Android开发实现ImageView加载摄像头拍摄的大图功能

本文实例讲述了android开发实现imageview加载摄像头拍摄的大图功能。分享给大家供大家参考，具体如下：

这个方法是从官方demo中摘录的，在此记录学习。

权限

<uses-permission android:name="android.permission.write_external_storage" />
<uses-feature
  android:name="android.hardware.camera2"
  android:required="false" />

另：关于权限控制还可参考：android manifest功能与权限描述大全

设置变量保存文件存储路径

private string mcurrentphotopath;
/**
* 拍照flag
*/
private static final int request_image_capture_o = 2;

创建存储路径及文件名

 /**
* 创建拍摄的图片的存储路径及文件名
* @return
* @throws ioexception
*/
private file createimagefile() throws ioexception{
  string timestamp = new simpledateformat("yyyymmdd_hhmmss").format(new date());
  string imagefilename = "jpeg_" + timestamp + "_";
  file storagedir = environment.getexternalstoragepublicdirectory(environment.directory_pictures);
  log.d("trainingfirstactivity", "storagedir:" + storagedir);
  file image = file.createtempfile(imagefilename, ".jpg", storagedir);
  mcurrentphotopath = image.getabsolutepath();
  log.d("image.getabsolutepath()", image.getabsolutepath() + "");
  return image;
}

拍摄图片并保存

intent takepictureointent = new intent(mediastore.action_image_capture);
if (takepictureointent.resolveactivity(getpackagemanager()) != null){
 file photofile = null;
 try {
  photofile = createimagefile();
 } catch (ioexception e) {
  e.printstacktrace();
 }
 if (photofile != null){
  takepictureointent.putextra(mediastore.extra_output, uri.fromfile(photofile));
  startactivityforresult(takepictureointent, request_image_capture_o);
 }
}

处理并压缩拍照结果,takephotothentoshowimg是一个imageview控件

@override
protected void onactivityresult(int requestcode, int resultcode, intent data) {
  if (requestcode == request_image_capture_o && resultcode == result_ok){
   int targetw = takephotothentoshowimg.getwidth();
   int targeth = takephotothentoshowimg.getheight();
  /* get the size of the image */
   bitmapfactory.options bmoptions = new bitmapfactory.options();
   bmoptions.injustdecodebounds = true;
   bitmapfactory.decodefile(mcurrentphotopath, bmoptions);
   int photow = bmoptions.outwidth;
   int photoh = bmoptions.outheight;
  /* figure out which way needs to be reduced less */
   int scalefactor = 1;
   if ((targetw > 0) || (targeth > 0)) {
    scalefactor = math.min(photow/targetw, photoh/targeth);
   }
  /* set bitmap options to scale the image decode target */
   bmoptions.injustdecodebounds = false;
   bmoptions.insamplesize = scalefactor;
   bmoptions.inpurgeable = true;
  /* decode the jpeg file into a bitmap */
   bitmap bitmap = bitmapfactory.decodefile(mcurrentphotopath, bmoptions);
  /* associate the bitmap to the imageview */
   takephotothentoshowimg.setimagebitmap(bitmap);
   galleryaddpic();
  }
}

最后可以将拍摄到的照片添加到media provider的数据库中，以便图库或者其他程序读取照片

/**
* 将拍摄到的照片添加到media provider的数据库中
*/
private void galleryaddpic(){
  intent mediascanintent = new intent(intent.action_media_scanner_scan_file);
  file f = new file(mcurrentphotopath);
  uri contenturi = uri.fromfile(f);
  mediascanintent.setdata(contenturi);
  this.sendbroadcast(mediascanintent);
}

如果只需要缩略图的话，只要调摄像头拍摄直接处理结果就行

@override
protected void onactivityresult(int requestcode, int resultcode, intent data) {
 if (requestcode == request_image_capture && resultcode == result_ok){//展示图片
   bundle extras = data.getextras();
   bitmap imagebitmap = (bitmap) extras.get("data");
   takephotothentoshowimg.setimagebitmap(imagebitmap);
  }
}

更多关于android相关内容感兴趣的读者可查看本站专题：《android拍照与图片处理技巧总结》、《android图形与图像处理技巧总结》、《android开发入门与进阶教程》、《android调试技巧与常见问题解决方法汇总》、《android基本组件用法总结》、《android视图view技巧总结》、《android布局layout技巧总结》及《android控件用法总结》

希望本文所述对大家android程序设计有所帮助。