Question

我是Android编程新手。我正在开发一个名为放大镜的简单应用程序，它将使用相机镜头放大和缩小预览。但是由于放大和缩小都不起作用，我对我的代码感到困惑。下面是我的预览课程，当我在手机上运行应用程序时，没有错误，但放大和缩小都无法正常工作。有人请帮我修复此错误

class Preview extends SurfaceView implements SurfaceHolder.Callback {    
private static final String TAG = "Preview";

SurfaceHolder mHolder;
public Camera camera;
int currentZoomLevel = 0;
int maxZoomLevel = 0;
int MAX_ZOOM = 4;
Button buttonzoomin;
Button buttonzoomout;


Preview(Context context) {
    super(context);

    // Install a SurfaceHolder.Callback so we get notified when the
    // underlying surface is created and destroyed.
    mHolder = getHolder();
    mHolder.addCallback(this);
    mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}

public void surfaceCreated(SurfaceHolder holder) {
    // The Surface has been created, acquire the camera and tell it where
    // to draw.
    camera = Camera.open();

    try {
        camera.setPreviewDisplay(holder);

        camera.setPreviewCallback(new PreviewCallback() {

            public void onPreviewFrame(byte[] data, Camera arg1) {
                FileOutputStream outStream = null;
                try {
                    outStream = new FileOutputStream(String.format(
                            "/sdcard/%d.jpg", System.currentTimeMillis()));
                    outStream.write(data);
                    outStream.close();
                    Log.d(TAG, "onPreviewFrame - wrote bytes: "
                            + data.length);
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                } finally {
                }
                Preview.this.invalidate();
            }
        });
    } catch (IOException e) {
        e.printStackTrace();
    }
}

public void surfaceDestroyed(SurfaceHolder holder) {
    // Surface will be destroyed when we return, so stop the preview.
    // Because the CameraDevice object is not a shared resource, it's very
    // important to release it when the activity is paused.
    //camera.setPreviewCallback(null);
    camera.stopPreview();
    camera.release();
    camera = null;
}




public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
    // Now that the size is known, set up the camera parameters and begin
    // the preview.

    final Camera.Parameters parameters = camera.getParameters();
    List<Camera.Size> previewSizes = parameters.getSupportedPreviewSizes();
    buttonzoomin = (Button) findViewById(R.id.buttonzoomin);
    buttonzoomout = (Button) findViewById(R.id.buttonzoomout);

    // You need to choose the most appropriate previewSize for your app
    Camera.Size previewSize = previewSizes.get(0);

   Display display = ((WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();

    if(display.getRotation() == Surface.ROTATION_0)
    {
        parameters.setPreviewSize(previewSize.height, previewSize.width);                           
        camera.setDisplayOrientation(90);
    }

    if(display.getRotation() == Surface.ROTATION_90)
    {
        parameters.setPreviewSize(previewSize.width, previewSize.height);                           
    }

    if(display.getRotation() == Surface.ROTATION_180)
    {
        parameters.setPreviewSize(previewSize.height, previewSize.width);               
    }

    if(display.getRotation() == Surface.ROTATION_270)
    {
        parameters.setPreviewSize(previewSize.width, previewSize.height);
        camera.setDisplayOrientation(180);
    }


    if(parameters.isSmoothZoomSupported()){    
        buttonzoomin.setEnabled(true);
        buttonzoomout.setEnabled(true);
        maxZoomLevel = parameters.getMaxZoom();
            buttonzoomin.setOnClickListener(new OnClickListener(){
                public void onClick(View v){
                        currentZoomLevel=currentZoomLevel + 1;
                        if(currentZoomLevel > maxZoomLevel)
                        {
                            currentZoomLevel = maxZoomLevel;;
                        }
                        //camera.startSmoothZoom(currentZoomLevel);
                        parameters.setZoom(currentZoomLevel);
                        camera.stopPreview();
                        camera.startPreview();
                        camera.setParameters(parameters);

                }
            });

        buttonzoomout.setOnClickListener(new OnClickListener(){
                public void onClick(View v){
                        currentZoomLevel = currentZoomLevel-1;
                        if(currentZoomLevel < 0)
                        {
                            currentZoomLevel = 0;
                        }
                        //camera.startSmoothZoom(currentZoomLevel);
                        parameters.setZoom(currentZoomLevel);
                        camera.stopPreview();
                        camera.startPreview();
                        camera.setParameters(parameters);
                }
            });    
       }
     camera.setParameters(parameters);
     camera.startPreview(); }   
@Override
public void draw(Canvas canvas) 
{
    super.draw(canvas);
    Paint p = new Paint(Color.RED);
    Log.d(TAG, "draw");
    canvas.drawText("PREVIEW", canvas.getWidth() / 2,
            canvas.getHeight() / 2, p);
} }

Answer 1

尝试不使用平滑缩放。许多设备不一定支持平滑缩放，目前您没有支持平滑缩放的备份情况 - 例如，您的放大按钮永远不会启用！

无法在Android相机预览中使用zoomcontrols

1 个答案: