我创建了自己的相机应用程序。当我点击按钮时，它会拍摄照片并将其保存在小册子中。我想要的是在没有预览的情况下拍摄照片而不点击任何按钮。
我的主要活动课程。
package themiya.camera.android;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import android.app.Activity;
import android.content.Context;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.hardware.Camera.PictureCallback;
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.FrameLayout;
import android.widget.Toast;
public class CameraActivity extends Activity {
private Camera mCamera;
private CameraPreview mPreview;
public static final int MEDIA_TYPE_IMAGE = 1;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button captureButton = (Button) findViewById(R.id.button_capture);
System.out.println("Starting!");
// 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);
final PictureCallback mPicture = new PictureCallback() {
public void onPictureTaken(byte[] data, Camera camera) {
File pictureFile = getOutputMediaFile(MEDIA_TYPE_IMAGE);
if (pictureFile == null){
return;
}
try {
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
MediaStore.Images.Media.insertImage(getContentResolver(), pictureFile.getAbsolutePath(), pictureFile.getName(), pictureFile.getName());
} catch (FileNotFoundException e) {
} catch (IOException e) {
}
}
};
// Add a listener to the Capture button
captureButton.setOnClickListener(
new View.OnClickListener() {
public void onClick(View v) {
// get an image from the camera
System.out.println("Photo Taking!");
mCamera.takePicture(null, null, mPicture);
}
}
);
}
/** 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
}
@Override
protected void onPause() {
super.onPause();
releaseCamera(); // release the camera immediately on pause event
}
private void releaseCamera(){
if (mCamera != null){
mCamera.release(); // release the camera for other applications
mCamera = null;
}
}
/** Create a File for saving an image or video */
private 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()){
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 {
return null;
}
return mediaFile;
}
}
预览课程。
package themiya.camera.android;
import android.content.Context;
import android.hardware.Camera;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback{
private SurfaceHolder mHolder;
private Camera mCamera;
public CameraPreview(Context context,Camera camera) {
super(context);
mCamera = camera;
/*SurfaceView view = new SurfaceView(this);
c.setPreviewDisplay(view.getHolder());
c.startPreview();
c.takePicture(shutterCallback, rawPictureCallback, jpegPictureCallback);
* */
// 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 surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// TODO Auto-generated method stub
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){
}
}
public void surfaceCreated(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
}
在活动类中，点击方法就是这样。
captureButton.setOnClickListener(
new View.OnClickListener() {
public void onClick(View v) {
// get an image from the camera
System.out.println("Photo Taking!");
mCamera.takePicture(null, null, mPicture);
}
}
);
当我删除该侦听器部分并仅放置
时mCamera.takePicture(null, null, mPicture);
部分应用程序崩溃。我认为这可能是由于应用程序打开相机所需的延迟。因此代码在打开相机之前尝试获取照片。还等一下（10000）;不适合我。
而且我想在没有预览的情况下拍摄照片。根据我的知识，我必须更改预览类来做到这一点。但我不知道这样做的正确方法。
任何人都可以帮助我使用这个asp。
答案 0 :(得分：5)
诀窍是给Camera Class一个不属于视图层次结构的SurfaceView。以下代码来自我的一个应用程序，我使用此技术来显示我自己的
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
@Override
protected void onPause() {
super.onPause();
if (mCamera != null) {
mCamera.stopPreview();
mCamera.release();
mCamera = null;
}
}
@Override
protected void onResume() {
super.onResume();
mCamera = Camera.open();
startPreview();
}
private void startPreview() {
if (mCamera != null) {
mCamera.stopPreview();
try {
mCamera.setPreviewDisplay(new SurfaceView(this).getHolder());
} catch (IOException e) {
e.printStackTrace();
}
mCamera.setPreviewCallbackWithBuffer(this);
Camera.Parameters parameters = mCamera.getParameters();
parameters.setPreviewSize(IMAGE_W, IMAGE_H);
mCamera.setParameters(parameters);
PixelFormat p = new PixelFormat();
PixelFormat.getPixelFormatInfo(parameters.getPreviewFormat(), p);
int bufSize = (IMAGE_W * IMAGE_H * p.bitsPerPixel) / 8;
mCamera.addCallbackBuffer(new byte[bufSize]);
mCamera.startPreview();
}
}
public void onPreviewFrame(final byte[] data, Camera camera) {
if (mCamera == null) {
return;
}
mCamera.addCallbackBuffer(data);
}
}
答案 1 :(得分：0)
好的我找到了自动拍照的答案。添加为对他人使用的评论。
final Timer t = new Timer();
t.schedule(new TimerTask() {
@Override
public void run() {
mCamera.takePicture(null, null, mPicture); t.cancel();
}
},5000);
答案 2 :(得分：-1)
它的简单创建另一个方法，带有10000个延迟的计时器变量，完成预览活动，然后你就完成了。逻辑是这些方法将在定时器1活动完成后运行5秒。