java Android - 将 ImageView 设置为 URL
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Android - Set ImageView to URL
提问by user222786
I am trying to set an Imageview to a URL.
我正在尝试将 Imageview 设置为 URL。
Below is my code
下面是我的代码
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.getpic);
ImageView i = (ImageView)findViewById(R.id.ivget);
URL url;
try {
url = new URL("http://0-media-cdn.foolz.us/ffuuka/board/sp/thumb/1359/41/1359419073599s.jpg");
Bitmap image = BitmapFactory.decodeStream(url.openConnection().getInputStream());
i.setImageBitmap(image);
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
But whenever I try to open/run the app it crashes, why isnt it working?
但是每当我尝试打开/运行应用程序时它就会崩溃，为什么它不起作用？
06-15 00:37:20.977: E/AndroidRuntime(8579): FATAL EXCEPTION: main
06-15 00:37:20.977: E/AndroidRuntime(8579): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.OptimusApps.stayhealthy/com.OptimusApps.stayhealthy.Practice2}: java.lang.NullPointerException
06-15 00:37:20.977: E/AndroidRuntime(8579): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1993)
06-15 00:37:20.977: E/AndroidRuntime(8579): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2104)
06-15 00:37:20.977: E/AndroidRuntime(8579): at android.app.ActivityThread.access0(ActivityThread.java:132)
06-15 00:37:20.977: E/AndroidRuntime(8579): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1157)
06-15 00:37:20.977: E/AndroidRuntime(8579): at android.os.Handler.dispatchMessage(Handler.java:99)
06-15 00:37:20.977: E/AndroidRuntime(8579): at android.os.Looper.loop(Looper.java:137)
06-15 00:37:20.977: E/AndroidRuntime(8579): at android.app.ActivityThread.main(ActivityThread.java:4575)
06-15 00:37:20.977: E/AndroidRuntime(8579): at java.lang.reflect.Method.invokeNative(Native Method)
06-15 00:37:20.977: E/AndroidRuntime(8579): at java.lang.reflect.Method.invoke(Method.java:511)
06-15 00:37:20.977: E/AndroidRuntime(8579): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
06-15 00:37:20.977: E/AndroidRuntime(8579): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:556)
06-15 00:37:20.977: E/AndroidRuntime(8579): at dalvik.system.NativeStart.main(Native Method)
06-15 00:37:20.977: E/AndroidRuntime(8579): Caused by: java.lang.NullPointerException
06-15 00:37:20.977: E/AndroidRuntime(8579): at android.app.Activity.findViewById(Activity.java:1794)
06-15 00:37:20.977: E/AndroidRuntime(8579): at com.OptimusApps.stayhealthy.Practice2.<init>(Practice2.java:17)
06-15 00:37:20.977: E/AndroidRuntime(8579): at java.lang.Class.newInstanceImpl(Native Method)
06-15 00:37:20.977: E/AndroidRuntime(8579): at java.lang.Class.newInstance(Class.java:1319)
06-15 00:37:20.977: E/AndroidRuntime(8579): at android.app.Instrumentation.newActivity(Instrumentation.java:1023)
06-15 00:37:20.977: E/AndroidRuntime(8579): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1984)
06-15 00:37:20.977: E/AndroidRuntime(8579): ... 11 more
above is the logcat, I am not sure where the error is in it specificaly though..............................................................................................................................................................
上面是 logcat，但我不确定错误具体在哪里...................................... ………………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………
回答by Raghunandan
You should not do network related operation on the main ui thread.
你不应该在主 ui 线程上做网络相关的操作。
You can findViewById of the current view hierachy set to the activity. check if you have imageview in ivget.xml. Also use a asynctask as below and make a http get request to get the image.
您可以找到设置为活动的当前视图层次结构的ViewById。检查 ivget.xml 中是否有 imageview。还使用如下异步任务并发出 http get 请求以获取图像。
activity_main.xml
活动_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="173dp"
android:src="@drawable/ic_launcher" />
</RelativeLayout>
MainActivity.java
主活动.java
public class AndroidCustomGalleryActivity extends Activity {
ImageView iv;
Bitmap image ;
ProgressDialog pd;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
iv = (ImageView) findViewById(R.id.imageView1);
pd = new ProgressDialog(this);
pd.setMessage("Loading..");
new TheTask().execute();
}
class TheTask extends AsyncTask<Void,Void,Void>
{
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
pd.show();
}
@Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
try
{
//URL url = new URL( "http://a3.twimg.com/profile_images/670625317/aam-logo-v3-twitter.png");
image = downloadBitmap("http://a3.twimg.com/profile_images/670625317/aam-logo-v3-twitter.png");
}
catch(Exception e)
{
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Void result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
pd.dismiss();
if(image!=null)
{
iv.setImageBitmap(image);
}
}
}
private Bitmap downloadBitmap(String url) {
// initilize the default HTTP client object
final DefaultHttpClient client = new DefaultHttpClient();
//forming a HttoGet request
final HttpGet getRequest = new HttpGet(url);
try {
HttpResponse response = client.execute(getRequest);
//check 200 OK for success
final int statusCode = response.getStatusLine().getStatusCode();
if (statusCode != HttpStatus.SC_OK) {
Log.w("ImageDownloader", "Error " + statusCode +
" while retrieving bitmap from " + url);
return null;
}
final HttpEntity entity = response.getEntity();
if (entity != null) {
InputStream inputStream = null;
try {
// getting contents from the stream
inputStream = entity.getContent();
// decoding stream data back into image Bitmap that android understands
image = BitmapFactory.decodeStream(inputStream);
} finally {
if (inputStream != null) {
inputStream.close();
}
entity.consumeContent();
}
}
} catch (Exception e) {
// You Could provide a more explicit error message for IOException
getRequest.abort();
Log.e("ImageDownloader", "Something went wrong while" +
" retrieving bitmap from " + url + e.toString());
}
return image;
}
}
回答by Paresh Mayani
android.app.Activity.findViewById(Activity.java:1794)
=> It says you haven't initialized your ImageView i.e. "i" in your code.
=> 它说你没有在你的代码中初始化你的 ImageView 即“i”。
ImageView i = (ImageView) findViewById(R.id.myImageViewInXML);
回答by Tanmay Ranjan
Use Glide
使用滑行
Implementation 'com.github.bumptech.glide:glide:4.2.0'
执行 'com.github.bumptech.glide:glide:4.2.0'
Or
或者
in java
在 Java 中
Glide.with(getApplicationContext())
.load(image)
.into(imageView);
