尝试在空对象引用上调用虚方法'java.lang.String org.jsoup.nodes.Element.ownText()'

Question

我使用下面的代码通过使用jsoup 从playstore获取versionName我正在获取详细信息,但它抛出了一些异常.

我的代码是

public class ForceUpdateAsync extends AsyncTask<String, String, JSONObject>{

private String latestVersion;
private String currentVersion;
private Context context;
public ForceUpdateAsync(String currentVersion, Context context){
    this.currentVersion = currentVersion;
    this.context = context;
}

@Override
protected JSONObject doInBackground(String... params) {

    try {
         latestVersion = Jsoup.connect("https://play.google.com/store/apps/details?id="+context.getPackageName()+"&hl=en")
                .timeout(30000)
                .userAgent("Mozilla/5.0 (Windows; U; WindowsNT 5.1; en-US; rv1.8.1.6) Gecko/20070725 Firefox/2.0.0.6")
                .referrer("http://www.google.com")
                .get()
                .select("div[itemprop=softwareVersion]")
                .first()
                 .ownText();

    } catch (IOException e) {
        e.printStackTrace();
    }
    return new JSONObject();
}

@Override
protected void onPostExecute(JSONObject jsonObject) {
    if(latestVersion!=null){
        if(!currentVersion.equalsIgnoreCase(latestVersion)){
           // Toast.makeText(context,"update is available.",Toast.LENGTH_LONG).show();
            if(!(context instanceof SplashActivity)) {
                if(!((Activity)context).isFinishing()){
                    showForceUpdateDialog();
                }
            }
        }
    }
    super.onPostExecute(jsonObject);
}

public void showForceUpdateDialog(){
    AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(new ContextThemeWrapper(context,
            R.style.DialogDark));

    alertDialogBuilder.setTitle(context.getString(R.string.youAreNotUpdatedTitle));
    alertDialogBuilder.setMessage(context.getString(R.string.youAreNotUpdatedMessage) + " " + latestVersion + context.getString(R.string.youAreNotUpdatedMessage1));
    alertDialogBuilder.setCancelable(false);
    alertDialogBuilder.setPositiveButton(R.string.update, new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int id) {
            context.startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("market://details?id=" + context.getPackageName())));
            dialog.cancel();
        }
    });
    alertDialogBuilder.show();
}
}

但我得到空指针异常错误

致命异常:的AsyncTask#1的方法:com.yabeee.yabeee,PID:15893了java.lang.RuntimeException:而在java的在android.os.AsyncTask $ 3.done(AsyncTask.java:304)执行doInBackground()发生错误. util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)在java.util.concurrent.FutureTask.setException(FutureTask.java:222)在java.util.concurrent.FutureTask.run(FutureTask.java:242)在安卓.os.AsyncTask $ SerialExecutor $ 1.run(AsyncTask.java:231)在java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)在java.util.concurrent.ThreadPoolExecutor中的$ Worker.run(ThreadPoolExecutor.java: 587)at java.lang.Thread.run(Thread.java:818)引起:java.lang.NullPointerException:尝试调用虚方法'java.lang.String org.jsoup.nodes.Element.ownText()'on在com.yabeee.yabeee.ModelClasses.ForceUpdateAsync.doInBackground(ForceUpdateAsync.java:53)在com.yabeee.yabeee.ModelClasses.ForceUpdateAsync.doInBackground(ForceUpdateAsy空对象引用 nc.java:28)在android.os.AsyncTask $在2.call(AsyncTask.java:292)在java.util.concurrent.FutureTask.run(FutureTask.java:237)android.os.AsyncTask $ SerialExecutor $ 1.run (AsyncTask.java:231)在java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)在java.util.concurrent.ThreadPoolExecutor中的$ Worker.run(ThreadPoolExecutor.java:587)在java.lang.Thread中.运行(Thread.java:818)

请有人帮我解决这个问题.

Answer 1

使用更新的代码:

 newVersion = Jsoup.connect("https://play.google.com/store/apps/details?id=" + mCom.getPackageName()+ "&hl=en")
                            .timeout(30000)
                            .userAgent("Mozilla/5.0 (Windows; U; WindowsNT 5.1; en-US; rv1.8.1.6) Gecko/20070725 Firefox/2.0.0.6")
                            .referrer("http://www.google.com")
                            .get()
                            .select("div.hAyfc:nth-child(4) > span:nth-child(2) > div:nth-child(1) > span:nth-child(1)")
                            .first()
                            .ownText();

Answer 2

我使用了相同的代码，也得到了相同的错误。我通过网络开发人员的帮助解决了这个错误，以便更好地理解谷歌游戏商店更新的代码。使用下面的代码工作正常（代码更新于 10/08/2018）

公共类 ForceUpdateAsync 扩展 AsyncTask {

    private String latestVersion;
    private String currentVersion;
    private Context context;
    public ForceUpdateAsync(String currentVersion, Context context){
        this.currentVersion = currentVersion;
        this.context = context;
    }

    @Override
    protected JSONObject doInBackground(String... params) {

        try {
            latestVersion = Jsoup.connect("https://play.google.com/store/apps/details?id=" + context.getPackageName()+ "&hl=en")
                    .timeout(30000)
                    .userAgent("Mozilla/5.0 (Windows; U; WindowsNT 5.1; en-US; rv1.8.1.6) Gecko/20070725 Firefox/2.0.0.6")
                    .referrer("http://www.google.com")
                    .get()
                    .select("div.hAyfc:nth-child(4) > span:nth-child(2) > div:nth-child(1) > span:nth-child(1)")
                    .first()
                    .ownText();
            Log.e("latestversion","---"+latestVersion);

        } catch (IOException e) {
            e.printStackTrace();
        }
        return new JSONObject();
    }

    @Override
    protected void onPostExecute(JSONObject jsonObject) {
        if(latestVersion!=null){
            if(!currentVersion.equalsIgnoreCase(latestVersion)){
                // Toast.makeText(context,"update is available.",Toast.LENGTH_LONG).show();
                if(!(context instanceof SplashActivity)) {
                    if(!((Activity)context).isFinishing()){
                        showForceUpdateDialog();
                    }
                }
            }
        }
        super.onPostExecute(jsonObject);
    }

    public void showForceUpdateDialog(){

        context.startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("market://details?id=" + context.getPackageName())));
    }

}