WebView,HttpURLConnection,HttpClient的簡單使用

1、WebView的簡單使用

安卓程序有的需要瀏覽網頁，因此android提供了一個控件叫WebView,話不多說，直接使用

界面佈局代碼,就顯示一個WebView

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
   >


    <WebView
        android:id="@+id/main_show_webView" 
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        
        />
</RelativeLayout>

處理的代碼

public class MainActivity extends Activity {
	
	private WebView mShowWebView;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		
		//設置隱藏標題
		requestWindowFeature(Window.FEATURE_NO_TITLE);
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		mShowWebView=(WebView) findViewById(R.id.main_show_webView);
		
		//通過getSettings進行設置，然後設置支持javaScript
		mShowWebView.getSettings().setJavaScriptEnabled(true);
		
		mShowWebView.setWebViewClient(new WebViewClient(){
			@Override
			//該方法表明如果從當前網頁跳轉到別的網頁，還是在當前的webView中顯示，不使用系統的瀏覽器
			public boolean shouldOverrideUrlLoading(WebView view, String url) {
				view.loadUrl(url);
				return true;
			}
		});
		//加載頁面
		mShowWebView.loadUrl("http://www.baidu.com");
	}
}

注意設置網絡訪問權限

2、HttpURLConnection的簡單使用

寫一個小例子，向百度發送請求，然後得到請求結果

界面佈局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    >
    <Button 
        android:id="@+id/second_sendButton"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="sendRequestWithHttpURLConnection"
        />
  
    
    <ScrollView 
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        >
       <TextView
           android:id="@+id/second_responseTextView" 
           android:layout_width="match_parent"
           android:layout_height="wrap_content"
           />
        
    </ScrollView>

    

</LinearLayout>

處理代碼（解釋見代碼註釋）

public class SecondActivity extends Activity {

	private Button mSendButton;
	
	private TextView mShowTextView;
	
	private Handler mHandler;
	
	private static final String TAG="SecondActivity";
	
	private static final int SEND_REQUEST=1;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		
		requestWindowFeature(Window.FEATURE_NO_TITLE);
		super.onCreate(savedInstanceState);
		
		setContentView(R.layout.activity_second);
		mSendButton=(Button) findViewById(R.id.second_sendButton);
		
		mShowTextView=(TextView) findViewById(R.id.second_responseTextView);
		//通過handler接收到從網頁獲取到的數據，在主線程進行更新
		mHandler=new Handler(){
			public void handleMessage(android.os.Message msg) {
				if(msg.what==SEND_REQUEST){
					StringBuilder result=(StringBuilder) msg.obj;
					mShowTextView.setText(result);
				}
			};
		};
		
		mSendButton.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				sendRequestWithHttpURLConection();
			}
		});
	}
	
	private void sendRequestWithHttpURLConection(){
		//由於訪問網絡是耗時操作，因此開一個子線程
		new Thread(new Runnable() {
			
			@Override
			public void run() {
				HttpURLConnection connection=null;
				try {
					URL url=new URL("http://www.baidu.com");
					//通過給定的url獲得connection
					connection=(HttpURLConnection) url.openConnection();
					//設置請求方法，GET表明從獲得數據
					connection.setRequestMethod("GET");
					//設置超時操作
					connection.setReadTimeout(5000);
					connection.setConnectTimeout(5000);
					//得到輸入流
					InputStream in=connection.getInputStream();
					//通過輸入流讀取數據
					BufferedReader reader=new BufferedReader(new InputStreamReader(in));
					
					StringBuilder content=new StringBuilder();
					String line="";
					
					while((line=reader.readLine())!=null){
						content.append(line);
					}
					
					//將得到的結果通過handler發送到主線程，在主線程進行UI操作
					Message msg=mHandler.obtainMessage(SEND_REQUEST,content);
					mHandler.sendMessage(msg);
				} catch (Exception e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				
				}
			}
		}).start();
	}

}

3、HttpClient

HttpClient是Apche提供的HTTP網絡訪問接口，使用比較簡單，因爲他對一些參數都進行了封裝，解釋見代碼註釋

界面代碼略

private void sendRequestWithHttpClient() {
		new Thread(new Runnable() {

			@Override
			public void run() {
				
				try {
					//HttpClient是一個接口，因此一般new DefaultHttpClient
					HttpClient client=new DefaultHttpClient();
					//獲得HttpClient
					HttpGet get=new HttpGet("www.baidu.com");
					//執行get請求，得到responce
					HttpResponse response=client.execute(get);
					//判斷是否成功
					if(response.getStatusLine().getStatusCode()==200){
						//通過EntityUtils將返回內容轉化成字符串
						String content=EntityUtils.toString(response.getEntity(), "ytf-8");
						//發送給mHandler
						 Message msg = mHandler.obtainMessage(SHOW_RESPONSE,
						 content); mHandler.sendMessage(msg);
					}
				} catch (ClientProtocolException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
				
				
		}).start();
	}

結果略