android照相機

使用相機的兩種方式：
1 使用Intent跳轉到系統相機,action為:android.media.action.STILL_IMAGE_CAMERA 這中方法一般是最常用的方便簡單畢竟自定義相機比較復雜而且花費時間比較長

代碼片段，雙擊復制
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83	`package` `barry.android.c;` `import` `java.io.File;` `import` `java.io.FileNotFoundException;` `import` `java.io.FileOutputStream;` `import` `java.io.IOException;` `import` `android.app.Activity;` `import` `android.content.Intent;` `import` `android.graphics.Bitmap;` `import` `android.os.Bundle;` `import` `android.os.Environment;` `import` `android.provider.MediaStore;` `import` `android.util.Log;` `import` `android.view.View;` `import` `android.view.View.OnClickListener;` `import` `android.widget.Button;` `import` `android.widget.ImageView;` `/*` ` * @title MyCaremaActivity.java` `* @package barry.android.c` `* @email cjhszh@126.com` `* @author szh` `* @update 2013-1-11 上午9:27:03` `* @description` `*/` `public` `class` `MyCaremaActivityextends` `Activity {` `@Override` `public` `void` `onCreate(Bundle savedInstanceState) {` `super.onCreate(savedInstanceState);` `setContentView(R.layout.main);` `Button button = (Button) findViewById(R.id.button);` `button.setOnClickListener(new` `OnClickListener() {` `@Override` `public` `void` `onClick(View v) {` `Intent intent =new` `Intent(MediaStore.ACTION_IMAGE_CAPTURE);//open camera` `startActivityForResult(intent,1);` `}` `});` `}` `@Override` `protected` `void` `onActivityResult(int` `requestCode,int` `resultCode, Intent data) {` `super.onActivityResult(requestCode, resultCode, data);` `if` `(resultCode == Activity.RESULT_OK) {` `String sdStatus = Environment.getExternalStorageState();` `if` `(sdStatus.equals(Environment.MEDIA_MOUNTED)) {// 檢測sd是否可用` `Log.v("TestFile",` `sdStatus+"SD card is not avaiable/writeable right now.");` `}` `Bundle bundle = data.getExtras();` `Bitmap bitmap = (Bitmap) bundle.get("data");// 獲取相機返回的數據，並轉換為Bitmap圖片格式` `FileOutputStream b =null;` `File file =new` `File("/sdcard/myImage/");` `file.mkdirs();// 創建文件夾` `String fileName ="/sdcard/myImage/111.jpg";` `try` `{` `b =new` `FileOutputStream(fileName);` `bitmap.compress(Bitmap.CompressFormat.JPEG,100, b);// 把數據寫入文件` `}catch` `(FileNotFoundException e) {` `e.printStackTrace();` `}finally` `{` `try` `{` `b.flush();` `b.close();` `}catch` `(IOException e) {` `e.printStackTrace();` `}` `}` `((ImageView) findViewById(R.id.imageView)).setImageBitmap(bitmap);// 將圖片顯示在ImageView裡` `}` `}` `}`

2 （1）首先我們要自己創建一個照相，必須考慮用什麼控件顯示照相機中的預覽效果，顯然android已經幫我們做好瞭選擇，那就是
SurfaceView,而控制SurfaceView則需要一個surfaceHolder,他是系統提供的一個用來設置surfaceView的一個對象，而它通過surfaceView.getHolder()這個方法來獲得。而Camera提供一個setPreviewDisplay(SurfaceHolder)的方法來連接
surfaceHolder,並通過他來控制surfaceView,而我們則使用android的Camera類提供瞭startPreview()和stopPreview()來開啟和關閉預覽.
關系如下：
Camera — –>SurfaceHolder——>SurfaceView.
（2）知道怎麼預覽瞭，當然也要知道怎麼開啟相機.Camera.open()這是個靜態方法，如果相機沒有別人用著，則會返回一個相機引用，如果被人用著，則會拋出異常。很奇怪的是，這個方法，不能隨便放，如放在構造方法或者onCreate()方法中，都會照成沒有預覽效果.
（3） SurfaceHolder.Callback,這是個holder用來顯示surfaceView
數據的接口,他分別必須實現3個方法
surfaceCreated（）這個方法是surface 被創建後調用的
surfaceChanged()這個方法是當surfaceView發生改變後調用的
surfaceDestroyed()這個是當surfaceView銷毀時調用的.
surfaceHolde通過addCallBack()方法將響應的接口綁定到他身上.
surfaceHolder還必須設定一個setType()方法，查看api的時候，發現這個方法已經過時，但是沒有寫，又會報錯。。各種奇怪。
（4）
我用以上知識寫瞭一個MySurfaceView類，他繼承於SurfaceView,並在裡面實現瞭照相機的預覽功能.這個我覺得最簡單的照相機預覽代碼:

