我正在开发一个应用程序，当我按下按钮时会启动一个活动（结果）来拍照并存储它。比之前的活动将显示照片。
我正在使用CameraPreview类和CameraActivity活动来实现它。
一切都必须处于纵向模式，并且一切都运行良好：我使用预览开始新活动，以纵向模式拍摄照片并返回上一个活动，并在框中显示图片。
唯一的问题是图片显示（和存储）逆时针旋转90°。我怎么能避免它？
这是我的活动：
public class CameraActivity extends Activity {
private Camera mCamera;
private CameraPreview mPreview;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera);
// Create an instance of Camera
mCamera = getCameraInstance();
mCamera.setDisplayOrientation(90);
Parameters params = mCamera.getParameters();
params.setRotation(90);
params.setPictureSize(100, 200);
mCamera.setParameters(params);
// 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);
}
private PictureCallback mPicture = new PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
File pictureFile = getOutputMediaFile();
if (pictureFile == null){
Log.d(TAG, "Error creating media file, check storage permissions");
Intent intent = getIntent();
setResult(RESULT_CANCELED, intent);
finish();
if (mCamera != null){
mCamera.release(); // release the camera for other applications
mCamera = null;
}
return;
}
try {
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
Intent intent = getIntent();
setResult(RESULT_OK, intent);
finish();
if (mCamera != null){
mCamera.release(); // release the camera for other applications
mCamera = null;
}
return;
} catch (FileNotFoundException e) {
Log.d(TAG, "File not found: " + e.getMessage());
} catch (IOException e) {
Log.d(TAG, "Error accessing file: " + e.getMessage());
}
Intent intent = getIntent();
setResult(RESULT_CANCELED, intent);
finish();
if (mCamera != null){
mCamera.release(); // release the camera for other applications
mCamera = null;
}
return;
}
};
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
}
public void scatta(View v) {
mCamera.takePicture(null, null, mPicture);
}
private File getOutputMediaFile(){
HERE I RETURN A VALID FILE.
return file;
}
}
这是预览：
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
mCamera.setDisplayOrientation(90);
Parameters params = mCamera.getParameters();
params.setRotation(90);
mCamera.setParameters(params);
// start preview with new settings
try {
mCamera.setPreviewDisplay(mHolder);
mCamera.startPreview();
} catch (Exception e){
Log.d(TAG, "Error starting camera preview: " + e.getMessage());
}
}
}
谢谢
答案 0 :(得分：-2)
是的，我找到了解决方案：
这是我的相机活动：
package it......utils;
import it.......R;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import android.app.Activity;
import android.content.Intent;
import android.graphics.ImageFormat;
import android.hardware.Camera;
import android.hardware.Camera.AutoFocusCallback;
import android.hardware.Camera.Parameters;
import android.hardware.Camera.PictureCallback;
import android.hardware.Camera.Size;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.View;
import android.widget.FrameLayout;
import android.widget.TextView;
public class CameraActivity extends Activity {
private Camera mCamera;
private CameraPreview mPreview;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_cam);
// Create an instance of Camera
mCamera = getCameraInstance();
Parameters params = mCamera.getParameters();
params.setFocusMode(Parameters.FOCUS_MODE_AUTO);
params.setPictureFormat(ImageFormat.JPEG);
Camera.Size size = getSmallestPictureSize(params);
params.setPictureSize(size.width, size.height);
mCamera.setParameters(params);
// 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);
}
private Camera.Size getSmallestPictureSize(Camera.Parameters parameters) {
List<Size> list = parameters.getSupportedPictureSizes();
Collections.sort(list, new AreasComparator());
return list.get(1); // I choose the second one becasue the first one is too small.
}
private PictureCallback mPicture = new PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
File pictureFile = getOutputMediaFile();
if (pictureFile == null){
Intent intent = getIntent();
setResult(RESULT_CANCELED, intent);
finish();
if (mCamera != null){
mCamera.release(); // release the camera for other applications
mCamera = null;
}
System.gc();
return;
}
try {
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
System.gc();
if (mCamera != null){
mCamera.release(); // release the camera for other applications
mCamera = null;
}
Intent intent = getIntent();
setResult(RESULT_OK, intent);
finish();
System.gc();
return;
} catch (FileNotFoundException e) {
//TODO
} catch (IOException e) {
//TODO
}
Intent intent = getIntent();
setResult(RESULT_CANCELED, intent);
finish();
if (mCamera != null){
mCamera.release(); // release the camera for other applications
mCamera = null;
}
System.gc();
return;
}
};
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
}
public void scatta(View v) {
mCamera.autoFocus(new AutoFocusCallback() {
@Override
public void onAutoFocus(boolean success, Camera camera) {
if (success) {
mCamera.takePicture(null, null, mPicture);
}
}
});
}
private File getOutputMediaFile(){
File downloads = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
String filePath = downloads.getParent() + File.separator + "PicturesTaken";
File path = new File(filePath);
path.mkdirs();
File file;
file = new File(path, "pic.jpg");
if (file.exists()) {
file.delete();
}
return file;
}
@Override
public void onBackPressed() {
if (mCamera != null){
mCamera.release(); // release the camera for other applications
mCamera = null;
}
mPreview = null;
System.gc();
super.onBackPressed();
}
public class AreasComparator implements Comparator<Camera.Size> {
@Override
public int compare(Camera.Size s1, Camera.Size s2) {
int resultArea=s1.width * s1.height;
int newArea=s2.width * s2.height;
if (newArea < resultArea) {
return 1;
}
return -1;
}
}
}
用它的＆＃39;布局：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="20dp"
tools:context=".CameraActivity" >
<FrameLayout
android:id="@+id/camera_preview"
android:onClick="scatta"
android:layout_width="match_parent"
android:layout_height="700dp" >
</FrameLayout>
</RelativeLayout>
这是我的相机预览：
package it........utils;
import java.io.IOException;
import java.util.List;
import android.content.Context;
import android.hardware.Camera;
import android.hardware.Camera.Parameters;
import android.hardware.Camera.Size;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
/** 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) {
//TODO
}
}
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
mCamera.setDisplayOrientation(90);
Parameters params = mCamera.getParameters();
params.setRotation(90);
mCamera.setParameters(params);
// start preview with new settings
try {
mCamera.setPreviewDisplay(mHolder);
mCamera.startPreview();
} catch (Exception e){
//TODO
}
}
}
最后，这就是我在主要活动中所做的事情，即调用相机并显示拍摄的照片：
private void startCamera() {
Intent intent = new Intent(Pag4Activity.this, CameraActivity.class);
startActivityForResult(intent, CODE_CAM);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if(resultCode==RESULT_OK) {
if(requestCode == CODE_CAM){
File downloads = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
String filePath = downloads.getParent() + File.separator + "PicturesTaken";
File path = new File(filePath);
path.mkdirs();
File file = new File(path, "pic.jpg");
ImageView iv = (ImageView)findViewById(R.id.imageTaken);
Bitmap img = decodeScaledBitmapFromSdCard(file.getPath(), 170, 210);
if(img!=null) {
iv.setImageBitmap(img);
}
}
}
}
public static Bitmap decodeScaledBitmapFromSdCard(String filePath,
int reqWidth, int reqHeight) {
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(filePath, options);
options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
options.inJustDecodeBounds = false;
return BitmapFactory.decodeFile(filePath, options);
}
public static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 1;
if (height > reqHeight || width > reqWidth) {
final int heightRatio = Math.round((float) height / (float) reqHeight);
final int widthRatio = Math.round((float) width / (float) reqWidth);
inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
}
return inSampleSize;
}