if (rotation > 340) {
if (currentCameraID == 0) {
toRotate = 90;
} else {
toRotate =270;
Log.e("POSITION_TITLT", "-> Potrait Front camera");
}
} else if (rotation < 80 && rotation > 30) {
toRotate = 180;
Log.e("POSITION_TILT", "-> Landscape Right " + rotation);
} else if (rotation < 280 && rotation > 240) {
toRotate = 0;
Log.e("POSITION_TILT", "-> Landscape Left " + rotation);
}
}
};
if (myOrientationEventListener.canDetectOrientation()) {
myOrientationEventListener.enable();
} else {
Toast.makeText(this, "Can't DetectOrientation", Toast.LENGTH_LONG).show();
finish();
}
}
private boolean checkifCamera(Context context) {
if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
return true;
} else {
return false;
}
}
public Camera getCameraInstance() {
Camera c = null;
try {
releaseCameraAndPreview();
c = Camera.open();
} catch (Exception e) {
Toast.makeText(this, "Print error" + e.getMessage(), Toast.LENGTH_LONG).show();
}
return c;
}
public void onCompleteInstanceCameraAysnc(Camera camera)
{
mCamera = camera;
surface_view = new CameraHandler(this, mCamera);
params = mCamera.getParameters();
preview.addView(surface_view);
set_image_gallery();
}
public void switchC(View view) {
if (!imageSwitchClicked) {
mSwitch_cam.setAlpha(1.0f);
imageSwitchClicked = true;
} else {
mSwitch_cam.setAlpha(0.5f);
imageSwitchClicked = false;
}
setCameraID();
mCamera = surface_view.switchCamera();
params=mCamera.getParameters();
}
public void flash_onOf(View view) {
if (!mShowFlash) {
params.setFlashMode(Camera.Parameters.FLASH_MODE_ON);
mFlashBut.setAlpha(1.0f);
mShowFlash = true;
} else {
params.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
mFlashBut.setAlpha(0.5f);
mShowFlash = false;
}
}
private void releaseCameraAndPreview() {
if (mCamera != null) {
mCamera.stopPreview();
mCamera.setPreviewCallback(null);
mCamera.lock();
mCamera.release();
mCamera=null;
}
else
{
Log.e("Cert","Lerts");
}
}
@Override
protected void onResume() {
super.onResume();
}
@Override
protected void onDestroy() {
Log.e("LLL", "Dessssdccc");
super.onDestroy();
try {
mCamera.stopPreview();
mCamera.setPreviewCallback(null);
mCamera.lock();
myOrientationEventListener.disable();
mCamera.release();
mCamera=null;
permCode=15;
} catch (Exception e) {
e.printStackTrace();
}
}
@Override
protected void onPause() {
Log.e("LLL", "Dessssdccc");
super.onPause();
try {
mCamera.stopPreview();
mCamera.setPreviewCallback(null);
mCamera.lock();
myOrientationEventListener.disable();
mCamera.release();
mCamera=null;
permCode=15;
} catch (Exception e) {
e.printStackTrace();
}
}
public void takePH(View view) {
if(mShowFlash && !imageSwitchClicked)
{
params.setFlashMode(Camera.Parameters.FLASH_MODE_ON);
}
params.set("rotation", toRotate);
mCamera.setParameters(params);
mCamera.takePicture(null, null, mPicture);
}
Camera.PictureCallback mPicture = new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
File pictureFile = getOutputMediaFile(MEDIA_TYPE_IMAGE);
if (pictureFile == null) {
Log.d(TAG, "Error creating media file, check storage permissions: ");
return;
}
try {
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
} catch (FileNotFoundException e) {
Log.d(TAG, "File not found: " + e.getMessage());
} catch (IOException e) {
Log.d(TAG, "Error accessing file: " + e.getMessage());
}
Intent i=new Intent(getApplicationContext(),ShowOut.class);
i.putExtra("purpose",recievedType);
i.putExtra("img-url",pictureFile.toString());
startActivity(i);
}
};
/**
* Create a file Uri for saving an image or video
*/
private static Uri getOutputMediaFileUri(int type) {
return Uri.fromFile(getOutputMediaFile(type));
}
/**
* Create a File for saving an image or video
*/
private static File getOutputMediaFile(int type) {
// To be safe, you should check that the SDCard is mounted
// using Environment.getExternalStorageState() before doing this.
File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES), "Plates");
// This location works best if you want the created images to be shared
// between applications and persist after your app has been uninstalled.
