我想创建一个应用程序，使用设备的相机拍照，将图像保存在内部存储器中，然后在下一个活动中显示该图像。预览工作完美，但是当我点击“捕获”按钮时，应用程序将转到下一个活动，并且只显示一个空白的白色屏幕。也许我没有正确地写文件或阅读文件？
以下是主要活动：
public class MainActivity extends ActionBarActivity {
public final static String EXTRA_MESSAGE = "File_name";
private Camera mCamera;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Create an instance of Camera
mCamera = getCameraInstance();
// Create our Preview view and set it as the content of our activity.
CameraPreview mPreview = new CameraPreview(this, mCamera);
FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
preview.addView(mPreview);
// Add a listener to the Capture button
Button captureButton = (Button) findViewById(R.id.button_capture);
captureButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// get an image from the camera
mCamera.takePicture(null, null, mPicture);
}
}
);
}
//////////////////////
public void sendInfo(String pathway) {
Intent intent = new Intent(this, show_image.class);
intent.putExtra(EXTRA_MESSAGE,pathway);
startActivity(intent);
}
/////////////////
private Camera.PictureCallback mPicture = new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data , Camera camera) {
Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
ContextWrapper cw = new ContextWrapper(getApplicationContext());
// path to /data/data/yourapp/app_data/imageDir
File directory = cw.getDir("imageDir", Context.MODE_PRIVATE);
// Create imageDir
File mypath=new File(directory,"pic.jpg");
FileOutputStream fos = null;
if (directory == null){
Log.d("Logtag", "Error creating media file, check storage permissions: ");
return;
}
try {
fos = new FileOutputStream(mypath);
bitmap.compress(Bitmap.CompressFormat.PNG, 100, fos);
fos.close();
String path = directory.getAbsolutePath();
sendInfo(path);
} catch (FileNotFoundException e) {
Log.d("Logtag", "File not found: " + e.getMessage());
} catch (IOException e) {
Log.d("Logtag", "Error accessing file: " + e.getMessage());
}
}
};
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A safe way to get an instance of the Camera object.
*/
public 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)
Toast.makeText(getApplicationContext(), "Camera is not available (in use or does not exist)",
Toast.LENGTH_LONG).show();
}
return c; // returns null if camera is unavailable
}
}
这是第二个应该显示刚刚拍摄的图像的活动：
public class show_image extends ActionBarActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Intent intent = getIntent();
String path = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
try {
File f = new File(path, "pic.jpg");
Bitmap b = BitmapFactory.decodeStream(new FileInputStream(f));
ImageView img= new ImageView(this);
img.setImageBitmap(b);
}
catch (FileNotFoundException e)
{
e.printStackTrace();
}
}
public static Bitmap decodeFile(File f, final int maxSize) {
Bitmap b = null;
// Decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
FileInputStream fis = null;
try {
fis = new FileInputStream(f);
BitmapFactory.decodeStream(fis, null, o);
fis.close();
int scale = 1;
if (o.outHeight > maxSize || o.outWidth > maxSize) {
scale = (int) Math.pow(2, (int) Math.round(Math.log(maxSize / (double) Math.max(o.outHeight, o.outWidth)) / Math.log(0.5)));
}
// Decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
fis = new FileInputStream(f);
b = BitmapFactory.decodeStream(fis, null, o2);
} catch (Exception e) {
Log.e("Logtag", "Error processing bitmap", e);
} finally {
//FileUtil.closeQuietly(fis);
}
return b;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
Android Studio中的LogCat：
02-25 12:32:49.389 17041-17041/edu.ramapo.camer I/System.out﹕ debugger has settled (1496)
02-25 12:32:49.620 17041-17041/edu.ramapo.camer I/dalvikvm﹕ Could not find method android.view.ViewGroup.onNestedScrollAccepted, referenced from method android.support.v7.internal.widget.ActionBarOverlayLayout.onNestedScrollAccepted
02-25 12:32:49.620 17041-17041/edu.ramapo.camer W/dalvikvm﹕ VFY: unable to resolve virtual method 11360: Landroid/view/ViewGroup;.onNestedScrollAccepted (Landroid/view/View;Landroid/view/View;I)V
02-25 12:32:49.620 17041-17041/edu.ramapo.camer D/dalvikvm﹕ VFY: replacing opcode 0x6f at 0x0000