代碼片段，雙擊復制
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145	`package` `com.hipikids.mycamerademo;` `import` `java.io.BufferedOutputStream;` `import` `java.io.File;` `import` `java.io.FileOutputStream;` `import` `java.io.IOException;` `import` `android.app.Activity;` `import` `android.content.pm.ActivityInfo;` `import` `android.graphics.Bitmap;` `import` `android.graphics.BitmapFactory;` `import` `android.graphics.PixelFormat;` `import` `android.hardware.Camera;` `import` `android.hardware.Camera.AutoFocusCallback;` `import` `android.hardware.Camera.PictureCallback;` `import` `android.os.Bundle;` `import` `android.view.SurfaceHolder;` `import` `android.view.SurfaceView;` `import` `android.view.View;` `import` `android.view.Window;` `import` `android.view.SurfaceHolder.Callback;` `import` `android.view.View.OnClickListener;` `/*` ` * @title MainActivity.java` `` ` @package com.hipikids.mycamerademo` `* @email cjhszh@126.com` `* @author szh` `* @update 2013-1-10 下午5:21:00` `* @description` `/` `public` `class` `MainActivityextends` `Activityimplements` `Callback,` `OnClickListener, AutoFocusCallback {` `SurfaceView mySurfaceView;// surfaceView聲明` `SurfaceHolder holder;// surfaceHolder聲明` `Camera myCamera;// 相機聲明` `String filePath ="/sdcard/wjh.jpg";// 照片保存路徑` `boolean` `isClicked =false;// 是否點擊標識` `// 創建jpeg圖片回調數據對象` `PictureCallback jpeg =new` `PictureCallback() {` `@Override` `public` `void` `onPictureTaken(byte[] data, Camera camera) {` `// TODO Auto-generated method stub` `try` `{// 獲得圖片` `Bitmap bm = BitmapFactory.decodeByteArray(data,0, data.length);` `File file =new` `File(filePath);` `BufferedOutputStream bos =new` `BufferedOutputStream(` `new` `FileOutputStream(file));` `bm.compress(Bitmap.CompressFormat.JPEG,100, bos);// 將圖片壓縮到流中` `bos.flush();// 輸出` `bos.close();// 關閉` `}catch` `(Exception e) {` `e.printStackTrace();` `}` `}` `};` `/* Called when the activity is first created. */` `@Override` `public` `void` `onCreate(Bundle savedInstanceState) {` `super.onCreate(savedInstanceState);` `requestWindowFeature(Window.FEATURE_NO_TITLE);// 無標題` `// 設置拍攝方向` `this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);` `setContentView(R.layout.activity_main);` `// 獲得控件` `mySurfaceView = (SurfaceView) findViewById(R.id.surface);` `// 獲得句柄` `holder = mySurfaceView.getHolder();` `// 添加回調` `holder.addCallback(this);` `// 設置類型` `holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);` `// 設置監聽` `mySurfaceView.setOnClickListener(this);` `}` `@Override` `public` `void` `surfaceChanged(SurfaceHolder holder,int` `format,int` `width,` `int` `height) {` `// TODO Auto-generated method stub` `// 設置參數並開始預覽` `Camera.Parameters params = myCamera.getParameters();` `params.setPictureFormat(PixelFormat.JPEG);` `params.setPreviewSize(640,480);` `myCamera.setParameters(params);` `myCamera.startPreview();// open display` `}` `@Override` `public` `void` `surfaceCreated(SurfaceHolder holder) {` `// TODO Auto-generated method stub` `// 開啟相機` `if` `(myCamera ==null) {` `myCamera = Camera.open();// this method is a static method` `try` `{` `myCamera.setPreviewDisplay(holder);// connection SurfaceHolder` `}catch` `(IOException e) {` `// TODO Auto-generated catch block` `e.printStackTrace();` `}` `}` `}` `@Override` `public` `void` `surfaceDestroyed(SurfaceHolder holder) {` `// TODO Auto-generated method stub` `// 關閉預覽並釋放資源` `myCamera.stopPreview();// close display` `myCamera.release();` `myCamera =null;` `}` `@Override` `public` `void` `onClick(View v) {` `// TODO Auto-generated method stub` `if` `(!isClicked) {` `myCamera.autoFocus(this);// 自動對焦` `isClicked =true;` `}else` `{` `myCamera.startPreview();// 開啟預覽` `isClicked =false;` `}` `}` `@Override` `public` `void` `onAutoFocus(boolean` `success, Camera camera) {` `// TODO Auto-generated method stub` `if` `(success) {` `// 設置參數,並拍照` `Camera.Parameters params = myCamera.getParameters();` `params.setPictureFormat(PixelFormat.JPEG);` `params.setPreviewSize(640,480);` `myCamera.setParameters(params);` `myCamera.takePicture(null,null, jpeg);` `}` `}` `}`

最後別忘瞭加權限

代碼片段，雙擊復制
01 02 03	`<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>` `<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>` `<uses-permission android:name="android.permission.CAMERA"/>`

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