如何实现Android相机的自动对焦，而且是连续自动对焦的。当然直接调用系统相机就不用说了，那个很简单的。下面我们主要来看看如如何自己实现一个相机，并且实现自动连续对焦。

代码如下：

public class MainActivity extends Activity {     private SurfaceView surfaceView;   private SurfaceHolder surfaceHolder;   private boolean flag = false;   private String fileUrl="";   Camera camera;   Camera.Parameters parameters;      @Override      protected void onCreate(Bundle savedInstanceState) {          super.onCreate(savedInstanceState);               setContentView(R.layout.activity_main);        surfaceView =  (SurfaceView) findViewById(R.id.surfaceView1);        Button  button=(Button) findViewById(R.id.takepicture);        surfaceHolder =  surfaceView.getHolder();        surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);        surfaceHolder.setKeepScreenOn(true);        surfaceView.setFocusable(true);        surfaceView.setBackgroundColor(TRIM_MEMORY_BACKGROUND);        surfaceHolder.addCallback(new Callback() {        @Override    public void surfaceDestroyed(SurfaceHolder holder) {     // TODO Auto-generated method stub      camera.stopPreview();      camera.release();      camera=null;         }         @Override    public void surfaceCreated(SurfaceHolder holder) {     // TODO Auto-generated method stub     if(null==camera){        camera=Camera.open();              try {            camera.setPreviewDisplay(surfaceHolder);            initCamera();                    camera.startPreview();      } catch (IOException e) {       // TODO Auto-generated catch block       e.printStackTrace();      }            }         }               @Override    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height){           //实现自动对焦              camera.autoFocus(new AutoFocusCallback() {                  @Override      public void onAutoFocus(boolean success, Camera camera) {                   if(success){                    initCamera();//实现相机的参数初始化                   camera.cancelAutoFocus();//只有加上了这一句，才会自动对焦。                   }                  }       });          }     });    }    //相机参数的初始化设置        private void initCamera()    {          parameters=camera.getParameters();          parameters.setPictureFormat(PixelFormat.JPEG);          //parameters.setPictureSize(surfaceView.getWidth(), surfaceView.getHeight());  // 部分定制手机，无法正常识别该方法。     parameters.setFlashMode(Parameters.FLASH_MODE_TORCH);      parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);//1连续对焦     setDispaly(parameters,camera);     camera.setParameters(parameters);     camera.startPreview();     camera.cancelAutoFocus();// 2如果要实现连续的自动对焦，这一句必须加上         }           //控制图像的正确显示方向        private void setDispaly(Camera.Parameters parameters,Camera camera)        {        if (Integer.parseInt(Build.VERSION.SDK) >= 8){      setDisplayOrientation(camera,90);     }    else{      parameters.setRotation(90);     }               }              //实现的图像的正确显示        private void setDisplayOrientation(Camera camera, int i) {        Method downPolymorphic;    try{        downPolymorphic=camera.getClass().getMethod("setDisplayOrientation", new Class[]{int.class});            if(downPolymorphic!=null) {             downPolymorphic.invoke(camera, new Object[]{i});              }     }     catch(Exception e){      Log.e("Came_e", "图像出错");     }        }           @Override      public boolean onCreateOptionsMenu(Menu menu) {          // Inflate the menu; this adds items to the action bar if it is present.          getMenuInflater().inflate(R.menu.main, menu);                   return true;      }             }