初学Android,多媒体之使用Camera进行拍照(七十九)

Android中提供了Camera类来控制拍照，下面是一个例子，运行的时候最好是真机调试，因为模拟器没有真正的摄像头

首先还是增加使用摄像头的权限

    <uses-permission android:name="android.permission.CAMERA" />
    <uses-feature android:name="android.hardware.camera" />
    <uses-feature android:name="android.hardware.camera.autofocus" />

package WangLi.Media.Camera;

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

import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.graphics.BitmapFactory;
import android.graphics.PixelFormat;
import android.hardware.Camera;
import android.hardware.Camera.PictureCallback;
import android.os.Bundle;
import android.os.Environment;
import android.view.Display;
import android.view.KeyEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceHolder.Callback;
import android.view.SurfaceView;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.EditText;
import android.widget.ImageView;

public class CaptureImage extends Activity {
	SurfaceView sView;
	SurfaceHolder surfaceHolder;
	int screenWidth, screenHeight;
	// 定义系统所用的照相机
	Camera camera;
	// 是否在浏览中
	boolean isPreview = false;

	PictureCallback myjpegCallback = new PictureCallback() {
		@Override
		public void onPictureTaken(byte[] data, Camera camera) {
			// 根据拍摄所得的数据创建位图
			final Bitmap bm = BitmapFactory.decodeByteArray(data, 0,
					data.length);
			// 加载/layout/save.xml文件对应的布局资源
			View saveDialog = getLayoutInflater().inflate(R.layout.save, null);
			final EditText photoName = (EditText) saveDialog
					.findViewById(R.id.phone_name);
			// 获取saveDialog对话框上的ImageView组件
			ImageView show = (ImageView) saveDialog.findViewById(R.id.show);
			// 显示刚刚拍得的照片
			show.setImageBitmap(bm);
			// 使用对话框显示saveDialog组件
			new AlertDialog.Builder(CaptureImage.this).setView(saveDialog)
					.setPositiveButton("保存", new OnClickListener() {
						@Override
						public void onClick(DialogInterface dialog, int which) {
							// 创建一个位于SD卡上的文件
							File file = new File(Environment
									.getExternalStorageDirectory(), photoName
									.getText().toString() + ".jpg");
							FileOutputStream outStream = null;
							try {
								// 打开指定文件对应的输出流
								outStream = new FileOutputStream(file);
								// 把位图输出到指定文件中
								bm.compress(CompressFormat.JPEG, 100, outStream);
								outStream.close();
							} catch (Exception e) {
								e.printStackTrace();
							}
						}
					}).setNegativeButton("取消", null).show();
			// 重新浏览
			camera.stopPreview();
			camera.startPreview();
			isPreview = true;
		}
	};

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		// 设置全屏
		requestWindowFeature(Window.FEATURE_NO_TITLE);
		getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
				WindowManager.LayoutParams.FLAG_FULLSCREEN);
		setContentView(R.layout.main);
		WindowManager wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE);
		Display display = wm.getDefaultDisplay();
		// 获取屏幕的宽和高
		screenWidth = display.getWidth();
		screenHeight = display.getHeight();
		// 获取界面中的SurfaceView组件
		sView = (SurfaceView) findViewById(R.id.sView);
		// 获取SurfaceView的SurfaceHolder
		surfaceHolder = sView.getHolder();
		// 为surfaceHolder添加一个回调监听器
		surfaceHolder.addCallback(new Callback() {
			@Override
			public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2,
					int arg3) {
				// TODO Auto-generated method stub
			}

			@Override
			public void surfaceCreated(SurfaceHolder holder) {
				// TODO Auto-generated method stub
				initCamera();
			}

			@Override
			public void surfaceDestroyed(SurfaceHolder arg0) {
				// 如果camera不为null,释放摄像头
				if (camera != null) {
					if (isPreview)
						camera.startPreview();
					camera.release();
					camera = null;
				}
			}
		});
		//设置SurfaceView自己不维护缓冲
		surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
	}

	private void initCamera() {
		if (!isPreview) {
			camera = Camera.open();
		}
		if (camera != null && !isPreview) {
			try {
				Camera.Parameters parameters = camera.getParameters();
				// 设置预览照片的大小　
				parameters.setPreviewSize(screenWidth, screenHeight);
				// 每秒显示4帧
				parameters.setPreviewFrameRate(4);
				// 设置图片格式
				parameters.setPictureFormat(PixelFormat.JPEG);
				// 设置JPG照片质量
				parameters.set("jpeg-quality", 85);
				// 设置照片的大小　
				parameters.setPictureSize(screenWidth, screenHeight);
				// Android2.3.3以后不需要下面这行代码
				camera.setParameters(parameters);
				// 通过SurfaceView显示取景画面
				camera.setPreviewDisplay(surfaceHolder);
				// 通过SurfaceView显示取景画面
				camera.setPreviewDisplay(surfaceHolder);
				// 开始预览
				camera.startPreview();
				// 自动对焦
				camera.autoFocus(null);
			} catch (Exception e) {
				e.printStackTrace();
			}
			isPreview = true;
		}
	}

	@Override
	public boolean onKeyDown(int KeyCode, KeyEvent event) {
		switch (KeyCode) {
		// 当用户单击照相键，*键时执行拍照
		case KeyEvent.KEYCODE_DPAD_CENTER:
		case KeyEvent.KEYCODE_CAMERA:
			if (camera != null && event.getRepeatCount() == 0) {
				// 拍照
				camera.takePicture(null, null, myjpegCallback);
				return true;
			}
			break;
		}
		return super.onKeyDown(KeyCode, event);
	}
}