Android摄像头编程及注意事项

做了Android摄像头编程的测试，自己总结一下代码和其中的注意事项。

CameraTestActivity.java：

  1 package test.cameratest;

  2 

  3 import java.io.IOException;

  4 import java.util.Iterator;

  5 import java.util.List;

  6 

  7 import android.hardware.Camera;

  8 import android.hardware.Camera.Size;

  9 import android.os.Bundle;

 10 import android.app.Activity;

 11 import android.content.Context;

 12 import android.content.res.Configuration;

 13 import android.util.Log;

 14 import android.view.Display;

 15 import android.view.SurfaceHolder;

 16 import android.view.SurfaceView;

 17 import android.view.Window;

 18 import android.view.WindowManager;

 19 import android.widget.LinearLayout;

 20 

 21 public class MainActivity extends Activity implements SurfaceHolder.Callback {

 22 

 23     private String Tag = "CameraTest";

 24     private SurfaceView mSurfaceView;

 25     private SurfaceHolder mSurfaceHolder;

 26     private Camera mCamera;

 27     private Size previewSize;

 28     private int screenWidth;

 29     private int screenHeight;

 30     

 31     @Override

 32     protected void onCreate(Bundle savedInstanceState) {

 33         super.onCreate(savedInstanceState);

 34         //全屏

 35         requestWindowFeature(Window.FEATURE_NO_TITLE);

 36         getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,

 37         WindowManager.LayoutParams.FLAG_FULLSCREEN);

 38         getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

 39         setContentView(R.layout.activity_main);

 40         

 41         WindowManager wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE);

 42         Display display = wm.getDefaultDisplay();

 43         //获取屏幕的宽和高

 44         screenWidth = display.getWidth();

 45         screenHeight = display.getHeight();

 46         

 47         mSurfaceView = (SurfaceView) findViewById(R.id.surfaceview);

 48         mSurfaceHolder = mSurfaceView.getHolder();

 49         mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

 50         mSurfaceHolder.addCallback(this);

 51     }

 52 

 53     @Override

 54     protected void onResume() {

 55         super.onResume();

 56         Log.d(Tag, "resume");

 57     }

 58     

 59     @Override

 60     protected void onPause() {

 61         super.onPause();

 62         Log.d(Tag, "pause");

 63     }

 64     

 65     @Override

 66     protected void onStop() {

 67         super.onStop();

 68         Log.d(Tag, "stop");

 69     }

 70     

 71     @Override

 72     protected void onDestroy() {

 73         super.onDestroy();

 74         Log.d(Tag, "destroy");

 75     }

 76     

 77     @Override

 78     public void surfaceCreated(SurfaceHolder holder) {

 79         Log.d(Tag, "surface created");

 80         mCamera = Camera.open();

 81         if (mCamera == null) {

 82             Log.d(Tag, "camera null");

 83         }

 84         try {

 85             mCamera.setPreviewDisplay(holder);

 86         } catch (IOException e) {

 87             Log.e(Tag, "IOException caused by setPreviewDisplay");

 88         }

 89         mCamera.setPreviewCallback(mPreviewCallback);

 90         Camera.Parameters parameters = mCamera.getParameters();

 91         //Log.d(Tag, parameters.flatten());

 92         if (this.getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {

 93             parameters.set("orientation", "portrait");

 94             mCamera.setDisplayOrientation(90);

 95         } else {

 96             parameters.set("orientation", "landscape");

 97             mCamera.setDisplayOrientation(0);

 98         }

 99         int previewWidth = 0;

100         int previewHeight = 0;

101         List<Camera.Size> previewSizes = parameters.getSupportedPreviewSizes();

102         Iterator<Camera.Size> iter = previewSizes.iterator();

103         while (iter.hasNext()) {

104             Camera.Size size = iter.next();

105             Log.d(Tag, "" + size.width + " by " + size.height);

106             if (size.width >= previewWidth && size.width <= screenHeight &&

107                     size.height >= previewHeight && size.height <= screenWidth) {//640

108                 previewWidth = size.width;

109                 previewHeight = size.height;

110             }

111         }

112         parameters.setPreviewSize(previewWidth, previewHeight);

113         Log.d(Tag, "preivewWidth: " + previewWidth + " preivewHeight: " + previewHeight);

114         List<String> focusModes = parameters.getSupportedFocusModes();

115         if (focusModes != null && focusModes.contains(Camera.Parameters.FOCUS_MODE_AUTO)) {

116             parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);

117         }

118         mCamera.setParameters(parameters);

119         previewSize = mCamera.getParameters().getPreviewSize();

120     }

121     

122     @Override

123     public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

124         Log.d(Tag, "surface changed");

125         //Log.d(Tag, "surface size: " + width + " by " + height);

126         //Log.d(Tag, "preview size: " + previewSize.width + " by " + previewSize.height);

127         //使SurfaceView大小和预览大小比例相同

128         mSurfaceView.setLayoutParams(new LinearLayout.LayoutParams(width, (int)(width * previewSize.width / previewSize.height)));

129         //Log.d(Tag, "surface size2: " + width + " by " + (int)(width * previewSize.width / previewSize.height));

130         mCamera.startPreview();

131         mCamera.autoFocus(mAutoFocusCallback);

132     }

133     

134     @Override

135     public void surfaceDestroyed(SurfaceHolder holder) {

136         Log.d(Tag, "surface destroyed");

137         if (mCamera != null) {

138             mCamera.autoFocus(null);

139             mCamera.stopPreview();

140             mCamera.setPreviewCallback(null);

141             mCamera.release();

142             mCamera = null;

143         }

144     }

145     

146     Camera.AutoFocusCallback mAutoFocusCallback = new Camera.AutoFocusCallback() {

147         @Override

148         public void onAutoFocus(boolean success, Camera camera) {

149             Log.d(Tag, "AutoFocus: " + success);

150             if (success) {

151                 //自动对焦成功

152                 // ...

153             } else {

154                 //自动对焦失败，再次对焦

155                 mCamera.autoFocus(mAutoFocusCallback);

156             }

157         }

158     };

159     

160     Camera.PreviewCallback mPreviewCallback = new Camera.PreviewCallback() {

161         @Override

162         public void onPreviewFrame(byte[] data, Camera camera)

163         {

164             

165         }

166     };

167     

168 }

 

布局文件activity_camera_test.xml：

 1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

 2     xmlns:tools="http://schemas.android.com/tools"

 3     android:layout_width="match_parent"

 4     android:layout_height="match_parent"

 5     android:orientation="vertical"

 6     tools:context=".MainActivity" >

 7 

 8     <SurfaceView  

 9         android:layout_width="fill_parent" 

10            android:layout_height="wrap_content" 

11         android:id="@+id/surfaceview"/>

12 

13 </LinearLayout>

注意事项：（新发现的会再补充上）

1，在surfaceChanged函数里面，mCamera.autoFocus(mAutoFocusCallback)，如果写成autoFocus(null)的话，程序安装后第一次打开时预览会很亮很模糊。