Android獲取網絡圖片應用示例

1、養成好習慣，配置字符串資源文件 strings.xml

 xml version="1.0" encoding="utf-8"?> 
<resources> 
    <string name="app_name">網絡圖片查看器</string> 
    <string name="action_settings">Settings</string> 
    <string name="hello_world">Hello world!</string> 
    <string name="imgpath">輸入圖片地址：</string> 
    <string name="getBtn">獲取圖片</string> 
    <string name="error">獲取圖片失敗</string> 
</resources> 

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="app_name">網絡圖片查看器</string>
    <string name="action_settings">Settings</string>
    <string name="hello_world">Hello world!</string>
 <string name="imgpath">輸入圖片地址：</string>
 <string name="getBtn">獲取圖片</string>
 <string name="error">獲取圖片失敗</string>
</resources>

2、布局文件，使用垂直布局

LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:orientation="vertical" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:paddingBottom="@dimen/activity_vertical_margin" 
    android:paddingLeft="@dimen/activity_horizontal_margin" 
    android:paddingRight="@dimen/activity_horizontal_margin" 
    android:paddingTop="@dimen/activity_vertical_margin" 
    tools:context=".MainActivity" > 
 
    <TextView  
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" 
        android:text="@string/imgpath" 
        /> 
     
    <EditText android:layout_width="fill_parent" 
        android:layout_height="wrap_content" 
        android:id="@+id/imgpathInput" 
        android:text="http://avatar.csdn.net/B/E/7/1_gaotong2055.jpg" 
        android:inputType="text" /> 
    <Button  
         android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
        android:text="@string/getBtn" 
        android:id="@+id/getBtn" 
        /> 
    <ImageView  
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
        android:id="@+id/imgView" 
        /> 
</LinearLayout> 

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/imgpath"
        />
 
    <EditText android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:id="@+id/imgpathInput"
        android:text="http://avatar.csdn.net/B/E/7/1_gaotong2055.jpg"
        android:inputType="text" />
    <Button
         android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/getBtn"
        android:id="@+id/getBtn"
        />
    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/imgView"
        />
</LinearLayout>

、編寫代碼

這裡為了方便看代碼，都寫在一個類裡面了。

可以把裡面的靜態方法單獨拆分出來，寫在一個工具類中，結構更好。

public class MainActivity extends Activity implements OnClickListener { 
    private EditText pathText; 
    private ImageView imageView; 
 
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.activity_main); 
        pathText = (EditText) this.findViewById(R.id.imgpathInput); 
        imageView = (ImageView) this.findViewById(R.id.imgView); 
        Button button = (Button) this.findViewById(R.id.getBtn); 
        button.setOnClickListener(this); 
    } 
 
    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
        getMenuInflater().inflate(R.menu.main, menu); 
        return true; 
    } 
 
    @Override 
    public void onClick(View v) { 
        String path = pathText.getText().toString(); 
        byte[] data = null; 
        try { 
            data = getImgData(path); 
        } catch (Exception e) { 
            e.printStackTrace(); 
            Toast.makeText(this, R.string.error, 1).show(); 
        } 
        Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length); 
        imageView.setImageBitmap(bitmap); 
    } 
 
    public static byte[] getImgData(String path) throws Exception { 
 
        URL url = new URL(path); 
        HttpURLConnection conn = (HttpURLConnection) url.openConnection(); 
        conn.setConnectTimeout(5000);// 超時時間5秒  
        conn.setRequestMethod("GET"); 
        if (conn.getResponseCode() == 200) { 
            InputStream in = conn.getInputStream(); 
            return read(in); 
        } else { 
            Log.d("tong.getImg", "服務器無響應"); 
        } 
 
        return null; 
    } 
 
    /**
     * 從一個輸入流中讀取數據，並返回
     * 
     * @param in
     * @return byte[] 數據
     * @throws IOException
     */ 
    public static byte[] read(InputStream in) throws IOException { 
        // 開辟一個內存的區域，以寫入數據  
        ByteArrayOutputStream outStream = new ByteArrayOutputStream(); 
        byte[] buffer = new byte[10240]; 
        int len = 0; 
        while ((len = in.read(buffer)) != -1) { 
            outStream.write(buffer, 0, len); 
        } 
        outStream.close(); 
 
        return outStream.toByteArray(); // 返回內存中的數據  
    } 
 
} 

public class MainActivity extends Activity implements OnClickListener {
 private EditText pathText;
 private ImageView imageView;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  pathText = (EditText) this.findViewById(R.id.imgpathInput);
  imageView = (ImageView) this.findViewById(R.id.imgView);
  Button button = (Button) this.findViewById(R.id.getBtn);
  button.setOnClickListener(this);
 }

 @Override
 public boolean onCreateOptionsMenu(Menu menu) {
  getMenuInflater().inflate(R.menu.main, menu);
  return true;
 }

 @Override
 public void onClick(View v) {
  String path = pathText.getText().toString();
  byte[] data = null;
  try {
   data = getImgData(path);
  } catch (Exception e) {
   e.printStackTrace();
   Toast.makeText(this, R.string.error, 1).show();
  }
  Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
  imageView.setImageBitmap(bitmap);
 }

 public static byte[] getImgData(String path) throws Exception {

  URL url = new URL(path);
  HttpURLConnection conn = (HttpURLConnection) url.openConnection();
  conn.setConnectTimeout(5000);// 超時時間5秒
  conn.setRequestMethod("GET");
  if (conn.getResponseCode() == 200) {
   InputStream in = conn.getInputStream();
   return read(in);
  } else {
   Log.d("tong.getImg", "服務器無響應");
  }

  return null;
 }

 /**
  * 從一個輸入流中讀取數據，並返回
  *
  * @param in
  * @return byte[] 數據
  * @throws IOException
  */
 public static byte[] read(InputStream in) throws IOException {
  // 開辟一個內存的區域，以寫入數據
  ByteArrayOutputStream outStream = new ByteArrayOutputStream();
  byte[] buffer = new byte[10240];
  int len = 0;
  while ((len = in.read(buffer)) != -1) {
   outStream.write(buffer, 0, len);
  }
  outStream.close();

  return outStream.toByteArray(); // 返回內存中的數據
 }

}