在使用后台线程进行活动后，应用程序崩溃

时间：2015-11-03 17:20:54

标签： java android json android-intent

我现在已经有一整天这个问题了。我创建了一个应用程序，它使用JSON从我的服务器获取数据并将其转换并在应用程序中显示。我把它作为一个单独的工作应用程序，只有一个活动。下一步是创建一个使用多个活动的应用程序。我创建了一个带有按钮的主屏幕，该按钮旨在实现与其他应用程序相同的活动。当我打开应用程序时一切正常，但当我打算到另一个（Recepten）屏幕时，应用程序崩溃了。我想这是因为它没有在ui线程上运行，但我无法弄清楚..如果有人可以帮助我，那就太棒了！非常感谢。

错误 

11-03 18:03:35.460    6159-6235/me.janvandijk.receptenapp E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #1
Process: me.janvandijk.receptenapp, PID: 6159
java.lang.RuntimeException: An error occured while executing doInBackground()
        at android.os.AsyncTask$3.done(AsyncTask.java:304)
        at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
        at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
        at java.util.concurrent.FutureTask.run(FutureTask.java:242)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
        at java.lang.Thread.run(Thread.java:818)
Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
        at android.os.Handler.<init>(Handler.java:200)
        at android.os.Handler.<init>(Handler.java:114)
        at android.app.Activity.<init>(Activity.java:794)
        at me.janvandijk.receptenapp.Recepten.<init>(Recepten.java:24)
        at me.janvandijk.receptenapp.ReceptenDefine.<init>(ReceptenDefine.java:12)
        at me.janvandijk.receptenapp.Recepten$ReceptenAsynTask.doInBackground(Recepten.java:60)
        at me.janvandijk.receptenapp.Recepten$ReceptenAsynTask.doInBackground(Recepten.java:42)
        at android.os.AsyncTask$2.call(AsyncTask.java:292)
        at java.util.concurrent.FutureTask.run(FutureTask.java:237)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
        at java.lang.Thread.run(Thread.java:818)

JSON： 

[{"id":"1",
    "naam":"Bastogneparfait a la Kim",
    "beschrijving":"Gemaakt van Bastogne, het lekkerste gerecht ooit!",
    "ingredienten":"Bastogne parfait ingredi\u00ebnten\r\n40 gram eierdooiers (gepasteuriseerd)\r\n45 gram hele eieren (gepasteuriseerd)\r\n100 gram suiker \r\n2,5 dl slagroom ongezoet\r\n4  bastognekoeken \r\nKaralmelsaus ingredi\u00ebnten\r\n100 gram suiker \r\n2 dl koksroom ",
    "bereiding":"Slagroom opkloppen tot yoghurt dikte. De eidooiers, hele eieren en suiker in een bekken doen en au bain-marie verwarmen tot 37 graden Celsius. Koud kloppen in de keukenmachine tot een luchtige massa. Spatel de massa door de slagroom. Kruimel de bastognekoeken en spatel ze voorzichtig door de massa. Vul de vormpjes en zet in diepvries.\nBereidingswijze karamelsaus\nDoe de suiker in een pan en verwarm de suiker tot deze is gekaramelliseerd. Haal de pan van het vuur en voeg de koksroom toe. Laat de karamel goed oplossen in de koksroom regelmatig roeren. Als de massa glad is af laten koelen.\nOpdienen\nHaal de parfait uit de vorm en leg in een tapasschaaltje. Doe er karamelsaus bij en een toefje slagroom op de parfait. