我正在学习android编程并使用android studio创建了一个基本项目。
单击getdata按钮时，我的应用程序崩溃。
MainActivity.java：
package com.cs_infotech.newpathshala;
import android.app.Activity;
import android.app.FragmentTransaction;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.content.Context;
import android.os.Build;
import android.os.Bundle;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.support.v4.widget.DrawerLayout;
import android.widget.ArrayAdapter;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends ActionBarActivity
implements NavigationDrawerFragment.NavigationDrawerCallbacks {
/**
* Fragment managing the behaviors, interactions and presentation of the navigation drawer.
*/
private NavigationDrawerFragment mNavigationDrawerFragment;
/**
* Used to store the last screen title. For use in {@link #restoreActionBar()}.
*/
private CharSequence mTitle;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mNavigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
mTitle = getTitle();
// Set up the drawer.
mNavigationDrawerFragment.setUp(
R.id.navigation_drawer,
(DrawerLayout) findViewById(R.id.drawer_layout));
}
@Override
public void onNavigationDrawerItemSelected(int position) {
// update the main content by replacing fragments
Fragment fragment = null;
switch (position) {
case 0:
fragment = new ExampleFragment();
break;
case 1:
fragment = new Example1Fragment();
break;
case 2:
fragment = new Example2Fragment();
break;
}
if (fragment != null) {
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.container, fragment).commit();
} }
public void onSectionAttached(int number) {
switch (number) {
case 1:
mTitle = "ePathshala";
break;
case 2:
mTitle = "Daily Collection";
break;
case 3:
mTitle = "New Enrolled";
break;
}
}
public void restoreActionBar() {
ActionBar actionBar = getSupportActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
actionBar.setDisplayShowTitleEnabled(true);
actionBar.setTitle(mTitle);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
if (!mNavigationDrawerFragment.isDrawerOpen()) {
// Only show items in the action bar relevant to this screen
// if the drawer is not showing. Otherwise, let the drawer
// decide what to show in the action bar.
getMenuInflater().inflate(R.menu.main, menu);
restoreActionBar();
return true;
}
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
return rootView;
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
((MainActivity) activity).onSectionAttached(
getArguments().getInt(ARG_SECTION_NUMBER));
}
}
}
test1.xml：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<Button
android:id="@+id/getdata"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginBottom="23dp"
android:text="Get Data" />
<ListView
android:id="@+id/list"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_above="@+id/getdata" />
<TextView
android:id="@+id/vers"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
<TextView
android:id="@+id/name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
<TextView
android:id="@+id/api"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>
Example1Fragment.java：
package com.cs_infotech.newpathshala;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.Toast;
import com.cs_infotech.newpathshala.R;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.HashMap;
public class Example1Fragment extends Fragment {
ListView list;
TextView ver;
TextView name;
TextView api;
Button btngetdata;
ArrayList<HashMap<String, String>> oslist = new ArrayList<HashMap<String, String>>();
//URL to get JSON Array
private static String url = "http://api.learn2crack.com/android/jsonos/";
//JSON Node Names
private static final String TAG_OS = "android";
private static final String TAG_VER = "ver";
private static final String TAG_NAME = "name";
private static final String TAG_API = "api";
JSONArray android = null;
private View v;
public Example1Fragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.test1, container, false);
oslist = new ArrayList<HashMap<String, String>>();
btngetdata = (Button) rootView.findViewById(R.id.getdata);
v=rootView;
btngetdata.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
new JSONParse().execute();
//Toast.makeText(getActivity(), "You Clicked at " , Toast.LENGTH_SHORT).show();
}
});
return rootView;
}
private class JSONParse extends AsyncTask<String, String, JSONObject> {
private ProgressDialog pDialog;
@Override
protected void onPreExecute() {
super.onPreExecute();
name = (TextView) v.findViewById(R.id.name);
ver = (TextView) v.findViewById(R.id.vers);
api = (TextView) v.findViewById(R.id.api);
pDialog = new ProgressDialog(getActivity());
pDialog.setMessage("Getting Data ...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
@Override
protected JSONObject doInBackground(String... args) {
JSONParser jParser = new JSONParser();
// Getting JSON from URL
JSONObject json = jParser.getJSONFromUrl("http://api.learn2crack.com/android/jsonos/");
return json;
}
@Override
protected void onPostExecute(JSONObject json) {
