android SurfaceView 设置一帧RBG 数据 android camera surfaceview

转载

mob64ca13f30cc8 2023-08-26 12:54:05

文章标签 android ide java 文章分类 Android 移动开发

在android中，通过相机获取预览界面的需求似乎很变态，好像也没有什么使用场景。但是，有一个场景需要获取预览界面的图像，就是扫码，比如微信，支付宝的扫一扫，就是需要获取预览界面的图像数据的。

实现逻辑比较简单，不过肯定比打开系统相机要麻烦一点的。

下面简单说一下实现步骤：

实例化一个SurfaceView。
在surfaceCreated()回调中去实例化Camera对象，去自动对焦。
在onAutoFocus()回调中去调用camera.takePicture(null,null,callback);。
在第3步的callback里面去获取预览图像数据int data[]。
（可选）将获取的数据换成成文件。
（可选）将该文件对象加载成bitmap对象。
在不使用的使用释放相机资源。

代码细节：

清单文件：

<uses-feature android:name="android.hardware.camera" />
    <uses-feature android:name="android.hardware.camera.autofocus" />

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

java代码：

package com.python.cat.testgradle;

import android.Manifest;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.hardware.Camera;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.Toast;

import com.apkfuns.logutils.LogUtils;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.ChecksumException;
import com.google.zxing.FormatException;
import com.google.zxing.NotFoundException;
import com.google.zxing.RGBLuminanceSource;
import com.google.zxing.Result;
import com.google.zxing.common.GlobalHistogramBinarizer;
import com.google.zxing.qrcode.QRCodeReader;
import com.yanzhenjie.permission.Action;
import com.yanzhenjie.permission.AndPermission;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;

public class UseCameraActivity extends Activity {


    private Activity get() {
        return this;
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_asome);
        setTitle(getClass().getSimpleName());
        final FrameLayout frameLayout = findViewById(R.id.prev_content_layout);
        Button btn = findViewById(R.id.start_camera_preview);

        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                AndPermission.with(get())
                        .permission(Manifest.permission.CAMERA,
                                Manifest.permission.WRITE_EXTERNAL_STORAGE
                        )
                        .onDenied(new Action() {
                            @Override
                            public void onAction(List<String> permissions) {
                                LogUtils.e("error....." + permissions);
                            }
                        })
                        .onGranted(new Action() {
                            @Override
                            public void onAction(List<String> permissions) {
                                LogUtils.w("you can do..");
                                ScanView scanView = new ScanView(get());
                                frameLayout.removeAllViews();
                                frameLayout.addView(scanView);
                            }
                        }).start();
            }
        });
    }


    static class ScanView extends SurfaceView implements SurfaceHolder.Callback,
            Camera.AutoFocusCallback {
        private Camera mCamera;
        private final File fileImg;

        private ScanView self;

        public ScanView(Context context) {
            super(context);
            fileImg = new File(context.getCacheDir(), "prev_view.jpg");
            SurfaceHolder mHolder = getHolder();
            self = this;
            mHolder.addCallback(this);
            // deprecated setting, but required on Android versions prior to 3.0
            mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        }

        @Override
        public void onAutoFocus(boolean success, Camera camera) {
            LogUtils.w("auto focus..." + success);
            if (mCamera != null) {
                mCamera.takePicture(null, null, null, new Camera.PictureCallback() {
                    @Override
                    public void onPictureTaken(byte[] data, Camera camera) {

                        mCamera.cancelAutoFocus();
                        mCamera.stopPreview(); // 拿到数据就停止！！！
                        LogUtils.w("========data========");
                        LogUtils.w("----------data-----------------");
//                        camera.startPreview();
                        File pictureFile = fileImg;
                        if (pictureFile == null) {
                            LogUtils.e("Error creating media file, check storage permissions: " +
                                    null);
                            return;
                        }

