在5.0之前的版本中自定义相机是按如下步骤：
一,做一个自定义相机的步骤
1.找到并获取相机的权限
检测相机的存在，并获取权限
检测是否有相机设备代码
if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)){ // 有相机设备 return true; } else { // 没有相机设备 return false; }
检测相机是否可用代码
Camera c = null; try { c = Camera.open(); // 得到一个相机的实例 } catch (Exception e){ // 相机不存在或正在被使用 }
2.建一个预览视图类
该类应为SurfaceView的子类
作为一个自定义的视图类
其主要业务是在在不同的事件内，通过传入的Camera实例控制预览视图(Preview)
具体API的演示代码如下：
/** A basic Camera preview class */public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback { 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) { // 如果你的视图可以改变或旋转，需关注这个事件 // 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()); } }}
3.建一个预览布局
布局相对比较简单，之后显示相机预览图的SurfaceView将通过代码加在FrameLayout中
<??><LinearLayout ="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>
在与之对应的Activity中主要代码如下：
public class CameraActivity extends Activity { private Camera mCamera; private CameraPreview mPreview; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); // 创建Camera的实例 mCamera = Camera.open(); //为Activity添加Preview视图SurfaceView mPreview = new CameraPreview(this, mCamera); FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview); preview.addView(mPreview); }}
4.监听拍照动作
按钮监听动作，然后就开始聚焦
具体代码实现就是和普通监听一样，聚焦则可以使用camera.autoFocus(autoFocusCallBack);
autoFocusCallBack是AutoFocusCallback的实例，主要用来回调对焦完成后的操作。
比如通过Camera.takePicture(shutter,PictureCallback,PictureCallback)捕获图片
5.捕获图片并保存
通过Camera.takePicture(shutter,PictureCallback,PictureCallback)捕获图片后，需要对图片进行保存
private PictureCallback mPicture = new PictureCallback() { @Override public void onPictureTaken(byte[] data, Camera camera) { File pictureFile = getOutputMediaFile(MEDIA_TYPE_IMAGE); if (pictureFile == null){ Log.d(TAG, "Error creating media file, check storage permissions: " + e.getMessage()); return; } try { FileOutputStream fos = new FileOutputStream(pictureFile); fos.write(data); fos.close(); } catch (FileNotFoundException e) { Log.d(TAG, "File not found: " + e.getMessage()); } catch (IOException e) { Log.d(TAG, "Error accessing file: " + e.getMessage()); } }};
以上是官方API中的Demo，通过onPictureTaken方法获取捕获到的图片数据，可供参考
6.释放相机资源
在之前的surfaceDestroyed中可以通过camera.release释放相机资源以免影响其他应用的使用
以下是自己写的demo，图简单，省了很多，结构也很乱，不过基本的照相功能已实现
package com.rw.demo;import java.io.File;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import android.app.Activity;import android.graphics.Bitmap;import android.graphics.Bitmap.CompressFormat;import android.graphics.BitmapFactory;import android.graphics.ImageFormat;import android.hardware.Camera;import android.hardware.Camera.AutoFocusCallback;import android.hardware.Camera.PictureCallback;import android.hardware.Camera.ShutterCallback;import android.os.Bundle;import android.os.Environment;import android.util.Log;import android.view.SurfaceHolder;import android.view.SurfaceHolder.Callback;import android.view.SurfaceView;import android.view.View;import android.view.Window;import android.view.WindowManager;public class CameraDemo extends Activity { private SurfaceView cameraSurface; private SurfaceHolder myHolder; private boolean isPreview=false; Camera camera; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_NO_TITLE); getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN); setContentView(R.layout.camera_layout); getView(); //添加回调函数 myHolder=cameraSurface.getHolder(); myHolder.addCallback(new Callback() { @Override public void surfaceDestroyed(SurfaceHolder holder) { } @Override public void surfaceCreated(SurfaceHolder holder) { try { CameraDemo.this.initCamera(holder); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } @Override public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) { } }); } /** * 初始化相机 * @param holder * @throws IOException */ @SuppressWarnings("deprecation") protected void initCamera(SurfaceHolder holder) throws IOException { if(!isPreview) camera=Camera.open(1); camera.setDisplayOrientation(90); if(camera!=null && !isPreview){ camera.setPreviewDisplay(holder); camera.startPreview(); isPreview=true; } } /** * 获取视图控件 */ private void getView() { cameraSurface=(SurfaceView) findViewById(R.id.camera_surface_id); } /** * 捕获图片 * @param v */ public void takePhoto(View v){ if(camera!=null){ Log.i("CameraDemo","开始照相了！"); camera.autoFocus(autoFocusCallBack); } } //完成自动聚焦后的回调方法 AutoFocusCallback autoFocusCallBack =new AutoFocusCallback() { @Override public void onAutoFocus(boolean success, Camera camera) { if(success){ camera.takePicture(new ShutterCallback() { @Override public void onShutter() { } }, new PictureCallback(){ @Override public void onPictureTaken(byte[] data, Camera camera) { } }, jpeg); } } }; //捕获到图片后的回调方法 PictureCallback jpeg=new PictureCallback() { @Override public void onPictureTaken(byte[] data, Camera camera) { //根据拍照的数据创建位图 final Bitmap bm=BitmapFactory.decodeByteArray(data,0, data.length); File file=new File(Environment.getExternalStorageDirectory(),"testPicture.jpg"); FileOutputStream outStream =null; try { outStream=new FileOutputStream(file); bm.compress(CompressFormat.JPEG, 100, outStream); outStream.close(); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } camera.stopPreview(); camera.startPreview(); isPreview=true; } }; //释放将相机资源 @Override protected void onDestroy() { super.onDestroy(); if(camera!=null){ camera.release(); } } @Override protected void onPause() { // TODO Auto-generated method stub super.onPause(); } }原标题：自定义相机（一）
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