// Create the storage directory if it does not exist
if (!mediaStorageDir.exists()) {
if (!mediaStorageDir.mkdirs()) {
Log.d("MyCameraApp", "failed to create directory");
return null;
}
}
// Create a media file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
File mediaFile;
if (type == MEDIA_TYPE_IMAGE) {
mediaFile = new File(mediaStorageDir.getPath() + File.separator +
"IMG_" + timeStamp + ".jpg");
} else if (type == MEDIA_TYPE_VIDEO) {
mediaFile = new File(mediaStorageDir.getPath() + File.separator +
"VID_" + timeStamp + ".mp4");
} else {
return null;
}
return mediaFile;
}
public void handleHeaderText(String type) {
Log.e("Type",type);
headerCameraText.setText("");
if (type.equals("ADD_COVER_PLATES")) {
headerCameraText.setText("Take a cover image for your plate");
}
else if(type.equals("ADD_PROFILE_USER"))
{
imageGallery.setVisibility(View.GONE);
}
else if(type.equals("PLATE_UPLOAD_SINGLETON")) {
headerCameraText.setText("Click an image for a plate");
}
}
public void setCameraID() {
if (currentCameraID == Camera.CameraInfo.CAMERA_FACING_BACK) {
currentCameraID = Camera.CameraInfo.CAMERA_FACING_FRONT;
toRotate = 270;
} else {
currentCameraID = Camera.CameraInfo.CAMERA_FACING_BACK;
toRotate = 90;
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
// Get the pointer ID
Camera.Parameters params = mCamera.getParameters();
int action = event.getAction();
if (event.getPointerCount() > 1) {
// handle multi-touch events
if (action == MotionEvent.ACTION_POINTER_DOWN) {
mDist = getFingerSpacing(event);
} else if (action == MotionEvent.ACTION_MOVE && params.isZoomSupported()) {
mCamera.cancelAutoFocus();
handleZoom(event, params);
}
} else {
// handle single touch events
if (action == MotionEvent.ACTION_UP) {
handleFocus(event, params);
}
}
return true;
}
private void handleZoom(MotionEvent event, Camera.Parameters params) {
int maxZoom = params.getMaxZoom();
int zoom = params.getZoom();
double newDist = getFingerSpacing(event);
if (newDist > mDist) {
//zoom in
if (zoom < maxZoom)
zoom++;
} else if (newDist < mDist) {
//zoom out
if (zoom > 0)
zoom--;
}
mDist = newDist;
params.setZoom(zoom);
mCamera.setParameters(params);
}
public void handleFocus(MotionEvent event, Camera.Parameters params) {
int pointerId = event.getPointerId(0);
int pointerIndex = event.findPointerIndex(pointerId);
// Get the pointer's current position
float x = event.getX(pointerIndex);
float y = event.getY(pointerIndex);
List<String> supportedFocusModes = params.getSupportedFocusModes();
if (supportedFocusModes != null && supportedFocusModes.contains(Camera.Parameters.FOCUS_MODE_AUTO)) {
mCamera.autoFocus(new Camera.AutoFocusCallback() {
@Override
public void onAutoFocus(boolean b, Camera camera) {
// currently set to auto-focus on single touch
}
});
}
}
/**
* Determine the space between the first two fingers
*/
private double getFingerSpacing(MotionEvent event) {
// ...
float x = event.getX(0) - event.getX(1);
float y = event.getY(0) - event.getY(1);
double pres;
pres = Math.sqrt(x * x + y * y);
return pres;
}
public void set_image_gallery() {
// Find the last picture
String[] projection = new String[]{
MediaStore.Images.ImageColumns._ID,
MediaStore.Images.ImageColumns.DATA,
MediaStore.Images.ImageColumns.BUCKET_DISPLAY_NAME,
MediaStore.Images.ImageColumns.DATE_TAKEN,
MediaStore.Images.ImageColumns.MIME_TYPE
};
final Cursor cursor = getContentResolver()
.query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, projection, null,
null,MediaStore.Images.ImageColumns._ID + " DESC");
// Put it in the image view
if (cursor.moveToFirst()) {
String imageLocation = cursor.getString(1);
File imageFile = new File(imageLocation);
if (imageFile.exists()) { // TODO: is there a better way to do this?
Bitmap bm=decodeFile(imageFile);
imageGallery.setImageBitmap(bm);
}
}
cursor.close();
}
public Bitmap decodeFile(File f) {
try {
//Decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
BitmapFactory.decodeStream(new FileInputStream(f), null, o);
//The new size we want to scale to
final int REQUIRED_SIZE = 490;
//Find the correct scale value. It should be the power of 2.
