从服务器下载图像到android并在imageview中显示

时间：2017-04-22 08:46:24

标签： java android

我有一台服务器（我使用GlassFish）。我可以用http发送Json或XML等到我的android设备。我看到了一个示例，将我的Android设备上的图片上传到服务器。这会将我选择的图像转换为字节，转换为String并返回到我的服务器。所以我可以把它放在我的电脑（服务器）上。 现在我只想要反过来：从我的电脑上获取一张照片并使用URL获取图像（这里是位图）到imageview。但是通过调试bmp似乎是＆＃34; null＆＃34;。谷歌说，因为我的图像不是一个有效的位图（所以我的服务器编码可能有问题吗？）。 我需要更改为此代码才能使其正常工作？

服务器代码：

public class getImage{
    String imageDataString = null;

    @GET
    @Path("imageid/{id}")
    public String findImageById(@PathParam("id") Integer id) {
        //todo: schrijf een query voor het juiste pad te krijgen!
        System.out.println("in findImageById");
        File file = new File("C:\\Users\\vulst\\Desktop\\MatchIDImages\\Results\\R\\Tensile_Hole_2177N.tif_r.bmp");

        try{
            // Reading a Image file from file system
            FileInputStream imageInFile = new FileInputStream(file);
            byte imageData[] = new byte[(int) file.length()];
            imageInFile.read(imageData);

            // Converting Image byte array into Base64 String
            imageDataString = Base64.encodeBase64URLSafeString(imageData);
            imageInFile.close();

            System.out.println("Image Successfully Manipulated!");
        } catch (FileNotFoundException e) {
            System.out.println("Image not found" + e);
        } catch (IOException ioe) {
            System.out.println("Exception while reading the Image " + ioe);
        }
        return imageDataString;

    }

}

这是android方面（android studio）：

public class XMLTask extends AsyncTask<String, String, String> {

    @Override
    protected String doInBackground(String... urls) {
        HttpURLConnection connection = null;
        BufferedReader reader = null;
        try {
            java.net.URL url = new URL(urls[0]);
            connection = (HttpURLConnection) url.openConnection();
            connection.connect();
            InputStream stream = connection.getInputStream();
            reader = new BufferedReader(new InputStreamReader(stream));
            StringBuffer buffer = new StringBuffer();
            String line = "";
            while ((line = reader.readLine()) != null) {
                buffer.append(line);
            }

            return buffer.toString();

        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (connection != null) {
                connection.disconnect();
            }
            try {
                if (reader != null) {
                    reader.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return null;
    }

    @Override
    protected void onPostExecute(String line) {
        super.onPostExecute(line);
        byte[] imageByteArray = Base64.decode(line , Base64.DEFAULT);

        try {
            Bitmap bmp = BitmapFactory.decodeByteArray(imageByteArray, 0, imageByteArray.length);
            ivFoto.setImageBitmap(bmp);
        }catch (Exception e){
            Log.d("tag" , e.toString());
        }
    }
}

6 个答案:

答案 0 :(得分：3)

您是否尝试过var p = require('./test.js'); var l = require('./test.js').lm console.log(p); //hello console.log(l); //undefined ？

以下是示例代码：

HttpURlConnection

我希望我能提供帮助

答案 1 :(得分：1)

你可以使用Glide这是加载图像最简单的方法 这就是保存图像的方法

Glide.with(context)
                        .load(image)
                        .asBitmap()
                        .into(new SimpleTarget<Bitmap>() {
                            @Override
                            public void onResourceReady(Bitmap resource, GlideAnimation<? super Bitmap> glideAnimation) {

                                String name = new Date().toString() + ".jpg";

                                imageName = imageName + name.replaceAll("\\s+", "");
                                Log.d(TAG, "onResourceReady: imageName = " + imageName);
                                ContextWrapper contextWrapper = new ContextWrapper(mContext);
                                File directory = contextWrapper.getDir("imageDir", Context.MODE_PRIVATE);

                                File myPath = new File(directory, imageName);


                                FileOutputStream fileOutputStream = null;
                                try {
                                    fileOutputStream = new FileOutputStream(myPath);
                                    resource.compress(Bitmap.CompressFormat.PNG, 100, fileOutputStream);
                                } catch (Exception e) {
                                    e.printStackTrace();
                                } finally {
                                    try {
                                        fileOutputStream.close();
                                    } catch (IOException e) {
                                        e.printStackTrace();
                                    }
                                }
                            }
                        });

