android 之 Camera

標籤：

由於我剛入職現在的這家公司的時候，他們對涉及到圖片的比較多，所以打算寫一系列圖片的文章，首先就從製造圖片的地方開始寫起–Camera

如果你的app裡面只是需要拍一張照片，只需要調用系統的照相機就可以滿足你的需求了

通過ACTION_IMAGE_CAPTURE調用系統的照相機

intent.setAction(MediaStore.ACTION_IMAGE_CAPTURE);

然後在通過startActivityForResult方法跳轉

onActivityResult：

Bundle extras = data.getExtras();Bitmap bitmap = (Bitmap) extras.get("data");showImage.setImageBitmap(bitmap);

一般的情況下這樣就滿足了你的需求，也不需要增加許可權，但是這裡需要注意的是通過data獲得的是一張縮圖，如果想獲得一張原圖，就需要指定圖片的儲存地址

Uri  uri = Uri.fromFile(new File(path));                intent.setAction(MediaStore.ACTION_IMAGE_CAPTURE);            intent.putExtra(MediaStore.EXTRA_OUTPUT,uri);

同樣使用startActivityForResult方法跳轉

onActivityResult：

FileInputStream fileInputStream = null;Bitmap output;try {     int degree = PhotoUtil.readPictureDegree(path);     fileInputStream = new FileInputStream(new File(path));     output = BitmapFactory.decodeStream(fileInputStream);                    showImage.setImageBitmap(PhotoUtil.rotaingImageView(degree,output));} catch (FileNotFoundException e) {     e.printStackTrace();}finally {     if (fileInputStream != null){     try {          fileInputStream.close();         } catch (IOException e) {               e.printStackTrace();         }     }}

其實拿到這個需要一下兩句話就能拿到這個bitmap

fileInputStream = new FileInputStream(new File(path));output = BitmapFactory.decodeStream(fileInputStream);

但是儲存在本地的圖片，直接這樣取得的照片旋轉了90度，其中圖片的旋轉角度是記錄在exif中的，所以為了把圖片旋轉過來，索性直接利用exif去取角度

/**     * 讀取圖片屬性：旋轉的角度     * @param path 圖片絕對路徑     * @return degree旋轉的角度     */    public static int readPictureDegree(String path) {        int degree  = 0;        try {            ExifInterface exifInterface = new ExifInterface(path);            int orientation = exifInterface.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);            switch (orientation) {                case ExifInterface.ORIENTATION_ROTATE_90:                    degree = 90;                    break;                case ExifInterface.ORIENTATION_ROTATE_180:                    degree = 180;                    break;                case ExifInterface.ORIENTATION_ROTATE_270:                    degree = 270;                    break;            }        } catch (IOException e) {            e.printStackTrace();        }        return degree;    }

然後根據取到的角度旋轉bitmap

public static Bitmap rotaingImageView(int angle , Bitmap bitmap) {        Matrix matrix = new Matrix();        matrix.postRotate(angle);        Bitmap resizedBitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);        return resizedBitmap;    }

對於圖片的操作後面再說

這樣就能實現獲得原圖，並且能夠正向的顯示圖片，但是很多app不只是拍一張照片而已，所以下面開始介紹自訂Camera

package com.zimo.guo.customcamera.view;import android.content.Context;import android.content.pm.PackageManager;import android.graphics.ImageFormat;import android.hardware.Camera;import android.os.Environment;import android.util.AttributeSet;import android.view.SurfaceHolder;import android.view.SurfaceView;import java.io.File;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;/** * Created by zimo on 15/12/27. */public class CameraView extends SurfaceView implements SurfaceHolder.Callback {    private Camera camera;    private SurfaceHolder holder;    private Context context;    private String picUrl;    public CameraView(Context context) {        super(context);        this.context = context;        initHolder();    }    public CameraView(Context context, AttributeSet attrs) {        super(context, attrs);        this.context = context;        initHolder();    }    public CameraView(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        this.context = context;        initHolder();    }    private void initHolder() {        holder = this.getHolder();        holder.addCallback(this);    }    private boolean existCamera(Context context) {        return context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA);    }    /**     * 初始化相機     */    private void initCamera() {        if (camera == null) {            camera = Camera.open();        }    }    private void imagePreview(SurfaceHolder holder) {        try {            if (camera != null) {                camera.setPreviewDisplay(holder);                camera.setDisplayOrientation(90);                camera.startPreview();            }        } catch (IOException e) {            e.printStackTrace();        }    }    private void setParameters() {        if (camera != null) {            Camera.Parameters parameters = camera.getParameters();            parameters.setPictureFormat(ImageFormat.JPEG);//            parameters.setRotation(90);            parameters.setFlashMode(Camera.Parameters.FLASH_MODE_AUTO);            camera.setParameters(parameters);        }    }    private void releaseCamera() {        if (camera != null) {            camera.setPreviewCallback(null);            camera.stopPreview();            camera.release();            camera = null;        }    }    public void autoFocus(){        if (camera != null){            camera.autoFocus(new Camera.AutoFocusCallback() {                @Override                public void onAutoFocus(boolean success, Camera camera) {                    if (success){                        takePicture();                    }                }            });        }    }    public void takePicture(){        if (camera != null){            camera.takePicture(null, null, new Camera.PictureCallback() {                @Override                public void onPictureTaken(byte[] data, Camera camera) {                    if (picUrl == null) {                        picUrl = Environment.getExternalStorageDirectory() + File.separator + "zimo.jpg";                    }                    File file = new File(picUrl);                    if (file.exists()) {                        file.delete();                    }                    try {                        FileOutputStream fos = new FileOutputStream(file);                        fos.write(data);                        fos.close();                    } catch (FileNotFoundException e) {                        e.printStackTrace();                    } catch (IOException e) {                        e.printStackTrace();                    }                    imagePreview(holder);                }            });        }    }    @Override    public void surfaceCreated(SurfaceHolder holder) {        if (existCamera(context)){            initCamera();        }    }    @Override    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {        setParameters();        imagePreview(holder);    }    @Override    public void surfaceDestroyed(SurfaceHolder holder) {        releaseCamera();    }    public void setPicUrl(String picUrl) {        this.picUrl = picUrl;    }}

上面是一個自訂的Camera，繼承了SurfaceView

1. 檢查Camera是否存在
2. 初始化Camera
3. 設定參數
4. 預覽圖片
5. 拍照
6. 釋放Camera

這就是自訂Camera實現的步驟了，當然還有增加許可權

<uses-permission android:name="android.permission.CAMERA"/><uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

只要把CameraView當成自訂控制項使用就好

<com.zimo.guo.customcamera.view.CameraView        android:id="@+id/camera"        android:layout_width="match_parent"        android:layout_height="match_parent" />

點擊拍照按鈕直接調用takePicture()，當然也可以自己定義圖片地址

cameraView.setPicUrl(path);cameraView.takePicture();

還可以實現聚焦之後自動拍照

cameraView.autoFocus();

下篇開始研究圖片了，這篇就先到這！

android 之 Camera