int scale = 1;
while (o.outWidth / scale / 2 >= REQUIRED_SIZE && o.outHeight / scale / 2 >= REQUIRED_SIZE)
scale *= 2;
//Decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
} catch (FileNotFoundException e) {
}
return null;
}
public void imagePick(View view)
{
Intent photoPickerIntent = new Intent(Intent.ACTION_PICK);
photoPickerIntent.setType("image/*");
startActivityForResult(photoPickerIntent, RESULT_LOAD_IMAGE);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == RESULT_LOAD_IMAGE && resultCode == RESULT_OK && null != data) {
Uri selectedImage = data.getData();
String[] filePathColumn = {MediaStore.Images.Media.DATA};
Cursor cursor = getContentResolver().query(selectedImage,
filePathColumn, null, null, null);
cursor.moveToFirst();
int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
String picturePath = cursor.getString(columnIndex);
cursor.close();
Intent transfer=null;
if(recievedType.equals("ADD_COVER_PLATES")) {
transfer = new Intent(this, create_plates.class);
}
else if(recievedType.equals("PLATE_UPLOAD_SINGLETON"))
{
transfer=new Intent(this,plate_select_upload.class);
}
transfer.putExtra("imagUrl",picturePath);
startActivity(transfer);
}
}
}
相机处理程序代码
package com.example.skmishra.plates;
import android.content.Context;
import android.hardware.Camera;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import java.io.IOException;
/**
* Created by skmishra on 12/28/2015.
*/
public class CameraHandler extends SurfaceView implements SurfaceHolder.Callback {
private SurfaceHolder mHolder;
private Camera mCamera=null;
public int currentCameraID=0;
public CameraHandler(Context context,Camera camera) {
super(context);
mCamera=camera;
mHolder=getHolder();
mHolder.addCallback(this);
mHolder.setType(SurfaceHolder.SURFACE_TYPE_GPU);
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
try {
if(mCamera==null)
{
mCamera=Camera.open();
}
mCamera.setPreviewDisplay(holder);
Camera.Parameters p = mCamera.getParameters();
}
catch (IOException e)
{
Log.d("--DS", "Error setting camera preview: " + e.getMessage());
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
fixOr();
if(mHolder.getSurface()==null)
{
return;
}
if (mHolder.getSurface() == null){
// preview surface does not exist
return;
}
// stop preview before making changes
try {
mCamera.stopPreview();
} catch (Exception e){
// ignore: tried to stop a non-existent preview
}
// set preview size and make any resize, rotate or
// reformatting changes here
// start preview with new settings
try {
mCamera.setPreviewDisplay(mHolder);
mCamera.startPreview();
} catch (Exception e){
Log.d("--DS", "Error starting camera preview: " + e.getMessage());
}
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
mCamera.release();
mCamera = null;
}
public void fixOr()
{
mCamera.stopPreview();
mCamera.setDisplayOrientation(90);
mCamera.startPreview();
}
public Camera switchCamera() {
mCamera.stopPreview();
mCamera.release();
if(currentCameraID==Camera.CameraInfo.CAMERA_FACING_BACK)
{
currentCameraID = Camera.CameraInfo.CAMERA_FACING_FRONT;
}
else
{
currentCameraID=Camera.CameraInfo.CAMERA_FACING_BACK;
}
mCamera=Camera.open(currentCameraID);
fixOr();
try {
mCamera.setPreviewDisplay(mHolder);
} catch (IOException e) {
e.printStackTrace();
}
mCamera.startPreview();
return mCamera;
}
}
更新** StackTrace
Process: com.example.skmishra.plates, PID: 10575
java.lang.RuntimeException: Fail to connect to camera service
at android.hardware.Camera.<init>(Camera.java:545)
at android.hardware.Camera.open(Camera.java:403)
at com.example.skmishra.plates.CameraHandler.surfaceCreated(CameraHandler.java:35)
at android.view.SurfaceView.updateWindow(SurfaceView.java:599)
at android.view.SurfaceView.onWindowVisibilityChanged(SurfaceView.java:243)
at android.view.View.dispatchWindowVisibilityChanged(View.java:9034)
at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:1275)
at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:1275)
at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:1275)
at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:1275)
at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:1275)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1319)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1062)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5873)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
at android.view.Choreographer.doCallbacks(Choreographer.java:580)
at android.view.Choreographer.doFrame(Choreographer.java:550)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5753)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1405)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1200)
答案 0 :(得分：0)
经过大量研究，我终于找到了问题所在。问题出在FrameLayout上，我不得不在Pause上删除它并在OnResume上重新创建它
@Override
protected void onResume() {
super.onResume();
mCamAsync = new CameraAsync(this);//Async task to get the camera instance
mCamAsync.execute();
}
@Override
protected void onPause() {
super.onPause();
releaseCameraAndPreview();
preview = (FrameLayout) findViewById(R.id.camera_preview);
preview.removeViewAt(0);
}
**编辑**
我还从onCreate中删除了cameraAsync的执行，这意味着我只在OnResume中实例化相机