Question

我正在处理地图apiv2。在编写Dialog Fragment类时，我收到以下错误。

错误： Avoid non-default constructors in fragments: use a default constructor plus Fragment#setArguments(Bundle) instead:

这是代码：

public PlaceDialogFragment(){
    super();
}

public PlaceDialogFragment(Place place, DisplayMetrics dm){
    super();
    this.mPlace = place;
    this.mMetrics = dm;
}

任何帮助都值得赞赏..

修改：这是整个代码...我是一个新手，从来没有处理过片段。我正在通过地图啧啧发现这个......你现在详细说明了你在试图解释..

package com.example.travelplanner;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.DialogFragment;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.ViewFlipper;

// Defining DialogFragment class to show the place details with photo
public class PlaceDialogFragment extends DialogFragment{

    TextView mTVPhotosCount = null;
    TextView mTVVicinity = null;
    ViewFlipper mFlipper = null;
    Place mPlace = null;
    DisplayMetrics mMetrics = null;

    public PlaceDialogFragment(){
        super();
    }

    public PlaceDialogFragment(Place place, DisplayMetrics dm){
        super();
        this.mPlace = place;
        this.mMetrics = dm;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {

        // For retaining the fragment on screen rotation
        setRetainInstance(true);
        super.onCreate(savedInstanceState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                            Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.dialog_layout, null);

        // Getting reference to ViewFlipper
        mFlipper = (ViewFlipper) v.findViewById(R.id.flipper);

        // Getting reference to TextView to display photo count
        mTVPhotosCount = (TextView) v.findViewById(R.id.tv_photos_count);

        // Getting reference to TextView to display place vicinity
        mTVVicinity = (TextView) v.findViewById(R.id.tv_vicinity);

        if(mPlace!=null){

            // Setting the title for the Dialog Fragment
            getDialog().setTitle(mPlace.mPlaceName);

            // Array of references of the photos
            Photo[] photos = mPlace.mPhotos;

            // Setting Photos count
            mTVPhotosCount.setText("Photos available : " + photos.length);

            // Setting the vicinity of the place
            mTVVicinity.setText(mPlace.mVicinity);

            // Creating an array of ImageDownloadTask to download photos
            ImageDownloadTask[] imageDownloadTask = new ImageDownloadTask[photos.length];

            int width = (int)(mMetrics.widthPixels*3)/4;
            int height = (int)(mMetrics.heightPixels*1)/2;

            String url = "https://maps.googleapis.com/maps/api/place/photo?";
            String key = "key=AIzaSyBSo1xlML-tOFTCdJb6qIbVnF9e7y5nj0o";
            String sensor = "sensor=true";
            String maxWidth="maxwidth=" + width;
            String maxHeight = "maxheight=" + height;
            url = url + "&" + key + "&" + sensor + "&" + maxWidth + "&" + maxHeight;

            // Traversing through all the photoreferences
            for(int i=0;i<photos.length;i++){
                // Creating a task to download i-th photo
                imageDownloadTask[i] = new ImageDownloadTask();

                String photoReference = "photoreference="+photos[i].mPhotoReference;

                // URL for downloading the photo from Google Services
                url = url + "&" + photoReference;

                // Downloading i-th photo from the above url
                imageDownloadTask[i].execute(url);
            }
        }
        return v;
    }

    @Override
    public void onDestroyView() {
        if (getDialog() != null && getRetainInstance())
            getDialog().setDismissMessage(null);
            super.onDestroyView();
    }

    private Bitmap downloadImage(String strUrl) throws IOException{
        Bitmap bitmap=null;
        InputStream iStream = null;
        try{
            URL url = new URL(strUrl);

            /** Creating an http connection to communcate with url */
            HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();

            /** Connecting to url */
            urlConnection.connect();

            /** Reading data from url */
            iStream = urlConnection.getInputStream();

            /** Creating a bitmap from the stream returned from the url */
            bitmap = BitmapFactory.decodeStream(iStream);

        }catch(Exception e){
            Log.d("Exception while downloading url", e.toString());
        }finally{
            iStream.close();
        }
        return bitmap;
    }

    private class ImageDownloadTask extends AsyncTask<String, Integer, Bitmap>{
        Bitmap bitmap = null;
        @Override
        protected Bitmap doInBackground(String... url) {
            try{
                // Starting image download
                bitmap = downloadImage(url[0]);
            }catch(Exception e){
                Log.d("Background Task",e.toString());
            }
            return bitmap;
        }

        @Override
        protected void onPostExecute(Bitmap result) {
            // Creating an instance of ImageView to display the downloaded image
            ImageView iView = new ImageView(getActivity().getBaseContext());

            // Setting the downloaded image in ImageView
            iView.setImageBitmap(result);

            // Adding the ImageView to ViewFlipper
            mFlipper.addView(iView);

            // Showing download completion message
            Toast.makeText(getActivity().getBaseContext(), "Image downloaded successfully", Toast.LENGTH_SHORT).show();
        }
    }
}

Answer 1

如果您不想遵守规则，请执行下一步

@SuppressLint("ValidFragment")
public PlaceDialogFragment(Place place, DisplayMetrics dm){
        super();
        this.mPlace = place;
        this.mMetrics = dm;
    }

Answer 2

由于片段的性质以及如何在屏幕上进行管理和显示，因此建议不要创建非默认构造函数，并且在许多情况下这会导致运行时出现问题。如果您应该这样做：

public static final GridFragment newInstance(String tabId)
{
    GridFragment f = new GridFragment();
    Bundle bdl = new Bundle(2);
    bdl.putString(TAB_ID, tabId);
    f.setArguments(bdl);
    return f;
}

并在onCreate中提取捆绑包中所需的数据：

@Override
public void onCreate(Bundle savedInstanceState) 
{
    String tabId = getArguments().getString(TAB_ID);
    }

看看这个问题：

Do fragments really need an empty constructor?

Answer 3

@SuppressLint({"NewApi", "ValidFragment"})
public PlaceDialogFragment(Place place, DisplayMetrics dm){
        super();
      }

Answer 4

更简单的方法是将这些添加到gradle：

android {
      lintOptions {
          checkReleaseBuilds false
      }
  }

或者您可以在每个片段中添加此行

@SuppressLint("ValidFragment")
public PlaceDialogFragment(Place place, DisplayMetrics dm){
    super();
    this.mPlace = place;
    this.mMetrics = dm;
}

最佳解决方案是简单地在gradle中添加行。

Answer 5

解决方案对我有用

{
  "query": {
    "bool": {
      "must": [
        {
          "term": {
            "team.keyword": "search_phrase"
          }
        }
      ]
    }
  },
  "script": {
    "inline": "ctx._source.field_name = params.new_field",
    "params": {
      "new_field": {
        "a": "b"
      }
    }
  }
}

错误片段中的非默认构造函数

5 个答案: