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从相册或相机中选取照片上传之前，应先调整图片大小。

androidfile-uploadimage-resizing
4
我网站上有一个表单，允许用户上传照片。我的安卓应用程序使用WebView让用户访问该网站。在点击上传按钮时，应用程序允许用户选择从相册中已经存在的图像或拍摄新照片并上传该图像。我使用的代码是：
showAttachmentDialog是由openFileChooser调用的。
private void showAttachmentDialog(ValueCallback<Uri> uploadMsg) {
        this.mUploadMessage = uploadMsg;

        File imageStorageDir = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), "MyApp");
        // Create the storage directory if it does not exist
        if (! imageStorageDir.exists()){
            imageStorageDir.mkdirs();                  
        }
        File file = new File(imageStorageDir + File.separator + "IMG_" + String.valueOf(System.currentTimeMillis()) + ".jpg");


        this.imageUri= Uri.fromFile(file);


        final List<Intent> cameraIntents = new ArrayList<Intent>();
        final Intent captureIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
        final PackageManager packageManager = getPackageManager();
        final List<ResolveInfo> listCam = packageManager.queryIntentActivities(captureIntent, 0);
        for(ResolveInfo res : listCam) {
            final String packageName = res.activityInfo.packageName;
            final Intent intent = new Intent(captureIntent);
            intent.setComponent(new ComponentName(res.activityInfo.packageName, res.activityInfo.name));
            intent.setPackage(packageName);
            intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
            cameraIntents.add(intent);
        }


       // mUploadMessage = uploadMsg; 
        Intent intent = new Intent(Intent.ACTION_GET_CONTENT);  
        intent.addCategory(Intent.CATEGORY_OPENABLE);  
        intent.setType("image/*"); 
        Intent chooserIntent = Intent.createChooser(intent,"Image Chooser");
        chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS, cameraIntents.toArray(new Parcelable[]{}));
        this.startActivityForResult(chooserIntent,  FILECHOOSER_RESULTCODE);
    }

我的onActivityResult

protected void onActivityResult(int requestCode, int resultCode, Intent intent) {
        if (requestCode == FILECHOOSER_RESULTCODE) {

            if (null == this.mUploadMessage) {
                return;
            }

            Uri result;
            if (resultCode != RESULT_OK) {
                result = null;
            } else {
                result = intent == null ? this.imageUri : intent.getData(); // retrieve from the private variable if the intent is null
            }

            this.mUploadMessage.onReceiveValue(result);
            this.mUploadMessage = null;



        }
    }

我希望能够在上传图片之前就能够改变图片的大小，并且这个操作需要在手机上完成，而不是在网页上。我还想在完成这个操作后从手机中删除调整过大小的图片，但保留原型。你能给我建议吗？我在SO上看到了几种情况，其中建议使用createScaledBitmap创建位图并将其调整为所需大小，但我不确定在我的情况下哪种方法最好。这应该发生在哪里？在我的onActivityResult中吗？
谢谢！
--------------------编辑---------------------- private File imageStorageDir, file;
我在我的主Activity中声明了这些，并在我的onActivityResult中添加了以下代码片段。
String newPath=file.getAbsolutePath();
            Bitmap bMap= BitmapFactory.decodeFile(newPath);
            Bitmap out = Bitmap.createScaledBitmap(bMap, 150, 150, false);
            File resizedFile = new File(imageStorageDir, "resized.png");

            OutputStream fOut=null;
            try {
                fOut = new BufferedOutputStream(new FileOutputStream(resizedFile));
                out.compress(Bitmap.CompressFormat.PNG, 100, fOut);
                fOut.flush();
                fOut.close();
                bMap.recycle();
                out.recycle();

            } catch (Exception e) { // TODO

            }

现在使用相机拍照时，图像会被调整大小并上传，但当我使用相册时，会出现空指针异常。
05-23 10:12:50.354: E/BitmapFactory(1376): Unable to decode stream: java.io.FileNotFoundException: /storage/sdcard/Pictures/MyApp/IMG_1400854361171.jpg: open failed: ENOENT (No such file or directory)
05-23 10:12:50.364: D/AndroidRuntime(1376): Shutting down VM
05-23 10:12:50.414: W/dalvikvm(1376): threadid=1: thread exiting with uncaught exception (group=0x41465700)
05-23 10:12:50.494: E/AndroidRuntime(1376): FATAL EXCEPTION: main
05-23 10:12:50.494: E/AndroidRuntime(1376): java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=1, result=-1, data=Intent { dat=content://media/external/images/media/76 }} to activity {com.example.sinatra19/com.example.sinatra19.Sinatra22Activity}: java.lang.NullPointerException
05-23 10:12:50.494: E/AndroidRuntime(1376):     at android.app.ActivityThread.deliverResults(ActivityThread.java:3367)
05-23 10:12:50.494: E/AndroidRuntime(1376):     at android.app.ActivityThread.handleSendResult(ActivityThread.java:3410)
05-23 10:12:50.494: E/AndroidRuntime(1376):     at android.app.ActivityThread.access$1100(ActivityThread.java:141)
05-23 10:12:50.494: E/AndroidRuntime(1376):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1304)
05-23 10:12:50.494: E/AndroidRuntime(1376):     at android.os.Handler.dispatchMessage(Handler.java:99)
05-23 10:12:50.494: E/AndroidRuntime(1376):     at android.os.Looper.loop(Looper.java:137)
05-23 10:12:50.494: E/AndroidRuntime(1376):     at android.app.ActivityThread.main(ActivityThread.java:5103)
05-23 10:12:50.494: E/AndroidRuntime(1376):     at java.lang.reflect.Method.invokeNative(Native Method)
05-23 10:12:50.494: E/AndroidRuntime(1376):     at java.lang.reflect.Method.invoke(Method.java:525)
05-23 10:12:50.494: E/AndroidRuntime(1376):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
05-23 10:12:50.494: E/AndroidRuntime(1376):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
05-23 10:12:50.494: E/AndroidRuntime(1376):     at dalvik.system.NativeStart.main(Native Method)
05-23 10:12:50.494: E/AndroidRuntime(1376): Caused by: java.lang.NullPointerException
05-23 10:12:50.494: E/AndroidRuntime(1376):     at android.graphics.Bitmap.createScaledBitmap(Bitmap.java:482)
05-23 10:12:50.494: E/AndroidRuntime(1376):     at com.example.sinatra19.Sinatra22Activity.onActivityResult(Sinatra22Activity.java:158)
05-23 10:12:50.494: E/AndroidRuntime(1376):     at android.app.Activity.dispatchActivityResult(Activity.java:5322)
05-23 10:12:50.494: E/AndroidRuntime(1376):     at android.app.ActivityThread.deliverResults(ActivityThread.java:3363)
05-23 10:12:50.494: E/AndroidRuntime(1376):     ... 11 more

