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当我尝试使用以下代码在程序中设置评分栏的评分（从远程数据库检索）时，我收到如下所示的错误...

  09-18 19:57:16.858: D/dalvikvm(1411): GC_CONCURRENT freed 43K, 7% free 2775K/2960K, paused 16ms+21ms, total 134ms
  09-18 19:57:17.057: I/Choreographer(1411): Skipped 40 frames!  The application may be doing too much work on its main thread.
  09-18 19:57:17.077: D/gralloc_goldfish(1411): Emulator without GPU emulation detected.
  09-18 19:57:21.146: D/dalvikvm(1411): GC_CONCURRENT freed 20K, 5% free 3211K/3376K, paused 73ms+6ms, total 260ms
  09-18 19:57:21.737: D/dalvikvm(1411): GC_FOR_ALLOC freed 361K, 15% free 3032K/3540K, paused 167ms, total 196ms
  09-18 19:57:21.776: I/dalvikvm-heap(1411): Grow heap (frag case) to 3.940MB for 883132-byte allocation
  09-18 19:57:21.976: D/dalvikvm(1411): GC_FOR_ALLOC freed 1K, 12% free 3894K/4404K, paused 204ms, total 206ms
  09-18 19:57:22.146: D/dalvikvm(1411): GC_CONCURRENT freed <1K, 12% free 3893K/4404K, paused 8ms+29ms, total 170ms
  09-18 19:57:22.146: D/dalvikvm(1411): WAIT_FOR_CONCURRENT_GC blocked 94ms
  09-18 19:57:22.156: I/dalvikvm-heap(1411): Grow heap (frag case) to 4.313MB for 392920-byte allocation
  09-18 19:57:22.316: D/dalvikvm(1411): GC_FOR_ALLOC freed <1K, 11% free 4277K/4788K, paused 154ms, total 154ms
  09-18 19:57:25.196: E/demo(1411): {"success":1,"product":[{"site_name":"Lynda","rating":"3.00"}]}
  09-18 19:57:25.297: D/Rating(1411): {"product":[{"site_name":"Lynda","rating":"3.00"}],"success":1}
  09-18 19:57:25.306: D/AndroidRuntime(1411): Shutting down VM
  09-18 19:57:25.306: W/dalvikvm(1411): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
  09-18 19:57:25.526: E/AndroidRuntime(1411): FATAL EXCEPTION: main
  09-18 19:57:25.526: E/AndroidRuntime(1411): java.lang.NullPointerException
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at com.khizer.myproject.online_tut$MyAdapter.getView(online_tut.java:106)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.widget.AbsListView.obtainView(AbsListView.java:2159)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.widget.ListView.measureHeightOfChildren(ListView.java:1246)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.widget.ListView.onMeasure(ListView.java:1158)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.view.View.measure(View.java:15518)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.widget.RelativeLayout.measureChild(RelativeLayout.java:666)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:477)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.view.View.measure(View.java:15518)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4825)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.view.View.measure(View.java:15518)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.widget.LinearLayout.measureVertical(LinearLayout.java:847)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.view.View.measure(View.java:15518)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4825)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2176)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.view.View.measure(View.java:15518)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1874)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1089)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1265)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:989)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4351)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.view.Choreographer.doCallbacks(Choreographer.java:562)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.view.Choreographer.doFrame(Choreographer.java:532)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.os.Handler.handleCallback(Handler.java:725)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.os.Handler.dispatchMessage(Handler.java:92)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.os.Looper.loop(Looper.java:137)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at android.app.ActivityThread.main(ActivityThread.java:5041)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at java.lang.reflect.Method.invokeNative(Native Method)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at java.lang.reflect.Method.invoke(Method.java:511)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
  09-18 19:57:25.526: E/AndroidRuntime(1411):   at dalvik.system.NativeStart.main(Native Method)
  09-18 19:57:28.536: I/Process(1411): Sending signal. PID: 1411 SIG: 9

