android 手机拍照流程

1. 在布局文件中添加一个 surfaceView (摄影平面)

2.根据 SurfaceView 获得 Holder (固定器)

3.给固定器设置 SurfaceHolder.Callback ; 这个 Callback 有一系列的周期方法,

比如:surfaceCreated,surfaceChanged,surfaceDestroyed等方法.

①.在surfaceDestroyed 中 打开相机,设置预览效果 ;

②.在surfaceChanged中可以初始化相机( Camera );比如相机的参数: 像素, 大小,格式,开始预览,等等

③.在surfaceDestroyed可以可以停止相机拍摄;释放相机资源

4. 相机自动对焦 的回调处理

Camera.autoFocus( AutoFocusCallback )

AutoFocusCallback 有个接口方法
public void onAutoFocus(boolean focused, Camera camera) {
/* 对到焦点拍照 */
if (focused) {
takePicture();//见第5步
}
}

5.Camera.takePicture(ShutterCallback shutter/*摄像*/, PictureCallback raw/*拍照*/, PictureCallback jpeg/*照片*/)

查看API或者源码,可以发现,这些callback里面都有包含摄像,或者被拍照时的byte[]数据,而这些数据可以根据BitmapFactory变成Bitmap图片.

见源代码如下：

public class ScanBarZBarActivity extends Activity implements SurfaceHolder.Callback{
private static String TAG = "ScanBarZBarActivity";
private Camera mCamera;
private Button mButton, mButton1, mButton2;
private SurfaceView mSurfaceView;
private SurfaceHolder holder;
private AutoFocusCallback mAutoFocusCallback = new AutoFocusCallback();
private String path = "WXJSMyPhoto";
private String path1;
private Bitmap bmp;
private int cnt = 1;
private Calendar c;
public native String getISBN(Bitmap bmp);
private int flag=5;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
/* 隐藏状态栏 */
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
/* 隐藏标题栏 */
requestWindowFeature(Window.FEATURE_NO_TITLE);
/* 设定屏幕显示为横向 */
this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);

setContentView(R.layout.camera);
/* SurfaceHolder设定 */
mSurfaceView = (SurfaceView) findViewById(R.id.mSurfaceView);
holder = mSurfaceView.getHolder();
holder.addCallback(ScanBarZBarActivity.this);
holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
c = Calendar.getInstance();

/* Button初始化 */
mButton = (Button) findViewById(R.id.myButton);
mButton1 = (Button) findViewById(R.id.myButton1);
mButton2 = (Button) findViewById(R.id.myButton2);
/* 拍照Button的事件处理 */
mButton.setOnClickListener(new Button.OnClickListener() {
@Override
public void onClick(View arg0) {
/* 告动对焦后拍照 */
mCamera.autoFocus(mAutoFocusCallback);
}
});
/* Button的事件处理 */
mButton1.setOnClickListener(new Button.OnClickListener() {
@Override
public void onClick(View arg0) {
/* 保存文件 */
Log.i(TAG,"click button2");
if (bmp != null) {
/* 检查SDCard是否存在 */
if (!Environment.MEDIA_MOUNTED.equals(Environment
.getExternalStorageState())) {
/* SD卡不存在，显示Toast信息 */
Toast.makeText(ScanBarZBarActivity.this,
"SD卡不存在!无法保存相片,请插入SD卡。", Toast.LENGTH_LONG)
.show();
} else {
try {
/* 文件不存在就创建 */
File f = new File(Environment
.getExternalStorageDirectory(), path);
Log.i(TAG,"click button2:" + f.getAbsolutePath());
if (!f.exists()) {
f.mkdir();
}
/* 保存相片文件 */
path1 = String.valueOf(c.get(Calendar.MILLISECOND))
+ "camera.jpg";
File n = new File(f, path1);
FileOutputStream bos = new FileOutputStream(n
.getAbsolutePath());
/* 文件转换 */
bmp.compress(Bitmap.CompressFormat.JPEG, 100, bos);
/* 调用flush()方法，更新BufferStream */
bos.flush();
/* 结束OutputStream */
bos.close();
Toast.makeText(ScanBarZBarActivity.this,
path1 + "保存成功!", Toast.LENGTH_LONG).show();
cnt++;
} catch (Exception e) {
e.printStackTrace();
}
}
}