pDialog.dismiss();
try {
// Getting JSON Array from URL
android = json.getJSONArray(TAG_OS);
for(int i = 0; i < android.length(); i++){
JSONObject c = android.getJSONObject(i);
// Storing JSON item in a Variable
String ver = c.getString(TAG_VER);
String name = c.getString(TAG_NAME);
String api = c.getString(TAG_API);
// Adding value HashMap key => value
HashMap<String, String> map = new HashMap<String, String>();
map.put(TAG_VER, ver);
map.put(TAG_NAME, name);
map.put(TAG_API, api);
oslist.add(map);
list=(ListView) v.findViewById(R.id.list);
ListAdapter adapter = new SimpleAdapter(getActivity(), oslist,
R.layout.list_v,
new String[] { TAG_VER,TAG_NAME, TAG_API }, new int[] {
R.id.vers,R.id.name, R.id.api});
list.setAdapter(adapter);
list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Toast.makeText(getActivity(), "You Clicked at " + oslist.get(+position).get("name"), Toast.LENGTH_SHORT).show();
}
});
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}
logcat的：
04-10 10:12:52.253 30126-30126/com.cs_infotech.newpathshala D/ActivityThread﹕ handleBindApplication:com.cs_infotech.newpathshala
04-10 10:12:52.343 30126-30126/com.cs_infotech.newpathshala W/ApplicationPackageManager﹕ getCSCPackageItemText()
04-10 10:12:52.343 30126-30126/com.cs_infotech.newpathshala D/DisplayManager﹕ DisplayManager()
04-10 10:12:52.423 30126-30126/com.cs_infotech.newpathshala I/dalvikvm﹕ Could not find method android.view.ViewGroup.onNestedScrollAccepted, referenced from method android.support.v7.internal.widget.ActionBarOverlayLayout.onNestedScrollAccepted
04-10 10:12:52.423 30126-30126/com.cs_infotech.newpathshala W/dalvikvm﹕ VFY: unable to resolve virtual method 11359: Landroid/view/ViewGroup;.onNestedScrollAccepted (Landroid/view/View;Landroid/view/View;I)V
04-10 10:12:52.423 30126-30126/com.cs_infotech.newpathshala D/dalvikvm﹕ VFY: replacing opcode 0x6f at 0x0000
04-10 10:12:52.423 30126-30126/com.cs_infotech.newpathshala I/dalvikvm﹕ Could not find method android.view.ViewGroup.onStopNestedScroll, referenced from method android.support.v7.internal.widget.ActionBarOverlayLayout.onStopNestedScroll
04-10 10:12:52.423 30126-30126/com.cs_infotech.newpathshala W/dalvikvm﹕ VFY: unable to resolve virtual method 11365: Landroid/view/ViewGroup;.onStopNestedScroll (Landroid/view/View;)V
04-10 10:12:52.423 30126-30126/com.cs_infotech.newpathshala D/dalvikvm﹕ VFY: replacing opcode 0x6f at 0x0000
04-10 10:12:52.433 30126-30126/com.cs_infotech.newpathshala I/dalvikvm﹕ Could not find method android.support.v7.internal.widget.ActionBarOverlayLayout.stopNestedScroll, referenced from method android.support.v7.internal.widget.ActionBarOverlayLayout.setHideOnContentScrollEnabled
04-10 10:12:52.433 30126-30126/com.cs_infotech.newpathshala W/dalvikvm﹕ VFY: unable to resolve virtual method 9053: Landroid/support/v7/internal/widget/ActionBarOverlayLayout;.stopNestedScroll ()V
04-10 10:12:52.433 30126-30126/com.cs_infotech.newpathshala D/dalvikvm﹕ VFY: replacing opcode 0x6e at 0x000e
04-10 10:12:52.443 30126-30126/com.cs_infotech.newpathshala I/dalvikvm﹕ Could not find method android.content.res.TypedArray.getChangingConfigurations, referenced from method android.support.v7.internal.widget.TintTypedArray.getChangingConfigurations
04-10 10:12:52.443 30126-30126/com.cs_infotech.newpathshala W/dalvikvm﹕ VFY: unable to resolve virtual method 374: Landroid/content/res/TypedArray;.getChangingConfigurations ()I
04-10 10:12:52.443 30126-30126/com.cs_infotech.newpathshala D/dalvikvm﹕ VFY: replacing opcode 0x6e at 0x0002
04-10 10:12:52.443 30126-30126/com.cs_infotech.newpathshala I/dalvikvm﹕ Could not find method android.content.res.TypedArray.getType, referenced from method android.support.v7.internal.widget.TintTypedArray.getType
04-10 10:12:52.443 30126-30126/com.cs_infotech.newpathshala W/dalvikvm﹕ VFY: unable to resolve virtual method 396: Landroid/content/res/TypedArray;.getType (I)I
04-10 10:12:52.443 30126-30126/com.cs_infotech.newpathshala D/dalvikvm﹕ VFY: replacing opcode 0x6e at 0x0002
04-10 10:12:52.834 30126-30126/com.cs_infotech.newpathshala D/OpenGLRenderer﹕ Enabling debug mode 0
04-10 10:12:52.934 30126-30126/com.cs_infotech.newpathshala I/Timeline﹕ Timeline: Activity_idle id: android.os.BinderProxy@41e049e0 time:9101016
04-10 10:15:04.772 30126-30126/com.cs_infotech.newpathshala I/Timeline﹕ Timeline: Activity_idle id: android.os.BinderProxy@41e049e0 time:9232856
04-10 10:15:11.359 30126-30656/com.cs_infotech.newpathshala W/dalvikvm﹕ threadid=11: thread exiting with uncaught exception (group=0x416c8bc0)
04-10 10:15:11.379 30126-30656/com.cs_infotech.newpathshala E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #1
Process: com.cs_infotech.newpathshala, PID: 30126
java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:300)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:841)
Caused by: java.lang.SecurityException: Permission denied (missing INTERNET permission?)
