我有兴趣为Android编写应用程序，在应用程序中的某个事件后，使用Android上的相机自动拍摄照片。
我需要的东西：
无预览照片
没有按钮供用户按下拍照
只需运行操作即可拍照并将其存储到相册中。
这是我在线教程尝试的一些代码：
public void snap(){
mCamera = Camera.open();
SurfaceView sv = new SurfaceView(getApplicationContext());
try {
mCamera.setPreviewDisplay(sv.getHolder());
parameters = mCamera.getParameters();
//set camera parameters
mCamera.setParameters(parameters);
mCamera.startPreview();
mCamera.takePicture(null, null, mCall);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//Get a surface
sHolder = sv.getHolder();
}
Camera.PictureCallback mCall = new Camera.PictureCallback()
{
public void onPictureTaken(byte[] data, Camera camera)
{
//decode the data obtained by the camera into a Bitmap
FileOutputStream outStream = null;
try{
outStream = new FileOutputStream("/sdcard/Image.jpg");
outStream.write(data);
outStream.close();
} catch (FileNotFoundException e){
Log.d("CAMERA", e.getMessage());
} catch (IOException e){
Log.d("CAMERA", e.getMessage());
}
}
};
public IBinder onBind(Intent intent) {
// TODO Auto-generated method stub
return null;
}
以及它所做的logcat
11-24 01:54:37.738: E/AndroidRuntime(6971): FATAL EXCEPTION: main
11-24 01:54:37.738: E/AndroidRuntime(6971): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.udptest/com.example.udptest.Main}: java.lang.RuntimeException: takePicture failed
11-24 01:54:37.738: E/AndroidRuntime(6971): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2308)
11-24 01:54:37.738: E/AndroidRuntime(6971): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2358)
11-24 01:54:37.738: E/AndroidRuntime(6971): at android.app.ActivityThread.access$600(ActivityThread.java:153)
11-24 01:54:37.738: E/AndroidRuntime(6971): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1247)
11-24 01:54:37.738: E/AndroidRuntime(6971): at android.os.Handler.dispatchMessage(Handler.java:99)
11-24 01:54:37.738: E/AndroidRuntime(6971): at android.os.Looper.loop(Looper.java:137)
11-24 01:54:37.738: E/AndroidRuntime(6971): at android.app.ActivityThread.main(ActivityThread.java:5227)
11-24 01:54:37.738: E/AndroidRuntime(6971): at java.lang.reflect.Method.invokeNative(Native Method)
11-24 01:54:37.738: E/AndroidRuntime(6971): at java.lang.reflect.Method.invoke(Method.java:511)
11-24 01:54:37.738: E/AndroidRuntime(6971): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
11-24 01:54:37.738: E/AndroidRuntime(6971): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:562)
11-24 01:54:37.738: E/AndroidRuntime(6971): at dalvik.system.NativeStart.main(Native Method)
11-24 01:54:37.738: E/AndroidRuntime(6971): Caused by: java.lang.RuntimeException: takePicture failed
11-24 01:54:37.738: E/AndroidRuntime(6971): at android.hardware.Camera.native_takePicture(Native Method)
11-24 01:54:37.738: E/AndroidRuntime(6971): at android.hardware.Camera.takePicture(Camera.java:1101)
11-24 01:54:37.738: E/AndroidRuntime(6971): at android.hardware.Camera.takePicture(Camera.java:1046)
11-24 01:54:37.738: E/AndroidRuntime(6971): at com.example.udptest.Main.snap(Main.java:129)
11-24 01:54:37.738: E/AndroidRuntime(6971): at com.example.udptest.Main.onCreate(Main.java:84)
11-24 01:54:37.738: E/AndroidRuntime(6971): at android.app.Activity.performCreate(Activity.java:5104)
11-24 01:54:37.738: E/AndroidRuntime(6971): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
11-24 01:54:37.738: E/AndroidRuntime(6971): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2262)
11-24 01:54:37.738: E/AndroidRuntime(6971): ... 11 more
任何想法可能会在这里发生什么，或者更好的方法来完成这项任务？
答案 0 :(得分：3)
这是服务来捕捉背景中的照片，希望它有所帮助：
public class CapPhoto extends Service
{
private SurfaceHolder sHolder;
private Camera mCamera;
private Parameters parameters;
@Override
public void onCreate()
{
super.onCreate();
Log.d("CAM", "start");
if (android.os.Build.VERSION.SDK_INT > 9) {
StrictMode.ThreadPolicy policy =
new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);}
Thread myThread = null;
}
@Override
public void onStart(Intent intent, int startId) {
super.onStart(intent, startId);
if (Camera.getNumberOfCameras() >= 2) {
mCamera = Camera.open(CameraInfo.CAMERA_FACING_FRONT); }
if (Camera.getNumberOfCameras() < 2) {
mCamera = Camera.open(); }
SurfaceView sv = new SurfaceView(getApplicationContext());
try {
mCamera.setPreviewDisplay(sv.getHolder());
parameters = mCamera.getParameters();
mCamera.setParameters(parameters);
mCamera.startPreview();
mCamera.takePicture(null, null, mCall);
} catch (IOException e) { e.printStackTrace(); }
sHolder = sv.getHolder();
sHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
Camera.PictureCallback mCall = new Camera.PictureCallback()
{
public void onPictureTaken(final byte[] data, Camera camera)
{
FileOutputStream outStream = null;
try{
File sd = new File(Environment.getExternalStorageDirectory(), "A");
if(!sd.exists()) {
sd.mkdirs();
Log.i("FO", "folder" + Environment.getExternalStorageDirectory());
}
Calendar cal = Calendar.getInstance();
SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd_HHmmss");
String tar = (sdf.format(cal.getTime()));
outStream = new FileOutputStream(sd+tar+".jpg");
outStream.write(data); outStream.close();
Log.i("CAM", data.length + " byte written to:"+sd+tar+".jpg");
camkapa(sHolder);
} catch (FileNotFoundException e){
Log.d("CAM", e.getMessage());
} catch (IOException e){
Log.d("CAM", e.getMessage());
}}
};
@Override
public IBinder onBind(Intent intent) {
return null;
}
public void camkapa(SurfaceHolder sHolder) {
if (null == mCamera)
return;
mCamera.stopPreview();
mCamera.release();
mCamera = null;
Log.i("CAM", " closed");
}
}
<强>的AndroidManifest.xml
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-feature android:name="android.hardware.camera" />
<service android:name=".CapPhoto" android:enabled="true">
<intent-filter>
</intent-filter>
</service>
在 MainActivity 中调用此方法来呼叫服务：
Intent service;
....
Calendar cal = Calendar.getInstance();
service = new Intent(getBaseContext(), CapPhoto.class);
cal.add(Calendar.SECOND, 15);
//TAKE PHOTO EVERY 15 SECONDS
PendingIntent pintent = PendingIntent.getService(this, 0, service, 0);
AlarmManager alarm = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
alarm.setRepeating(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis(),
60*60*1000, pintent);
startService(service);
答案 1 :(得分：1)
几点提示：
首先，不要硬编码文件路径。您的/ SD卡可能根本不存在，因此您的outStream将为null，并且当您从outStream调用任何方法时它将崩溃。相反，请使用 Environment.getExternalStoragePublicDirectory 或 Environment.getExternalStorageDirectory （适用于Android版本＆lt; 2.2的设备）。请参阅here
没有照片预览 - 您可以预览1像素x像素1像素，因此几乎看不见
您需要在AndroidManifest中声明权限：
“android.permission.CAMERA”和“android.permission.WRITE_EXTERNAL_STORAGE”（如果你想保存图片）
我建议您通过example形式完成文档和实验。
答案 2 :(得分：0)
本指南告诉您如何构建相机应用程序。我希望这可以帮助您。 http://developer.android.com/guide/topics/media/camera.html#custom-camera
答案 3 :(得分：0)
也许你可以获得服务吗？