我正在使用列表视图来显示提供在线教程的站点的名称以及评分。日志提到错误在第 106 行，第 106 行是此行之后的行

String f=new GetRating().execute("Lynda").get();

即（下面的行是第106行）

rbs.setRating(Float.parseFloat(f));

这是完整的代码...

package com.khizer.myproject;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutionException;

import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.ListActivity;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;

import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.RatingBar;
import android.widget.TextView;



public class online_tut extends ListActivity {


//   ProgressDialog pDialog;
final JSONParser jsonParser = new JSONParser();
final String url_get_rating = "http://192.168.1.4/webguide/getrating.php";
final String TAG_SUCCESS = "success";
final String TAG_RATE = "rating";
String TAG_SITE="site_name";
String TAG_PRODUCT = "product";


protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.online_tut);

setListAdapter(new MyAdapter
(this, android.R.layout.simple_list_item_1,R.id.ot_custlist_textview1,
        getResources().getStringArray(R.array.online_tutorials_menu)));
}
private class MyAdapter extends ArrayAdapter<String>
{

    public MyAdapter(Context context,int resource,
            int textViewResourceId,String[] strings){

        super(context,resource,textViewResourceId,strings);

    }

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {
        LayoutInflater infalter= (LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);
        View row=infalter.inflate(R.layout.online_tut_menu, parent, false);
        final String[] items= getResources().getStringArray(R.array.online_tutorials_menu);

        RatingBar rbs=(RatingBar) findViewById(R.id.ratingbar_Small);
        ImageView iv= (ImageView) row.findViewById(R.id.imageView1);
        TextView tv=(TextView) row.findViewById(R.id.ot_info_head);
        ImageView iv1=(ImageView) row.findViewById(R.id.image_info);
        TextView tv1= (TextView) findViewById(R.id.rating_text);
        tv.setText(items[position]);


        iv1.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                Intent in=new Intent(online_tut.this,Info.class);
                if(items[position].equals("Lynda"))
                {
                    in.putExtra("name","Lynda");
                }
                else if(items[position].equals("My Bring Back"))
                {
                    in.putExtra("name","My Bring Back");
                }else if(items[position].equals("New Boston"))
                {
                    in.putExtra("name","New Boston");
                }else if(items[position].equals("NPTEL"))
                {
                    in.putExtra("name","NPTEL");
                }
                startActivity(new Intent(in));

            }
        });

        if(items[position].equals("Lynda"))
        {
            iv.setImageResource(R.drawable.lynda);
            try {

                String f=new GetRating().execute("Lynda").get();
                rbs.setRating(Float.parseFloat(f));
            } catch (InterruptedException e) {
                Log.d("khizer","IEX");
                e.printStackTrace();
            } catch (ExecutionException e) {
                Log.d("khzer","khzier");
                e.printStackTrace();
            }

            }
        else if(items[position].equals("My Bring Back"))
        {
            iv.setImageResource(R.drawable.grey);

                try {
                    String f=new GetRating().execute("My Bring Back").get();
                    tv1.setText(f);
                    rbs.setRating(Float.parseFloat(f));
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (ExecutionException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }


        }
        else if(items[position].equals("New Boston"))
        {
            iv.setImageResource(R.drawable.grey);
            try {

                String f=new GetRating().execute("New Boston").get();
                tv1.setText(f);
                rbs.setRating(Float.parseFloat(f));
            } catch (InterruptedException e) {
                Log.d("khizer","IEX");
                e.printStackTrace();
            } catch (ExecutionException e) {
                Log.d("khzer","khzier");
                e.printStackTrace();
            }
        }
        else if(items[position].equals("NPTEL"))
        {
            iv.setImageResource(R.drawable.grey);
            try {
                String f=new GetRating().execute("NPTEL").get();
                tv1.setText(f);
                rbs.setRating(Float.parseFloat(f));
            } catch (InterruptedException e) {
                Log.d("khizer","IEX");
                e.printStackTrace();
            } catch (ExecutionException e) {
                Log.d("khzer","khzier");
                e.printStackTrace();
            }
        }
        return row;
    }
}
class GetRating extends AsyncTask<String,String,String>{

