android - 自定义相机安卓

Question

我想在 Activity 中使用相机预览。我想添加图像(表面 View 上的透明框架)。我尝试了以下代码，以便我可以轻松地自定义 xml 布局:

package com.demo;


import java.io.IOException;

import android.app.Activity;
import android.graphics.PixelFormat;
import android.hardware.Camera;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.widget.Toast;

public class CameraDemoActivity extends Activity implements SurfaceHolder.Callback{
    /** Called when the activity is first created. */
     Camera camera;
     SurfaceView surfaceView;
     SurfaceHolder surfaceHolder;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        getWindow().setFormat(PixelFormat.UNKNOWN);
        surfaceView = (SurfaceView)findViewById(R.id.surfaceview);
        surfaceHolder = surfaceView.getHolder();
        surfaceHolder.addCallback(this);
        surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        camera = Camera.open();
        if(camera!=null){

            try {
             camera.setPreviewDisplay(surfaceHolder);
             camera.startPreview();
            } catch (IOException e) {
             Toast.makeText(this, (CharSequence) e, Toast.LENGTH_LONG).show();
            }

        }


    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width,
            int height) {
        // TODO Auto-generated method stub

    }

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

    }

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

    }
}

这是我的 list :

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.demo"
      android:versionCode="1"
      android:versionName="1.0">
    <uses-sdk android:minSdkVersion="8" />

    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".CameraDemoActivity"
                  android:label="@string/app_name" android:screenOrientation="portrait">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

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

这是我的布局:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<SurfaceView 
android:id="@+id/surfaceview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"/>
</LinearLayout>

不知道为什么camera的预览不显示？

Answer 1

使用此代码

PreviewDemo.java

public class PreviewDemo extends Activity implements OnClickListener {

    private SurfaceView preview = null;
    private SurfaceHolder previewHolder = null;
    private Camera camera = null;
    private boolean inPreview = false;
    ImageView image;
    Bitmap bmp, itembmp;
    static Bitmap mutableBitmap;
    PointF start = new PointF();
    PointF mid = new PointF();
    float oldDist = 1f;
    File imageFileName = null;
    File imageFileFolder = null;
    private MediaScannerConnection msConn;
    Display d;
    int screenhgt, screenwdh;
    ProgressDialog dialog;



    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.preview);

        image = (ImageView) findViewById(R.id.image);
        preview = (SurfaceView) findViewById(R.id.surface);

        previewHolder = preview.getHolder();
        previewHolder.addCallback(surfaceCallback);
        previewHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

        previewHolder.setFixedSize(getWindow().getWindowManager()
            .getDefaultDisplay().getWidth(), getWindow().getWindowManager()
            .getDefaultDisplay().getHeight());


    }


    @Override
    public void onResume() {
        super.onResume();
        camera = Camera.open();
    }

    @Override
    public void onPause() {
        if (inPreview) {
            camera.stopPreview();
        }

        camera.release();
        camera = null;
        inPreview = false;
        super.onPause();
    }

    private Camera.Size getBestPreviewSize(int width, int height, Camera.Parameters parameters) {
        Camera.Size result = null;
        for (Camera.Size size: parameters.getSupportedPreviewSizes()) {
            if (size.width <= width && size.height <= height) {
                if (result == null) {
                    result = size;
                } else {
                    int resultArea = result.width * result.height;
                    int newArea = size.width * size.height;
                    if (newArea > resultArea) {
                        result = size;
                    }
                }
            }
        }
        return (result);
    }

    SurfaceHolder.Callback surfaceCallback = new SurfaceHolder.Callback() {
        public void surfaceCreated(SurfaceHolder holder) {
            try {
                camera.setPreviewDisplay(previewHolder);
            } catch (Throwable t) {
                Log.e("PreviewDemo-surfaceCallback",
                    "Exception in setPreviewDisplay()", t);
                Toast.makeText(PreviewDemo.this, t.getMessage(), Toast.LENGTH_LONG)
                    .show();
            }
        }

        public void surfaceChanged(SurfaceHolder holder,
        int format, int width,
        int height) {
            Camera.Parameters parameters = camera.getParameters();
            Camera.Size size = getBestPreviewSize(width, height,
            parameters);

            if (size != null) {
                parameters.setPreviewSize(size.width, size.height);
                camera.setParameters(parameters);
                camera.startPreview();
                inPreview = true;
            }
        }

        public void surfaceDestroyed(SurfaceHolder holder) {
            // no-op
        }
    };


    Camera.PictureCallback photoCallback = new Camera.PictureCallback() {
        public void onPictureTaken(final byte[] data, final Camera camera) {
            dialog = ProgressDialog.show(PreviewDemo.this, "", "Saving Photo");
            new Thread() {
                public void run() {
                    try {
                        Thread.sleep(1000);
                    } catch (Exception ex) {}
                    onPictureTake(data, camera);
                }
            }.start();
        }
    };



    public void onPictureTake(byte[] data, Camera camera) {

        bmp = BitmapFactory.decodeByteArray(data, 0, data.length);
        mutableBitmap = bmp.copy(Bitmap.Config.ARGB_8888, true);
        savePhoto(mutableBitmap);
        dialog.dismiss();
    }



    class SavePhotoTask extends AsyncTask < byte[], String, String > {@Override
        protected String doInBackground(byte[]...jpeg) {
            File photo = new File(Environment.getExternalStorageDirectory(), "photo.jpg");
            if (photo.exists()) {
                photo.delete();
            }
            try {
                FileOutputStream fos = new FileOutputStream(photo.getPath());
                fos.write(jpeg[0]);
                fos.close();
            } catch (java.io.IOException e) {
                Log.e("PictureDemo", "Exception in photoCallback", e);
            }
            return (null);
        }
    }


    public void savePhoto(Bitmap bmp) {
        imageFileFolder = new File(Environment.getExternalStorageDirectory(), "Rotate");
        imageFileFolder.mkdir();
        FileOutputStream out = null;
        Calendar c = Calendar.getInstance();
        String date = fromInt(c.get(Calendar.MONTH)) + fromInt(c.get(Calendar.DAY_OF_MONTH)) + fromInt(c.get(Calendar.YEAR)) + fromInt(c.get(Calendar.HOUR_OF_DAY)) + fromInt(c.get(Calendar.MINUTE)) + fromInt(c.get(Calendar.SECOND));
        imageFileName = new File(imageFileFolder, date.toString() + ".jpg");
        try {
            out = new FileOutputStream(imageFileName);
            bmp.compress(Bitmap.CompressFormat.JPEG, 100, out);
            out.flush();
            out.close();
            scanPhoto(imageFileName.toString());
            out = null;
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public String fromInt(int val) {
        return String.valueOf(val);
    }

    public void scanPhoto(final String imageFileName) {
        msConn = new MediaScannerConnection(PreviewDemo.this, new MediaScannerConnectionClient() {
            public void onMediaScannerConnected() {
                msConn.scanFile(imageFileName, null);
                Log.i("msClient obj  in Photo Utility", "connection established");
            }
            public void onScanCompleted(String path, Uri uri) {
                msConn.disconnect();
                Log.i("msClient obj in Photo Utility", "scan completed");
            }
        });
        msConn.connect();
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_MENU && event.getRepeatCount() == 0) {
            onBack();
        }
        return super.onKeyDown(keyCode, event);
    }

    public void onBack() {
        Log.e("onBack :", "yes");
        camera.takePicture(null, null, photoCallback);
        inPreview = false;
    }

    @Override
    public void onClick(View v) {

    }

}

Preview.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent">

  <android.view.SurfaceView
  android:id="@+id/surface"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  />

</RelativeLayout>

使用设备菜单按钮拍照。

在 Manifest 文件中添加权限

检查图片库中的旋转文件夹以获取捕获的图像。