at java.net.InetAddress.lookupHostByName(InetAddress.java:418)
at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
at java.net.InetAddress.getAllByName(InetAddress.java:214)
at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
at com.cs_infotech.newpathshala.JSONParser.getJSONFromUrl(JSONParser.java:44)
at com.cs_infotech.newpathshala.Example1Fragment$JSONParse.doInBackground(Example1Fragment.java:80)
at com.cs_infotech.newpathshala.Example1Fragment$JSONParse.doInBackground(Example1Fragment.java:62)
at android.os.AsyncTask$2.call(AsyncTask.java:288)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:841)
Caused by: libcore.io.GaiException: getaddrinfo failed: EAI_NODATA (No address associated with hostname)
at libcore.io.Posix.getaddrinfo(Native Method)
at libcore.io.ForwardingOs.getaddrinfo(ForwardingOs.java:61)
at java.net.InetAddress.lookupHostByName(InetAddress.java:405)
at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
at java.net.InetAddress.getAllByName(InetAddress.java:214)
at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
at com.cs_infotech.newpathshala.JSONParser.getJSONFromUrl(JSONParser.java:44)
at com.cs_infotech.newpathshala.Example1Fragment$JSONParse.doInBackground(Example1Fragment.java:80)
at com.cs_infotech.newpathshala.Example1Fragment$JSONParse.doInBackground(Example1Fragment.java:62)
at android.os.AsyncTask$2.call(AsyncTask.java:288)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:841)
Caused by: libcore.io.ErrnoException: getaddrinfo failed: EACCES (Permission denied)
at libcore.io.Posix.getaddrinfo(Native Method)
at libcore.io.ForwardingOs.getaddrinfo(ForwardingOs.java:61)
at java.net.InetAddress.lookupHostByName(InetAddress.java:405)
at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
at java.net.InetAddress.getAllByName(InetAddress.java:214)
at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
at com.cs_infotech.newpathshala.JSONParser.getJSONFromUrl(JSONParser.java:44)
at com.cs_infotech.newpathshala.Example1Fragment$JSONParse.doInBackground(Example1Fragment.java:80)
at com.cs_infotech.newpathshala.Example1Fragment$JSONParse.doInBackground(Example1Fragment.java:62)
at android.os.AsyncTask$2.call(AsyncTask.java:288)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:841)
04-10 10:15:12.330 30126-30126/com.cs_infotech.newpathshala E/OpenGLRenderer﹕ SFEffectCache:clear(), mSize = 0
04-10 10:15:12.360 30126-30126/com.cs_infotech.newpathshala E/WindowManager﹕ android.view.WindowLeaked: Activity com.cs_infotech.newpathshala.MainActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView{41e91890 V.E..... R......D 0,0-471,144} that was originally added here
at android.view.ViewRootImpl.<init>(ViewRootImpl.java:388)
at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:248)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:69)
at android.app.Dialog.show(Dialog.java:286)
at com.cs_infotech.newpathshala.Example1Fragment$JSONParse.onPreExecute(Example1Fragment.java:74)
at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:587)
at android.os.AsyncTask.execute(AsyncTask.java:535)
at com.cs_infotech.newpathshala.Example1Fragment$1.onClick(Example1Fragment.java:56)
at android.view.View.performClick(View.java:4508)
at android.view.View$PerformClick.run(View.java:18675)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5584)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1268)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1084)
at dalvik.system.NativeStart.main(Native Method)
04-10 10:15:14.992 30126-30656/com.cs_infotech.newpathshala I/Process﹕ Sending signal. PID: 30126 SIG: 9
我该如何解决这个问题？