我是Android开发新手，开发的程序可以从Camera中捕获图像并存储在SD卡中。问题是我单独创建Camera类并尝试调用capture_image Activity。这是我的代码。请帮我解决这个问题。
这就是我调用Camera class
的方式Camera cam=new Camera();
fileUri= cam.captureImage();
这是capture_image活动
package com.example.imagecapture;
import java.io.File;
import java.io.FileOutputStream;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.location.Location;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.ImageView.ScaleType;
import android.widget.Toast;
public class capture_image extends Activity {
private Uri fileUri;
private static final int CAMERA_CAPTURE_IMAGE_REQUEST_CODE = 100;
private static int RESULT_LOAD_IMAGE = 1;
private ImageView image1;
private ImageView image2;
private ImageView image3;
private ImageView image4;
private ImageView image5;
private ImageView image6;
private ImageView image7;
private ImageView image8;
//private LocationManager locationManager;
private ImageView[] IMGS = { image1, image2, image3,image4,image5,image6,image7,image8 };
private File file;
private String[] FileNameStrings = new String[8];
private File[] listFile;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.capture_details);
Button buttonLoadImage = (Button) findViewById(R.id.btnBrowseimage);
buttonLoadImage.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
Intent i = new Intent(
Intent.ACTION_PICK,
android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
startActivityForResult(i, RESULT_LOAD_IMAGE);
}
});
Button buttonLoadCamera = (Button) findViewById(R.id.btnCapture);
buttonLoadCamera.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// capture picture
try
{
Camera cam=new Camera();
fileUri= cam.captureImage();
} catch (NullPointerException e) {
e.printStackTrace();
//Toast.makeText(getBaseContext(), "Error:1 on uplod file", Toast.LENGTH_LONG).show();
} catch (Exception e) {
e.printStackTrace();
//Toast.makeText(getBaseContext(), "Error:2 File may be already exists", Toast.LENGTH_LONG).show();
}
}
});
Button buttonSendData = (Button) findViewById(R.id.btnSend);
buttonSendData.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
new PostDataAsyncTask().execute();
}
});
Button buttonCancel = (Button) findViewById(R.id.btnCancel);
buttonCancel.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
finish();
System.exit(0);
}
});
/**
* Checking GPS
* */
//locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
//Toast.makeText(getBaseContext(), "Gps turned on ", Toast.LENGTH_LONG).show();
/**/
//TelephonyManager mTelephonyMgr;
//mTelephonyMgr = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
//String myPhoneNumber = mTelephonyMgr.getLine1Number();
//myPhoneNumber.substring(2);
}
/**
* Checking GPS
* */
public void onLocationChanged(Location location) {
String str = "Latitude: "+location.getLatitude()+" Longitude: "+location.getLongitude();
Toast.makeText(getBaseContext(), str, Toast.LENGTH_LONG).show();
}
public void onProviderDisabled(String provider) {
Toast.makeText(getBaseContext(), "Gps turned off ", Toast.LENGTH_LONG).show();
}
public void onProviderEnabled(String provider) {
Toast.makeText(getBaseContext(), "Gps turned on ", Toast.LENGTH_LONG).show();
}
/**/
/**
* Display image from a path to ImageView
*/
@SuppressLint("SdCardPath")
private void previewCapturedImage() {
try {
// bimatp factory
BitmapFactory.Options options = new BitmapFactory.Options();
// downsizing image as it throws OutOfMemory Exception for larger
options.inSampleSize = 8;
final Bitmap bitmap = BitmapFactory.decodeFile(fileUri.getPath(), options);
//Saving captured image to sdcard/cers
String filaname= Get_next_file_name();
try {
FileOutputStream out = new FileOutputStream(Environment.getExternalStorageDirectory() + File.separator + "cers"+ File.separator+ filaname+".jpg");
bitmap.compress(Bitmap.CompressFormat.PNG, 80, out);
out.close();
} catch (Exception e) {
e.printStackTrace();
}
//imgPreview.setImageBitmap(bitmap);
IMGS[0] = (ImageView) findViewById(R.id.imageViewphoto1);
IMGS[1] = (ImageView) findViewById(R.id.imageViewphoto2);
IMGS[2] = (ImageView) findViewById(R.id.imageViewphoto3);
IMGS[3] = (ImageView) findViewById(R.id.imageViewphoto4);
IMGS[4] = (ImageView) findViewById(R.id.imageViewphoto5);
IMGS[5] = (ImageView) findViewById(R.id.imageViewphoto6);
IMGS[6] = (ImageView) findViewById(R.id.imageViewphoto7);
IMGS[7] = (ImageView) findViewById(R.id.imageViewphoto8);
for(int i=0;i<8;i++)
{
if((String) IMGS[i].getTag()==null)
{
IMGS[i].setImageBitmap(bitmap);
File finalFile = new File(Environment.getExternalStorageDirectory() + File.separator + "cers"+ File.separator+ filaname+".jpg");
FileNameStrings[i]= new String(finalFile.getAbsolutePath().toString());
IMGS[i].setTag( "image" +i);
IMGS[i].getLayoutParams().height = 100;
IMGS[i].getLayoutParams().width = 100;
break;
}
}
} catch (NullPointerException e) {
e.printStackTrace();
}
}
public String Get_next_file_name()
{
int fn,ofn=0;
String[] filename;
// Check for SD Card
if (!Environment.getExternalStorageState().equals(
Environment.MEDIA_MOUNTED)) {
Toast.makeText(this, "Error! No SDCARD Found!", Toast.LENGTH_LONG).show();
} else {
// Locate the image folder in your SD Card
file = new File(Environment.getExternalStorageDirectory() + File.separator +"cers");
// Create a new folder if no folder named SDImageTutorial exist
file.mkdirs();
}
if (file.isDirectory()) {
listFile = file.listFiles();
for (int i = 0; i < listFile.length; i++) {
filename =listFile[i].getName().split(".");
try
{
fn=Integer.parseInt(filename[0]);
if(ofn<fn)
{
ofn=fn;
}
ofn=ofn+1;
}
catch(Exception e)
{
e.printStackTrace();
}
}
}
StringBuilder sb = new StringBuilder();
sb.append("");
sb.append(ofn);
return sb.toString();
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
// if the result is capturing Image
if (requestCode == CAMERA_CAPTURE_IMAGE_REQUEST_CODE) {
if (resultCode == RESULT_OK) {
// successfully captured the image
// display it in image view
previewCapturedImage();
} else if (resultCode == RESULT_CANCELED) {
// user cancelled Image capture
Toast.makeText(getApplicationContext(),
"User cancelled image capture", Toast.LENGTH_SHORT)
.show();
} else {
// failed to capture image
Toast.makeText(getApplicationContext(),
"Sorry! Failed to capture image", Toast.LENGTH_SHORT)
.show();
}
}
// Browse Images
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();
IMGS[0] = (ImageView) findViewById(R.id.imageViewphoto1);
IMGS[1] = (ImageView) findViewById(R.id.imageViewphoto2);
IMGS[2] = (ImageView) findViewById(R.id.imageViewphoto3);
IMGS[3] = (ImageView) findViewById(R.id.imageViewphoto4);
IMGS[4] = (ImageView) findViewById(R.id.imageViewphoto5);
IMGS[5] = (ImageView) findViewById(R.id.imageViewphoto6);
IMGS[6] = (ImageView) findViewById(R.id.imageViewphoto7);
IMGS[7] = (ImageView) findViewById(R.id.imageViewphoto8);
for(int i=0;i<8;i++)
{
if((String) IMGS[i].getTag()==null)
{
//IMGS[i].setImageBitmap(decodeSampledBitmapFromResource(getResources(), R.id.tempimage, 100, 100));
IMGS[i].setImageBitmap(BitmapFactory.decodeFile(picturePath));
File finalFile = new File(picturePath);
FileNameStrings[i]= new String(finalFile.getAbsolutePath().toString());
IMGS[i].setTag( "image" +i);
IMGS[i].getLayoutParams().height = 100;
IMGS[i].getLayoutParams().width = 100;
IMGS[i].setScaleType(ScaleType.FIT_CENTER);
break;
}
}
}
}
}
此处出现错误（相机类）
// start the image capture Intent
startActivityForResult(intent, CAMERA_CAPTURE_IMAGE_REQUEST_CODE);
这是相机类
package com.example.imagecapture;
import java.io.File;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
import android.app.Activity;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.util.Log;
public class Camera extends Activity{
private Uri fileUri;
private static final int CAMERA_CAPTURE_IMAGE_REQUEST_CODE = 100;
private static final int CAMERA_CAPTURE_VIDEO_REQUEST_CODE = 200;
public static final int MEDIA_TYPE_IMAGE = 1;
public static final int MEDIA_TYPE_VIDEO = 2;
private static final String IMAGE_DIRECTORY_NAME = "CERS";
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
}
public boolean DeviceSupportCamera()
{
if (!isDeviceSupportCamera()) {
return false;
}
else
{
return true;
}
}
/**
* Checking device has camera hardware or not
* */
public boolean isDeviceSupportCamera() {
if (getApplicationContext().getPackageManager().hasSystemFeature(
PackageManager.FEATURE_CAMERA)) {
// this device has a camera
return true;
} else {
// no camera on this device
return false;
}
}
/**
* Capturing Camera Image will lauch camera app requrest image capture
*/
public Uri captureImage() {
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
fileUri = getOutputMediaFileUri(MEDIA_TYPE_IMAGE);
intent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri);
// start the image capture Intent
startActivityForResult(intent, CAMERA_CAPTURE_IMAGE_REQUEST_CODE);
return fileUri;
}
/**
* Here we store the file url as it will be null after returning from camera
* app
*/
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
// save file url in bundle as it will be null on scren orientation
// changes
outState.putParcelable("file_uri", fileUri);
}
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
// get the file url
fileUri = savedInstanceState.getParcelable("file_uri");
}
/**
* ------------ Helper Methods ----------------------
* */
/**
* Creating file uri to store image
*/
public Uri getOutputMediaFileUri(int type) {
return Uri.fromFile(getOutputMediaFile(type));
}
/**
* returning image / video
*/
private static File getOutputMediaFile(int type) {
// External sdcard location
File mediaStorageDir = new File(
Environment
.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),
IMAGE_DIRECTORY_NAME);
// Create the storage directory if it does not exist
if (!mediaStorageDir.exists()) {
if (!mediaStorageDir.mkdirs()) {
Log.d(IMAGE_DIRECTORY_NAME, "Oops! Failed create "
+ IMAGE_DIRECTORY_NAME + " 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 if (type == MEDIA_TYPE_VIDEO) {
mediaFile = new File(mediaStorageDir.getPath() + File.separator
+ "VID_" + timeStamp + ".mp4");
} else {
return null;
}
return mediaFile;
}
}
答案 0 :(得分：1)
您永远不应该创建Activity类的实例。检查Raghav Sood的答案
Can i Create the object of a activity in other class?
Camera cam=new Camera();
你有
public class Camera extends Activity{
活动在清单中声明并具有生命周期。而是使用startActivity或startActivityForResult。
此外，您不需要
public static void main(String[] args) {
// TODO Auto-generated method stub
}
将捕获图像代码移至capture_image并使用startActivityForResult。
答案 1 :(得分：1)
使用意图开始新课程。
Intent i = new Intent(capture_image.this, Camera.class);
startActivity(i);
OR
startActivityForResult(i); // if you need to get back a result from Camera class
确保在Manifest文件中声明它。