保存多个文件而不替换存在的文件
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【中文标题】保存多个文件而不替换存在的文件【英文标题】：Save multiple files without replacing the one that exists 【发布时间】：2016-10-13 23:54:18 【问题描述】：我正在尝试将多个图像保存在特定文件夹中，第一个图像保存正确，但下一个只是替换了第一个。如何保存多张图片？如何动态命名并保存具有相同名称但具有不同扩展名的图像，如图像、图像1、图像2 ...等 下面是我的代码
public class CameraView extends Activity implements SurfaceHolder.Callback, OnClickListener
private static final String TAG = "CameraTest";
Camera mCamera;
boolean mPreviewRunning = false;
@SuppressWarnings("deprecation")
public void onCreate(Bundle icicle)
super.onCreate(icicle);
Log.e(TAG, "onCreate");
getWindow().setFormat(PixelFormat.TRANSLUCENT);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.cameraview);
ImageView img = (ImageView) findViewById(R.id.blankImage);
if(ImageViewActivity.isBlack)
img.setBackgroundResource(android.R.color.black);
else
img.setBackgroundResource(android.R.color.white);
mSurfaceView = (SurfaceView) findViewById(R.id.surface_camera);
mSurfaceView.setOnClickListener(this);
mSurfaceHolder = mSurfaceView.getHolder();
mSurfaceHolder.addCallback(this);
mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState)
super.onRestoreInstanceState(savedInstanceState);
private void copy(File src, File dst) throws IOException
InputStream in = new FileInputStream(src);
OutputStream out = new FileOutputStream(dst);
// Transfer bytes from in to out
byte[] buf = new byte[1024];
int len;
while ((len = in.read(buf)) > 0)
out.write(buf, 0, len);
in.close();
out.close();
private File getAlbumStorageDir(Context context, String albumName)
// Get the directory for the app's private pictures directory.
File file = new File(context.getExternalFilesDir(
Environment.DIRECTORY_PICTURES), albumName);
if(file.exists())
return null;
if (!file.mkdirs())
Log.e("MainActivity.error", "Directory not created");
return file;
Camera.PictureCallback mPictureCallback = new Camera.PictureCallback()
public void onPictureTaken(byte[] data, Camera camera)
// TODO Auto-generated method stub
if (data != null)
//Intent mIntent = new Intent();
//mIntent.putExtra("image",imageData);
mCamera.stopPreview();
mPreviewRunning = false;
mCamera.release();
Bitmap resizedBitmap=null;
try
BitmapFactory.Options opts = new BitmapFactory.Options();
Bitmap bitmap= BitmapFactory.decodeByteArray(data, 0, data.length,opts);
bitmap = Bitmap.createScaledBitmap(bitmap, 300, 300, false);
int width = bitmap.getWidth();
int height = bitmap.getHeight();
int newWidth = 300;
int newHeight = 300;
// calculate the scale - in this case = 0.4f
float scaleWidth = ((float) newWidth) / width;
float scaleHeight = ((float) newHeight) / height;
// createa matrix for the manipulation
Matrix matrix = new Matrix();
// resize the bit map
matrix.postScale(scaleWidth, scaleHeight);
// rotate the Bitmap
matrix.postRotate(90);
resizedBitmap = Bitmap.createBitmap(bitmap, 0, 0,
width, height, matrix, true);
ImageViewActivity.image.setImageBitmap(resizedBitmap);
catch(Exception e)
e.printStackTrace();
//StoreByteImage(mContext, imageData, 50,"ImageName");
//setResult(FOTO_MODE, mIntent);
FileOutputStream out = null;
File picturesDir = getAlbumStorageDir(getBaseContext(), "myDirName");
File savedPic = new File(picturesDir.getAbsolutePath() + "/mynewpic.jpg");
