Android实现拍照及图片显示效果

<uses-feature android:name="android.hardware.camera2"    <!-- required为false时，不强制要求设备支持该功能 -->    <!-- 如果不设置该值，一旦设备不支持camera，就不能安装该应用-->    android:required="false"/>

public File getPhotoFile(Crime crime) {  //获取应用对应的存储照片的外部存储路径  File externalFilesDir = mContext      .getExternalFilesDir(Environment.DIRECTORY_PICTURES);  if (externalFilesDir == null) {    return null;  }  //创建指向文件的File对象  return new File(externalFilesDir, crime.getPhotoFilename());}.............//每个crime对应的文件名public String getPhotoFilename() {  return "IMG_" + getId().toString() + ".jpg";}

mPhotoButton = (ImageButton) v.findViewById(R.id.crime_camera);//隐式Intent触发相机拍照final Intent captureImageIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);//mPhotoFile保存着上文创建的指向指定地址的File//此处判断是否有能够处理隐式Intent的组件boolean canTakePhoto = mPhotoFile != null    && captureImageIntent.resolveActivity(packageManager) != null;mPhotoButton.setEnabled(canTakePhoto);if (canTakePhoto) {  //得到File文件对应的Uri地址  Uri uri = Uri.fromFile(mPhotoFile);  //将Uri地址存入到Intent中，相机拍照得到的图像将会存入到该Uri地址对应的File里  captureImageIntent.putExtra(MediaStore.EXTRA_OUTPUT, uri);}mPhotoButton.setOnClickListener(new View.OnClickListener() {  @Override  public void onClick(View v) {    startActivityForResult(captureImageIntent, REQUEST_PHOTO);  }});

@Overridepublic void onActivityResult(int requestCode, int resultCode, Intent data) {  .........  } else if (requestCode == REQUEST_PHOTO) {    updatePhotoView();  }  .........}private void updatePhotoView() {  if (mPhotoFile == null || !mPhotoFile.exists()) {    mPhotoView.setImageDrawable(null);  } else {    //加载图片对应的缩略图    Bitmap bitmap = PictureUtils.getScaledBitmap(mPhotoFile.getPath(), getActivity());    mPhotoView.setImageBitmap(bitmap);  }}

//在具体视图未加载前，无法得到视图的实际大小//因此根据屏幕尺寸，使用估算值进行缩放public static Bitmap getScaledBitmap(String path, Activity activity) {  Point size = new Point();  activity.getWindowManager().getDefaultDisplay().getSize(size);  return getScaledBitmap(path, size.x, size.y);}public static Bitmap getScaledBitmap(String path, int destWidth, int destHeight) {  BitmapFactory.Options options = new BitmapFactory.Options();  options.inJustDecodeBounds = true;  //按照正常尺寸解析文件  BitmapFactory.decodeFile(path, options);  //得到原始文件的宽和高  float srcWidth = options.outWidth;  float srcHeight = options.outHeight;  //inSampleSize表示水平/竖直抽样比  //例如，inSampleSize为2时，水平和数值均在原始基础上，每2个点抽取1个点  //于是，新图的大小变为原来的1/4  int inSampleSize = 1;  if (srcHeight > destHeight || srcWidth > destWidth) {    if (srcWidth > srcHeight) {      inSampleSize = Math.round(srcHeight / destHeight);    } else {      inSampleSize = Math.round(srcWidth / destWidth);    }   }  options = new BitmapFactory.Options();  options.inSampleSize = inSampleSize;  //按新的抽样比，重新解析文件  return BitmapFactory.decodeFile(path, options);}