mButton.setVisibility(View.VISIBLE);
mButton1.setVisibility(View.VISIBLE);
mButton2.setVisibility(View.VISIBLE);
/* 重新设定Camera */
stopCamera();
initCamera();
}
});
/* 放弃Button的事件处理 */
mButton2.setOnClickListener(new Button.OnClickListener() {
@Override
public void onClick(View arg0) {
mButton.setVisibility(View.VISIBLE);
mButton1.setVisibility(View.VISIBLE);
mButton2.setVisibility(View.VISIBLE);
/* 重新设定Camera */
stopCamera();
initCamera();
}
});
}

@Override
public void surfaceCreated(SurfaceHolder surfaceholder) {
try {
/* 打开相机， */
mCamera = Camera.open();
mCamera.setPreviewDisplay(holder);
} catch (IOException exception) {
mCamera.release();
mCamera = null;
}
}

@Override
public void surfaceChanged(SurfaceHolder surfaceholder, int format, int w,
int h) {
/* 相机初始化 */
Log.i(TAG,"init camera");
initCamera();
}

@Override
public void surfaceDestroyed(SurfaceHolder surfaceholder) {
Log.i(TAG,"destoryed camera");
stopCamera();
mCamera.release();
mCamera = null;
}

/* 拍照的method */
private void takePicture() {
if (mCamera != null) {
Log.i(TAG,"takePicture");
mCamera.takePicture(shutterCallback, rawCallback, jpegCallback);
}
}

private ShutterCallback shutterCallback = new ShutterCallback() {
public void onShutter() {

}
};

private PictureCallback rawCallback = new PictureCallback() {
public void onPictureTaken(byte[] _data, Camera _camera) {
}
};

private PictureCallback jpegCallback = new PictureCallback() {
public void onPictureTaken(byte[] _data, Camera _camera) {
/* 取得相仞 */
try {
/* 设定Button?视性 */
mButton.setVisibility(View.GONE);
mButton1.setVisibility(View.VISIBLE);
mButton2.setVisibility(View.VISIBLE);
/* 取得相仞Bitmap对象 */
bmp = BitmapFactory.decodeByteArray(_data, 0, _data.length);
//发送给isbn分析
// String isbn = getISBN(bmp);获得图片解析后的信息
//  Log.i(TAG, "isbn:" + flag + isbn);
flag--;
if(flag>0){
mCamera.autoFocus(mAutoFocusCallback);
}

} catch (Exception e) {
e.printStackTrace();
}
}
};

/* 告定义class AutoFocusCallback */
public final class AutoFocusCallback implements
android.hardware.Camera.AutoFocusCallback {
public void onAutoFocus(boolean focused, Camera camera) {
/* 对到焦点拍照 */
if (focused) {
takePicture();
}
}
};

/* 相机初始化的method */
private void initCamera() {
if (mCamera != null) {
try {
Camera.Parameters parameters = mCamera.getParameters();
/*
* 设定相片大小为1024*768， 格式为JPG
*/
parameters.setPictureFormat(PixelFormat.JPEG);
parameters.setPictureSize(1024, 768);
mCamera.setParameters(parameters);
/* 开启预览画面 */
mCamera.startPreview();
} catch (Exception e) {
e.printStackTrace();
}
}
}

/* 停止相机的method */
private void stopCamera() {
if (mCamera != null) {
try {
/* 停止预览 */
mCamera.stopPreview();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}

xml布局文件如下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >

<SurfaceView
android:id="@+id/mSurfaceView"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" />

<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >

<Button
android:id="@+id/myButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="拍照" />

<Button
android:id="@+id/myButton1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="保存" />

<Button
android:id="@+id/myButton2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="退出" />
</LinearLayout>

</LinearLayout>