try
out = new FileOutputStream(savedPic);
resizedBitmap.compress(Bitmap.CompressFormat.PNG, 100, out); // bmp is your Bitmap instance
// PNG is a lossless format, the compression factor (100) is ignored
catch (Exception e)
e.printStackTrace();
finally
try
if (out != null)
out.close();
catch (IOException e)
e.printStackTrace();
try
copy(picturesDir, savedPic);
catch (IOException e)
Log.e("MainActivity.err", "failed to copy");
setResult(585);
finish();
;
protected void onResume()
Log.e(TAG, "onResume");
super.onResume();
protected void onSaveInstanceState(Bundle outState)
super.onSaveInstanceState(outState);
protected void onStop()
Log.e(TAG, "onStop");
super.onStop();
@TargetApi(9)
public void surfaceCreated(SurfaceHolder holder)
Log.e(TAG, "surfaceCreated");
mCamera = Camera.open(ImageViewActivity.cameraID);
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h)
Log.e(TAG, "surfaceChanged");
// XXX stopPreview() will crash if preview is not running
if (mPreviewRunning)
mCamera.stopPreview();
Camera.Parameters p = mCamera.getParameters();
p.setPreviewSize(300, 300);
if(ImageViewActivity.cameraID == 0)
String stringFlashMode = p.getFlashMode();
if (stringFlashMode.equals("torch"))
p.setFlashMode("on"); // Light is set off, flash is set to normal 'on' mode
else
p.setFlashMode("torch");
/*mCamera.setParameters(p);*/
try
mCamera.setPreviewDisplay(holder);
catch (Exception e)
// TODO Auto-generated catch block
e.printStackTrace();
mCamera.startPreview();
mPreviewRunning = true;
mCamera.takePicture(null, mPictureCallback, mPictureCallback);
public void surfaceDestroyed(SurfaceHolder holder)
Log.e(TAG, "surfaceDestroyed");
//mCamera.stopPreview();
//mPreviewRunning = false;
//mCamera.release();
private SurfaceView mSurfaceView;
private SurfaceHolder mSurfaceHolder;
public void onClick(View v)
// TODO Auto-generated method stub
mCamera.takePicture(null, mPictureCallback, mPictureCallback);
【问题讨论】：
如果你想积累一堆不同的图像，你需要保存到不同的文件名。尝试为每个保存操作自动生成一个唯一的文件名。 【参考方案1】：您可以在 Activity 中使用计数器变量：
int counter = 0;
将其附加到您的文件名中，并在成功保存后递增：
File savedPic = new File(picturesDir.getAbsolutePath() + "/mynewpic" + counter + ".jpg");
try
out = new FileOutputStream(savedPic);
resizedBitmap.compress(Bitmap.CompressFormat.PNG, 100, out); // bmp is your Bitmap instance
// PNG is a lossless format, the compression factor (100) is ignored
counter++; // no exception thrown, increment the counter
catch (Exception e)
e.printStackTrace();
您应该使用某种持久存储来存储计数器的当前值，例如SharedPreferences。
或者，您可以使用一些唯一标识符来代替计数器，例如 System.currentTimeMillis，这样您就不必处理跟踪值的问题。
【讨论】：
【参考方案2】：将时间戳设置为 ImageName，这样每次保存时都会使用不同的名称..
添加时间戳参考：here
【讨论】：
【参考方案3】：使用递归调用，可以轻松实现。下面是代码。
/**
* fileCount - to avoid overwrite and save file
* with order ie - test - (1).pdf, test - (2).pdf
*/
fun savePdf(directoryPath: String, fileName: String, fileCount: Int = 0)
val newFileName = if (fileCount == 0)
"$fileName.pdf"
else
"$fileName - ($fileCount).pdf"
val targetFilePath = File(directoryPath, newFileName)
if (targetFilePath.exists())
savePdf(directoryPath, fileName, fileCount + 1)
return
// add your logic to save file in targetFilePath
并在你的代码中这样调用它。
savePdf(directoryPath, fileName)
【讨论】：
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