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Android 从url加载图像

android

Android 从url加载图像,android,Android,我有一个图像URL。我想在ImageView中显示此URL中的图像，但我无法这样做 如何做到这一点 import java.io.IOException; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.URL; import android.graphics.Bitmap; import android.g

我有一个图像URL。我想在ImageView中显示此URL中的图像，但我无法这样做

如何做到这一点

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

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.widget.ImageView;
import android.widget.Toast;

public class imageDownload {

    Bitmap bmImg;
    void downloadfile(String fileurl,ImageView img)
    {
        URL myfileurl =null;
        try
        {
            myfileurl= new URL(fileurl);

        }
        catch (MalformedURLException e)
        {

            e.printStackTrace();
        }

        try
        {
            HttpURLConnection conn= (HttpURLConnection)myfileurl.openConnection();
            conn.setDoInput(true);
            conn.connect();
            int length = conn.getContentLength();
            int[] bitmapData =new int[length];
            byte[] bitmapData2 =new byte[length];
            InputStream is = conn.getInputStream();
            BitmapFactory.Options options = new BitmapFactory.Options();

            bmImg = BitmapFactory.decodeStream(is,null,options);

            img.setImageBitmap(bmImg);

            //dialog.dismiss();
            } 
        catch(IOException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
//          Toast.makeText(PhotoRating.this, "Connection Problem. Try Again.", Toast.LENGTH_SHORT).show();
        }


    }


}
在你的活动中 拍摄图像查看和设置资源 图像下载（url，yourImageview）

在你的活动中 拍摄图像查看和设置资源
图像下载（url，yourImageview）

下面是从URL显示图像的示例代码

public static Void downloadfile(String fileurl, ImageView img) {
        Bitmap bmImg = null;
        URL myfileurl = null;
        try {
            myfileurl = new URL(fileurl);
        } catch (MalformedURLException e) {
            e.printStackTrace();
        }
        try {
            HttpURLConnection conn = (HttpURLConnection) myfileurl.openConnection();
            conn.setDoInput(true);
            conn.connect();
            int length = conn.getContentLength();
            if (length > 0) {
                int[] bitmapData = new int[length];
                byte[] bitmapData2 = new byte[length];
                InputStream is = conn.getInputStream();
                bmImg = BitmapFactory.decodeStream(is);
                img.setImageBitmap(bmImg);
            }

        } catch (IOException e) {
            e.printStackTrace();
        }
    }
下面是从URL显示图像的示例代码

public static Void downloadfile(String fileurl, ImageView img) {
        Bitmap bmImg = null;
        URL myfileurl = null;
        try {
            myfileurl = new URL(fileurl);
        } catch (MalformedURLException e) {
            e.printStackTrace();
        }
        try {
            HttpURLConnection conn = (HttpURLConnection) myfileurl.openConnection();
            conn.setDoInput(true);
            conn.connect();
            int length = conn.getContentLength();
            if (length > 0) {
                int[] bitmapData = new int[length];
                byte[] bitmapData2 = new byte[length];
                InputStream is = conn.getInputStream();
                bmImg = BitmapFactory.decodeStream(is);
                img.setImageBitmap(bmImg);
            }

        } catch (IOException e) {
            e.printStackTrace();
        }
    }
如果您是基于按钮单击加载图像，那么上面接受的答案是很好的，但是如果您是在新活动中执行此操作，它会使UI冻结一两秒钟。环顾四周，我发现一个简单的异步任务消除了这个问题

要在活动结束时使用asynctask添加此类，请执行以下操作：

private class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
  ImageView bmImage;

  public DownloadImageTask(ImageView bmImage) {
      this.bmImage = bmImage;
  }

  protected Bitmap doInBackground(String... urls) {
      String urldisplay = urls[0];
      Bitmap mIcon11 = null;
      try {
        InputStream in = new java.net.URL(urldisplay).openStream();
        mIcon11 = BitmapFactory.decodeStream(in);
      } catch (Exception e) {
          Log.e("Error", e.getMessage());
          e.printStackTrace();
      }
      return mIcon11;
  }

  protected void onPostExecute(Bitmap result) {
      bmImage.setImageBitmap(result);
  }
}
别忘了在清单文件中添加以下权限

<uses-permission android:name="android.permission.INTERNET"/>
对我来说很有用。：）

如果您是基于按钮点击加载图像，那么上面接受的答案是非常好的，但是如果您是在新活动中加载图像，它会使UI冻结一两秒钟。环顾四周，我发现一个简单的异步任务消除了这个问题

要在活动结束时使用asynctask添加此类，请执行以下操作：

private class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
  ImageView bmImage;

  public DownloadImageTask(ImageView bmImage) {
      this.bmImage = bmImage;
  }

  protected Bitmap doInBackground(String... urls) {
      String urldisplay = urls[0];
      Bitmap mIcon11 = null;
      try {
        InputStream in = new java.net.URL(urldisplay).openStream();
        mIcon11 = BitmapFactory.decodeStream(in);
      } catch (Exception e) {
          Log.e("Error", e.getMessage());
          e.printStackTrace();
      }
      return mIcon11;
  }

  protected void onPostExecute(Bitmap result) {
      bmImage.setImageBitmap(result);
  }
}
别忘了在清单文件中添加以下权限

<uses-permission android:name="android.permission.INTERNET"/>
对我来说很有用。：）

UrlImageViewHelper将使用在URL中找到的图像填充ImageView。UrlImageViewHelper将自动下载、保存和缓存BitmapDrawables中的所有图像URL。重复的URL不会两次加载到内存中。位图内存是通过使用弱引用哈希表来管理的，因此一旦图像不再被您使用，它就会被自动垃圾收集

UrlImageViewHelper.setUrlDrawable（imageView，“http://example.com/image.png");

UrlImageViewHelper将使用在URL中找到的图像填充ImageView。UrlImageViewHelper将自动下载、保存和缓存BitmapDrawables中的所有图像URL。重复的URL不会两次加载到内存中。位图内存是通过使用弱引用哈希表来管理的，因此一旦图像不再被您使用，它就会被自动垃圾收集

UrlImageViewHelper.setUrlDrawable（imageView，“http://example.com/image.png");

给你

void loadImage(String image_location) {
    URL imageURL = null;
    if (image_location != null) {
        try {
            imageURL = new URL(image_location);         
            HttpURLConnection connection = (HttpURLConnection) imageURL
                    .openConnection();
            connection.setDoInput(true);
            connection.connect();
            InputStream inputStream = connection.getInputStream();
            bitmap = BitmapFactory.decodeStream(inputStream);// Convert to bitmap
            ivdpfirst.setImageBitmap(bitmap);
        } catch (IOException e) {
            e.printStackTrace();
        }
    } else {
        //set any default
    }
}
给你

void loadImage(String image_location) {
    URL imageURL = null;
    if (image_location != null) {
        try {
            imageURL = new URL(image_location);         
            HttpURLConnection connection = (HttpURLConnection) imageURL
                    .openConnection();
            connection.setDoInput(true);
            connection.connect();
            InputStream inputStream = connection.getInputStream();
            bitmap = BitmapFactory.decodeStream(inputStream);// Convert to bitmap
            ivdpfirst.setImageBitmap(bitmap);
        } catch (IOException e) {
            e.printStackTrace();
        }
    } else {
        //set any default
    }
}
试试这个：

InputStream input = contentResolver.openInputStream(httpuri);
Bitmap b = BitmapFactory.decodeStream(input, null, options);
试试这个：

InputStream input = contentResolver.openInputStream(httpuri);
Bitmap b = BitmapFactory.decodeStream(input, null, options);
试试这个 添加毕加索库jar文件

Picasso.with(context)
                .load(ImageURL)
                .resize(width,height).noFade().into(imageView);
试试这个 添加毕加索库jar文件

Picasso.with(context)
                .load(ImageURL)
                .resize(width,height).noFade().into(imageView);

公共类MainActivity扩展活动{
位图b；
图像视图img；
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity_main）；
img=（ImageView）findViewById（R.id.imageView1）；
信息信息=新信息（）；
信息。执行（“”）；
}
公共类信息扩展异步任务
{
@凌驾
受保护的字符串doInBackground（字符串…arg0）{
尝试
{
URL=新URL（“http://10.119.120.10:80/img.jpg");
InputStream is=new BufferedInputStream（url.openStream（））；
b=位图工厂.decodeStream（is）；
}捕获（例外e）{}
返回null；
}
@凌驾
受保护的void onPostExecute（字符串结果）{
img.setImageBitmap（b）；
}
}
}

公共类MainActivity扩展活动{
位图b；
图像视图img；
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity_main）；
img=（ImageView）findViewById（R.id.imageView1）；
信息信息=新信息（）；
信息。执行（“”）；
}
公共类信息扩展异步任务
{
@凌驾
受保护的字符串doInBackground（字符串…arg0）{
尝试
{
URL=新URL（“http://10.119.120.10:80/img.jpg");
InputStream is=new BufferedInputStream（url.openStream（））；
b=位图工厂.decodeStream（is）；
}捕获（例外e）{}
返回null；
}
@凌驾
受保护的void onPostExecute（字符串结果）{
img.setImageBitmap（b）；
}
}
}
基于我自己编写的加载程序

具有加载效果和显示效果：

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.AlphaAnimation;
import android.view.animation.Animation;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.ProgressBar;

import java.io.InputStream;

/**
 * Created by Sergey Shustikov (pandarium.shustikov@gmail.com) at 2015.
 */
public class DownloadImageTask extends AsyncTask<String, Void, Bitmap>
{
    public static final int ANIMATION_DURATION = 250;
    private final ImageView mDestination, mFakeForError;
    private final String mUrl;
    private final ProgressBar mProgressBar;
    private Animation.AnimationListener mOutAnimationListener = new Animation.AnimationListener()
    {
        @Override
        public void onAnimationStart(Animation animation)
        {

        }

        @Override
        public void onAnimationEnd(Animation animation)
        {
            mProgressBar.setVisibility(View.GONE);
        }

        @Override
        public void onAnimationRepeat(Animation animation)
        {

        }
    };
    private Animation.AnimationListener mInAnimationListener = new Animation.AnimationListener()
    {
        @Override
        public void onAnimationStart(Animation animation)
        {
            if (isBitmapSet)
                mDestination.setVisibility(View.VISIBLE);
            else
                mFakeForError.setVisibility(View.VISIBLE);
        }

        @Override
        public void onAnimationEnd(Animation animation)
        {

        }

        @Override
        public void onAnimationRepeat(Animation animation)
        {

        }
    };
    private boolean isBitmapSet;

    public DownloadImageTask(Context context, ImageView destination, String url)
    {
        mDestination = destination;
        mUrl = url;
        ViewGroup parent = (ViewGroup) destination.getParent();
        mFakeForError = new ImageView(context);
        destination.setVisibility(View.GONE);
        FrameLayout layout = new FrameLayout(context);
        mProgressBar = new ProgressBar(context);
        FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
        params.gravity = Gravity.CENTER;
        mProgressBar.setLayoutParams(params);
        FrameLayout.LayoutParams copy = new FrameLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
        copy.gravity = Gravity.CENTER;
        copy.width = dpToPx(48);
        copy.height = dpToPx(48);
        mFakeForError.setLayoutParams(copy);
        mFakeForError.setVisibility(View.GONE);
        mFakeForError.setImageResource(android.R.drawable.ic_menu_close_clear_cancel);
        layout.addView(mProgressBar);
        layout.addView(mFakeForError);
        mProgressBar.setIndeterminate(true);
        parent.addView(layout, new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
    }

    protected Bitmap doInBackground(String... urls)
    {
        String urlDisplay = mUrl;
        Bitmap bitmap = null;
        try {
            InputStream in = new java.net.URL(urlDisplay).openStream();
            bitmap = BitmapFactory.decodeStream(in);
        } catch (Exception e) {
            Log.e("Error", e.getMessage());
            e.printStackTrace();
        }
        return bitmap;
    }

