Question

我发布了这个示例并且它制作了一张照片让你看到了预览但我有一个问题：问题是，如果你试试这个代码，你会看到预览，但它没有正确定位请到那里有人能解决这个问题吗？

public class MainActivity extends ActionBarActivity {

private ImageSurfaceView mImageSurfaceView;
private Camera camera;

private FrameLayout cameraPreviewLayout;
private ImageView capturedImageHolder;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);

    cameraPreviewLayout = (FrameLayout)findViewById(R.id.camera_preview);
    capturedImageHolder = (ImageView)findViewById(R.id.captured_image);

    camera = checkDeviceCamera();
    mImageSurfaceView = new ImageSurfaceView(MainActivity.this, camera);
    cameraPreviewLayout.addView(mImageSurfaceView);

    Button captureButton = (Button)findViewById(R.id.button);
    captureButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            camera.takePicture(null, null, pictureCallback);
        }
    });
}
private Camera checkDeviceCamera(){
    Camera mCamera = null;
    try {
        mCamera = Camera.open();
    } catch (Exception e) {
        e.printStackTrace();
    }
    return mCamera;
}

PictureCallback pictureCallback = new PictureCallback() {
    @Override
    public void onPictureTaken(byte[] data, Camera camera) {
        Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
        if(bitmap==null){
            Toast.makeText(MainActivity.this, "Captured image is empty", Toast.LENGTH_LONG).show();
            return;
        }
        capturedImageHolder.setImageBitmap(scaleDownBitmapImage(bitmap, 300, 200 ));
    }
};

private Bitmap scaleDownBitmapImage(Bitmap bitmap, int newWidth, int newHeight){
    Bitmap resizedBitmap = Bitmap.createScaledBitmap(bitmap, newWidth, newHeight, true);
    return resizedBitmap;
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}
}

ImageSurfaceView类

public class ImageSurfaceView extends SurfaceView implements SurfaceHolder.Callback {

private Camera camera;
private SurfaceHolder surfaceHolder;

public ImageSurfaceView(Context context, Camera camera) {
    super(context);
    this.camera = camera;
    this.surfaceHolder = getHolder();
    this.surfaceHolder.addCallback(this);
}

@Override
public void surfaceCreated(SurfaceHolder holder) {
    try {
        this.camera.setPreviewDisplay(holder);
        this.camera.startPreview();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

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

}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {
    this.camera.stopPreview();
    this.camera.release();
}
}

XML

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context=".MainActivity"
android:baselineAligned="false">

<FrameLayout
    android:id="@+id/camera_preview"
    android:layout_width="match_parent"
    android:layout_height="300dp"/>

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/capture_button"
    android:id="@+id/button"
    android:layout_below="@+id/camera_preview"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="15dp" />

<ImageView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/captured_image"
    android:layout_below="@+id/button"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_marginTop="15dp"
    android:contentDescription="@string/desc" />

问题是如果您尝试使用此代码，您会看到预览，但它没有正确定位，请问有人可以解决此问题吗？

Answer 1

您必须使用Exifinterface和Matrix才能获得正确的方向。试试这个：

 public static void handleImageRotation(Context context, File mFileTemp) {

    if (!mFileTemp.exists()) {
        Toast.makeText(context, "File not found", Toast.LENGTH_SHORT).show();
        return;
    }


    ExifInterface exif = null;
    int orientation = ExifInterface.ORIENTATION_NORMAL;
    try {
        exif = new ExifInterface(mFileTemp.getAbsolutePath());

        orientation = exif.getAttributeInt(
                ExifInterface.TAG_ORIENTATION,
                ExifInterface.ORIENTATION_NORMAL);
    } catch (Exception e) {
        e.printStackTrace();
    }

    Bitmap temp = BitmapFactory.decodeFile(mFileTemp.getAbsolutePath());

    if (temp == null) Log.e(TAG, "Bitmap from File is null");

    Matrix matrix = new Matrix();

    if (orientation == ExifInterface.ORIENTATION_ROTATE_90) {
        matrix.postRotate(90);
        temp = Bitmap.createBitmap(temp, 0, 0, temp.getWidth(), temp.getHeight(), matrix, true);
    } else if (orientation == ExifInterface.ORIENTATION_ROTATE_180) {
        matrix.postRotate(180);
        temp = Bitmap.createBitmap(temp, 0, 0, temp.getWidth(), temp.getHeight(), matrix, true);
    } else if (orientation == ExifInterface.ORIENTATION_ROTATE_270) {
        matrix.postRotate(270);
        temp = Bitmap.createBitmap(temp, 0, 0, temp.getWidth(), temp.getHeight(), matrix, true);
    }

    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    temp.compress(Bitmap.CompressFormat.JPEG, 40, bos);

    byte[] bitmapdata = bos.toByteArray();

    // write the bytes in file
    try {
        FileOutputStream fos = new FileOutputStream(mFileTemp);
        fos.write(bitmapdata);
        fos.flush();
        fos.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

Answer 2

这是有问题的代码：

ImageButton GButton = (ImageButton) findViewById(R.id.blueButton);

您好我对此示例有疑问

2 个答案: