java - 无法启动 Activity ComponentInfo

Question

我正在尝试将其作为我的主要 Activity 以打开另一个 Activity (ListAtivity)。但是，当我单击按钮时，应用程序崩溃并出现以下异常:

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)

这是主要 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);


                }              
            }
        });

    }       
}

这里是我要打开的 ListView

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在最近的 API 中(参见 NetworkOnMainThreadException)。您需要将获取 JSON 对象的代码移动到另一个 Thread ，也许使用 AsyncTask .