Android开发教程之调用摄像头功能的方法详解

Window window = getWindow();//得到窗口

requestWindowFeature(Window.FEATURE_NO_TITLE);//没有标题

setContentView(R.layout.main);

surfaceView = (SurfaceView) findViewById(R.id.surfaceview);

surfaceView.getHolder().setFixedSize(800, 480);
//下面设置surfaceView不维护自己的缓冲区,而是等待屏幕的渲染引擎将内容推送到用户面前
surfaceView.getHolder().setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

surfaceView.getHolder().addCallback(new SurfaceCallback());

private class SurfaceCallback implements SurfaceHolder.Callback{
@Override
public void surfaceCreated(SurfaceHolder holder) {
try {
camera = Camera.open();//打开硬件摄像头，这里导包得时候一定要注意是android.hardware.Camera
WindowManager wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE);//得到窗口管理器
Display display = wm.getDefaultDisplay();//得到当前屏幕
Camera.Parameters parameters = camera.getParameters();//得到摄像头的参数
parameters.setPreviewSize(display.getWidth(), display.getHeight());//设置预览照片的大小
parameters.setPreviewFrameRate(3);//设置每秒3帧
parameters.setPictureFormat(PixelFormat.JPEG);//设置照片的格式
parameters.setJpegQuality(85);//设置照片的质量
parameters.setPictureSize(display.getHeight(), display.getWidth());//设置照片的大小，默认是和   屏幕一样大
camera.setParameters(parameters);
camera.setPreviewDisplay(surfaceView.getHolder());//通过SurfaceView显示取景画面
camera.startPreview();//开始预览
isPreview = true;//设置是否预览参数为真
} catch (IOException e) {
Log.e(TAG, e.toString());
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// TODO Auto-generated method stub
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
if(camera!=null){
if(isPreview){//如果正在预览
camera.stopPreview();
camera.release();
}
}
}
}

public boolean onKeyDown(int keyCode, KeyEvent event) {//处理按键事件
if(camera!=null&&event.getRepeatCount()==0)//代表只按了一下
{
switch(keyCode){
case KeyEvent.KEYCODE_BACK://如果是搜索键
   camera.autoFocus(null);//自动对焦
 break;
  case KeyEvent.KEYCODE_DPAD_CENTER://如果是中间键
   camera.takePicture(null, null, new TakePictureCallback());//将拍到的照片给第三个对象中，这里的TakePictureCallback()是自己定义的，在下面的代码中
 break;
}
}
return true;//阻止事件往下传递，否则按搜索键会变成系统默认的
}

private final class TakePictureCallback implements PictureCallback{
public void onPictureTaken(byte[] data, Camera camera) {
try {
Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
File file = new File(Environment.getExternalStorageDirectory(),System.currentTimeMillis()+".jpg");
FileOutputStream outputStream = new FileOutputStream(file);
bitmap.compress(CompressFormat.JPEG, 100, outputStream);
outputStream.close();
camera.stopPreview();
camera.startPreview();//处理完数据之后可以预览
} catch (Exception e) {
Log.e(TAG, e.toString());
}
}
}

package cn.camera.rxm;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Calendar;
import java.util.Locale;
import org.apache.commons.logging.Log;
import android.text.format.DateFormat;
import android.util.*;
import android.app.Activity;
import android.content.Context;
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.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
//import android.widget.Toast;
public class MycamActivity extends Activity {
private Preview mPreview;
private Camera mCamera;
Bitmap CameraBitmap;
SurfaceHolder mHolder;
private static final int OPTION_SNAPSHOT = 0;
private static final int OPTION_STOPCAMERA = 1;
private View viewStart;
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    LayoutInflater flater = this.getLayoutInflater();
    viewStart = flater.inflate(R.layout.main, null);
    setContentView(viewStart);
    Button btn1 = (Button)findViewById(R.id.button1);
    btn1.setOnClickListener(
    new OnClickListener(){
    public void onClick(View v){
    mPreview = new Preview(getBaseContext());
    setContentView(mPreview);
    };
    }
    );
  }
  public boolean onCreateOptionsMenu(Menu menu){
//
menu.add(0, OPTION_SNAPSHOT, 0, R.string.take);
//
menu.add(0, OPTION_STOPCAMERA, 1, R.string.back);
//
return true;//super.onCreateOptionsMenu(menu);
}
public boolean onOptionsItemSelected(MenuItem item) {
//
int itemId = item.getItemId();
//
switch(itemId){
case OPTION_SNAPSHOT:
//拍摄照片
mCamera.takePicture(null, null, jpegCallback);
try {
Thread.sleep(4000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
mCamera.startPreview();
break;
case OPTION_STOPCAMERA:
mPreview = null;
setContentView(viewStart);
break;
}
return true;
}
private PictureCallback jpegCallback = new PictureCallback(){
//
public void onPictureTaken(byte[] data, Camera camera) {
try {
String name = new DateFormat().format("yyyyMMdd_hhmmss",
Calendar.getInstance(Locale.CHINA)) + ".jpg";
FileOutputStream fileout = new FileOutputStream("/mnt/sdcard/sdcard/DCIM/"+ name);
System.out.println(name);
fileout.write(data,0,data.length);
fileout.flush();
fileout.close();
} catch (IOException e) {
// TODO: handle exception
System.out.println(e);
}
}
};
class Preview extends SurfaceView implements SurfaceHolder.Callback
{
Preview(Context context)
{
super(context);
mHolder=getHolder();
mHolder.addCallback(this);
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(SurfaceHolder holder)
{
mCamera=Camera.open();
try
{
mCamera.setPreviewDisplay(holder);
}
catch(IOException exception)
{
mCamera.release();
mCamera=null;
}
}
public void surfaceDestroyed(SurfaceHolder holder)
{
mCamera.stopPreview();
mCamera.release();
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// TODO Auto-generated method stub
Camera.Parameters parameters=mCamera.getParameters();
parameters.setPictureFormat(PixelFormat.JPEG);
parameters.setPreviewSize(1024, 1024);
mCamera.setParameters(parameters);
mCamera.setDisplayOrientation(90);
mCamera.startPreview();
}
}
}