                        if (data == null) {
                            return;
                        }
                        try {
                            LogUtils.d(data);
                            FileOutputStream fos = new FileOutputStream(pictureFile);
                            fos.write(data);
                            fos.close();
                            LogUtils.e("save preview complete###!!!");
                            LogUtils.e("save preview complete###!!!" + pictureFile);
                            BitmapFactory.Options options = new BitmapFactory.Options();
                            options.inJustDecodeBounds = true;
                            BitmapFactory.decodeFile(pictureFile.getAbsolutePath(), options);
                            options.inJustDecodeBounds = false;
                            int outWidth = options.outWidth;
                            int outHeight = options.outHeight;
                            if (outWidth >= getWidth() * 2) {
                                options.inSampleSize = outWidth / getWidth();
                            }
                            if (outHeight >= getHeight() * 2) {
                                options.inSampleSize = outHeight / getHeight();
                            }
                            Bitmap bmp = BitmapFactory.decodeFile(pictureFile.getAbsolutePath(), options);
                            Result result = parseInfoFromBitmap(bmp);
                            if (result != null) {
                                Toast.makeText(getContext(), "INFO:" + result.getText(), Toast.LENGTH_SHORT).show();
                                LogUtils.w("解析成功：" + result);
                            } else {
                                LogUtils.e("再次尝试中....");
                                mCamera.startPreview();
                                mCamera.autoFocus(self);
                                // todo:这里也可以做最大重试次数的限制...
                            }
                        } catch (Exception e) {
                            LogUtils.e("Error accessing file: " + e.getMessage());
                        }
                    }
                });
            }
        }

        public Result parseInfoFromBitmap(Bitmap bitmap) {
            int[] pixels = new int[bitmap.getWidth() * bitmap.getHeight()];
            bitmap.getPixels(pixels, 0, bitmap.getWidth(), 0, 0, bitmap.getWidth(), bitmap.getHeight());
            LogUtils.w("### pixels dest==" + Arrays.toString(pixels));

            RGBLuminanceSource source = new RGBLuminanceSource(bitmap.getWidth(),
                    bitmap.getHeight(), pixels);
            GlobalHistogramBinarizer binarizer = new GlobalHistogramBinarizer(source);
            BinaryBitmap image = new BinaryBitmap(binarizer);
            Result result = null;
            try {
                result = new QRCodeReader().decode(image);
                return result;
            } catch (NotFoundException e) {
                e.printStackTrace();
                Toast.makeText(getContext(), "非二维码图片，不能解析", Toast.LENGTH_SHORT).show();
            } catch (ChecksumException e) {
                e.printStackTrace();
            } catch (FormatException e) {
                e.printStackTrace();
            }

            return null;

        }

        @Override
        public void surfaceCreated(SurfaceHolder holder) {
            LogUtils.e("x surfaceCreated.. #####");
            try {
                mCamera = Camera.open();
                mCamera.setPreviewDisplay(holder);
                mCamera.setDisplayOrientation(90);
                Camera.Parameters parameters = mCamera.getParameters();
//                parameters.setPictureSize(1600, 1200);
//                parameters.setPreviewSize(640, 480);
                mCamera.setParameters(parameters);
                mCamera.startPreview();
                mCamera.autoFocus(this);
                LogUtils.e("surfaceCreated.. #####");

            } catch (IOException e) {
                LogUtils.e("Error setting camera preview: " + e.getMessage());
            }
        }

        @Override
        public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

            LogUtils.w("--change-");
        }

        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
            LogUtils.w("destroy--");
            if (mCamera != null) {
                mCamera.cancelAutoFocus();
                mCamera.stopPreview();
                mCamera.release();
            }
        }
    }
}

布局文件：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".UseCameraActivity">


    <Button
        android:id="@+id/start_camera_preview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:text="@string/start_camera_preview" />

    <FrameLayout
        android:id="@+id/prev_content_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@id/start_camera_preview"></FrameLayout>
</RelativeLayout>

gradle配置（可选）：

implementation 'com.yanzhenjie:permission:2.0.0-rc4' // 运行时权限语法糖
implementation 'com.google.zxing:core:3.3.1' // zxing 解析二维码图片

嗯，以上就是获取相机预览图像数据的代码了。不过，这里用的Camera接口是过时的了，不建议使用。不过可以运行。我目前的compileSdkVersion=26。

就酱咯。完整app代码也许有的吧。

=======

update: 关于Camera2，我选择放弃….

官方的说法是：

The android.hardware.camera2 package provides an interface to individual camera devices connected to an Android device. It replaces the deprecated Camera class.

This package models a camera device as a pipeline, which takes in input requests for capturing a single frame, captures the single image per the request, and then outputs one capture result metadata packet, plus a set of output image buffers for the request. The requests are processed in-order, and multiple requests can be in flight at once. Since the camera device is a pipeline with multiple stages, having multiple requests in flight is required to maintain full framerate on most Android devices.

反正是看懂了一句话，就是用来替代Camera的。

但是，真的很麻烦。我没有找到中文的，可以直接运行的案例，找到了两个外国人写的博客，里面给了完整的代码。不过估计不能直接访问。我把拷贝到我的项目里面去了。可以直接运行。

完整app代码
因为每一篇代码都很长，我就不贴出来了，说一下路径。