java - 如何在 Android 中的 onCreate 方法而不是 onClick 中拍照？

Question

我正在做一个拍照的项目。当我保持原样时它目前工作正常，但是当我尝试更改它以便尝试以不同的方法拍摄照片(而不是通过 onClick() 方法激活)时，它每次都会出错.目前工作代码如下:

public class Testing123 extends Activity {

    private SurfaceView preview=null;
    private SurfaceHolder previewHolder=null;
    private Camera camera=null;
    private boolean inPreview=false;
    private boolean cameraConfigured=false;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);
        preview = (SurfaceView)findViewById(R.id.preview);
        previewHolder = preview.getHolder();
        previewHolder.addCallback(surfaceCallback);
        previewHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

        testing();   //HERE is where I am testing, but cannot get it to work. [See part 2]
    }

    public void onResume() {
        super.onResume();
        if (camera == null) {
            camera=Camera.open();
            L.m("Camera open in onResume");
        }
        startPreview();
    }   

    public void onPause() {
        if (inPreview) {
            camera.stopPreview();
        }
        camera.release();
        camera=null;
        inPreview=false;
        super.onPause();
    }

    public boolean onCreateOptionsMenu(Menu menu) {
        new MenuInflater(this).inflate(R.menu.options, menu);
        return(super.onCreateOptionsMenu(menu));
    }

    public boolean onOptionsItemSelected(MenuItem item) {
        if (item.getItemId() == R.id.camera) {
            if (inPreview) {
                camera.takePicture(null, null, photoCallback);    //THIS IS WHERE THE PHOTO IS BEING TAKEN
                inPreview=false;
            }
        }

        return(super.onOptionsItemSelected(item));
    }

    private void initPreview(int width, int height) {
        if (camera != null && previewHolder.getSurface() != null) {
            try {
                camera.setPreviewDisplay(previewHolder);
            }
            catch (Throwable t) {
                Log.e("PreviewDemo-surfaceCallback", "Exception in setPreviewDisplay()", t);
            }

            if (!cameraConfigured) {
                Camera.Parameters parameters=camera.getParameters();
                setCameraResolution(); //Leaving this method out for now
                camera.setParameters(parameters);
                cameraConfigured=true;
            }

        }
    }

    private void startPreview() {
        camera.startPreview();
    }   

    SurfaceHolder.Callback surfaceCallback=new SurfaceHolder.Callback() {
        public void surfaceCreated(SurfaceHolder holder) {
        }

        public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
            initPreview(width, height);
            startPreview();
        }

        public void surfaceDestroyed(SurfaceHolder holder) {
        }
    };

    Camera.PictureCallback photoCallback = new Camera.PictureCallback() {
        public void onPictureTaken(byte[] data, Camera camera) {
            //This part is no problem, I am able to write it to the file and use the data from the output of the camera
        }
    }

当我尝试进行新调用时出现问题，如您在 onCreate() 方法中所见，称为 testing();每当我调用测试方法(试图绕过按下按钮的需要)时，它都会出错。这是测试()代码:

private void testing() {
    try{
        cameraConfigured=true; 
        inPreview=true; 
        camera=Camera.open();
        Camera.Parameters parameters=camera.getParameters();
        setCameraResolution();
        camera.setParameters(parameters);
        camera.setPreviewDisplay(previewHolder);
        startPreview();
        camera.takePicture(null, null, photoCallback);    //THIS IS WHERE THE PHOTO IS BEING TAKEN
    } catch (Exception e) {
        L.m(e.toString());
    }
}

然后它出错了，具体说:java.lang.RuntimeException: 拍照失败

重申一下，当我单击一个图标/按钮时，它可以很好地拍照，我想要完成的是让它运行该代码而无需点击按钮/图标。我认为这是我所缺少的非常简单的东西，我似乎无法弄清楚。

Answer 1

在 SurfaceHolder.Callback#onSurfaceCreated 调用 testing()。
:-)