package com.example.x_yp.system_camera;

 import java.io.File;

 import java.io.FileOutputStream;

 import android.os.Bundle;

 import android.util.Log;

 import android.view.View;

 import android.widget.Button;

 import android.widget.FrameLayout;

 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;

 public class MainActivity extends Activity {

     protected static final String TAG = "main";

     private Camera mCamera;

     private CameraPreview mPreview;

     @Override

     protected void onCreate(Bundle savedInstanceState) {

         super.onCreate(savedInstanceState);

         setContentView(R.layout.activity_main);

         mCamera = getCameraInstance();

         // 创建预览类，并与Camera关联，最后添加到界面布局中

         mPreview = new CameraPreview(this, mCamera);

         FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);

         preview.addView(mPreview);

         Button captureButton = (Button) findViewById(R.id.button_capture);

         captureButton.setOnClickListener(new View.OnClickListener() {

             @Override

             public void onClick(View v) {

                 // 在捕获图片前进行自动对焦

                 mCamera.autoFocus(new AutoFocusCallback() {

                     @Override

                     public void onAutoFocus(boolean success, Camera camera) {

                         // 从Camera捕获图片

                         mCamera.takePicture(null, null, mPicture);

                     }

                 });

             }

         });

     }

     /** 检测设备是否存在Camera硬件 */

     private boolean checkCameraHardware(Context context) {

         if (context.getPackageManager().hasSystemFeature(

                 PackageManager.FEATURE_CAMERA)) {

             // 存在

             return true;

         } else {

             // 不存在

             return false;

         }

     }

     /** 打开一个Camera */

     public static Camera getCameraInstance() {

         Camera c = null;

         try {

             c = Camera.open();

         } catch (Exception e) {

             Log.d(TAG, "打开Camera失败失败");

         }

         return c;

     }

     private PictureCallback mPicture = new PictureCallback() {

         @Override

         public void onPictureTaken(byte[] data, Camera camera) {

             // 获取Jpeg图片，并保存在sd卡上

             File pictureFile = new File("/sdcard/" + System.currentTimeMillis() + ".jpg");

             try {

                 FileOutputStream fos = new FileOutputStream(pictureFile);

                 fos.write(data);

                 fos.close();

             } catch (Exception e) {

                 Log.d(TAG, "保存图片失败");

             }

         }

     };

     @Override

     protected void onDestroy() {

         // 回收Camera资源

         if(mCamera!=null){

             mCamera.stopPreview();

             mCamera.release();

             mCamera=null;

         }

         super.onDestroy();

     }

 }

package com.example.x_yp.system_camera;

import java.io.IOException;

import android.content.Context;

import android.hardware.Camera;

import android.util.Log;

import android.view.SurfaceHolder;

import android.view.SurfaceView;

/**

 * 定义一个预览类

 */

public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {

    private static final String TAG = "main";

    private SurfaceHolder mHolder;

    private Camera mCamera;

    public CameraPreview(Context context, Camera camera) {

        super(context);

        mCamera = camera;

        // 通过SurfaceView获得SurfaceHolder

        mHolder = getHolder();

        // 为SurfaceHolder指定回调

        mHolder.addCallback(this);

        // 设置Surface不维护自己的缓冲区，而是等待屏幕的渲染引擎将内容推送到界面 在Android3.0之后弃用

        mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

    }

    public void surfaceCreated(SurfaceHolder holder) {

        // 当Surface被创建之后，开始Camera的预览

        try {

            mCamera.setPreviewDisplay(holder);

            mCamera.startPreview();

        } catch (IOException e) {

            Log.d(TAG, "预览失败");

        }

    }

    public void surfaceDestroyed(SurfaceHolder holder) {

    }

    public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {

        // Surface发生改变的时候将被调用，第一次显示到界面的时候也会被调用

        if (mHolder.getSurface() == null){

          // 如果Surface为空，不继续操作

          return;

        }

        // 停止Camera的预览

        try {

            mCamera.stopPreview();

        } catch (Exception e){

            Log.d(TAG, "当Surface改变后，停止预览出错");

        }

        // 在预览前可以指定Camera的各项参数

        // 重新开始预览

        try {

            mCamera.setPreviewDisplay(mHolder);

            mCamera.startPreview();

        } catch (Exception e){

            Log.d(TAG, "预览Camera出错");

        }

    }

}

<?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>

 <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" />

    <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />