1.Android 自定义拍照（支持前后摄像头切换）
1.布局
2.实现代码
public class MainActivity extends Activity implements View.OnClickListener,
SurfaceHolder.Callback {
private static final String TAG = MainActivity.class.getSimpleName();
private static final int MEDIA_TYPE_IMAGE = 1;
private Button switchCameraBtn, captureBtn;
private SurfaceView surfaceSv;
private SurfaceHolder mHolder;
private Camera mCamera;
// 0表示后置，1表示前置
private int cameraPosition = 1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_main);
findById();
initData();
}
/**
* 初始化view
*/
private void findById() {
switchCameraBtn = this.findViewById(R.id.id_switch_camera_btn);
captureBtn = this.findViewById(R.id.id_capture_btn);
surfaceSv = this.findViewById(R.id.id_area_sv);
switchCameraBtn.setOnClickListener(this);
captureBtn.setOnClickListener(this);
}
/**
* 初始化相关data
*/
private void initData() {
// 获得句柄
mHolder = surfaceSv.getHolder();
// 添加回调
mHolder.addCallback(this);
}
@Override
public void onStart() {
super.onStart();
if (this.checkCameraHardware(this) && (mCamera == null)) {
// 打开camera
mCamera = getCamera();
if (mHolder != null) {
setStartPreview(mCamera,mHolder);
}
}
}
private Camera getCamera() {
Camera camera = null;
try {
camera = Camera.open();
} catch (Exception e) {
// Camera is not available (in use or does not exist)
camera = null;
Log.e(TAG, "Camera is not available (in use or does not exist)");
}
return camera;
}
@Override
public void onPause() {
super.onPause();
/**
* 记得释放camera，方便其他应用调用
*/
releaseCamera();
}
@Override
public void onDestroy() {
super.onDestroy();
}
/**
* 释放mCamera
*/
private void releaseCamera() {
if (mCamera != null) {
mCamera.setPreviewCallback(null);
mCamera.stopPreview();// 停掉原来摄像头的预览
mCamera.release();
mCamera = null;
}
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.id_switch_camera_btn:
// 切换前后摄像头
int cameraCount = 0;
Camera.CameraInfo cameraInfo = new Camera.CameraInfo();
cameraCount = Camera.getNumberOfCameras();// 得到摄像头的个数
for (int i = 0; i < cameraCount; i++) {
Camera.getCameraInfo(i, cameraInfo);// 得到每一个摄像头的信息
if (cameraPosition == 1) {
// 现在是后置，变更为前置
if (cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
/**
* 记得释放camera，方便其他应用调用
*/
releaseCamera();
// 打开当前选中的摄像头
mCamera = Camera.open(i);
// 通过surfaceview显示取景画面
setStartPreview(mCamera,mHolder);
cameraPosition = 0;
break;
}
} else {
// 现在是前置， 变更为后置
if (cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_BACK) {
/**
* 记得释放camera，方便其他应用调用
*/
releaseCamera();
mCamera = Camera.open(i);
setStartPreview(mCamera,mHolder);
cameraPosition = 1;
break;
}
}
}
break;
case R.id.id_capture_btn:
mCamera.takePicture(null, null, picture);
break;
}
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
setStartPreview(mCamera,mHolder);
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// If your preview can change or rotate, take care of those events here.
// Make sure to stop the preview before resizing or reformatting it.
if (mHolder.getSurface() == null) {
// preview surface does not exist
return;
}
// stop preview before making changes
try {
mCamera.stopPreview();
} catch (Exception e) {
// ignore: tried to stop a non-existent preview
}
// set preview size and make any resize, rotate or
// reformatting changes here
// start preview with new settings
setStartPreview(mCamera,mHolder);
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// 当surfaceview关闭时，关闭预览并释放资源
/**
* 记得释放camera，方便其他应用调用
*/
releaseCamera();
holder = null;
surfaceSv = null;
}
/**
* 创建png图片回调数据对象
*/
Camera.PictureCallback picture = new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
Toast.makeText(MainActivity.this,"拍照",Toast.LENGTH_SHORT).show();
camera.startPreview();//拍完照 重新打开预览
}
};
/** Check if this device has a camera */
private boolean checkCameraHardware(Context context) {
if (context.getPackageManager().hasSystemFeature(
PackageManager.FEATURE_CAMERA)) {
// this device has a camera
return true;
} else {
// no camera on this device
return false;
}
}
/**
* 设置camera显示取景画面,并预览
* @param camera
*/
private void setStartPreview(Camera camera,SurfaceHolder holder){
try {
Camera.Parameters parameters = mCamera.getParameters();
setDispaly(parameters, mCamera);
camera.setPreviewDisplay(holder);
camera.startPreview();
} catch (IOException e) {
Log.d(TAG, "Error starting camera preview: " + e.getMessage());
}
}
// 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");
}
}
}