做应用可能有时候需要调用本地的摄像头，所以这里就记录意下如何调用。

摄像头预览需要在布局文件添加surfaceview, 这里需要注意，其实用FrameLayout也可以，大家可以参考

http://www.cnblogs.com/over140/archive/2011/11/16/2251344.html

1、布局

<SurfaceView 
     android:layout_width="fill_parent"
     android:layout_height="fill_parent"
     android:id="@+id/surfaceview"/>

只要在布局文件添加这个即可。

2、摄像头预览

public class MainActivity extends Activity implements SurfaceHolder.Callback

继承Activity，实现SurfaceHolder.Callback，MainActivity里需要我们复写以下几个方法：

@Override
    public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) {
        System.out.println("surfacechanged");
    }

@Override
    public void surfaceCreated(SurfaceHolder holder) {
        System.out.println("surfacecreated");
        //获取camera对象
        camera = Camera.open();
        try {
            //设置预览监听
            camera.setPreviewDisplay(holder);
            Camera.Parameters parameters = camera.getParameters();
            
            if (this.getResources().getConfiguration().orientation 
                        != Configuration.ORIENTATION_LANDSCAPE) {
                parameters.set("orientation", "portrait");
                camera.setDisplayOrientation(90);
                parameters.setRotation(90);
            } else {
                parameters.set("orientation", "landscape");
                camera.setDisplayOrientation(0);
                parameters.setRotation(0);
            }
            camera.setParameters(parameters);
            //启动摄像头预览
            camera.startPreview();
            System.out.println("camera.startpreview");
            
        } catch (IOException e) {
            e.printStackTrace();
            camera.release();
            System.out.println("camera.release");
        }
    }

@Override
    public void surfaceDestroyed(SurfaceHolder arg0) {
        System.out.println("surfaceDestroyed");
        if (camera != null) {
            camera.stopPreview();
            camera.release();            
        }
    }

当然还有onCreate方法

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        context = this;
        
        surfaceview = (SurfaceView)findViewById(R.id.surfaceview);
        surfaceholder = surfaceview.getHolder();
        surfaceholder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        surfaceholder.addCallback(SafeActivity.this);
    }

,

当然有些变量还需要定义，

private static Context context = null;
    private SurfaceView surfaceview;
    private SurfaceHolder surfaceholder;
    private Camera camera = null;