在imageView的editText中输入的图像URL

Question

When the user clicks this button the app should retrieve the image from the web. It should do this in a separate thread and When the image is downloaded it should be displayed on the same Screen using ImageView.I can't seem to get it to work but I feel like I'm really close can anyone help me out please? Thanks!

My Manifest File

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.stephen.asyncdownloadimageurl">
<uses-permission android:name="android.permission.INTERNET">
</uses-permission>

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

My XML FIle

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">

<ImageView
    android:id="@+id/imageView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    app:srcCompat="@android:drawable/alert_light_frame"
    android:layout_marginBottom="146dp"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true" />

<Button
    android:id="@+id/button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@+id/imageView"
    android:layout_centerHorizontal="true"
    android:layout_marginBottom="91dp" />

<EditText
    android:id="@+id/editText"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@+id/button"
    android:layout_centerHorizontal="true"
    android:layout_marginBottom="51dp"
    android:ems="10" />

My Jave File

public class MainActivity extends AppCompatActivity {
Button btn;
EditText et;

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

    btn = (Button) findViewById(R.id.button);
    et = (EditText) findViewById(R.id.editText);

    btn.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            try {
                URL url = new URL(et.getText().toString());
                new MyDownloadTask().execute(url);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}

private class MyDownloadTask extends AsyncTask<URL, Integer, Bitmap> {
    @Override
    protected Bitmap doInBackground(URL... params) {
        URL url = params[0];
        Bitmap bitmap = null;
        try {
            URLConnection connection = url.openConnection();
            connection.connect();
            InputStream is = connection.getInputStream();
            BufferedInputStream bis = new BufferedInputStream(is);
            bitmap = BitmapFactory.decodeStream(bis);
            bis.close();
            is.close();
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }

        return bitmap;
    }

    @Override
    protected void onPostExecute(Bitmap bitmap) {
        if (bitmap != null) {
            ImageView myImage = (ImageView) findViewById(R.id.imageView);
            myImage.setImageBitmap(bitmap);
        } else {
            Toast.makeText(getApplicationContext(), "Failed to Download Image", Toast.LENGTH_LONG).show();
        }
    }
}

}

Answer 1

Use special android libraries like Glide or Picasso to load images. It's really easy to use it, they have disk/memory cache, you can load image in separate thread without using complex solutions.

Answer 2

As you mentionned in a comment, your image is at this url

http://tny.im/ayy

This url does not point to an image. It points to a redirects, (http status 301).

It is possible that your connection is not following redirects.

You can instruct the connection to follow the redirection by:

((HttpURLConnection) connection).setInstanceFollowRedirects(true);

Answer 3

Ok so here is my thoughts after talking in the comments

1) I copied your code and xml EXACTLY as you posted and it WORKS fine for me, with that said I want to add a few things

EDIT: not sure if this matters but these were my imports

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Toast;
import java.io.BufferedInputStream;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;

I think it could be a combination of these possibilities

2) make sure your url is ok, make sure you add the http or https part. make sure your auto correct does not add anything (mine added a period at the end). since this is the only part I can't test, I feel like this could be it

3) Log everything, log the url right before its passed into your URL object just to be sure it is correct, look for ANY exceptions

4) the toast will not show up if url is wrong, if url can't parse a valid URL ( like mentioned earlier), it will be caught in the try catch surrounding the URL object being created and will not call the async task (happen to me when I put fake url in and I got exception, so try keep an eye out)

EDIT: for number 4, i got exception for incorrect protocol (left out the http) but if link was wrong then yes, toast showed up

5) try another image, you never know :D

EDIT: try this with Glide,

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

btn = (Button) findViewById(R.id.button);
et = (EditText) findViewById(R.id.editText);

btn.setOnClickListener(new View.OnClickListener() {
    public void onClick(View v) {
        try {
            Glide.with(MainActivity.this)
                    .load(et.getText().toString())
                    .into((ImageView) findViewById(R.id.imageView));

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

no need for async

and one more solution without Glide

  @Override
        protected Bitmap doInBackground(URL... params) {
            URL url = params[0];
            HttpURLConnection connection = null;
            Bitmap bitmap = null;


            try {
                connection = (HttpURLConnection) url.openConnection();
                connection.setDoInput(true);
                connection.connect();
                InputStream input = connection.getInputStream();
                BufferedInputStream bis = new BufferedInputStream(input);
                bitmap = BitmapFactory.decodeStream(bis);
                bis.close();
                input.close();
            } catch (IOException e) {
                e.printStackTrace();
            }



  return bitmap;
    }

Answer 4

// Add following dependecny for glide

compile 'com.github.bumptech.glide:glide:3.7.0'



new LoadImageFromUrlTask().execute(imageURL);




public class LoadImageFromUrlTask extends AsyncTask<String, Void, Bitmap> {
        String downloadPath = "";
        String sdCardBasePath = Environment.getExternalStorageDirectory().toString();
        @Override
        protected Bitmap doInBackground(String... args) {
            try {
                downloadPath = args[0];
                return BitmapFactory.decodeStream((InputStream) new URL(downloadPath).getContent());