    protected void onPostExecute(Bitmap result)
    {
        AlphaAnimation in = new AlphaAnimation(0f, 1f);
        AlphaAnimation out = new AlphaAnimation(1f, 0f);
        in.setDuration(ANIMATION_DURATION * 2);
        out.setDuration(ANIMATION_DURATION);
        out.setAnimationListener(mOutAnimationListener);
        in.setAnimationListener(mInAnimationListener);
        in.setStartOffset(ANIMATION_DURATION);
        if (result != null) {
            mDestination.setImageBitmap(result);
            isBitmapSet = true;
            mDestination.startAnimation(in);
        } else {
            mFakeForError.startAnimation(in);
        }
        mProgressBar.startAnimation(out);
    }
    public int dpToPx(int dp) {
        DisplayMetrics displayMetrics = mDestination.getContext().getResources().getDisplayMetrics();
        int px = Math.round(dp * (displayMetrics.xdpi / DisplayMetrics.DENSITY_DEFAULT));
        return px;
    }
}
基于此，我编写了自己的加载程序

具有加载效果和显示效果：

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.AlphaAnimation;
import android.view.animation.Animation;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.ProgressBar;

import java.io.InputStream;

/**
 * Created by Sergey Shustikov (pandarium.shustikov@gmail.com) at 2015.
 */
public class DownloadImageTask extends AsyncTask<String, Void, Bitmap>
{
    public static final int ANIMATION_DURATION = 250;
    private final ImageView mDestination, mFakeForError;
    private final String mUrl;
    private final ProgressBar mProgressBar;
    private Animation.AnimationListener mOutAnimationListener = new Animation.AnimationListener()
    {
        @Override
        public void onAnimationStart(Animation animation)
        {

        }

        @Override
        public void onAnimationEnd(Animation animation)
        {
            mProgressBar.setVisibility(View.GONE);
        }

        @Override
        public void onAnimationRepeat(Animation animation)
        {

        }
    };
    private Animation.AnimationListener mInAnimationListener = new Animation.AnimationListener()
    {
        @Override
        public void onAnimationStart(Animation animation)
        {
            if (isBitmapSet)
                mDestination.setVisibility(View.VISIBLE);
            else
                mFakeForError.setVisibility(View.VISIBLE);
        }

        @Override
        public void onAnimationEnd(Animation animation)
        {

        }

        @Override
        public void onAnimationRepeat(Animation animation)
        {

        }
    };
    private boolean isBitmapSet;

    public DownloadImageTask(Context context, ImageView destination, String url)
    {
        mDestination = destination;
        mUrl = url;
        ViewGroup parent = (ViewGroup) destination.getParent();
        mFakeForError = new ImageView(context);
        destination.setVisibility(View.GONE);
        FrameLayout layout = new FrameLayout(context);
        mProgressBar = new ProgressBar(context);
        FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
        params.gravity = Gravity.CENTER;
        mProgressBar.setLayoutParams(params);
        FrameLayout.LayoutParams copy = new FrameLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
        copy.gravity = Gravity.CENTER;
        copy.width = dpToPx(48);
        copy.height = dpToPx(48);
        mFakeForError.setLayoutParams(copy);
        mFakeForError.setVisibility(View.GONE);
        mFakeForError.setImageResource(android.R.drawable.ic_menu_close_clear_cancel);
        layout.addView(mProgressBar);
        layout.addView(mFakeForError);
        mProgressBar.setIndeterminate(true);
        parent.addView(layout, new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
    }

    protected Bitmap doInBackground(String... urls)
    {
        String urlDisplay = mUrl;
        Bitmap bitmap = null;
        try {
            InputStream in = new java.net.URL(urlDisplay).openStream();
            bitmap = BitmapFactory.decodeStream(in);
        } catch (Exception e) {
            Log.e("Error", e.getMessage());
            e.printStackTrace();
        }
        return bitmap;
    }

    protected void onPostExecute(Bitmap result)
    {
        AlphaAnimation in = new AlphaAnimation(0f, 1f);
        AlphaAnimation out = new AlphaAnimation(1f, 0f);
        in.setDuration(ANIMATION_DURATION * 2);
        out.setDuration(ANIMATION_DURATION);
        out.setAnimationListener(mOutAnimationListener);
        in.setAnimationListener(mInAnimationListener);
        in.setStartOffset(ANIMATION_DURATION);
        if (result != null) {
            mDestination.setImageBitmap(result);
            isBitmapSet = true;
            mDestination.startAnimation(in);
        } else {
            mFakeForError.startAnimation(in);
        }
        mProgressBar.startAnimation(out);
    }
    public int dpToPx(int dp) {
        DisplayMetrics displayMetrics = mDestination.getContext().getResources().getDisplayMetrics();
        int px = Math.round(dp * (displayMetrics.xdpi / DisplayMetrics.DENSITY_DEFAULT));
        return px;
    }
}
试试毕加索nice，一句话就完成了

Picasso.with(context)
                .load(ImageURL)
                .resize(width,height).into(imageView);
教程：

（注意：在最新版本中）

试试
picasso
nice，一句话就完成了

Picasso.with(context)
                .load(ImageURL)
                .resize(width,height).into(imageView);
教程：

（注意：在最新版本中）

我尝试过的最好的方法，而不是使用任何库

public Bitmap getbmpfromURL(String surl){
    try {
        URL url = new URL(surl);
        HttpURLConnection urlcon = (HttpURLConnection) url.openConnection();
        urlcon.setDoInput(true);
        urlcon.connect();
        InputStream in = urlcon.getInputStream();
        Bitmap mIcon = BitmapFactory.decodeStream(in);
        return  mIcon;
    } catch (Exception e) {
        Log.e("Error", e.getMessage());
        e.printStackTrace();
        return null;
    }
}
我尝试过的最好的方法，而不是使用任何库

public Bitmap getbmpfromURL(String surl){
    try {
        URL url = new URL(surl);
        HttpURLConnection urlcon = (HttpURLConnection) url.openConnection();
        urlcon.setDoInput(true);
        urlcon.connect();
        InputStream in = urlcon.getInputStream();
        Bitmap mIcon = BitmapFactory.decodeStream(in);
        return  mIcon;
    } catch (Exception e) {
        Log.e("Error", e.getMessage());
        e.printStackTrace();
        return null;
    }
}
对我来说，它是其他图书馆中最好的

只需使用Fresco，然后简单地设置imageURI，如下所示：

draweeView.setImageURI(uri);
查看解释壁画优点的答案。

对我来说，它是其他图书馆中最好的

只需使用Fresco，然后简单地设置imageURI，如下所示：

draweeView.setImageURI(uri);
查看解释Fresco优点的答案。

下面的代码向您展示了如何使用RxAndroid从url字符串设置ImageView。 首先，添加RxAndroid库2.0

dependencies {
    // RxAndroid
    compile 'io.reactivex.rxjava2:rxandroid:2.0.0'
    compile 'io.reactivex.rxjava2:rxjava:2.0.0'

    // Utilities
    compile 'org.apache.commons:commons-lang3:3.5'

}
现在使用setImageFromUrl设置图像

public void setImageFromUrl(final ImageView imageView, final String urlString) {

    Observable.just(urlString)
        .filter(new Predicate<String>() {
            @Override public boolean test(String url) throws Exception {
                return StringUtils.isNotBlank(url);
            }
        })
        .map(new Function<String, Drawable>() {
            @Override public Drawable apply(String s) throws Exception {
                URL url = null;
                try {
                    url = new URL(s);
                    return Drawable.createFromStream((InputStream) url.getContent(), "profile");
                } catch (final IOException ex) {
                    return null;
                }
            }
        })
        .filter(new Predicate<Drawable>() {
            @Override public boolean test(Drawable drawable) throws Exception {
                return drawable != null;
            }
        })
        .subscribeOn(Schedulers.io())
        .observeOn(AndroidSchedulers.mainThread())
        .subscribe(new Consumer<Drawable>() {
            @Override public void accept(Drawable drawable) throws Exception {
                imageView.setImageDrawable(drawable);
            }
        });
}

public void setImageFromUrl（最终ImageView ImageView，最终字符串urlString）{
可观察的.just（urlString）
.filter（新谓词（）{
@重写公共布尔测试（字符串url）引发异常{
返回StringUtils.isNotBlank（url）；
}
})
.map（新函数（）{
@重写公共可提取应用（字符串s）引发异常{
URL=null；
试一试{
url=新的url；
返回Drawable.createFr

URL url = new URL("YourUrl");
Bitmap bitmap = BitmapFactory.decodeStream(url.openConnection().getInputStream());
imageView.setImageBitmap(bitmap);