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;
}
} }