安卓相机教程（使用SurfaceView）

Question

这是我的示例代码：

package newslab.video.server;

import android.app.Activity;
import android.hardware.Camera;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class VideoServer extends Activity implements SurfaceHolder.Callback {
    TextView testView;

    Camera camera;
    SurfaceView surfaceView;
    SurfaceHolder surfaceHolder;

    private final String tag = "VideoServer";

    Button start, stop;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        start = (Button)findViewById(R.id.btn_start);
        start.setOnClickListener(new Button.OnClickListener() {
            public void onClick(View arg0) {
                start_camera();
            }
        });

        stop = (Button)findViewById(R.id.btn_stop);
        stop.setOnClickListener(new Button.OnClickListener() {
            public void onClick(View arg0) {
                stop_camera();
            }
        });

        surfaceView = (SurfaceView)findViewById(R.id.surfaceView1);
        surfaceHolder = surfaceView.getHolder();
        surfaceHolder.addCallback(this);
        surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

    private void start_camera() {
        try{
            camera = Camera.open();
        }catch(RuntimeException e){
            Log.e(tag, "init_camera: " + e);
            return;
        }
        Camera.Parameters param;
        param = camera.getParameters();
        //modify parameter
        param.setPreviewFrameRate(20);
        param.setPreviewSize(176, 144);
        camera.setParameters(param);
        try {
            camera.setPreviewDisplay(surfaceHolder);
            camera.startPreview();
        } catch (Exception e) {
            Log.e(tag, "init_camera: " + e);
            return;
        }
    }

    private void stop_camera() {
        camera.stopPreview();
        camera.release();
    }

    public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) {
        // TODO Auto-generated method stub
    }

    public void surfaceCreated(SurfaceHolder holder) {
        // TODO Auto-generated method stub
    }

    public void surfaceDestroyed(SurfaceHolder holder) {
        // TODO Auto-generated method stub
    }
}

然而，它只展示了预览并停止了相机。
还有其他的教程可以教如何保存图像或使用位图处理图像吗？

- jjLin

---

不使用本机相机意味着什么？你在使用哪个相机？ - Narendra Pal

你解决了你的基本问题吗？ - Narendra Pal

下面的评论还有一个问题^^ - jjLin

Answer 1

好的。这里是解决方案：

我没有添加任何try catch。 这只是为了捕获图像并将其存储到sd卡中。

public class VideoServer extends Activity implements SurfaceHolder.Callback {
    TextView testView;

    Camera camera;
    SurfaceView surfaceView;
    SurfaceHolder surfaceHolder;
    PictureCallback rawCallback;
    ShutterCallback shutterCallback;
    PictureCallback jpegCallback;
    private final String tag = "VideoServer";

    Button start, stop, capture;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        start = (Button)findViewById(R.id.btn_start);
        start.setOnClickListener(new Button.OnClickListener()
        {
            public void onClick(View arg0) {
                start_camera();
            }
        });
        stop = (Button)findViewById(R.id.btn_stop);
        capture = (Button) findViewById(R.id.capture);
        stop.setOnClickListener(new Button.OnClickListener()
        {
            public void onClick(View arg0) {
                stop_camera();
            }
        });
        capture.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                captureImage();
            }
        });

        surfaceView = (SurfaceView)findViewById(R.id.surfaceView1);
        surfaceHolder = surfaceView.getHolder();
        surfaceHolder.addCallback(this);
        surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        rawCallback = new PictureCallback() {
            public void onPictureTaken(byte[] data, Camera camera) {
                Log.d("Log", "onPictureTaken - raw");
            }
        };

        /** Handles data for jpeg picture */
        shutterCallback = new ShutterCallback() {
            public void onShutter() {
                Log.i("Log", "onShutter'd");
            }
        };
        jpegCallback = new PictureCallback() {
            public void onPictureTaken(byte[] data, Camera camera) {
                FileOutputStream outStream = null;
                try {
                    outStream = new FileOutputStream(String.format(
                            "/sdcard/%d.jpg", System.currentTimeMillis()));
                    outStream.write(data);
                    outStream.close();
                    Log.d("Log", "onPictureTaken - wrote bytes: " + data.length);
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                } finally {
                }
                Log.d("Log", "onPictureTaken - jpeg");
            }
        };
    }

    private void captureImage() {
        // TODO Auto-generated method stub
        camera.takePicture(shutterCallback, rawCallback, jpegCallback);
    }

    private void start_camera()
    {
        try{
            camera = Camera.open();
        }catch(RuntimeException e){
            Log.e(tag, "init_camera: " + e);
            return;
        }
        Camera.Parameters param;
        param = camera.getParameters();
        //modify parameter
        param.setPreviewFrameRate(20);
        param.setPreviewSize(176, 144);
        camera.setParameters(param);
        try {
            camera.setPreviewDisplay(surfaceHolder);
            camera.startPreview();
            //camera.takePicture(shutter, raw, jpeg)
        } catch (Exception e) {
            Log.e(tag, "init_camera: " + e);
            return;
        }
    }

    private void stop_camera()
    {
        camera.stopPreview();
        camera.release();
    }

    public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) {
        // TODO Auto-generated method stub
    }

    public void surfaceCreated(SurfaceHolder holder) {
        // TODO Auto-generated method stub
    }

    public void surfaceDestroyed(SurfaceHolder holder) {
        // TODO Auto-generated method stub
    }

}

在开始之前不要按下捕获按钮，因为我没有检查它。我只是想向你展示如何将图像捕获并存储到SD卡中。

- Narendra Pal

---

有关编程的内容，请访问此网站了解更多信息：http://marakana.com/forums/android/examples/39.html - Narendra Pal

您的解决方案非常完美。但是还有一个问题，我该如何将捕获的图像作为位图获取以进行进一步的处理？ - jjLin

使用以下代码从SD卡中获取捕获的图像。Bitmap bitmap = BitmapFactory.decodeFile("/path/images/imageName.jpg"); 然后，您可以对位图执行进一步操作。 - Narendra Pal

@mahdi，请查看我在评论中提到的完整示例代码，并告诉我是否无法正常工作。 - Narendra Pal

@NarendraPal，我无法访问那个链接，你能帮我解决一下吗？ - arvind.mohan

Answer 2

不要忘记在Android清单文件中获取使用相机的权限。

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

此外，您需要获取存储图像在SD卡上的权限。

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

- Sahil Mahajan Mj

Answer 3

manifiest文件中的相机权限:

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

在manifest文件中允许从sdcard存储图像的权限：

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

- Kunal Dharaiya

Answer 4

我遇到了与相机相关的问题，尝试着实现和使用它并找到了这些资源: 相机预览 。在页面底部，您可以看到最常见的场景示例以及原始问题中的一个示例: 拍照并预览。

- ViksaaSkool

Answer 5

如果您正在使用Android 10或更高版本，请不要忘记在清单文件中添加以下内容。

android:requestLegacyExternalStorage="true"
android:grantUriPermissions="true"

- Syed Rafaqat Hussain