    /* @Override
        protected void onPreExecute() {
            super.onPreExecute();
            //pDialog = new ProgressDialog(Rating.this);
            pDialog.setMessage("Populating list");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();
        }*/

    @Override
    protected String doInBackground(String... arg) {
        int success;
        String f=null;

           try {         
                List<NameValuePair> params = new ArrayList<NameValuePair>();
                    params.add(new BasicNameValuePair("site_name",arg[0]));
                    JSONObject json = jsonParser.makeHttpRequest(
                                   url_get_rating, "GET", params);
                   // TAG_SITE=arg[0];
                    Log.d("Rating", json.toString());
                    success = json.getInt(TAG_SUCCESS);
                    if (success == 1) {
                    JSONArray productObj = json
                                       .getJSONArray(TAG_PRODUCT); 
                    JSONObject product = productObj.getJSONObject(0);

                     f=product.getString(TAG_RATE);

                           }
                    else{
                               Log.d("Rating","Site Not Found");
                           }
                       }catch (JSONException e) {
                           e.printStackTrace();
                       }
        return f;

    }

    //protected void onPostExecute(String file_url) {
      // cancel(true);
     //}

}


}

以下是 xml 文件： 1) 对于列表视图...

 <?xml version="1.0" encoding="utf-8"?>

<RelativeLayout android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" 
xmlns:android="http://schemas.android.com/apk/res/android">

<TextView
    android:id="@+id/ot_custlist_textview1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:gravity="center"
    android:paddingTop="5dp"
    android:text="@string/ot_head"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:textSize="25sp" />

<ListView
    android:id="@android:id/list"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_below="@+id/ot_custlist_textview1"
    android:clipChildren="true" >

</ListView>

</RelativeLayout>

2）列表项的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="70dp"
android:orientation="horizontal" >

<ImageView
    android:id="@+id/imageView1"
    android:layout_width="70dp"
    android:layout_height="70dp"
    android:contentDescription="@string/logo"
    android:src="@drawable/lynda" />

<include
    android:layout_width="0dp"
    android:layout_height="70dp"
    android:layout_weight="1.75"
    layout="@layout/star" />

<ImageView
    android:id="@+id/image_info"
    android:layout_width="70dp"
    android:layout_height="70dp"
    android:contentDescription="@string/ot_info_image"
    android:paddingBottom="15dp"
    android:paddingLeft="15dp"
    android:paddingRight="15dp"
    android:paddingTop="15dp"
    android:src="@drawable/info" />

</LinearLayout>

使用的其他xml是...

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<TextView
    android:id="@+id/ot_info_head"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true"
    android:gravity="center|left"
    android:paddingBottom="2dp"
    android:paddingLeft="10dp"
    android:paddingTop="10dp"
    android:text="Large Text"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:textSize="23sp" />

<RatingBar
    android:id="@+id/ratingbar_Small"
    style="?android:attr/ratingBarStyleSmall"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/ot_info_head"
    android:layout_marginLeft="10dp"
    android:minHeight="14dp"
    android:numStars="5"
    android:paddingTop="4dp" />

<TextView
    android:id="@+id/rating_text"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignTop="@+id/ratingbar_Small"
    android:layout_toRightOf="@+id/ratingbar_Small"
    android:paddingLeft="3dp"
    android:paddingTop="2dp"
    android:text="Small Text"
    android:textAppearance="?android:attr/textAppearanceSmall" />

 </RelativeLayout>
4

1 回答 1

2

您的 tv1 和 rbs 丢失了行row.findViewById()，我认为这就是为什么您在尝试在 rbs 上设置 raiting 时获得空指针的原因。您还应该获得 tv1 的空指针 :)

或者你甚至没有膨胀包含这两个视图的视图。

于 2013-09-18T21:00:48.327 回答