照相機技術（二）
阿新 • • 發佈：2017-05-30
nac ddc dmi nbsp stop eas 大小 aced htm
1 //定制拍照： 2 public class MainActivity extends Activity { 3 private Camera mCamera; 4 private Preview mPreview; 5 6 @Override 7 protected void onCreate(Bundle savedInstanceState) { 8 super.onCreate(savedInstanceState); 9 // setContentView(R.layout.fragment_main);10 // 隱藏標題 11 requestWindowFeature(Window.FEATURE_NO_TITLE); 12 // 設置為全屏 13 getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN); 14 mPreview = new Preview(this); 15 setContentView(mPreview); 16 } 17 18 @Override 19 protectedvoid onResume() { 20 // TODO Auto-generated method stub 21 super.onResume(); 22 // 第一步：打開照相機 23 mCamera = Camera.open(0); 24 mPreview.setCamera(mCamera); 25 } 26 27 // 釋放焦點 28 @Override 29 protected void onPause() { 30 // TODO Auto-generated method stub31 super.onPause(); 32 if (mCamera != null) { 33 mCamera.release(); 34 mCamera = null; 35 mPreview.setCamera(null); 36 } 37 } 38 39 // 第三步：添加回調事件監聽器SurfaceHolder.addCallback 40 class Preview extends ViewGroup implements SurfaceHolder.Callback, 41 OnClickListener { 42 SurfaceView mSurfaceView; 43 SurfaceHolder mHolder; 44 Size mPreviewSize; 45 List<Size> msupportedPreviewSizes; 46 Camera mCamera; 47 Context mContext; 48 49 public Preview(Context context) { 50 super(context); 51 // TODO Auto-generated constructor stub 52 mContext = context; 53 mSurfaceView = new SurfaceView(context); 54 addView(mSurfaceView); 55 mHolder = mSurfaceView.getHolder(); 56 mHolder.addCallback(this); 57 } 58 59 public void setCamera(Camera camera) { 60 mCamera = camera; 61 if (mCamera != null) { 62 // 獲得所有預覽尺寸 63 msupportedPreviewSizes = mCamera.getParameters() 64 .getSupportedPictureSizes(); 65 requestLayout(); 66 67 } 68 } 69 70 @Override 71 public void surfaceCreated(SurfaceHolder holder) { 72 // TODO Auto-generated method stub 73 try { 74 if (mCamera != null) { 75 // 將Camera和SurfaceView關聯 76 mCamera.setPreviewDisplay(holder); 77 } 78 } catch (Exception e) { 79 // TODO: handle exception 80 } 81 } 82 83 private PictureCallback mpPictureCallback = new PictureCallback() { 84 85 @Override 86 public void onPictureTaken(byte[] data, Camera camera) { 87 mCamera.startPreview(); 88 File pictureFile = new File("/sdcard/image.jpg"); 89 try { 90 FileOutputStream fos = new FileOutputStream(pictureFile); 91 fos.write(data); 92 fos.close(); 93 } catch (Exception e) { 94 // TODO: handle exception 95 } 96 } 97 }; 98 99 @Override 100 public void surfaceChanged(SurfaceHolder holder, int format, int width, 101 int height) { 102 103 // 設置最佳預覽尺寸 104 Camera.Parameters parameters = mCamera.getParameters(); 105 106 parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height); 107 108 mCamera.setParameters(parameters); 109 mCamera.startPreview(); 110 } 111 112 @Override 113 public void surfaceDestroyed(SurfaceHolder holder) { 114 // TODO Auto-generated method stub 115 if (mCamera != null) { 116 mCamera.stopPreview(); 117 } 118 } 119 120 @Override 121 protected void onLayout(boolean changed, int l, int t, int r, int b) { 122 // 使預覽和實際窗口大小一致 123 if (changed && getChildCount() > 0) { 124 final View child = getChildAt(0); 125 int width = r - l; 126 int height = b - t; 127 int previewWidth = width; 128 int previewHeight = height; 129 if (mPreviewSize != null) { 130 previewWidth = mPreviewSize.width; 131 previewHeight = mPreviewSize.height; 132 133 } 134 // 手機屏幕的寬高比大於采集圖像的寬高比 135 if (width * previewHeight > height * previewWidth) { 136 final int scaledChildWidth = previewWidth * height 137 / previewHeight; 138 // child.layout((width - scaledChildWidth) / 2, 0, 139 // (width + scaledChildWidth) / 2, height); 140 child.layout(100, 100, 340, 240);// 設置照相框位置 141 } else { 142 final int scaledChildHeight = previewWidth * width 143 / previewWidth; 144 child.layout(0, (height - scaledChildHeight) / 2, width, 145 (height + scaledChildHeight) / 2); 146 } 147 } 148 149 } 150 151 private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) { 152 153 double ASPECT_TOLERANCE = 0.1; 154 double targetRatio = (double) w / h; 155 if (sizes == null) { 156 return null; 157 } 158 Size optimalSize = null; 159 double minDiff = Double.MAX_VALUE; 160 int targetHeight = h; 161 for (Size size : sizes) { 162 163 double ratio = (double) size.width / size.height; 164 if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE) { 165 continue; 166 } 167 if (Math.abs(size.height - targetHeight) < minDiff) { 168 optimalSize = size; 169 minDiff = Math.abs(size.height - targetHeight); 170 } 171 172 } 173 if (optimalSize == null) { 174 minDiff = Double.MAX_VALUE; 175 for (Size size : sizes) { 176 177 if (Math.abs(size.height - targetHeight) < minDiff) { 178 optimalSize = size; 179 minDiff = Math.abs(size.height - targetHeight); 180 } 181 182 } 183 } 184 185 return optimalSize; 186 187 } 188 189 @Override 190 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 191 // TODO Auto-generated method stub 192 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 193 int width = resolveSize(getSuggestedMinimumWidth(), 194 widthMeasureSpec); 195 int height = resolveSize(getSuggestedMinimumHeight(), 196 heightMeasureSpec); 197 setMeasuredDimension(width, height); 198 if (msupportedPreviewSizes != null) { 199 mPreviewSize = getOptimalPreviewSize(msupportedPreviewSizes, 200 width, height); 201 } 202 203 } 204 205 @Override 206 public void onClick(View v) { 207 // TODO Auto-generated method stub 208 mCamera.takePicture(null, null, mpPictureCallback); 209 } 210 211 } 212 213 }
照相機技術（二）