Camera

在app中使用相机的两种方式：

1.调用系统相机

隐式启动
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
startActivity(intent);

2.自定义相机

注册：

<intent-filter >    <action android:name="android.media.action.IMAGE_CAPTURE"/>    <category android:name="android.intent.category.DEFAULT"/></intent-filter>

3.获取拍照图片

private void startCamera1(View view) {    Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);    startActivityForResult(intent, 1);}private void startCamera2(View view) {    Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);    // 指定想要的文件输出路径，就不用去data里拿了    filePath = Environment.getExternalStorageState() + "/temp.png";    **Uri photoUri = Uri.fromFile(new File(filePath));    intent.putExtra(MediaStore.EXTRA_OUTPUT, photoUri);**    startActivityForResult(intent, 2);}protected void onActivityResult(int requestCode, int resultCode, Intent data) {    super.onActivityResult(requestCode, resultCode, data);    if (resultCode == RESULT_OK) {        if (resultCode == 1) {            **// 这样子拿的是缩略图，不用担心内存溢出            Bundle bundle = data.getExtras();            Bitmap bitmap = (Bitmap) bundle.get("data");            imageView.setImageBitmap(bitmap);**        } else if (resultCode == 2) {            // 直接拿原图            FileInputStream fis = null;            **fis = new FileInputStream(filePath);            Bitmap bitmap = BitmapFactory.decodeStream(fis);            imageView.setImageBitmap(bitmap);//为什么不用担心内存溢出？！**            fis.close();

4.自定义相机代码示例

总结一下：1.用open方法在onresume里创建camera实例，在onpause里释放camera
2.实现surfaceholder的addcallback接口，把camera与surfaceview绑定
3.实现camera.takepicture()相机回调方法

    //相机捕获图像是调用，此时图像数据处理还未完成private Camera.ShutterCallback mShutterCallback = new Camera.ShutterCallback(){    @Override    public void onShutter() {        // TODO Auto-generated method stub    }};//在原始图像数据可用时调用（拍好了,数据放在data中）private Camera.PictureCallback mJpegCallBack = new Camera.PictureCallback(){    @Override    public void onPictureTaken(byte[] data, Camera camera) {        File file = new File("/sdcard/temp.jpg");        try {            FileOutputStream fos = new FileOutputStream(file);            fos.write(data);//把照片放到指定位置            fos.close();            Intent intent = new Intent(CustomCameraActivity.this , ResultActivity.class);            intent.putExtra("PicPath", file.getAbsolutePath());            startActivity(intent);            CustomCameraActivity.this.finish();//拍完跳到另一个activity，并结束当前activity        } catch (FileNotFoundException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }};@Overrideprotected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.custom);    takeButton = (Button) findViewById(R.id.take);    takeButton.setOnClickListener(new OnClickListener() {        @Override        public void onClick(View v) {            //要实现三个接口传入            camera.takePicture(null, null, mJpegCallBack);        }    });    surfaceView = (SurfaceView) findViewById(R.id.preview);    surfaceView.setOnClickListener(new OnClickListener() {        @Override        public void onClick(View v) {            camera.autoFocus(null);//点击屏幕自动对焦（如何不用点就自动对焦？）        }    });    SurfaceHolder holder = surfaceView.getHolder();    holder.addCallback(new Callback() {        @Override        //surface与其客户端进行关联        public void surfaceCreated(SurfaceHolder holder) {                try {                    if(camera != null){                    camera.setPreviewDisplay(holder);//将camera与holder绑定                    camera.setDisplayOrientation(90);//默认横屏，设置旋转角度                    }                } catch (IOException e) {                    // TODO Auto-generated catch block                    e.printStackTrace();                }        }        @Override        //surface首次显示在屏幕上时调用。通过参数可以设置相关属性；通知客户端预览区域大小        public void surfaceChanged(SurfaceHolder holder, int format,                int width, int height) {            Parameters parameters = camera.getParameters();            parameters.setPictureFormat(ImageFormat.JPEG);//设置格式            parameters.setFocusMode(Camera.Parameters.FLASH_MODE_AUTO);//设置对焦模式（自动对焦）            //parameters.setPreviewSize(800, 600);//设置预览大小            List<Size> previewSizes = parameters.getSupportedPreviewSizes();//返回的数组中每个实例封装了一个具体的图片宽高            Size s1 = getBestSize(previewSizes, width, height);//拿到最佳尺寸            parameters.setPreviewSize(s1.width, s1.height);//设置预览大小            List<Size> pictureSizes = parameters.getSupportedPictureSizes();            Size s2 = getBestSize(pictureSizes, width, height);            parameters.setPictureSize(s1.width, s1.height);//设置最后图片创建大小            camera.setParameters(parameters);            try{                camera.startPreview();//开始预览            }catch(Exception e){                camera.release();//万一启动失败，释放资源            }        }        @Override        //surface从屏幕上移除时调用，被销毁，通知客户端停止使用surfa        public void surfaceDestroyed(SurfaceHolder holder) {            if(camera != null){                camera.stopPreview();            }        }    });}@Overrideprotected void onResume() {    super.onResume();    // 初始化camera    if (camera == null) {        camera = Camera.open();    }}@Overrideprotected void onPause() {    super.onPause();    // 释放camera    if (camera != null) {        camera.release();    }}//接受一组预览尺寸，找出最大像素数目的尺寸private Size getBestSize(List<Size> sizes ,int width , int height){    Size bestSize = sizes.get(0);    int largestArea = bestSize.width * bestSize.height;    for(Size s : sizes){        int area = s.width * s.height;        if(area > largestArea){            bestSize = s;            largestArea = area;        }    }    return bestSize;}

检查设备是否带有相机

 PackageManager pm = getPackageManager()； if (!pm.hasSystemFeature(PackageManager.FEATURE_CAMERA) &&         !pm.hasSystemFeature(PackageManager.FEATURE_CAMERA_FRONT)) {     mPhotoButton.setEnabled(false); }      

隐藏状态栏

getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);

使之能截获点击，不应响应 android:clickable="true"

水印：

<RelativeLayout     android:layout_width="match_parent"    android:layout_height="match_parent">     <SurfaceView         android:id="@+id/preview"        android:layout_width="match_parent"        android:layout_height="match_parent"/>     <TextView //也可加其他view         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:text="水印"         android:layout_alignParentBottom="true"         android:layout_centerHorizontal="true"         /></RelativeLayout>

相机拍摄的照片太大，需缩放

//拿屏幕宽高    Display display = getWindowManager().getDefaultDisplay();    int screenWidth = display.getWidth();    int screenHeight = display.getHeight();    //拿图片宽高    Options options = new Options();    options.inJustDecodeBounds = true;//不为图片申请内存，只获取宽高    BitmapFactory.decodeFile(pathName , options);    int srcWidth = options.outWidth;    int srcHeight = options.outHeight;    //计算缩放比例    int scale = 1;    if(srcWidth > screenWidth || srcWidth > screenHeight){        if(srcWidth > srcHeight){            scale = Math.round(srcHeight / screenHeight);        }else{            scale = Math.round(srcWidth / screenWidth);         }    }    //缩放    options.inSampleSize = scale;    options.inJustDecodeBounds = false;    Bitmap bitmap = BitmapFactory.decodeFile( pathName ,options);