Question

我只是：

HttpClient httpClient = new DefaultHttpClient();
// Creating HTTP Post
HttpPost httpPost = new HttpPost(
        "http://www.google.com/");

// Making HTTP Request
try {
    HttpResponse response = (HttpResponse) httpClient.execute(httpPost);
    // writing response to log
    Log.d("Http Response:", response.toString());
} catch (ClientProtocolException e) {
    // writing exception to log
    e.printStackTrace();
} catch (IOException e) {
    // writing exception to log
    e.printStackTrace();
}

但是当我运行应用程序时，它会崩溃并且无法正常工作。

这是我的日志：

02-05 14:33:42.217: E/AndroidRuntime(25026): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.app.myapppp/com.app.myapppp.Main}: android.os.NetworkOnMainThreadException
02-05 14:33:42.217: E/AndroidRuntime(25026):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2110)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2135)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at android.app.ActivityThread.access$700(ActivityThread.java:140)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1237)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at android.os.Handler.dispatchMessage(Handler.java:99)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at android.os.Looper.loop(Looper.java:137)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at android.app.ActivityThread.main(ActivityThread.java:4921)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at java.lang.reflect.Method.invokeNative(Native Method)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at java.lang.reflect.Method.invoke(Method.java:511)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at dalvik.system.NativeStart.main(Native Method)
02-05 14:33:42.217: E/AndroidRuntime(25026): Caused by: android.os.NetworkOnMainThreadException
02-05 14:33:42.217: E/AndroidRuntime(25026):    at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1118)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at java.net.InetAddress.getAllByName(InetAddress.java:214)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:670)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:509)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at com.app.myapppp.Main.onCreate(Main.java:133)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at android.app.Activity.performCreate(Activity.java:5206)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
02-05 14:33:42.217: E/AndroidRuntime(25026):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2074)
02-05 14:33:42.217: E/AndroidRuntime(25026):    ... 11 more

Answer 1

使用像Example

这样的AsyncTask进行API调用

点击API调用或在Main方法中

public void onClick(View v) {
// TODO Auto-generated method stub
if(value.getText().toString().length()<1){
// out of range
Toast.makeText(this, "please enter something", Toast.LENGTH_LONG).show();
}else{
pb.setVisibility(View.VISIBLE);
new MyAsyncTask().execute(value.getText().toString());  
}
}

AsynckTask

private class MyAsyncTask extends AsyncTask<String, Integer, Double>{
@Override
protected Double doInBackground(String... params) {
// TODO Auto-generated method stub
postData(params[0]);
return null;
}
}

// MyAsyncTask

private class MyAsyncTask extends AsyncTask<String, Integer, Double>{
@Override
protected Double doInBackground(String... params) {
// TODO Auto-generated method stub
postData(params[0]);
return null;
}

protected void onPostExecute(Double result){
pb.setVisibility(View.GONE);
Toast.makeText(getApplicationContext(), "command sent", Toast.LENGTH_LONG).show();
}
protected void onProgressUpdate(Integer... progress){
pb.setProgress(progress[0]);
}
}

您的API调用方法

public void postData(String valueIWantToSend) {

HttpClient httpclient = new DefaultHttpClient();
// specify the URL you want to post to
HttpPost httppost = new HttpPost("http://www.google.com/");
try {
// create a list to store HTTP variables and their values
List nameValuePairs = new ArrayList();
// add an HTTP variable and value pair
nameValuePairs.add(new BasicNameValuePair("myHttpData", valueIwantToSend));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
// send the variable and value, in other words post, to the URL
HttpResponse response = httpclient.execute(httppost);
} catch (ClientProtocolException e) {
// process execption
} catch (IOException e) {
// process execption
}
}

Answer 2

这种情况正在发生，因为您尝试在主要活动中执行与网络相关的操作。这是不允许的，而不是做网络相关任务的坏方法。要完成所有这样的任务，还有其他方法，例如AsyncTask类可以做到这一点。

这使您可以在应用程序的后台执行所有这些重大任务。这样你的主线程就不会忙碌，这显然会导致你的应用程序崩溃。

文档http://developer.android.com/reference/android/os/AsyncTask.html

简单的asyncTask示例http://programmerguru.com/android-tutorial/android-asynctask-example/

Answer 3

需要在单独的线程中执行网络操作。

protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        new NetworkOperation().execute();
    }

异步任务示例

private class NetworkOperation extends AsyncTask<String, Void, String> {

        @Override
        protected String doInBackground(String... params) {
            HttpClient httpClient = new DefaultHttpClient();
// Creating HTTP Post
            HttpPost httpPost = new HttpPost(
                    "http://www.google.com/");

// Making HTTP Request
            try {
                HttpResponse response = (HttpResponse) httpClient.execute(httpPost);
                // writing response to log
                Log.d("Http Response:", response.toString());
            } catch (ClientProtocolException e) {
                // writing exception to log
                e.printStackTrace();
            } catch (IOException e) {
                // writing exception to log
                e.printStackTrace();
            }

            return "";
        }

        @Override
        protected void onPostExecute(String result) {

        }

        @Override
        protected void onPreExecute() {
        }

        @Override
        protected void onProgressUpdate(Void... values) {
        }
    }

Android HttpPost不起作用，它崩溃了

3 个答案: