我尝试在我的应用程序中实现前置摄像头。我使用了以下代码。它与后置摄像头配合使用。但我不能将相机更换为前置摄像头。
package com.fsp.googleimagesearch;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.hardware.Camera;
import android.hardware.Camera.CameraInfo;
import android.hardware.Camera.Parameters;
import android.hardware.Camera.PictureCallback;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.Button;
import android.widget.FrameLayout;
public class PixtantCamera extends Activity {
private Camera mCamera;
private CameraPreview mCameraPreview;
Button btn_capture, btn_front_cam;
FrameLayout preview;
private SurfaceHolder mSurfaceHolder;
@Override
protected void onStop() {
super.onStop();
if (mCamera != null) {
// mCamera.stopPreview();
stopCamera();
mCamera.release();
}
}
@Override
protected void onPause() {
super.onPause();
if (mCamera != null) {
// mCamera.stopPreview();
stopCamera();
mCamera.release();
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.pixt_camera);
mCamera = getCameraInstance();
mCameraPreview = new CameraPreview(this, mCamera);
preview = (FrameLayout) findViewById(R.id.camera_preview);
preview.addView(mCameraPreview);
btn_front_cam = (Button) findViewById(R.id.btn_front_cam);
btn_capture = (Button) findViewById(R.id.btn_click_cam);
btn_capture.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
mCamera.takePicture(null, null, mPicture);
}
});
btn_front_cam.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (Camera.getNumberOfCameras() >= 2) {
// if you want to open front facing camera use this line
mCamera = Camera.open(CameraInfo.CAMERA_FACING_FRONT);
try {
mCameraPreview = new CameraPreview(PixtantCamera.this,
mCamera);
preview.addView(mCameraPreview);
}
catch (Exception e) {
mCamera.release();
}
mCamera.takePicture(null, null, mPicture);
}
}
});
}
public int getFrontCameraId() {
CameraInfo ci = new CameraInfo();
for (int i = 0; i < Camera.getNumberOfCameras(); i++) {
Camera.getCameraInfo(i, ci);
if (ci.facing == CameraInfo.CAMERA_FACING_FRONT)
return i;
}
return -1; // No front-facing camera found
}
private Camera getCameraInstance() {
Camera camera = null;
try {
camera = Camera.open();
} catch (Exception e) {
// cannot get camera or does not exist
}
return camera;
}
PictureCallback mPicture = new PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
File pictureFile = getOutputMediaFile();
if (pictureFile == null) {
return;
}
try {
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
} catch (FileNotFoundException e) {
} catch (IOException e) {
}
}
};
private static File getOutputMediaFile() {
File mediaStorageDir = new File(
Environment
.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),
"MyCameraApp");
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;
mediaFile = new File(mediaStorageDir.getPath() + File.separator
+ "IMG_" + timeStamp + ".jpg");
return mediaFile;
}
public void stopCamera() {
// mSurfaceHolder = getHolder();
mSurfaceHolder.removeCallback(mCameraPreview);
// mCamera.stopPreview();
}
public class CameraPreview extends SurfaceView implements
SurfaceHolder.Callback {
// private Camera mCamera;
// Constructor that obtains context and camera
@SuppressWarnings("deprecation")
public CameraPreview(Context context, Camera camera) {
super(context);
mCamera = camera;
mSurfaceHolder = this.getHolder();
mSurfaceHolder.addCallback(this);
mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
@Override
public void surfaceCreated(SurfaceHolder surfaceHolder) {
try {
mCamera.setPreviewDisplay(surfaceHolder);
mCamera.startPreview();
} catch (IOException e) {
// left blank for now
}
}
@Override
public void surfaceDestroyed(SurfaceHolder surfaceHolder) {
mCamera.stopPreview();
mCamera.release();
}
@Override
public void surfaceChanged(SurfaceHolder surfaceHolder, int format,
int width, int height) {
// start preview with new settings
try {
mCamera.setPreviewDisplay(surfaceHolder);
mCamera.startPreview();
} catch (Exception e) {
// intentionally left blank for a test
}
}
}
}
我收到以下错误。
04-23 23:27:34.260: E/AndroidRuntime(24320): FATAL EXCEPTION: main
04-23 23:27:34.260: E/AndroidRuntime(24320): java.lang.RuntimeException: Fail to connect to camera service
04-23 23:27:34.260: E/AndroidRuntime(24320): at android.hardware.Camera.native_setup(Native Method)
04-23 23:27:34.260: E/AndroidRuntime(24320): at android.hardware.Camera.<init>(Camera.java:353)
04-23 23:27:34.260: E/AndroidRuntime(24320): at android.hardware.Camera.open(Camera.java:312)
04-23 23:27:34.260: E/AndroidRuntime(24320): at com.fsp.googleimagesearch.PixtantCamera$3.onClick(PixtantCamera.java:88)
04-23 23:27:34.260: E/AndroidRuntime(24320): at android.view.View.performClick(View.java:4262)
04-23 23:27:34.260: E/AndroidRuntime(24320): at android.view.View$PerformClick.run(View.java:17351)
04-23 23:27:34.260: E/AndroidRuntime(24320): at android.os.Handler.handleCallback(Handler.java:615)
04-23 23:27:34.260: E/AndroidRuntime(24320): at android.os.Handler.dispatchMessage(Handler.java:92)
04-23 23:27:34.260: E/AndroidRuntime(24320): at android.os.Looper.loop(Looper.java:137)
04-23 23:27:34.260: E/AndroidRuntime(24320): at android.app.ActivityThread.main(ActivityThread.java:4935)
04-23 23:27:34.260: E/AndroidRuntime(24320): at java.lang.reflect.Method.invokeNative(Native Method)
04-23 23:27:34.260: E/AndroidRuntime(24320): at java.lang.reflect.Method.invoke(Method.java:511)
04-23 23:27:34.260: E/AndroidRuntime(24320): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
04-23 23:27:34.260: E/AndroidRuntime(24320): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
04-23 23:27:34.260: E/AndroidRuntime(24320): at dalvik.system.NativeStart.main(Native Method)
我也添加了权限..
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-feature android:name="android.hardware.camera" />
<uses-permission android:name="android.permission.CAMERA" />
答案 0 :(得分：0)
我认为问题在于，在发布应用当前持有的相机之前，您无法再次拨打Camera.open()。尝试添加mCamera.release()作为onClick btn_front_cam方法的第一行。
编辑：您可能还需要
<uses-feature android:name="android.hardware.camera.autofocus"/>
以及
<uses-feature android:name="android.hardware.camera.front"/>
在AndroidManifest.xml文件中。