Android 调用系统Camera 程序照相，获取照片

下面是我自己整理的源码，网络上好多不能够运行，或者有bug。

我在emulatorandroid2.1运行良好，源码注释一定程度能够自我解释

强烈推荐配合adblocatTake2:d*:s查看程序运行函数调用情况

对Activity生命周期不是很理解的，请先看我之前的一片文章

http://menuz.iteye.com/blog/1255320

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
	android:orientation="vertical" android:layout_width="fill_parent"
	android:layout_height="fill_parent">
	<Button android:layout_width="fill_parent"
		android:layout_height="wrap_content" android:id="@+id/cameraButton"
		android:text="拍照" />

	<SurfaceView android:id="@+id/surface_camera"
		android:layout_width="fill_parent" android:layout_height="10dip"
		android:layout_weight="1">
	</SurfaceView>
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.busclient"
      android:versionCode="1"
      android:versionName="1.0">
    <uses-sdk android:minSdkVersion="7" />
    
    <uses-permission android:name="android.permission.CAMERA" /> <!-- 注意必须在application上面-->
    <application android:icon="@drawable/icon" android:label="@string/app_name">
    <uses-library android:name="com.google.android.maps" />
        <activity android:name=".Take2"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
    <uses-permission android:name="android.permission.UPDATE_DEVICE_STATS"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
</manifest>

package com.busclient;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

import android.app.Activity;
import android.hardware.Camera;
import android.hardware.Camera.PictureCallback;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class Take2 extends Activity implements SurfaceHolder.Callback {
    private final static String TAG = "Take2";;

    private SurfaceView surfaceView;

    private SurfaceHolder surfaceHolder;

    private Camera mCam;

    private boolean hasStartPreview = false;

    private Button btnTakePicture;

    // Camera API:
    // Call release() to release the camera for use by other applications.
    // Applications should release the camera immediately in onPause() (and
    // re-open() it in onResume()).

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.takephoto);
        Log.d(TAG, "onCreate");

        // 取得surfaceView的引用,surface在surfaceView中展现
        // 当surfaceView可见时，surface会被创建，实现surfaceCreated进行特定操作
        surfaceView = (SurfaceView) findViewById(R.id.surface_camera);
        btnTakePicture = (Button) findViewById(R.id.cameraButton);
        // 注册按钮实现拍照
        btnTakePicture.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                if (mCam != null) {
                    // 调用mCam进行拍照
                    // param1 Camera.ShutterCallback 
                    // param2 Camera.PictureCallback raw 当原始图片数据获得时，会执行PictureCallback
                    // param3 Camera.PictureCallback compressed 当压缩数据获得时，会执行PictureCallback
                    mCam.takePicture(null, null, pictureCallBack);
                }
            }

        });

        // 要操作surface，只有通过surfaceHolder
        surfaceHolder = surfaceView.getHolder();
        surfaceHolder.addCallback(this);
        surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

    private PictureCallback pictureCallBack = new Camera.PictureCallback() {

        @Override
        public void onPictureTaken(byte[] data, Camera camera) {
            if (mCam != null) {
                if (data != null) {
                    File f = new File("/data/data/com.busclient/picture1.jpg");
                    FileOutputStream fout = null;
                    try {
                        if (!f.exists())
                            f.createNewFile();
                        fout = new FileOutputStream(f);
                        fout.write(data);
                        fout.close();
                        Log.d(TAG, "write success");
                        
                        Thread.sleep(1500);
                    } catch (IOException e) {
                        e.printStackTrace();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    } finally {
                        try {
                            if (fout != null) {
                                fout.close();
                                fout = null;
                            }
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    }
                }
                finish();
            }
        }
    };

    // surface只能够由一个线程操作，一旦被操作，其他线程就无法操作surface
    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        Log.d(TAG, "surfaceCreated");
        try {
            // 必须设置一个初始化的surfaceHolder，若没有surface（由holder操作surface），
            // 则camera无法启动预览 （就是一般打开照相机屏幕能够动态显示场景??描述的不够好）
            mCam.setPreviewDisplay(surfaceHolder);
        } catch (IOException e) {
            Log.d(TAG, "error");
            mCam.release();
            mCam = null;
        }
    }

    // 在surfaceCreated后调用，当surface发生变化也会触发该方法，这个方法
    // 一般至少被调用一次
    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width,
            int height) {
        Log.d(TAG, "surfaceChanged");
        // 调用startPreview使预览surface可以更新，拍照
        // 必须启动预览，而startPreview必须在setPreviewDisplay(surfaceHolder)之后
        if (mCam != null && hasStartPreview == false) {

            mCam.startPreview();
            hasStartPreview = true;
        }
    }

    // 析构surface
    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        Log.d(TAG, "surfaceDestroyed");
        // 活都被onPause抢去了
    }

    @Override
    protected void onDestroy() {
        Log.d(TAG, "onDestroy");
        super.onDestroy();
    }

    // onPause比surfaceDestroyed() 先调用
    @Override
    protected void onPause() {
        Log.d(TAG, "onPause");
        if (hasStartPreview) {
            mCam.stopPreview();
        }
        mCam.release();
        mCam = null;
        hasStartPreview = false;
        super.onPause();
    }

    @Override
    protected void onRestart() {
        Log.d(TAG, "onRestart");
        super.onRestart();
    }

    @Override
    protected void onResume() {
        Log.d(TAG, "onResume");
        if (mCam == null)
            mCam = Camera.open();
        super.onResume();
    }

    @Override
    protected void onStart() {
        Log.d(TAG, "onStart");
        super.onStart();
    }

    @Override
    protected void onStop() {
        Log.d(TAG, "onStop");
        super.onStop();
    }

}