在sdk中找到/sdk/docs/guide/topics/media/camera.html#custom-camera，里面有详细的api参考
在清单文件中添加相应的权限：
<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />
按照官方文档，分为下面几步：
- Detect and Access Camera - Create code to check for the existence of cameras and request access.
- Create a Preview Class - Create a camera preview class that extends
SurfaceViewand implements theSurfaceHolderinterface. This class previews the live images from the camera. - Build a Preview Layout - Once you have the camera preview class, create a view layout that incorporates the preview and the user interface controls you want.
- Setup Listeners for Capture - Connect listeners for your interface controls to start image or video capture in response to user actions, such as pressing a button.
- Capture and Save Files - Setup the code for capturing pictures or videos and saving the output.
- Release the Camera - After using the camera, your application must properly release it for use by other applications.
接下来分别实现：
1、检查设备是否有照相机
/** 检查设备是否存在照相机 */ 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; } }
2、得到一个照相机
/** 一种安全的方式获取Cameer对象的实例. */ public static Camera getCameraInstance(){ Camera c = null; try { c = Camera.open(); // attempt to get a Camera instance } catch (Exception e){ // Camera is not available (in use or does not exist) } return c; // returns null if camera is unavailable }
3、新建一个名为CameraPreview的类
package com.wuyudong.mycamera; import java.io.IOException; import android.content.Context; import android.hardware.Camera; import android.util.Log; import android.view.SurfaceHolder; import android.view.SurfaceView; /** A basic Camera preview class */ public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback { private static final String TAG = "CameraPreview"; private SurfaceHolder mHolder; private Camera mCamera; public CameraPreview(Context context, Camera camera) { super(context); mCamera = camera; // Install a SurfaceHolder.Callback so we get notified when the // underlying surface is created and destroyed. mHolder = getHolder(); mHolder.addCallback(this); // deprecated setting, but required on Android versions prior to 3.0 mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); } public void surfaceCreated(SurfaceHolder holder) { // The Surface has been created, now tell the camera where to draw the // preview. try { mCamera.setPreviewDisplay(holder); mCamera.startPreview(); } catch (IOException e) { Log.d(TAG, "Error setting camera preview: " + e.getMessage()); } } public void surfaceDestroyed(SurfaceHolder holder) { // empty. Take care of releasing the Camera preview in your activity. } public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) { // 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 try { mCamera.setPreviewDisplay(mHolder); mCamera.startPreview(); } catch (Exception e) { Log.d(TAG, "Error starting camera preview: " + e.getMessage()); } } }
4、设置一个预览功能的layout，将原来布局文件中的内容替换成下面的代码
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="horizontal" android:layout_width="fill_parent" android:layout_height="fill_parent" > <FrameLayout android:id="@+id/camera_preview" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1" /> <Button android:id="@+id/button_capture" android:text="Capture" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" /> </LinearLayout>
5、在清单文件中加入 android:screenOrientation="landscape" 调整相机为横向拍摄
6、在MainActivity中添加
public class MainActivity extends Activity { private Camera mCamera; private CameraPreview mPreview; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); // Create an instance of Camera mCamera = getCameraInstance(); // Create our Preview view and set it as the content of our activity. mPreview = new CameraPreview(this, mCamera); FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview); preview.addView(mPreview); } }
7、实现拍摄按钮的功能
（1）添加拍照回调方法
private PictureCallback mPicture = new PictureCallback() { @Override public void onPictureTaken(byte[] data, Camera camera) { File pictureFile = new File("/sdcard/" + System.currentTimeMillis()+".jpg"); try { FileOutputStream fos = new FileOutputStream(pictureFile); fos.write(data); fos.close(); } catch (IOException e) { Log.d("TAG", "Error accessing file: " + e.getMessage()); } } };
给拍照按钮添加注册事件：
// Add a listener to the Capture button Button captureButton = (Button) findViewById(R.id.button_capture); captureButton.setOnClickListener( new View.OnClickListener() { @Override public void onClick(View v) { // get an image from the camera mCamera.takePicture(null, null, mPicture); } } );
完整的代码如下：
package com.wuyudong.mycamera; import java.io.File; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.sql.Date; import android.os.Bundle; import android.app.Activity; import android.content.Context; import android.content.pm.PackageManager; import android.hardware.Camera; import android.hardware.Camera.AutoFocusCallback; import android.hardware.Camera.PictureCallback; import android.util.Log; import android.view.Menu; import android.view.View; import android.widget.Button; import android.widget.FrameLayout; public class MainActivity extends Activity { private Camera mCamera; private CameraPreview mPreview; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // 创建一个 Camera 的实例 mCamera = getCameraInstance(); // 创建一个预览界面 mPreview = new CameraPreview(this, mCamera); FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview); preview.addView(mPreview); // Add a listener to the Capture button Button captureButton = (Button) findViewById(R.id.button_capture); captureButton.setOnClickListener( new View.OnClickListener() { @Override public void onClick(View v) { mCamera.autoFocus(new AutoFocusCallback() { // 对焦 @Override public void onAutoFocus(boolean success, Camera camera) { // get an image from the camera mCamera.takePicture(null, null, mPicture); } }); } } ); } /** 检查设备是否存在照相机 */ 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; } } /** 一种安全的方式获取Cameer对象的实例. */ public static Camera getCameraInstance() { Camera c = null; try { c = Camera.open(); // attempt to get a Camera instance } catch (Exception e) { // Camera is not available (in use or does not exist) } return c; // returns null if camera is unavailable } private PictureCallback mPicture = new PictureCallback() { @Override public void onPictureTaken(byte[] data, Camera camera) { File pictureFile = new File("/sdcard/" + System.currentTimeMillis()+".jpg"); try { FileOutputStream fos = new FileOutputStream(pictureFile); fos.write(data); fos.close(); } catch (IOException e) { Log.d("TAG", "Error accessing file: " + e.getMessage()); } } }; protected void onDestory() { if(mCamera != null) { //释放资源 mCamera.release(); mCamera = null; } } }