            } catch (IOException e) {
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(Bitmap bitmap) {
            if (bitmap != null) {
                String photoFileName = downloadPath.substring(downloadPath.lastIndexOf('/') + 1);
                String saveImagePath = "";

                int dotposition = photoFileName.lastIndexOf(".");
                String filename_Without_Ext = photoFileName.substring(0, dotposition);
                String Ext = photoFileName.substring(dotposition + 1, photoFileName.length());
                String newFileName = filename_Without_Ext + "." + Ext;
                saveImagePath = sdCardBasePath + "/" + newFileName;
                saveBitmapToJPEGFile(MainActivity.this, bitmap, new File(saveImagePath), 900);
                saveBitmapToFile(MainActivity.this, myImageViewImage, saveImagePath);
            } else {
                myImageViewImage.setImageResource(R.drawable.default_photo);
            }
        }
    }

    public Boolean saveBitmapToFile(Context ctx, Bitmap tempBitmap, File targetFile, int i) {
        Boolean result = true;
        if (tempBitmap != null) {
            FileOutputStream out = null;
            try {
                out = new FileOutputStream(targetFile);
                tempBitmap.compress(Bitmap.CompressFormat.JPEG, CommonUtils.JPEG_COMPRESION_RATIO_DEFAULT, out);  

            } catch (FileNotFoundException e) {
                result = false;
                e.printStackTrace();
            }
            if (out != null) {
                try {
                    out.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        } else {
            result = false;
        }
        return result;
    }

    public void loadImageWithGlide(Context theCtx, ImageView theImageView, String theUrl) {
        Glide.with(theCtx)
                .load(theUrl)
                .diskCacheStrategy(DiskCacheStrategy.NONE)
                .skipMemoryCache(true)
                .into(theImageView);

    }

Answer 5

I couldn't get the code I originally posted to work even with all of you's guys help. Big thanks to anybody that posted with suggestions!!. Anyway I went back to scratch and finally got it to work with even less code! Here's my working code

public class MainActivity extends AppCompatActivity {
    EditText editText;
    Bitmap bitmap;
    ImageView view;
    Button btn;
    ProgressDialog pd;

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

        editText = (EditText) findViewById(R.id.inputFileUrl);
        view = (ImageView) findViewById(R.id.imageView);
        btn = (Button) findViewById(R.id.retrieveFileUrl);
    }

    public void buttonClicked(View view) {

        String stringUrl = editText.getText().toString();
        new DownloadTask().execute(stringUrl);
    }


    // Uses AsyncTask to create a task away from the main UI thread. This task takes
    // URL string and uses it to create an HttpUrlConnection. Once the connection
    // has been established, the AsyncTask downloads the contents of the webpage as
    // an InputStream. Finally, the InputStream is converted into a string, which is
    // displayed in the UI by the AsyncTask's onPostExecute method.
    public class DownloadTask extends AsyncTask<String, Void, Bitmap> {

        @Override
        protected void onPreExecute() {
            //Create PD, SET Properties
            pd = new ProgressDialog(MainActivity.this);
            pd.setTitle("Image Downloader");
            pd.setMessage("Downloading....");
            pd.setIndeterminate(false);
            pd.show();
        }

        @Override
        protected Bitmap doInBackground(String... urls) {

            String url = urls[0];

            try {
                bitmap = BitmapFactory.decodeStream(new URL(url).openConnection().getInputStream());
            } catch (IOException e) {
                e.printStackTrace();
            }
            return bitmap;
        }
        // onPostExecute displays the results of the AsyncTask.

        @Override
        protected void onPostExecute(Bitmap url) {
            if (bitmap != null) {
                super.onPostExecute(url);
                view.setImageBitmap(url);
                //Dismiss
                pd.dismiss();
            } else {
                Toast.makeText(getApplicationContext(), "Failed to Download Image", Toast.LENGTH_LONG).show();
                //Dismiss
                pd.dismiss();
            }
        }
    }
}

Answer 6

Use library like Glide. You can simply add Glide dependency in Gradle: compile 'com.github.bumptech.glide:glide:3.7.0'

and you can load image simply by writing: Glide.with(context).load("image_url").into(imagevie_name);