02-25 12:32:49.620 17041-17041/edu.ramapo.camer I/dalvikvm﹕ Could not find method android.view.ViewGroup.onStopNestedScroll, referenced from method android.support.v7.internal.widget.ActionBarOverlayLayout.onStopNestedScroll
02-25 12:32:49.620 17041-17041/edu.ramapo.camer W/dalvikvm﹕ VFY: unable to resolve virtual method 11366: Landroid/view/ViewGroup;.onStopNestedScroll (Landroid/view/View;)V
02-25 12:32:49.620 17041-17041/edu.ramapo.camer D/dalvikvm﹕ VFY: replacing opcode 0x6f at 0x0000
02-25 12:32:49.630 17041-17041/edu.ramapo.camer I/dalvikvm﹕ Could not find method android.support.v7.internal.widget.ActionBarOverlayLayout.stopNestedScroll, referenced from method android.support.v7.internal.widget.ActionBarOverlayLayout.setHideOnContentScrollEnabled
02-25 12:32:49.630 17041-17041/edu.ramapo.camer W/dalvikvm﹕ VFY: unable to resolve virtual method 9050: Landroid/support/v7/internal/widget/ActionBarOverlayLayout;.stopNestedScroll ()V
02-25 12:32:49.630 17041-17041/edu.ramapo.camer D/dalvikvm﹕ VFY: replacing opcode 0x6e at 0x000e
02-25 12:32:49.660 17041-17041/edu.ramapo.camer I/dalvikvm﹕ Could not find method android.content.res.TypedArray.getChangingConfigurations, referenced from method
android.support.v7.internal.widget.TintTypedArray.getChangingConfigurations
02-25 12:32:49.660 17041-17041/edu.ramapo.camer W/dalvikvm﹕ VFY: unable to resolve virtual method 367: Landroid/content/res/TypedArray;.getChangingConfigurations ()I
02-25 12:32:49.660 17041-17041/edu.ramapo.camer D/dalvikvm﹕ VFY: replacing opcode 0x6e at 0x0002
02-25 12:32:49.670 17041-17041/edu.ramapo.camer I/dalvikvm﹕ Could not find method android.content.res.TypedArray.getType, referenced from method android.support.v7.internal.widget.TintTypedArray.getType
02-25 12:32:49.670 17041-17041/edu.ramapo.camer W/dalvikvm﹕ VFY: unable to resolve virtual method 389: Landroid/content/res/TypedArray;.getType (I)I
02-25 12:32:49.670 17041-17041/edu.ramapo.camer D/dalvikvm﹕ VFY: replacing opcode 0x6e at 0x0002
02-25 12:32:50.611 17041-17041/edu.ramapo.camer D/libEGL﹕ loaded /system/lib/egl/libEGL_adreno200.so
02-25 12:32:50.621 17041-17041/edu.ramapo.camer D/libEGL﹕ loaded /system/lib/egl/libGLESv1_CM_adreno200.so
02-25 12:32:50.621 17041-17041/edu.ramapo.camer D/libEGL﹕ loaded /system/lib/egl/libGLESv2_adreno200.so
02-25 12:32:50.631 17041-17041/edu.ramapo.camer I/Adreno200-EGL﹕ <qeglDrvAPI_eglInitialize:265>: EGL 1.4 QUALCOMM build: HAREESHG_Nondeterministic_AU+PATCH[ES]_msm8960_JB_1.9.6_MR2_CL3219408_release_ENGG (CL3219408)
Build Date: 09/28/13 Sat
Local Branch: hhh
Remote Branch: quic/jb_1.9.6_1
Local Patches: 8d50ec23e42ef52b570aa6ff1650afac0b503d78 CL3219408: Fix in the Glreadpixels for negative offsets and larger dimensions.
801859126f6ca69482b39a34ca61447e3f7cded8 rb: fix panel settings to clear undrawn/undefined buffers
Reconstruct Branch: LOCAL_PATCH[ES]
02-25 12:32:50.991 17041-17041/edu.ramapo.camer D/OpenGLRenderer﹕ Enabling debug mode 0
02-25 12:32:51.552 17041-17041/edu.ramapo.camer I/Choreographer﹕ Skipped 59 frames! The application may be doing too much work on its main thread.
02-25 12:32:56.037 17041-17047/edu.ramapo.camer D/dalvikvm﹕ Debugger has detached; object registry had 4113 entries
02-25 12:33:18.651 17041-17041/edu.ramapo.camer D/dalvikvm﹕ GC_FOR_ALLOC freed 694K, 38% free 12155K/19420K, paused 29ms, total 32ms
02-25 12:33:18.771 17041-17041/edu.ramapo.camer I/dalvikvm-heap﹕ Grow heap (frag case) to 45.705MB for 31961104-byte allocation
02-25 12:33:24.507 17041-17041/edu.ramapo.camer D/dalvikvm﹕ GC_FOR_ALLOC freed 31627K, 40% free 11825K/19424K, paused 30ms, total 30ms
02-25 12:33:24.587 17041-17041/edu.ramapo.camer I/dalvikvm-heap﹕ Grow heap (frag case) to 45.382MB for 31961104-byte allocation
答案 0 :(得分：2)
那么我现在已经发了一个应用程序的副本，我发送的链接已经是代码：
public class GlassARTest extends FragmentActivity {
private static final String TAG = "CameraActivity";
public static final int MEDIA_TYPE_IMAGE = 1;
private Camera mCamera;
private CameraPreview mPreview;
private Context mContext;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_test);
mContext = this;
if(checkCameraHardware(mContext)){
// Create an instance of Camera
mCamera = getCameraInstance();
// Create our Preview view and set it as the content of our activity.