-----------------------EDIT2------------------------

这段代码

           String newPath=getRealPathFromURI(getApplicationContext(), result);


            Bitmap bMap= BitmapFactory.decodeFile(newPath);
            Bitmap out = Bitmap.createScaledBitmap(bMap, 150, 150, false);
            File resizedFile = new File(imageStorageDir, "resize.png");

            OutputStream fOut=null;
            try {
                fOut = new BufferedOutputStream(new FileOutputStream(resizedFile));
                out.compress(Bitmap.CompressFormat.PNG, 100, fOut);
                fOut.flush();
                fOut.close();
                bMap.recycle();
                out.recycle();

            } catch (Exception e) { // TODO

            }
this.mUploadMessage.onReceiveValue(Uri.fromFile(resizedFile));
        this.mUploadMessage = null;

电话通讯
public String getRealPathFromURI(Context context, Uri contentUri) {
          Cursor cursor = null;
          try { 
            String[] proj = { MediaStore.Images.Media.DATA };
            cursor = context.getContentResolver().query(contentUri,  proj, null, null, null);
            int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
            cursor.moveToFirst();
            return cursor.getString(column_index);
          } finally {
            if (cursor != null) {
              cursor.close();
            }
          }
        }

当用户从相册选择照片时，程序可以正常运行，但当用户使用相机拍照时，程序会崩溃。我需要找到解决方案来将它们结合起来。

1个回答
4

只需要使用一个if语句来检查用户选择了哪种方法。文件是在showAttachmentDialog中创建的，因此私有的imageUri始终具有该文件的Uri。当用户选择相机选项时，result也具有该值，而当他选择图库时，result具有所选图像的Uri。

if(result==this.imageUri){
            newPath=file.getAbsolutePath();}
            else{
            newPath=getRealPathFromURI(getApplicationContext(), result);}

最终代码如下：
@Override
    //Receives the results of startActivityFromResult
    protected void onActivityResult(int requestCode, int resultCode, Intent intent) {
        String newPath;
        if (requestCode == FILECHOOSER_RESULTCODE) {

            if (null == this.mUploadMessage) {
                return;
            }

            Uri result;
            if (resultCode != RESULT_OK) {
                result = null;
            } else {
                result = intent == null ? this.imageUri : intent.getData(); // retrieve from the private variable if the intent is null
                Log.e("result",result.toString() );
                Log.e("intent",this.imageUri.toString() );

            }

            if(result==this.imageUri){
            newPath=file.getAbsolutePath();}
            else{
            newPath=getRealPathFromURI(getApplicationContext(), result);}

            Bitmap bMap= BitmapFactory.decodeFile(newPath);
            Bitmap out = Bitmap.createScaledBitmap(bMap, 150, 150, false);
            File resizedFile = new File(imageStorageDir, "resize.png");

            OutputStream fOut=null;
            try {
                fOut = new BufferedOutputStream(new FileOutputStream(resizedFile));
                out.compress(Bitmap.CompressFormat.PNG, 100, fOut);
                fOut.flush();
                fOut.close();
                bMap.recycle();
                out.recycle();

            } catch (Exception e) { // TODO

            }


            this.mUploadMessage.onReceiveValue(Uri.fromFile(resizedFile));
            this.mUploadMessage = null;
            //resizedFile.delete();


        }
    }

    public String getRealPathFromURI(Context context, Uri contentUri) {
          Cursor cursor = null;
          try { 
            String[] proj = { MediaStore.Images.Media.DATA };
            cursor = context.getContentResolver().query(contentUri,  proj, null, null, null);
            int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
            cursor.moveToFirst();
            return cursor.getString(column_index);
          } finally {
            if (cursor != null) {
              cursor.close();
            }
          }
        }
如果我使用相机，bMap始终为空。有什么帮助吗？在这段代码中，file也未定义。 - Mark
嗨，马克。自上次我玩安卓以来已经很长时间了。这段代码在之前的套件猫 AVD 中可以运行，但在后面的安卓版本中可能会有问题。如果问题仍然存在，我建议你提供你的代码并发布一个新问题。 - magmike
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