Question

我正在尝试从我的Android应用程序访问Web API，我有Url，它应该返回一些XML文件。我在网上找了一些代码，但没有一个可以工作，我可以从VM浏览器访问url而不是应用程序，我设置了访问互联网的所有必要权限。

基本代码：

public class MainActivity extends Activity {
    private static final String URL = "http://192.168.15.12/api/values/2";
    protected static final String TAG = null;
    HttpResponse response3 = null;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Button btn = (Button) findViewById(R.id.button1);

        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
                Log.i(TAG, "2");
                try {
                    Log.i(TAG, "7");
                    Log.i(TAG, "9");
                    HttpClient client = new DefaultHttpClient();
                    HttpGet request = new HttpGet();
                    request.setURI(new URI(URL));
                    response3 = client.execute(request);
                    Log.i(TAG, "10");

                } catch (UnsupportedEncodingException e) {
                    e.printStackTrace();
                } catch (ClientProtocolException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                } catch (URISyntaxException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } 
                // return XML
                Log.i(TAG, "00");

            }
        });
    }
    @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;
    }

}

异常：

05-21 14:34:51.462: I/(789): 2
05-21 14:34:51.462: I/(789): 7
05-21 14:34:51.462: I/(789): 9
05-21 14:34:51.552: D/AndroidRuntime(789): Shutting down VM
05-21 14:34:51.552: W/dalvikvm(789): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
05-21 14:34:51.613: E/AndroidRuntime(789): FATAL EXCEPTION: main
05-21 14:34:51.613: E/AndroidRuntime(789): android.os.NetworkOnMainThreadException
05-21 14:34:51.613: E/AndroidRuntime(789):  at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117)
05-21 14:34:51.613: E/AndroidRuntime(789):  at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84)
05-21 14:34:51.613: E/AndroidRuntime(789):  at libcore.io.IoBridge.connectErrno(IoBridge.java:127)
05-21 14:34:51.613: E/AndroidRuntime(789):  at libcore.io.IoBridge.connect(IoBridge.java:112)
05-21 14:34:51.613: E/AndroidRuntime(789):  at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
05-21 14:34:51.613: E/AndroidRuntime(789):  at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459)
05-21 14:34:51.613: E/AndroidRuntime(789):  at java.net.Socket.connect(Socket.java:842)
05-21 14:34:51.613: E/AndroidRuntime(789):  at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:119)
05-21 14:34:51.613: E/AndroidRuntime(789):  at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:144)
05-21 14:34:51.613: E/AndroidRuntime(789):  at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
05-21 14:34:51.613: E/AndroidRuntime(789):  at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
05-21 14:34:51.613: E/AndroidRuntime(789):  at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
05-21 14:34:51.613: E/AndroidRuntime(789):  at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
05-21 14:34:51.613: E/AndroidRuntime(789):  at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
05-21 14:34:51.613: E/AndroidRuntime(789):  at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
05-21 14:34:51.613: E/AndroidRuntime(789):  at com.example.sms4.MainActivity$1.onClick(MainActivity.java:70)
05-21 14:34:51.613: E/AndroidRuntime(789):  at android.view.View.performClick(View.java:4204)
05-21 14:34:51.613: E/AndroidRuntime(789):  at android.view.View$PerformClick.run(View.java:17355)
05-21 14:34:51.613: E/AndroidRuntime(789):  at android.os.Handler.handleCallback(Handler.java:725)
05-21 14:34:51.613: E/AndroidRuntime(789):  at android.os.Handler.dispatchMessage(Handler.java:92)
05-21 14:34:51.613: E/AndroidRuntime(789):  at android.os.Looper.loop(Looper.java:137)
05-21 14:34:51.613: E/AndroidRuntime(789):  at android.app.ActivityThread.main(ActivityThread.java:5041)
05-21 14:34:51.613: E/AndroidRuntime(789):  at java.lang.reflect.Method.invokeNative(Native Method)
05-21 14:34:51.613: E/AndroidRuntime(789):  at java.lang.reflect.Method.invoke(Method.java:511)
05-21 14:34:51.613: E/AndroidRuntime(789):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
05-21 14:34:51.613: E/AndroidRuntime(789):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
05-21 14:34:51.613: E/AndroidRuntime(789):  at dalvik.system.NativeStart.main(Native Method)

Answer 1

您正在执行来自UI Thrad的HTTP请求。这是Android 3.0+以来的禁止。使用AsyncTask执行请求。 Here参考。所有阻塞代码都必须在不同的线程中执行。所有Http逻辑都必须在doInBackground方法

中执行

Answer 2

您应该使用AsyncTask在单独的线程上执行与网络相关的操作，而不是在主（UI）线程上执行。

从Android抛出Get请求抛出异常？

2 个答案: