编码并将图像保存到SD卡

Question

我遇到一个问题，我必须从图库中取出图像并在压缩后将其保存到存储卡中。我可以从图库中选择图像甚至保存它。但不知怎的，似乎有一些编码错误，因为我无法打开图像。这是代码：

public class MainActivity extends Activity {

ImageView image;
Button save, add;
String fileName;
final Context context = this;
Bitmap bitmap;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    save = (Button)findViewById(R.id.buttonSave);
    add = (Button)findViewById(R.id.buttonAdd);
    image = (ImageView)findViewById(R.id.imageView);

    add.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            Intent intent = new Intent(Intent.ACTION_PICK,
                    android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
                  startActivityForResult(intent, 0);
        }
    });

    save.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub

            LayoutInflater li = LayoutInflater.from(context);
            View promptsView = li.inflate(R.layout.rename_dialog, null);

            AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(
                    context);

            // set prompts.xml to alertdialog builder
            alertDialogBuilder.setView(promptsView);

            final EditText userInput = (EditText) promptsView
                    .findViewById(R.id.editRename);


            alertDialogBuilder
            .setTitle("Save Image")
            .setMessage("Enter name")
            .setNegativeButton("Save", new DialogInterface.OnClickListener() {
                //
                @Override
                public void onClick(DialogInterface dialog, int which) {

                    fileName = userInput.getText().toString();
                    Log.d("Name" , fileName);
                    saveFile(null, fileName);
                    Toast.makeText(getApplicationContext(), "Image saved", Toast.LENGTH_SHORT).show();
                }
            })
            .setPositiveButton("Cancel", new DialogInterface.OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {
                    // TODO Auto-generated method stub
                    dialog.cancel();
                    Toast.makeText(getApplicationContext(), "Image save cancelled", Toast.LENGTH_SHORT).show();
                }
            });
            AlertDialog build = alertDialogBuilder.create();
            build.show();

        }
    });

}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// TODO Auto-generated method stub
super.onActivityResult(requestCode, resultCode, data);

if (resultCode == RESULT_OK){
 Uri targetUri = data.getData();

 try {
  bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(targetUri));
  image.setImageBitmap(bitmap);
 } catch (FileNotFoundException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
 }
}

}

private void saveFile(Bitmap images, String fileName) {

    BitmapDrawable drawable = (BitmapDrawable) image.getDrawable();

    bitmap = drawable.getBitmap();

    File sdCard = Environment.getExternalStorageDirectory();

    File pic = new File(sdCard , fileName + ".jpeg");

    boolean success = false;

    FileOutputStream outStream;
    try {

        outStream = new FileOutputStream(pic);
        //bitmap.compress(Bitmap.CompressFormat.JPEG, 100, outStream); 
        /* 100 to keep full quality of the image */

        outStream.flush();
        outStream.close();
        success = true;
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

    if (success) {
        Toast.makeText(getApplicationContext(), "Image saved with success",
                Toast.LENGTH_LONG).show();
    } else {
        Toast.makeText(getApplicationContext(),
                "Error during image saving", Toast.LENGTH_LONG).show();
    }
}

}