CameraManager.java

package com.zbar.lib.camera;

import java.io.IOException;

import android.content.Context;
import android.graphics.Point;
import android.hardware.Camera;
import android.hardware.Camera.Parameters;
import android.os.Handler;
import android.view.SurfaceHolder;

/**
 * 作者: 陈涛(1076559197@qq.com)
 * 
 * 时间: 2014年5月9日 下午12:22:25
 *
 * 版本: V_1.0.0
 *
 * 描述: 相机管理
 */
public final class CameraManager {
	private static CameraManager cameraManager;

	static final int SDK_INT;
	static {
		int sdkInt;
		try {
			sdkInt = android.os.Build.VERSION.SDK_INT;
		} catch (NumberFormatException nfe) {
			sdkInt = 10000;
		}
		SDK_INT = sdkInt;
	}

	private final CameraConfigurationManager configManager;
	private Camera camera;
	private boolean initialized;
	private boolean previewing;
	private final boolean useOneShotPreviewCallback;
	private final PreviewCallback previewCallback;
	private final AutoFocusCallback autoFocusCallback;
	private Parameters parameter;

	public static void init(Context context) {
		if (cameraManager == null) {
			cameraManager = new CameraManager(context);
		}
	}

	public static CameraManager get() {
		return cameraManager;
	}

	private CameraManager(Context context) {
		this.configManager = new CameraConfigurationManager(context);

		useOneShotPreviewCallback = SDK_INT > 3;
		previewCallback = new PreviewCallback(configManager, useOneShotPreviewCallback);
		autoFocusCallback = new AutoFocusCallback();
	}

	public void openDriver(SurfaceHolder holder) throws IOException {
		if (camera == null) {
			camera = Camera.open();
			if (camera == null) {
				throw new IOException();
			}
			camera.setPreviewDisplay(holder);

			if (!initialized) {
				initialized = true;
				configManager.initFromCameraParameters(camera);
			}
			configManager.setDesiredCameraParameters(camera);
			FlashlightManager.enableFlashlight();
		}
	}

	public Point getCameraResolution() {
		return configManager.getCameraResolution();
	}

	public void closeDriver() {
		if (camera != null) {
			FlashlightManager.disableFlashlight();
			camera.release();
			camera = null;
		}
	}

	public void startPreview() {
		if (camera != null && !previewing) {
			camera.startPreview();
			previewing = true;
		}
	}

	public void stopPreview() {
		if (camera != null && previewing) {
			if (!useOneShotPreviewCallback) {
				camera.setPreviewCallback(null);
			}
			camera.stopPreview();
			previewCallback.setHandler(null, 0);
			autoFocusCallback.setHandler(null, 0);
			previewing = false;
		}
	}

	public void requestPreviewFrame(Handler handler, int message) {
		if (camera != null && previewing) {
			previewCallback.setHandler(handler, message);
			if (useOneShotPreviewCallback) {
				camera.setOneShotPreviewCallback(previewCallback);
			} else {
				camera.setPreviewCallback(previewCallback);
			}
		}
	}

	public void requestAutoFocus(Handler handler, int message) {
		if (camera != null && previewing) {
			autoFocusCallback.setHandler(handler, message);
			camera.autoFocus(autoFocusCallback);
		}
	}

	public void openLight() {
		if (camera != null) {
			parameter = camera.getParameters();
			parameter.setFlashMode(Parameters.FLASH_MODE_TORCH);
			camera.setParameters(parameter);
		}
	}

	public void offLight() {
		if (camera != null) {
			parameter = camera.getParameters();
			parameter.setFlashMode(Parameters.FLASH_MODE_OFF);
			camera.setParameters(parameter);
		}
	}
}