这就是你可以阅读图像的方法

ContextWrapper contextWrapper = new ContextWrapper(mContext);
    File directory = contextWrapper.getDir("imageDir", Context.MODE_PRIVATE);
    String path = directory.getAbsolutePath();
    path = path + "/" + imageName;
    Glide.with(mContext).load(path).into(your imageview);

答案 2 :(得分：0)

为什么不使用Glide？

对于您的应用模块中的build.gradle：

dependencies {
    compile 'com.github.bumptech.glide:glide:3.7.0'
    ...
}

然后：

Glide  
    .with(context) // replace with 'this' if it's in activity
    .load("http://www.google.com/.../image.gif")
    .into(R.id.imageView);

答案 3 :(得分：0)

尝试使用Base64.encodeBase64String(imageData)而不使用URLSafeString。

答案 4 :(得分：0)

如果有人也试图按照我的方式去做，那就行了：

public class XMLTask extends AsyncTask<String, String, String> {

    @Override
    protected String doInBackground(String... urls) {
        HttpURLConnection connection = null;
        BufferedReader reader = null;
        try {
            java.net.URL url = new URL(urls[0]);
            connection = (HttpURLConnection) url.openConnection();
            connection.connect();
            InputStream stream = connection.getInputStream();
            reader = new BufferedReader(new InputStreamReader(stream));
            StringBuffer buffer = new StringBuffer();
            String line = "";
            while ((line = reader.readLine()) != null) {
                buffer.append(line);
            }

            return buffer.toString();

        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (connection != null) {
                connection.disconnect();
            }
            try {
                if (reader != null) {
                    reader.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return null;
    }

    @Override
    protected void onPostExecute(String line) {
        super.onPostExecute(line);
        byte[] imageByteArray = Base64.decode(line , Base64.DEFAULT);
        try {
            Bitmap bmp = BitmapFactory.decodeByteArray(imageByteArray, 0, imageByteArray.length);
            ivFoto.setImageBitmap(bmp);
        }catch (Exception e){
            Log.d("tag" , e.toString());
        }
    }
}

@Stateless
@Path("getImage")
public class getImage {

    //todo: capture error inandroid +  take just path!
    String imageDataString = null;

    @GET
    @Path("imageid/{id}")
    public String findImageById(@PathParam("id") Integer id) {
        //todo: schrijf een query voor het juiste pad te krijgen!
        System.out.println("in findImageById");
        File file = new File("C:\\Users\\vulst\\Desktop\\MatchIDImages\\Results\\R\\Tensile_Hole_2177N.tif_r.bmp");

        try{
            // Reading a Image file from file system
            FileInputStream imageInFile = new FileInputStream(file);
            byte imageData[] = new byte[(int) file.length()];
            imageInFile.read(imageData);

            // Converting Image byte array into Base64 String
            imageDataString = Base64.encodeBase64String(imageData);
            imageInFile.close();

            System.out.println("Image Successfully Manipulated!");
        } catch (FileNotFoundException e) {
            System.out.println("Image not found" + e);
        } catch (IOException ioe) {
            System.out.println("Exception while reading the Image " + ioe);
        }
        return imageDataString;

    }
}

答案 5 :(得分：0)

我希望这段代码很有用。

转到MainActivity.java并尝试以下代码：

public class MainActivity extends AppCompatActivity {
ImageView imageView;

public void downloadImage(View view)
{

    Log.i("Button","Tapped");

    DownloadImage task = new DownloadImage();
    Bitmap result = null;
    try {
        result = task.execute("https://vignette.wikia.nocookie.net/disney/images/0/0a/ElsaPose.png/revision/latest?cb=20170221004839").get();
    }
    catch (InterruptedException | ExecutionException e) {
        e.printStackTrace();
    }
    imageView.setImageBitmap(result);

}

public class DownloadImage extends AsyncTask<String, Void, Bitmap>
{


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


        URL url;
        HttpURLConnection httpURLConnection;

        try {
            url = new URL(imageurls[0]);
            httpURLConnection = (HttpURLConnection) url.openConnection();
            httpURLConnection.connect();
            InputStream in =httpURLConnection.getInputStream();
            Bitmap myBitmap = BitmapFactory.decodeStream(in);
            return myBitmap;

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



    }
}

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

    imageView = (ImageView)findViewById(R.id.imageView);
}

}

不要忘记在AndroidManifest.xml中添加这段代码

       <uses-permission android:name="android.permission.INTERNET"/>
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