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;
}
}