尝试将图片发送到服务器时应用程序崩溃

Question

1.当我尝试将我拍摄的图片发送到服务器时，应用程序崩溃了，这表明第 101 行中有一些东西 这就是错误

E/AndroidRuntime: FATAL EXCEPTION: main
              Process: com.example.th3hokage.pfev1, PID: 25157
              java.lang.NullPointerException: Attempt to invoke virtual method 'android.graphics.Bitmap android.graphics.drawable.BitmapDrawable.getBitmap()' on a null object reference
                  at com.example.th3hokage.pfev1.SendPic.ImageUploadToServerFunction(SendPic.java:155)
                  at com.example.th3hokage.pfev1.SendPic$2.onClick(SendPic.java:101)
                  at android.view.View.performClick(View.java:6199)
                  at android.widget.TextView.performClick(TextView.java:11090)
                  at android.view.View$PerformClick.run(View.java:23647)
                  at android.os.Handler.handleCallback(Handler.java:751)
                  at android.os.Handler.dispatchMessage(Handler.java:95)
                  at android.os.Looper.loop(Looper.java:154)
                  at android.app.ActivityThread.main(ActivityThread.java:6682)
                  at java.lang.reflect.Method.invoke(Native Method)
                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1520)
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1410)

2. Send to server 方法的代码和我实例化 ImageView 的 Activity 的顶部，这几乎是整个代码，除了一些辅助方法

   public class SendPic extends Activity {

ImageView imageViewHolder;

EditText imageName;

ProgressDialog progressDialog ;

Intent intent ;

public  static final int RequestPermissionCode  = 1 ;

Bitmap bitmap;

boolean check = true;

String GetImageNameFromEditText;

String ImageNameFieldOnServer = "image_name" ;

String ImagePathFieldOnServer = "image_path" ;

String ImageUploadPathOnSever ="" ;
@Override
protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.send_pic);

Button CaptureImageFromCamera = (Button)findViewById(R.id.button);
 imageViewHolder = (ImageView)findViewById(R.id.imageView);
Button UploadImageToServer = (Button) findViewById(R.id.button2);
 imageName = (EditText)findViewById(R.id.editText);

 EnableRuntimePermissionToAccessCamera();

 CaptureImageFromCamera.setOnClickListener(new View.OnClickListener() {
  @Override
  public void onClick(View view) {

   intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);

    startActivityForResult(intent, 7);

  }
  });


public void ImageUploadToServerFunction() {

    ByteArrayOutputStream byteArrayOutputStreamObject ;

    byteArrayOutputStreamObject = new ByteArrayOutputStream();
    bitmap = ((BitmapDrawable) ImageViewHolder.getDrawable()).getBitmap();

    // Converting bitmap image to jpeg format, so by default image will upload in jpeg format.
    bitmap.compress(Bitmap.CompressFormat.JPEG, 100, 
    byteArrayOutputStreamObject);

    byte[] byteArrayVar = byteArrayOutputStreamObject.toByteArray();

    final String ConvertImage = Base64.encodeToString(byteArrayVar, 
 Base64.DEFAULT);

    class AsyncTaskUploadClass extends AsyncTask<Void,Void,String> {

        @Override
        protected void onPreExecute() {

            super.onPreExecute();

            // Showing progress dialog at image upload time.
            progressDialog = ProgressDialog.show(SendPic.this,"Image is Uploading","Please Wait",false,false);
        }

        @Override
        protected void onPostExecute(String string1) {

            super.onPostExecute(string1);

            // Dismiss the progress dialog after done uploading.
            progressDialog.dismiss();

            // Printing uploading success message coming from server on android app.
            Toast.makeText(SendPic.this,string1,Toast.LENGTH_LONG).show();

            // Setting image as transparent after done uploading.
            ImageViewHolder.setImageResource(android.R.color.transparent);
        }

        @Override
        protected String doInBackground(Void... params) {

            ImageProcessClass imageProcessClass = new ImageProcessClass();

            HashMap<String,String> HashMapParams = new HashMap<String,String>();

            HashMapParams.put(ImageNameFieldOnServer, GetImageNameFromEditText);

            HashMapParams.put(ImagePathFieldOnServer, ConvertImage);

            String FinalData = imageProcessClass.ImageHttpRequest(ImageUploadPathOnSever, HashMapParams);

            return FinalData;
        }
    }

    AsyncTaskUploadClass AsyncTaskUploadClassOBJ = new AsyncTaskUploadClass();

}

Answer 1

你的代码

bitmap = ((BitmapDrawable) ImageViewHolder.getDrawable()).getBitmap();

应该是

ImageView someImage= (ImageView) v.findViewById(R.id.image);
bitmap  = ((BitmapDrawable) someImage.getDrawable()).getBitmap();

您正在访问 ImageViewHolder 类的 getDrawable()，而不是您必须创建的对象。

你不见了：

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
        Bundle extras = data.getExtras();
        Bitmap imageBitmap = (Bitmap) extras.get("data");
        imageViewHolder.setImageBitmap(imageBitmap);
    }
}

只有在 onActivityResult() 中获得图像后，您才应该发送该执行代码以将其发送到服务器。在此之前没有，因为在此之前 ImageView 没有设置 Bitmap。

根据您的代码，REQUEST_IMAGE_CAPTURE 必须等于 7。 即 REQUEST_IMAGE_CAPTURE = 7

修改您的相机捕捉意图，如下所示：

if (intent.resolveActivity(getPackageManager()) != null) {
        startActivityForResult(intent, REQUEST_IMAGE_CAPTURE);
    }