Question

我使用示例here中的代码。

我的问题是有时图片无法加载到ImageView中。我最近才注意到这种行为。我发现，如果我通过代码进行调试，它可以100％的时间工作。

我的假设是图片文件有时无法及时创建，无法在onActivityResult中使用。有没有人遇到过这个问题？关于如何补偿的建议？

Answer 1

可能是移动处理速度问题！不能确切地告诉我，但我以这种方式尝试，它总是像魅力一样工作！

public class LaunchCamera extends Activity {
 ImageView imVCature_pic;
 Button btnCapture;

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

 private void initializeControls() {
  imVCature_pic=(ImageView)findViewById(R.id.imVCature_pic);
  btnCapture=(Button)findViewById(R.id.btnCapture);
  btnCapture.setOnClickListener(new OnClickListener() {

   @Override
   public void onClick(View v) {
    /* create an instance of intent
     * pass action android.media.action.IMAGE_CAPTURE 
     * as argument to launch camera
     */
    Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
    /*create instance of File with name img.jpg*/
    File file = new File(Environment.getExternalStorageDirectory()+File.separator + "img.jpg");
    /*put uri as extra in intent object*/
    intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(file));
    /*start activity for result pass intent as argument and request code */
    startActivityForResult(intent, 1);
   }
  });

 }

 @Override
 protected void onActivityResult(int requestCode, int resultCode, Intent data) {
  super.onActivityResult(requestCode, resultCode, data);
  //if request code is same we pass as argument in startActivityForResult
  if(requestCode==1){
   //create instance of File with same name we created before to get image from storage
   File file = new File(Environment.getExternalStorageDirectory()+File.separator + "img.jpg");
   //get bitmap from path with size of
   imVCature_pic.setImageBitmap(decodeSampledBitmapFromFile(file.getAbsolutePath(), 600, 450));
   }
 }
 public static Bitmap decodeSampledBitmapFromFile(String path,
   int reqWidth, int reqHeight) { 
  // First decode with inJustDecodeBounds=true to check dimensions
  final BitmapFactory.Options options = new BitmapFactory.Options();
  //Query bitmap without allocating memory
  options.inJustDecodeBounds = true;
  //decode file from path
  BitmapFactory.decodeFile(path, options);
  // Calculate inSampleSize
  // Raw height and width of image
  final int height = options.outHeight;
  final int width = options.outWidth;
  //decode according to configuration or according best match
  options.inPreferredConfig = Bitmap.Config.RGB_565;
  int inSampleSize = 1;
  if (height > reqHeight) {
   inSampleSize = Math.round((float)height / (float)reqHeight);
  }
  int expectedWidth = width / inSampleSize;
  if (expectedWidth > reqWidth) {
   //if(Math.round((float)width / (float)reqWidth) > inSampleSize) // If bigger SampSize..
   inSampleSize = Math.round((float)width / (float)reqWidth);
  }
  //if value is greater than 1,sub sample the original image
  options.inSampleSize = inSampleSize;
  // Decode bitmap with inSampleSize set
  options.inJustDecodeBounds = false;
  return BitmapFactory.decodeFile(path, options);
 }
}

我参考了 this和this。

拍照然后在ImageView中加载并不总是有效

1 个答案: