无法启动活动ComponentInfo

Question

I'm trying to make that my main activity to open another activity (ListAtivity). However, when I click on the button app crashes and following exception appears:

01-26 17:12:58.341: E/AndroidRuntime(790): FATAL EXCEPTION: main
01-26 17:12:58.341: E/AndroidRuntime(790): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.slideoutmenu/com.example.slideoutmenu.ListViewActivity}: android.os.NetworkOnMainThreadException
01-26 17:12:58.341: E/AndroidRuntime(790):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
01-26 17:12:58.341: E/AndroidRuntime(790):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
01-26 17:12:58.341: E/AndroidRuntime(790):  at android.app.ActivityThread.access$600(ActivityThread.java:141)
01-26 17:12:58.341: E/AndroidRuntime(790):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
01-26 17:12:58.341: E/AndroidRuntime(790):  at android.os.Handler.dispatchMessage(Handler.java:99)
01-26 17:12:58.341: E/AndroidRuntime(790):  at android.os.Looper.loop(Looper.java:137)
01-26 17:12:58.341: E/AndroidRuntime(790):  at android.app.ActivityThread.main(ActivityThread.java:5039)
01-26 17:12:58.341: E/AndroidRuntime(790):  at java.lang.reflect.Method.invokeNative(Native Method)
01-26 17:12:58.341: E/AndroidRuntime(790):  at java.lang.reflect.Method.invoke(Method.java:511)
01-26 17:12:58.341: E/AndroidRuntime(790):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
01-26 17:12:58.341: E/AndroidRuntime(790):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
01-26 17:12:58.341: E/AndroidRuntime(790):  at dalvik.system.NativeStart.main(Native Method)
01-26 17:12:58.341: E/AndroidRuntime(790): Caused by: android.os.NetworkOnMainThreadException
01-26 17:12:58.341: E/AndroidRuntime(790):  at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117)
01-26 17:12:58.341: E/AndroidRuntime(790):  at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
01-26 17:12:58.341: E/AndroidRuntime(790):  at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
01-26 17:12:58.341: E/AndroidRuntime(790):  at java.net.InetAddress.getAllByName(InetAddress.java:214)
01-26 17:12:58.341: E/AndroidRuntime(790):  at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
01-26 17:12:58.341: E/AndroidRuntime(790):  at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
01-26 17:12:58.341: E/AndroidRuntime(790):  at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
01-26 17:12:58.341: E/AndroidRuntime(790):  at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
01-26 17:12:58.341: E/AndroidRuntime(790):  at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
01-26 17:12:58.341: E/AndroidRuntime(790):  at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
01-26 17:12:58.341: E/AndroidRuntime(790):  at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
01-26 17:12:58.341: E/AndroidRuntime(790):  at com.example.slideoutmenu.JSONParser.getJSONFromUrl(JSONParser.java:34)
01-26 17:12:58.341: E/AndroidRuntime(790):  at com.example.slideoutmenu.ListViewActivity.onCreate(ListViewActivity.java:57)
01-26 17:12:58.341: E/AndroidRuntime(790):  at android.app.Activity.performCreate(Activity.java:5104)
01-26 17:12:58.341: E/AndroidRuntime(790):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
01-26 17:12:58.341: E/AndroidRuntime(790):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)

Here is the main activity:

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.util.DisplayMetrics;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.animation.Animation;
import android.view.animation.TranslateAnimation;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;
import android.widget.TextView;

public class LayerStack extends Activity {

    //Declare
    private LinearLayout slidingPanel;
    private boolean isExpanded;
    private DisplayMetrics metrics; 
    private WebView webView;
    private RelativeLayout headerPanel;
    private RelativeLayout menuPanel;
    private int panelWidth;
    private ImageView menuViewButton;
    private Button button;
    private TextView menubutton1;

    FrameLayout.LayoutParams menuPanelParameters;
    FrameLayout.LayoutParams slidingPanelParameters;
    LinearLayout.LayoutParams headerPanelParameters ;
    LinearLayout.LayoutParams listViewParameters;


    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_layer_stack);

        //Initialize
        metrics = new DisplayMetrics();
        getWindowManager().getDefaultDisplay().getMetrics(metrics);
        panelWidth = (int) ((metrics.widthPixels)*0.75);

        headerPanel = (RelativeLayout) findViewById(R.id.header);
        headerPanelParameters = (LinearLayout.LayoutParams) headerPanel.getLayoutParams();
        headerPanelParameters.width = metrics.widthPixels;
        headerPanel.setLayoutParams(headerPanelParameters);

        menuPanel = (RelativeLayout) findViewById(R.id.menuPanel);
        menuPanelParameters = (FrameLayout.LayoutParams) menuPanel.getLayoutParams();
        menuPanelParameters.width = panelWidth;
        menuPanel.setLayoutParams(menuPanelParameters);

        slidingPanel = (LinearLayout) findViewById(R.id.slidingPanel);
        slidingPanelParameters = (FrameLayout.LayoutParams) slidingPanel.getLayoutParams();
        slidingPanelParameters.width = metrics.widthPixels;
        slidingPanel.setLayoutParams(slidingPanelParameters);

        menubutton1 = (TextView) findViewById(R.id.menu_item_1);
        menubutton1.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                Intent i = new Intent(getApplicationContext(), ListViewActivity.class);
                startActivity(i);

            }
        });





        webView = (WebView) findViewById(R.id.webView1);
        webView.setWebViewClient(new WebViewClient() {
            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url){
                view.loadUrl(url);
                return true;
            }
        }); 
        webView.loadUrl("http://www.google.com.br");


        button = (Button) findViewById(R.id.button1);
        button.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                Intent i = new Intent(getApplicationContext(), ListViewActivity.class);
                startActivity(i);               
            }
        });

        //Slide the Panel   
        menuViewButton = (ImageView) findViewById(R.id.menuViewButton);
        menuViewButton.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                if(!isExpanded){
                    isExpanded = true;                                              

                    //Expand
                    new ExpandAnimation(slidingPanel, panelWidth,
                    Animation.RELATIVE_TO_SELF, 0.0f,
                    Animation.RELATIVE_TO_SELF, 0.75f, 0, 0.0f, 0, 0.0f);                                       
                }else{
                    isExpanded = false;

                    //Collapse
                    new CollapseAnimation(slidingPanel,panelWidth,
                    TranslateAnimation.RELATIVE_TO_SELF, 0.75f,
                    TranslateAnimation.RELATIVE_TO_SELF, 0.0f, 0, 0.0f, 0, 0.0f);


                }              
            }
        });

    }       
}

And here the list view that I want to open

package com.example.slideoutmenu;

import java.util.ArrayList;
import java.util.HashMap;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.ListActivity;

import android.content.Intent;

import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;

import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;


public class ListViewActivity extends ListActivity {

    // url to make request
    private static String url = "http://api.androidhive.info/contacts/";

    // JSON Node names
    private static final String TAG_CONTACTS = "contacts";
    private static final String TAG_ID = "id";
    private static final String TAG_NAME = "name";
    private static final String TAG_EMAIL = "email";
    private static final String TAG_ADDRESS = "address";
    private static final String TAG_GENDER = "gender";
    private static final String TAG_PHONE = "phone";
    private static final String TAG_PHONE_MOBILE = "mobile";
    private static final String TAG_PHONE_HOME = "home";
    private static final String TAG_PHONE_OFFICE = "office";
    JSONArray contacts = null;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_layer_2);


        ArrayList<HashMap<String, String>> contactList = new ArrayList<HashMap<String, String>>();


        JSONParser jParser = new JSONParser();


        JSONObject json = jParser.getJSONFromUrl(url);

        try {
            contacts = json.getJSONArray(TAG_CONTACTS);


            for(int i = 0; i < contacts.length(); i++){
                JSONObject c = contacts.getJSONObject(i);


                String id = c.getString(TAG_ID);
                String name = c.getString(TAG_NAME);
                String email = c.getString(TAG_EMAIL);
                String address = c.getString(TAG_ADDRESS);
                String gender = c.getString(TAG_GENDER);


                JSONObject phone = c.getJSONObject(TAG_PHONE);
                String mobile = phone.getString(TAG_PHONE_MOBILE);
                String home = phone.getString(TAG_PHONE_HOME);
                String office = phone.getString(TAG_PHONE_OFFICE);


                HashMap<String, String> map = new HashMap<String, String>();


                map.put(TAG_ID, id);
                map.put(TAG_NAME, name);
                map.put(TAG_EMAIL, email);
                map.put(TAG_PHONE_MOBILE, mobile);


                contactList.add(map);
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }


        ListAdapter adapter = new SimpleAdapter(this, contactList,
                R.layout.list_item,
                new String[] { TAG_NAME, TAG_EMAIL, TAG_PHONE_MOBILE }, new int[] {
                        R.id.name, R.id.email, R.id.mobile });

        setListAdapter(adapter);


        ListView lv = getListView();


        lv.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {

                String name = ((TextView) view.findViewById(R.id.name)).getText().toString();
                String cost = ((TextView) view.findViewById(R.id.email)).getText().toString();
                String description = ((TextView) view.findViewById(R.id.mobile)).getText().toString();

                Intent in = new Intent(getApplicationContext(), SingleMenuItemActivity.class);
                in.putExtra(TAG_NAME, name);
                in.putExtra(TAG_EMAIL, cost);
                in.putExtra(TAG_PHONE_MOBILE, description);
                startActivity(in);

            }
        });



    }

}

Answer 1

Caused by: android.os.NetworkOnMainThreadException

You cannot perform network operations on the main Thread in the recent APIs (see NetworkOnMainThreadException ). You need to move the code that fetches your JSON objects to another Thread , perhaps using an AsyncTask .