Android使用技巧：将当前摄像头预览图像保存为Bitmap对象 & 保存到本地

今天药忘吃喽~ 2023-03-13 11:33 38阅读 0赞

![12bc1e00199dab8f68418356c5d14127.png][]

# 前言 #

今天，Carson将结合示例讲解：**如何将当前摄像头预览图像保存为Bitmap对象 & 保存到本地**

> Carson带你学Android 文章系列：  
> [Carson带你学Android：页面活动-Activity][Carson_Android_-Activity]  
> [Carson带你学Android：广播-BroadcastReceiver][Carson_Android_-BroadcastReceiver]  
> [Carson带你学Android：服务-Service][Carson_Android_-Service]  
> [Carson带你学Android：内存承载器-ContentProvider][Carson_Android_-ContentProvider]

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# 1. 背景 #

正开启摄像头预览

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# 2. 需求 #

将当前摄像头预览的图像保存为Bitmap对象 & 保存到手机本地文件夹

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# 3. 具体实现 #

// 步骤1：定义存储路径 
    private static final String SD_PATH = "/sdcard/carsonfile/pic/";
    private static final String IN_PATH = "/carsonfile/pic/";
    
    
    // 步骤2：在摄像头回调数据时将数据存储为BitMap
    private Camera.PreviewCallback mPreivewCallback = new Camera.PreviewCallback() {
                @Override
                public void onPreviewFrame(final byte[] data, final Camera camera) {
                    // a. 异步处理
                    mPreviewHandlerThread.postToWorker(new Runnable() {
                        @Override
                        public void run() {
    
                            // b. 获得摄像头预览Size
                            Camera.Size size = mCamera.getParameters().getPreviewSize();
                            try {
                               // c. 创建YUV对象
                                YuvImage image = new YuvImage(data, ImageFormat.NV21, size.width, size.height, null);
                                if (image != null) {
    
                                    // d. 存为BitMap对象
                                    ByteArrayOutputStream stream = new ByteArrayOutputStream();
                                    image.compressToJpeg(new Rect(0, 0, size.width, size.height), 80, stream);
                                    Bitmap bmp = BitmapFactory.decodeByteArray(stream.toByteArray(), 0, stream.size());
    
                                    // e. 保存到文件 - 下面分析1
                                    saveBitmap(mContext, bmp);
                                    stream.close();
                                }
                            } catch (Exception ex) {
                                Log.e("carson", "Error:" + ex.getMessage());
                            }
                        }
    
                    });
    
                }
            };
    
    // 分析1：存到手机文件夹
    public static String saveBitmap(Context context, Bitmap mBitmap) {
            String savePath;
            File filePic;
            if (Environment.getExternalStorageState().equals(
                Environment.MEDIA_MOUNTED)) {
                savePath = SD_PATH;
            } else {
                savePath = context.getApplicationContext().getFilesDir()
                    .getAbsolutePath()
                    + IN_PATH;
            }
            try {
                filePic = new File(savePath + generateFileName() + ".jpg");
                if (!filePic.exists()) {
                    filePic.getParentFile().mkdirs();
                    filePic.createNewFile();
                }
                FileOutputStream fos = new FileOutputStream(filePic);
                mBitmap.compress(Bitmap.CompressFormat.JPEG, 100, fos);
                fos.flush();
                fos.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                return null;
            }
    
            Log.i(TAG, "carsonho：filePic.getAbsolutePath()：%s", filePic.getAbsolutePath());
    
            return filePic.getAbsolutePath();
        }
    
        private static String generateFileName() {
            return UUID.randomUUID().toString();
        }
        
    // 步骤3：设置回调
    mCamera.setPreviewCallBack(mPreivewCallback);

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# 4. 总结 #

接下来我将继续介绍 `Android`开发中的相关知识，感兴趣的同学可以继续关注**Carson带你学Android系列文章**  
[Carson带你学Android：学习方法][Carson_Android]  
[Carson带你学Android：四大组件][Carson_Android 1]  
[Carson带你学Android：自定义View][Carson_Android_View]  
[Carson带你学Android：异步-多线程][Carson_Android_-]  
[Carson带你学Android：性能优化][Carson_Android 2]  
[Carson带你学Android：动画][Carson_Android 3]

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# 欢迎关注Carson\_Ho的[CSDN博客][CSDN] 与 公众号！ #

博客链接：https://carsonho.blog.csdn.net/  
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# 请帮顶 / 评论点赞！因为你的鼓励是我写作的最大动力！ #

[12bc1e00199dab8f68418356c5d14127.png]: /images/20230312/646357ea0c3743979dca5bd8ef5d546b.png
[Carson_Android_-Activity]: https://blog.csdn.net/carson_ho/article/details/82848840
[Carson_Android_-BroadcastReceiver]: https://blog.csdn.net/carson_ho/article/details/52973504
[Carson_Android_-Service]: https://blog.csdn.net/carson_ho/article/details/53160049
[Carson_Android_-ContentProvider]: https://blog.csdn.net/carson_ho/article/details/76101093
[Carson_Android]: https://blog.csdn.net/carson_ho/category_9273178.html?spm=1001.2014.3001.5482
[Carson_Android 1]: https://blog.csdn.net/carson_ho/category_5959547.html?spm=1001.2014.3001.5482
[Carson_Android_View]: https://blog.csdn.net/carson_ho/category_6735474.html?spm=1001.2014.3001.5482
[Carson_Android_-]: https://blog.csdn.net/carson_ho/category_6440777.html?spm=1001.2014.3001.5482
[Carson_Android 2]: https://blog.csdn.net/carson_ho/category_7474499.html?spm=1001.2014.3001.5482
[Carson_Android 3]: https://blog.csdn.net/carson_ho/category_9268277.html?spm=1001.2014.3001.5482
[CSDN]: https://carsonho.blog.csdn.net/
[06b2ed0fbb8979f0aba34c14ede04b59.png]: /images/20230312/8c63eaa3a4804640b5aea1dd64c46cfa.png