Android_手機(jī)攝像頭編程入門

1、.智能手機(jī)中的攝像頭和普通手機(jī)中的攝像頭最大的區(qū)別在于，智能機(jī)上的攝像頭可以由程序員寫程序控制，做一些有趣的應(yīng)用譬如，畫中畫，做一些有用的應(yīng)用譬如二維碼識(shí)別，等等。本講打算通過(guò)一個(gè)實(shí)例，來(lái)介紹一下攝像頭編程，相關(guān)解釋都寫在代碼中了，請(qǐng)注意看代碼注釋。 實(shí)例：窈窈照相機(jī)，功能很簡(jiǎn)單，就是點(diǎn)擊程序彈出照相預(yù)覽界面，點(diǎn)擊相機(jī)按鈕完成照相功能，所照相片會(huì)存儲(chǔ)在手機(jī)存儲(chǔ)卡根目錄。 1、創(chuàng)立一個(gè)工程 Lesson36_Camera ，主程序文件為 MainActivity.java 2、AndroidManifest.xml 中設(shè)置屏幕為橫屏，并且聲明攝像頭和存儲(chǔ)卡的使用權(quán)限

2、，詳細(xì)代碼如下： <?xml version="1.0" encoding="utf-8"?><manifest package="basic.android.lesson36" xmlns:android=" :/schemas.android /apk/res/android" android:versioncode="1" android:versionname="1.0"><application android:label=&

3、quot;string/app_name" android:icon="drawable/icon"><activity android:label="string/app_name" android:name=".MainActivity" android:screenorientation="landscape" android:configchanges="orientation|keyboardHidden|keyboard"><intent -filt

4、er=""><action android:name="ent.action.MAIN"><category android:name="ent.category.LAUNCHER"></category></action></intent></activity> </application><uses -sdk="" android:minsdkversion=&q

5、uot;8"><uses -permission="" android:name="android.permission.CAMERA"></uses><uses -permission="" android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses><uses -feature="" android:name="android.hardware.

6、camera"></uses><uses -feature="" android:name="android.hardware.camera.autofocus"></uses></manifest>   3、本例中不需要布局文件main.xml，因?yàn)楸纠械腢I組建都是動(dòng)態(tài)添加上去的。 4、最后MainActivity.java的代碼如下： package myback. ablanxue ; import java.io.Buffered

7、OutputStream;import java.io.File;import java.io.FileOutputStream;import java.io.IOException;import java.util.Calendar;import java.util.Locale; import android.app.Activity;import android.content.Context;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.

8、PixelFormat;import android.hardware.Camera;import android.os.Bundle;import android.text.format.DateFormat;import android.util.Log;import android.view.KeyEvent;import android.view.SurfaceHolder;import android.view.SurfaceView;import android.view.Window;import android.view.WindowManager;import android

9、.widget.FrameLayout;import android.widget.TextView;import android.widget.Toast; public class MainActivity extends Activity  private CameraView cv;/準(zhǔn)備一個(gè)相機(jī)對(duì)象private Camera mCamera = null;/準(zhǔn)備一個(gè)Bitmap對(duì)象private Bitmap mBitmap = null; /準(zhǔn)備一個(gè)保存圖片的PictureCallback對(duì)象public Camera.PictureCallback

10、 pictureCallback = new Camera.PictureCallback  public void onPictureTakenbyte data, Camera camera Log.i"yao","onPictureTaken"Toast.makeTextgetApplicationContext, "正在保存", Toast.LENGTH_LONG.show;/用BitmapFactory.decodeByteArray方法可以把相機(jī)傳回的裸數(shù)據(jù)轉(zhuǎn)換成Bitmap對(duì)象mBitmap = BitmapF

11、actory.decodeByteArraydata, 0, data.length;/接下來(lái)的工作就是把Bitmap保存成一個(gè)存儲(chǔ)卡中的文件File file = new File"/sdcard/YY"+ new DateFormat.format"yyyyMMdd_hhmmss", Calendar.getInstanceLocale.CHINA + ".jpg"try file.createNewFile;BufferedOutputStream os = new BufferedOutputStreamnew FileOut

12、putStreamfile;mBitmap pressBitmap pressFormat.PNG, 100, os;os.flush;os.close;Toast.makeTextgetApplicationContext, "圖片保存完畢，在存儲(chǔ)卡的根目錄", Toast.LENGTH_LONG.show; catch IOException e e.printStackTrace;  /Activity的創(chuàng)立方法Overridepublic void onCreateBundle savedInstanceState super.onCreates

13、avedInstanceState; /窗口去掉標(biāo)題        requestWindowFeatureWindow.FEATURE_NO_TITLE;        /窗口設(shè)置為全屏        getWindow.setFlagsWindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN;        /

14、設(shè)置窗口為半透明        getWindow.setFormatPixelFormat.TRANSLUCENT;         /提供一個(gè)幀布局        FrameLayout  fl = new FrameLayoutthis;               /創(chuàng)立一個(gè)照相預(yù)覽用的SurfaceView子類，并放在幀布局的底層     

15、;   cv = new CameraViewthis;fl.addViewcv; /創(chuàng)立一個(gè)文本框添加在幀布局中，我們可以看到，文字自動(dòng)出如今了SurfaceView的前面，由此你可以在預(yù)覽窗口做出各種特殊效果TextView tv = new TextViewthis;tv.setText"請(qǐng)按"相機(jī)"按鈕拍攝"fl.addViewtv; /設(shè)置Activity的根內(nèi)容視圖setContentViewfl;  /相機(jī)按鍵按下的事件處理方法public boolean onKeyDownint keyC

16、ode, KeyEvent event Log.i"yao","MainActivity.onKeyDown"if keyCode = KeyEvent.KEYCODE_CAMERA if mCamera != null Log.i"yao","mCamera.takePicture"/當(dāng)按下相機(jī)按鈕時(shí)，執(zhí)行相機(jī)對(duì)象的takePicture方法,該方法有三個(gè)回調(diào)對(duì)象做入?yún)?，不需要的時(shí)候可以設(shè)nullmCamera.takePicturenull, null, pictureCallback;return cv.on

17、KeyDownkeyCode, event; / 照相視圖class CameraView extends SurfaceView  private SurfaceHolder holder = null; /構(gòu)造函數(shù)public CameraViewContext context supercontext;Log.i"yao","CameraView" / 操作surface的holderholder = this.getHolder;/ 創(chuàng)立SurfaceHolder.Callback對(duì)象holder.addC

18、allbacknew SurfaceHolder.Callback  Overridepublic void surfaceDestroyedSurfaceHolder holder / 停頓預(yù)覽mCamera.stopPreview;/ 釋放相機(jī)資源并置空mCamera.release;mCamera = null; Overridepublic void surfaceCreatedSurfaceHolder holder /當(dāng)預(yù)覽視圖創(chuàng)立的時(shí)候開(kāi)啟相機(jī)mCamera = Camera.open;try /設(shè)置預(yù)覽mCamera.setPreviewDisplayholder; catch IOException e / 釋放相機(jī)資源并置空mCamera.release;mCamera = null;  /當(dāng)surface視圖數(shù)據(jù)發(fā)生變化時(shí)，處理預(yù)覽信息Overridepublic void surfaceChangedSurfaceHolder