mPreview = new CameraPreview(this, mCamera);
FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
preview.addView(mPreview);
// Add a listener to the Capture button
Button captureButton = (Button) findViewById(R.id.button_capture);
captureButton.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
// get an image from the camera
mCamera.takePicture(null, null, mPicture);
}
}
);
}
}
private PictureCallback mPicture = new PictureCallback() {
@Override
public void onPictureTaken(final byte[] data, Camera camera) {
new AsyncTask<Void, Void, String>() {
@Override
protected String doInBackground(Void... params) {
File pictureFile = getOutputMediaFile(MEDIA_TYPE_IMAGE);
if (pictureFile == null){
Log.d(TAG, "Error creating media file, check storage permissions: ");
return null;
}
try {
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
return pictureFile.getPath();
} catch (FileNotFoundException e) {
Log.d(TAG, "File not found: " + e.getMessage());
return null;
} catch (IOException e) {
Log.d(TAG, "Error accessing file: " + e.getMessage());
return null;
}
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
if(result != null){
Intent intent = new Intent(mContext, ImageDisplayActivity.class);
intent.putExtra(ImageDisplayActivity.KEY_PATH, result);
startActivity(intent);
}
}
}.execute();
}
};
/** A basic Camera preview class */
public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
private SurfaceHolder mHolder;
private Camera mCamera;
public CameraPreview(Context context, Camera camera) {
super(context);
mCamera = camera;
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = getHolder();
mHolder.addCallback(this);
// deprecated setting, but required on Android versions prior to 3.0
mHolder.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.
try {
mCamera.setPreviewDisplay(holder);
mCamera.startPreview();
} catch (IOException e) {
Log.d(TAG, "Error setting camera preview: " + e.getMessage());
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
// empty. Take care of releasing the Camera preview in your activity.
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// If your preview can change or rotate, take care of those events here.
// Make sure to stop the preview before resizing or reformatting it.
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(TAG, "Error starting camera preview: " + e.getMessage());
}
}
}
/** A safe way to get an instance of the Camera object. */
public static 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
}
/** Check if this device has a camera */
private boolean checkCameraHardware(Context context) {
if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)){
// this device has a camera
return true;
} else {
// no camera on this device
return false;
}
}
/** 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), "MyCameraApp");
// 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", Locale.getDefault()).format(new Date());
File mediaFile;
if (type == MEDIA_TYPE_IMAGE){
mediaFile = new File(mediaStorageDir.getPath() + File.separator +
"IMG_"+ timeStamp + ".jpg");
} else {
return null;
}
return mediaFile;
}
} private SurfaceHolder mHolder;
private Camera mCamera;
public CameraPreview(Context context, Camera camera) {
super(context);
mCamera = camera;
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = getHolder();
mHolder.addCallback(this);
// deprecated setting, but required on Android versions prior to 3.0
mHolder.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.
try {
mCamera.setPreviewDisplay(holder);
mCamera.startPreview();
} catch (IOException e) {
Log.d(TAG, "Error setting camera preview: " + e.getMessage());
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
// empty. Take care of releasing the Camera preview in your activity.
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// If your preview can change or rotate, take care of those events here.
// Make sure to stop the preview before resizing or reformatting it.
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(TAG, "Error starting camera preview: " + e.getMessage());
}
}
}
/** A safe way to get an instance of the Camera object. */
public static 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
}
/** Check if this device has a camera */
private boolean checkCameraHardware(Context context) {
if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)){
// this device has a camera
return true;
} else {
// no camera on this device
return false;
}
}
/** 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), "MyCameraApp");
// 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", Locale.getDefault()).format(new Date());
File mediaFile;
if (type == MEDIA_TYPE_IMAGE){
mediaFile = new File(mediaStorageDir.getPath() + File.separator +
"IMG_"+ timeStamp + ".jpg");
} else {
return null;
}
return mediaFile;
}
}
和另一个活动：
public class ImageDisplayActivity extends FragmentActivity{
public static final String KEY_PATH = "path";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_image_display);
final ImageView imageDisplay = (ImageView)findViewById(R.id.image_displayer);
final Bundle extras = getIntent().getExtras();
if(extras != null){
final String path = extras.getString(KEY_PATH);
File imgFile = new File(path);
Bitmap bitmap = decodeFile(imgFile);
imageDisplay.setImageBitmap(bitmap);
}
}
private Bitmap decodeFile(File f){
Bitmap b = null;
try {
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
FileInputStream fis = new FileInputStream(f);
BitmapFactory.decodeStream(fis, null, o);
fis.close();
int scale = 1;
if (o.outHeight > 50 || o.outWidth > 50) {
scale = (int)Math.pow(2, (int) Math.round(Math.log(50 / (double) Math.max(o.outHeight, o.outWidth)) / Math.log(0.5)));
}
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
fis = new FileInputStream(f);
b = BitmapFactory.decodeStream(fis, null, o2);
fis.close();
} catch (IOException e) {
}
return b;
}
}
这段代码显示了我拍摄照片的像素化图像（因为我只是为了测试目的而以低质量解码它）。 我希望这能帮到你。