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java.lang.runtimeExeception无法启动活动组件信息

jsoup android java

Shiam Kannan · 技术社区 · 10 年前

package com.pollapp.presidentialelectionpolls;

import java.io.IOException;
import java.util.ArrayList;

import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;

import android.os.Bundle;
import android.os.StrictMode;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.view.Menu;
import android.widget.ArrayAdapter;
import android.widget.ListView;

@SuppressLint("NewApi")

public class MainActivity extends Activity {

Document doc;
Element table;
Elements rows;
ListView dispData;
ArrayList<String> nameOfSrc = new ArrayList<String>();
ArrayList<String> dateWidth = new ArrayList<String>();
ArrayList<String> Trump = new ArrayList<String>();
ArrayList<String> Clinton = new ArrayList<String>();

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    dispData = (ListView) findViewById(R.id.listView1);
    StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
            .permitAll().build();
    StrictMode.setThreadPolicy(policy);

    try {
        doc = Jsoup
                .connect(
                        "http://www.realclearpolitics.com/epolls/2016/president/us/general_election_trump_vs_clinton-5491.html")
                .get();
    } catch (IOException e) {
        e.printStackTrace();
    }

    table = doc.select("table").get(1);
    rows = table.select("tr");

    for (int i = 2; i < rows.size(); i++) { 
        Element row = rows.get(i);
        Elements cols = row.select("td");
        nameOfSrc.add(cols.get(0).text());
        dateWidth.add(cols.get(1).text());
        Trump.add(cols.get(4).text());
        Clinton.add(cols.get(5).text());
    }

    ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this,
            android.R.layout.simple_list_item_1, Trump);
    dispData.setAdapter(arrayAdapter);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}
}

这是我的日志信息:

08-10 06:42:13.999: E/AndroidRuntime(1748): FATAL EXCEPTION: main
08-10 06:42:13.999: E/AndroidRuntime(1748): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.pollapp.presidentialelectionpolls/com.pollapp.presidentialelectionpolls.MainActivity}: java.lang.NullPointerException
08-10 06:42:13.999: E/AndroidRuntime(1748):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
08-10 06:42:13.999: E/AndroidRuntime(1748):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
08-10 06:42:13.999: E/AndroidRuntime(1748):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
08-10 06:42:13.999: E/AndroidRuntime(1748):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
08-10 06:42:13.999: E/AndroidRuntime(1748):     at android.os.Handler.dispatchMessage(Handler.java:99)
08-10 06:42:13.999: E/AndroidRuntime(1748):     at android.os.Looper.loop(Looper.java:137)
08-10 06:42:13.999: E/AndroidRuntime(1748):     at android.app.ActivityThread.main(ActivityThread.java:5103)
08-10 06:42:13.999: E/AndroidRuntime(1748):     at java.lang.reflect.Method.invokeNative(Native Method)
08-10 06:42:13.999: E/AndroidRuntime(1748):     at java.lang.reflect.Method.invoke(Method.java:525)
08-10 06:42:13.999: E/AndroidRuntime(1748):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
08-10 06:42:13.999: E/AndroidRuntime(1748):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
08-10 06:42:13.999: E/AndroidRuntime(1748):     at dalvik.system.NativeStart.main(Native Method)
08-10 06:42:13.999: E/AndroidRuntime(1748): Caused by: java.lang.NullPointerException
08-10 06:42:13.999: E/AndroidRuntime(1748):     at com.pollapp.presidentialelectionpolls.MainActivity.onCreate(MainActivity.java:50)
08-10 06:42:13.999: E/AndroidRuntime(1748):     at android.app.Activity.performCreate(Activity.java:5133)
08-10 06:42:13.999: E/AndroidRuntime(1748):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
08-10 06:42:13.999: E/AndroidRuntime(1748):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
08-10 06:42:13.999: E/AndroidRuntime(1748):     ... 11 more

2 回复 | 直到 10 年前

Frederic Klein neocanable 10 年前

您使用了错误的表(边上有四个,而不是假设的两个),导致中只有两个条目 rows .

尝试:

table = doc.select("table.data.large").get(1);

我还建议核实 doc

Andrik007 10 年前

变量文档等于null。这可能是因为:

错误的url

试试这个

try{
    ConnectivityManager cm = (ConnectivityManager)this.getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo ni = cm.getActiveNetworkInfo();
    Boolean isConnect = ni == null ? false : ni.isConnectedOrConnecting();
    if(isConnect){
        doc = Jsoup
                    .connect("http://www.realclearpolitics.com/epolls/2016/president/us/general_election_trump_vs_clinton-5491.html")
                    .get();
    }
} catch(IOException ioe){
    ioe.printStackTrace();
}