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分享android http 请求问题
状况：TextView 已经显示 【可以上网】
出错代码行 ：HttpResponse response = client.execute(request);
但是 在 catch 模块 捕获异常信息时 结果为 null null ：result = e.getLocalizedMessage() + " " + e.getMessage(); 没有异常信息
本人初学 android 遇到这种出错，不能解决,请大家回答一下,谢谢大家
权限配置如下
出错代码行 ：HttpResponse response = client.execute(request);
但是 在 catch 模块 捕获异常信息时 结果为 null null ：result = e.getLocalizedMessage() + " " + e.getMessage(); 没有异常信息
本人初学 android 遇到这种出错，不能解决,请大家回答一下,谢谢大家
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_main);
btn = (Button) findViewById(R.id.btnRemote);
tv = (TextView) findViewById(R.id.txtRemoteResult);
btn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
String result = executeGet();
tv.setText(result);
}
});
tv.setText(isNetworkAvailable(this)?"可以上网":"不可以上网");
}
public String executeGet() {
String result = null;
BufferedReader reader = null;
try {
HttpClient client = new DefaultHttpClient();
HttpGet request = new HttpGet();
request.setURI(new URI("http://www.baidu.com"));
HttpResponse response = client.execute(request);
reader = new BufferedReader(new InputStreamReader(response
.getEntity().getContent()));
StringBuffer strBuffer = new StringBuffer("");
String line = null;
while ((line = reader.readLine()) != null) {
strBuffer.append(line);
}
result = strBuffer.toString();
} catch (Exception e) {
result = e.getLocalizedMessage() + " " + e.getMessage();
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
reader = null;
} catch (IOException e) {
e.printStackTrace();
}
}
}
return result;
}
public static boolean isNetworkAvailable(Context context) {
ConnectivityManager cm = (ConnectivityManager) context
.getSystemService(Context.CONNECTIVITY_SERVICE);
if (cm == null) {
} else {
//如果仅仅是用来判断网络连接
//则可以使用 cm.getActiveNetworkInfo().isAvailable();
NetworkInfo[] info = cm.getAllNetworkInfo();
if (info != null) {
for (int i = 0; i < info.length; i++) {
if (info[i].getState() == NetworkInfo.State.CONNECTED) {
return true;
}
}
}
}
return false;
}
权限配置如下
<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" >
</uses-permission>
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" >
</uses-permission>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" >
</uses-permission>
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" >
</uses-permission>
<uses-permission android:name="android.permission.INTERNET" >
</uses-permission>
<uses-permission android:name="android.permission.WAKE_LOCK" >
</uses-permission>
...全文
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lhf199501 2015-11-02
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太赞了！在写程序的时候遇到：XiaomiFirewall 报错，看了以后发现需要多开一个线程，防止在主线程响应时间过长。
navalphantom 2015-06-26
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哪里，客气了！刚好有时间罢了，以後一起学习～哎，真难 2015-06-26
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要异步请求，还是你设置了访问网络的mode
HYH_HENG 2015-06-26
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不得不说太感谢您了，这么用心帮组我，还分享自己的经验
navalphantom 2015-06-26
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你在主线程上作网络请求了，它有抛出异常，简单的说，这个异常就是要求你连网操作这类需要「等」的耗时操作，不要在主线程执行（，不然会造成 ANR）。
06-26 00:37:26.925 W/System.err( 1630): android.os.NetworkOnMainThreadException
06-26 00:37:27.195 W/System.err( 1630): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1128)
06-26 00:37:27.195 W/System.err( 1630): at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
06-26 00:37:27.195 W/System.err( 1630): at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
06-26 00:37:27.195 W/System.err( 1630): at java.net.InetAddress.getAllByName(InetAddress.java:214)
06-26 00:37:27.195 W/System.err( 1630): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
06-26 00:37:27.195 W/System.err( 1630): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
06-26 00:37:27.195 W/System.err( 1630): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
06-26 00:37:27.205 W/System.err( 1630): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
06-26 00:37:27.205 W/System.err( 1630): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
06-26 00:37:27.205 W/System.err( 1630): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
06-26 00:37:27.205 W/System.err( 1630): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
06-26 00:37:27.205 W/System.err( 1630): at testxxx.debug.MainActivity.executeGet(MainActivity.java:50)
06-26 00:37:27.205 W/System.err( 1630): at testxxx.debug.MainActivity$1.onClick(MainActivity.java:36)
06-26 00:37:27.205 W/System.err( 1630): at android.view.View.performClick(View.java:4171)
06-26 00:37:27.205 W/System.err( 1630): at android.view.View$PerformClick.run(View.java:17097)
06-26 00:37:27.205 W/System.err( 1630): at android.os.Handler.handleCallback(Handler.java:615)
06-26 00:37:27.205 W/System.err( 1630): at android.os.Handler.dispatchMessage(Handler.java:92)
06-26 00:37:27.205 W/System.err( 1630): at android.os.Looper.loop(Looper.java:137)
06-26 00:37:27.205 W/System.err( 1630): at android.app.ActivityThread.main(ActivityThread.java:4819)
06-26 00:37:27.215 W/System.err( 1630): at java.lang.reflect.Method.invokeNative(Native Method)
06-26 00:37:27.215 W/System.err( 1630): at java.lang.reflect.Method.invoke(Method.java:511)
06-26 00:37:27.215 W/System.err( 1630): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
06-26 00:37:27.215 W/System.err( 1630): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
06-26 00:37:27.215 W/System.err( 1630): at dalvik.system.NativeStart.main(Native Method)
06-26 00:37:27.445 I/XiaomiFirewall( 1210): firewall pkgName:android, result:0
import android.app.Activity;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URI;
public class MainActivity extends Activity implements View.OnClickListener {
private static int MSG_UPDATE_INFO = 100;
private static TextView sNetworkMsgTv;
private static Handler mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
if (msg.what == MSG_UPDATE_INFO) {
sNetworkMsgTv.setText((String) msg.obj);
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button btn = (Button) findViewById(R.id.btnRemote);
sNetworkMsgTv = (TextView) findViewById(R.id.txtRemoteResult);
sNetworkMsgTv.setText(isNetworkAvailable(this) ? "可以上网" : "不可以上网");
btn.setOnClickListener(this);
}
public String executeGet() {
String result = null;
BufferedReader reader = null;
try {
HttpClient client = new DefaultHttpClient();
HttpGet request = new HttpGet();
request.setURI(new URI("http://www.baidu.com"));
HttpResponse response = client.execute(request);
reader = new BufferedReader(new InputStreamReader(response
.getEntity().getContent()));
StringBuffer strBuffer = new StringBuffer("");
String line = null;
while ((line = reader.readLine()) != null) {
strBuffer.append(line);
}
result = strBuffer.toString();
} catch (Exception e) {
result = e.getLocalizedMessage() + " " + e.getMessage();
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return result;
}
public static boolean isNetworkAvailable(Context context) {
ConnectivityManager cm = (ConnectivityManager) context
.getSystemService(Context.CONNECTIVITY_SERVICE);
if (cm == null) {
} else {
//如果仅仅是用来判断网络连接
//则可以使用 cm.getActiveNetworkInfo().isAvailable();
NetworkInfo[] info = cm.getAllNetworkInfo();
if (info != null) {
for (int i = 0; i < info.length; i++) {
if (info[i].getState() == NetworkInfo.State.CONNECTED) {
return true;
}
}
}
}
return false;
}
@Override
public void onClick(View v) {
final int id = v.getId();
if (id == R.id.btnRemote) {
new Thread(new Runnable() {
@Override
public void run() {
String result = executeGet();
Message msg = Message.obtain();
msg.what = MSG_UPDATE_INFO;
msg.obj = result;
mHandler.sendMessage(msg);
}
}).start();
}
}
}
