如何在ImageView中使用URL引用的图像?
当前回答
来自Android开发者:
// show The Image in a ImageView
new DownloadImageTask((ImageView) findViewById(R.id.imageView1))
.execute("http://java.sogeti.nl/JavaBlog/wp-content/uploads/2009/04/android_icon_256.png");
public void onClick(View v) {
startActivity(new Intent(this, IndexActivity.class));
finish();
}
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);
}
}
确保你在AndroidManifest.xml中设置了以下权限来访问互联网。
<uses-permission android:name="android.permission.INTERNET" />
其他回答
你必须先下载图像
public static Bitmap loadBitmap(String url) {
Bitmap bitmap = null;
InputStream in = null;
BufferedOutputStream out = null;
try {
in = new BufferedInputStream(new URL(url).openStream(), IO_BUFFER_SIZE);
final ByteArrayOutputStream dataStream = new ByteArrayOutputStream();
out = new BufferedOutputStream(dataStream, IO_BUFFER_SIZE);
copy(in, out);
out.flush();
final byte[] data = dataStream.toByteArray();
BitmapFactory.Options options = new BitmapFactory.Options();
//options.inSampleSize = 1;
bitmap = BitmapFactory.decodeByteArray(data, 0, data.length,options);
} catch (IOException e) {
Log.e(TAG, "Could not load Bitmap from: " + url);
} finally {
closeStream(in);
closeStream(out);
}
return bitmap;
}
然后使用Imageview。setImageBitmap将位图设置为ImageView
我最近在这里找到了一个线程,因为我必须为带有图像的列表视图做类似的事情,但原理很简单,正如您可以在那里显示的第一个示例类中读到的那样(由jleedev)。 你得到图像的输入流(从网络)
private InputStream fetch(String urlString) throws MalformedURLException, IOException {
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpGet request = new HttpGet(urlString);
HttpResponse response = httpClient.execute(request);
return response.getEntity().getContent();
}
然后你将图像存储为可绘制的,你可以将它传递给ImageView(通过setImageDrawable)。同样从上面的代码片段来看一下整个线程。
InputStream is = fetch(urlString);
Drawable drawable = Drawable.createFromStream(is, "src");
imageView.setImageBitmap(BitmapFactory.decodeStream(imageUrl.openStream()));//try/catch IOException and MalformedURLException outside
来自Android开发者:
// show The Image in a ImageView
new DownloadImageTask((ImageView) findViewById(R.id.imageView1))
.execute("http://java.sogeti.nl/JavaBlog/wp-content/uploads/2009/04/android_icon_256.png");
public void onClick(View v) {
startActivity(new Intent(this, IndexActivity.class));
finish();
}
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);
}
}
确保你在AndroidManifest.xml中设置了以下权限来访问互联网。
<uses-permission android:name="android.permission.INTERNET" />
试试这个方法,希望能帮助你解决问题。
这里我解释了如何使用“AndroidQuery”外部库以asyncTask方式从url/server加载图像,并将加载的图像缓存到设备文件或缓存区。
从这里下载“AndroidQuery”库 复制/粘贴这个jar到项目lib文件夹,并将这个库添加到项目构建路径 现在我展示演示如何使用它。
activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center">
<FrameLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<ImageView
android:id="@+id/imageFromUrl"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:adjustViewBounds="true"/>
<ProgressBar
android:id="@+id/pbrLoadImage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"/>
</FrameLayout>
</LinearLayout>
MainActivity.java
public class MainActivity extends Activity {
private AQuery aQuery;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
aQuery = new AQuery(this);
aQuery.id(R.id.imageFromUrl).progress(R.id.pbrLoadImage).image("http://itechthereforeiam.com/wp-content/uploads/2013/11/android-gone-packing.jpg",true,true);
}
}
Note : Here I just implemented common method to load image from url/server but you can use various types of method which can be provided by "AndroidQuery"to load your image easily.
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