以編程方式創建ImageView並從URL加載它的內容

我有一個簡單的LinearLayout和Button，我想在按下按鈕時創建一個圖像並從URL加載它的內容。以編程方式創建ImageView並從URL加載它的內容

我創建了一個AsyncTask來做到這一點，但程序崩潰時，我按下按鈕。

這裏是我的代碼：

package com.example.image; 

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

import android.app.Activity; 
import android.graphics.Bitmap; 
import android.graphics.BitmapFactory; 
import android.os.AsyncTask; 
import android.os.Bundle; 
import android.view.Menu; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
import android.widget.ImageView; 
import android.widget.LinearLayout; 

public class MainActivity extends Activity { 

    Button testButton; 
    LinearLayout layout; 

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

     testButton = (Button) findViewById(R.id.button1); 
     layout = (LinearLayout) findViewById(R.id.LinearLayout1); 

     testButton.setOnClickListener(new OnClickListener() { 

      @Override 
      public void onClick(View arg0) { 
       new GetData().execute(); 
      } 

     }); 

    } 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.main, menu); 
     return true; 
    } 

    class GetData extends AsyncTask<String, Void, String> { 

     Bitmap bitmap; 
     ImageView image = new ImageView(MainActivity.this); 

     @Override 
     protected void onPreExecute() { 
     }; 

     @Override 
     protected String doInBackground(String... params) { 
      try { 
       URL url = new URL("http://www.android.com/images/logo.png"); 
       Bitmap bitmap = BitmapFactory.decodeStream(url.openConnection().getInputStream()); 
      } catch (MalformedURLException e) { 
       e.printStackTrace(); 
      } catch (IOException e) { 
       e.printStackTrace(); 
      } 
      return null; 
     } 

     @Override 
     protected void onPostExecute(String result) { 
      super.onPostExecute(result); 
      image.setImageBitmap(bitmap); 
      layout.addView(image); 
     } 
    } 

}

而這裏的logcat：

06-02 12:58:57.880: E/Trace(1572): error opening trace file: No such file or directory (2) 
06-02 12:58:58.580: D/gralloc_goldfish(1572): Emulator without GPU emulation detected. 
06-02 12:59:02.331: W/dalvikvm(1572): threadid=11: thread exiting with uncaught exception (group=0x40a13300) 
06-02 12:59:02.401: E/AndroidRuntime(1572): FATAL EXCEPTION: AsyncTask #1 
06-02 12:59:02.401: E/AndroidRuntime(1572): java.lang.RuntimeException: An error occured while executing doInBackground() 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at android.os.AsyncTask$3.done(AsyncTask.java:299) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at java.util.concurrent.FutureTask.setException(FutureTask.java:124) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at java.util.concurrent.FutureTask.run(FutureTask.java:137) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at java.lang.Thread.run(Thread.java:856) 
06-02 12:59:02.401: E/AndroidRuntime(1572): Caused by: java.lang.SecurityException: Permission denied (missing INTERNET permission?) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at java.net.InetAddress.lookupHostByName(InetAddress.java:418) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at java.net.InetAddress.getAllByName(InetAddress.java:214) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at libcore.net.http.HttpConnection.<init>(HttpConnection.java:70) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at libcore.net.http.HttpConnection.<init>(HttpConnection.java:50) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at libcore.net.http.HttpConnection$Address.connect(HttpConnection.java:341) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:87) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at libcore.net.http.HttpConnection.connect(HttpConnection.java:128) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:315) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at libcore.net.http.HttpEngine.connect(HttpEngine.java:310) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:289) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at libcore.net.http.HttpEngine.sendRequest(HttpEngine.java:239) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at libcore.net.http.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:273) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at libcore.net.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:168) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at com.example.image.MainActivity$GetData.doInBackground(MainActivity.java:63) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at com.example.image.MainActivity$GetData.doInBackground(MainActivity.java:1) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at android.os.AsyncTask$2.call(AsyncTask.java:287) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  ... 5 more 
06-02 12:59:02.401: E/AndroidRuntime(1572): Caused by: libcore.io.GaiException: getaddrinfo failed: EAI_NODATA (No address associated with hostname) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at libcore.io.Posix.getaddrinfo(Native Method) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at libcore.io.ForwardingOs.getaddrinfo(ForwardingOs.java:55) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  at java.net.InetAddress.lookupHostByName(InetAddress.java:405) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  ... 22 more 
06-02 12:59:02.401: E/AndroidRuntime(1572): Caused by: libcore.io.ErrnoException: getaddrinfo failed: EACCES (Permission denied) 
06-02 12:59:02.401: E/AndroidRuntime(1572):  ... 25 more

來源

2013-06-02 Christos Baziotis

刪除位圖

創建全局變量爲

 Bitmap bitmap = BitmapFactory.decodeStream(url.openConnection().getInputStream());

只寫這個

 bitmap = BitmapFactory.decodeStream(url.openConnection().getInputStream());

來源

2013-06-02 13:12:39 anddevmanu

謝謝！就是這樣。 –

在日誌中：

拋出：SecurityException：（？缺少INTERNET許可）許可被拒絕

表示您忘記添加INTERNET權限AndroidManifest。將其添加爲：

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

來源

2013-06-02 13:05:41

我增加了許可，現在它只是什麼也不做！（2） –

logcat：06-02 13：08：58.340：E/Trace（1623）：打開跟蹤文件時出錯：沒有這樣的文件或目錄（2） –

@koukouloforos：現在有一些其他問題plz更新登錄問題以獲取更多幫助 –

嘗試在Android清單中添加權限，如下所示。

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

來源

2013-06-02 13:06:28 CRUSADER

以編程方式創建ImageView並從URL加載它的內容

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