我的第一个问题在这里!我有一段代码有问题，该代码使用额外的输出选项启动相机 Intent ，然后在 Activity 结果中尝试调整该图像的大小。发生的事情是在回调的调整大小函数中抛出空指针异常。

原始大图仍然保存在文件系统中，因为我可以从文件系统访问它。

原始相机 jpeg 大小为 2560x1920，使用的手机是 google nexus one。

我不清楚为什么调整大小不起作用，有人有任何见解吗？

这是一些代码:

同样创建虚拟文件的 takePicture 函数:

        public boolean takePicture( ) {

            Log.e(TAG, "takePicture interface function");
            String FileUri = Environment.getExternalStorageDirectory()  + "/samples/";
            File file = new File(FileUri,"picture"+ pictureNumber +".jpg");
            try {
                file.createNewFile();
                } catch (IOException e) {
                e.printStackTrace();
                }
                Uri outputFileUri = Uri.fromFile(file);

            Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE); 
            cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, outputFileUri);
            startActivityForResult(cameraIntent, CAMERA_REQUEST);
            Log.e(TAG, "intent started");
            return true;
        }

on activity结果回调函数:

    protected void onActivityResult(int requestCode, int resultCode, Intent data) { 

        // handle the camera request returns and handle back button in camera.

        if (requestCode == CAMERA_REQUEST && resultCode == RESULT_CANCELED ) {
            Toast toast = Toast.makeText(this,"Canceled, no picture taken.", 1000);
            toast.show();
            return;
           }

        else if (requestCode == CAMERA_REQUEST && resultCode == RESULT_OK ) { 

            Log.e(TAG, "Camera intent return");

            Bitmap scaledphoto = null;
            int height = 300;
            int width = 300;    

            Bitmap photo = BitmapFactory.decodeFile( APP_DATA_PATH + "/samples/picture" + pictureNumber + ".jpg" );
            Log.e(TAG, "Picture fetched");

            scaledphoto = Bitmap.createScaledBitmap(photo, height, width, true);


            Log.e(TAG, "Picture scaled");

            saveImageToFile(scaledphoto, "picture" + pictureNumber + ".jpg");


            Log.e(TAG, "Scaled picture saved");

            myWebView.loadUrl("javascript:pictureTaken(\""+ pictureLoc + "\")");

            pictureNumber++;

这是 LogCat:

06-21 14:59:13.496: E/AndroidRuntime(6130): FATAL EXCEPTION: main
06-21 14:59:13.496: E/AndroidRuntime(6130): java.lang.RuntimeException: Failure     delivering result ResultInfo{who=null, request=1888, result=-1, data=null} to activity {test.test/test.test.CameraIntentTestActivity}: java.lang.NullPointerException
06-21 14:59:13.496: E/AndroidRuntime(6130):     at android.app.ActivityThread.deliverResults(ActivityThread.java:2980)
06-21 14:59:13.496: E/AndroidRuntime(6130):     at android.app.ActivityThread.handleSendResult(ActivityThread.java:3023)
06-21 14:59:13.496: E/AndroidRuntime(6130):     at android.app.ActivityThread.access$1100(ActivityThread.java:123)
06-21 14:59:13.496: E/AndroidRuntime(6130):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1177)
06-21 14:59:13.496: E/AndroidRuntime(6130):     at android.os.Handler.dispatchMessage(Handler.java:99)
06-21 14:59:13.496: E/AndroidRuntime(6130):     at android.os.Looper.loop(Looper.java:137)
06-21 14:59:13.496: E/AndroidRuntime(6130):     at android.app.ActivityThread.main(ActivityThread.java:4424)
06-21 14:59:13.496: E/AndroidRuntime(6130):     at java.lang.reflect.Method.invokeNative(Native Method)
06-21 14:59:13.496: E/AndroidRuntime(6130):     at java.lang.reflect.Method.invoke(Method.java:511)
06-21 14:59:13.496: E/AndroidRuntime(6130):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
06-21 14:59:13.496: E/AndroidRuntime(6130):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
06-21 14:59:13.496: E/AndroidRuntime(6130):     at dalvik.system.NativeStart.main(Native Method)
06-21 14:59:13.496: E/AndroidRuntime(6130): Caused by: java.lang.NullPointerException
06-21 14:59:13.496: E/AndroidRuntime(6130):     at android.graphics.Bitmap.createScaledBitmap(Bitmap.java:432)

最佳答案

改变

Bitmap photo = BitmapFactory.decodeFile( APP_DATA_PATH + "/samples/picture" + pictureNumber + ".jpg" );

到

  Bitmap photo = (Bitmap) data.getExtras().get("data");

关于java - 相机 Intent 回调后Android图像调整大小，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/11137832/