Question

我试图在android studio上为我的项目制作应用程序，但是当我试图运行这个java文件时，这个文件崩溃了，应用程序停止在我的模拟器上运行。我只是想尝试将图像从我的默认图库导入我的应用程序。

import ....


public class tenant_profile extends Fragment {

private final int SELECT_PHOTO = 1;
private ImageView imageView;
public tenant_profile() {
    // Required empty public constructor
}


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    // Inflate the layout for this fragment

    super.onCreateView(inflater, container, savedInstanceState);

    return inflater.inflate(R.layout.fragment_tenant_profile, container, false);
}


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);



    Button pickImage = (Button) getView().findViewById(R.id.btn_pick);
    pickImage.setOnClickListener(new OnClickListener() {
    //enter code here
        @Override
        public void onClick(View view) {
            Intent photoPickerIntent = new Intent(Intent.ACTION_PICK);
            photoPickerIntent.setType("image/*");
            startActivityForResult(photoPickerIntent, SELECT_PHOTO);
        }
    });
}

    @Override
    public void onActivityResult ( int requestCode, int resultCode, Intent imageReturnedIntent){
        super.onActivityResult(requestCode, resultCode, imageReturnedIntent);

        switch (requestCode) {
            case SELECT_PHOTO:
                if (resultCode == Activity.RESULT_OK) {
                    try {
                        final Uri imageUri = imageReturnedIntent.getData();
                        final InputStream imageStream = getContext().getContentResolver().openInputStream(imageUri);
                        final Bitmap selectedImage = BitmapFactory.decodeStream(imageStream);
                        imageView.setImageBitmap(selectedImage);
                    } catch (FileNotFoundException e) {
                        e.printStackTrace();
                    }


                }
        }
    }



}

我的例外如下：

01-29 08:04:13.233 1796-1796/? E/AndroidRuntime: FATAL EXCEPTION: main

01-29 08:04:13.233 1796-1796/? E/AndroidRuntime: java.lang.NullPointerException

01-29 08:04:13.233 1796-1796/? E/AndroidRuntime:     at com.example.sanchit.helloworld.tenant_profile.onCreate(tenant_profile.java:55)

01-29 08:04:13.233 1796-1796/? E/AndroidRuntime:     at android.support.v4.app.Fragment.performCreate(Fragment.java:1939)

01-29 08:04:13.233 1796-1796/? E/AndroidRuntime:     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:988)

01-29 08:04:13.233 1796-1796/? E/AndroidRuntime:     at android.support.v4.app.FragmentManagerImpl.moveToState
(FragmentManager.java:1207)

01-29 08:04:13.233 1796-1796/? E/AndroidRuntime:     at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:738)

01-29 08:04:13.233 1796-1796/? E/AndroidRuntime:     at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1572)

01-29 08:04:13.233 1796-1796/? E/AndroidRuntime:     at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:493)

请帮助

Answer 1

请查看android的开发者部分，特别是关于如何使用片段及其lifecycle的培训。

您甚至在布局膨胀之前尝试按ID查找。

要解决您的问题，您可以比较片段的生命周期，关于调用onCreate和onCreateView的顺序。

ArticleFragment extends Fragment {
   @Override
   public View onCreateView(LayoutInflater inflater, ViewGroup container,
       Bundle savedInstanceState) {
        // Inflate the layout for this fragment
       View view = inflater.inflate(R.layout.article_view, container, false);
       //Get Button here
       Button pickImage = (Button) view.findViewById(R.id.btn_pick);
       //Set listener etc.
       return view;

    }
}

此外，我建议您将pickImage设置为成员变量，以便能够在更多方法中使用它而不仅仅是onCreateView。

app停止在android studio上工作

1 个答案: