android中的多媒体应用camera

MainActivity.java

代码

                            package           com.amaker.ch11.app;

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

          import           android.app.Activity;
          import           android.graphics.PixelFormat;
          import           android.hardware.Camera;
          import           android.os.AsyncTask;
          import           android.os.Bundle;
          import           android.os.Environment;
          import           android.view.KeyEvent;
          import           android.view.SurfaceHolder;
          import           android.view.SurfaceView;

          public                     class           MainActivity           extends           Activity {
           //           声明拍照界面组件SurfaceView          
                     private           SurfaceView surfaceView;
           //           声明界面控制组件SurfaceHolder          
                     private           SurfaceHolder surfaceHolder;
           //           声明照相机          
                     private           Camera camera;
 
 @Override
           public                     void           onCreate(Bundle savedInstanceState) {
           super          .onCreate(savedInstanceState);
 setContentView(R.layout.main);
           //           实例化拍照界面组件          
           surfaceView           =           (SurfaceView)findViewById(R.id.preview);
           //           从SurfaceView中获得SurfaceHolder          
           surfaceHolder           =           surfaceView.getHolder();
           //           为SurfaceHolder 添加回调          
           surfaceHolder.addCallback(surfaceCallback);
 surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
 }
 
           //           响应按键事件          
           @Override
           public                     boolean           onKeyDown(          int           keyCode, KeyEvent event) {
           if          (keyCode          ==          KeyEvent.KEYCODE_CAMERA          ||          keyCode          ==          KeyEvent.KEYCODE_SEARCH){
 takePic();
           return                     true          ;
 }
           return                     super          .onKeyDown(keyCode, event);
 }
           //           拍照方法          
                     private                     void           takePic(){
           //           停止预览          
           camera.stopPreview();
           //           拍照          
           camera.takePicture(          null          ,          null          , pictureCallback);
 }
           //           照片回调          
           Camera.PictureCallback pictureCallback           =                     new           Camera.PictureCallback() {
 @Override
           public                     void           onPictureTaken(          byte          [] data, Camera camera) {
           new           SavePictureTask().execute(data);
 camera.startPreview();
 }
 };
 
           //           保存照片任务类          
                     class           SavePictureTask           extends           AsyncTask          <          byte          [],String,String          >          {
 @Override
           protected           String doInBackground(          byte          []... params) {
           //           创建文件          
           File picture           =                     new           File(Environment.getExternalStorageDirectory(),          "          picture.jpg          "          );
           //           如果文件存在删除掉          
                     if          (picture.exists())picture.delete();
           try           {
           //           获得文件输出流          
           FileOutputStream fos           =                     new           FileOutputStream(picture.getPath());
           //           写到该文件          
           fos.write(params[          0          ]);
           //           关闭文件流          
           fos.close();
 }           catch           (Exception e) {
 e.printStackTrace();
 }
           return                     null          ;
 }
 }
           //           SurfaceHodler 回调，处理打开相机，关闭相机以及照片尺寸的改变          
           SurfaceHolder.Callback surfaceCallback           =                     new           SurfaceHolder.Callback() {
 @Override
           public                     void           surfaceCreated(SurfaceHolder holder) {
           //           打开相机          
           camera           =           Camera.open();
           try           {
           //           设置预览          
           camera.setPreviewDisplay(holder);
 }           catch           (IOException e) {
 e.printStackTrace();
 }
 }
 
 @Override
           public                     void           surfaceChanged(SurfaceHolder holder,           int           format,           int           width,
           int           height) {
           //           获得相机参数          
           Camera.Parameters parameters           =           camera.getParameters();
           //           设置照片大小          
           parameters.setPreviewSize(width, height);
           //           设置照片格式          
           parameters.setPictureFormat(PixelFormat.JPEG);
           //           设置相机参数          
           camera.setParameters(parameters);
           //           开始预览          
           camera.startPreview();
 }
 
 @Override
           public                     void           surfaceDestroyed(SurfaceHolder holder) {
           //           停止预览          
           camera.stopPreview();
           //           释放相机资源          
           camera.release();
 camera           =                     null          ;
 }
 };
}

main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.view.SurfaceView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/preview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
</android.view.SurfaceView>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.amaker.ch11.app"
android:versionCode="1"
android:versionName="1.0">
<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".MainActivity"
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-sdk android:minSdkVersion="3" />

</manifest>

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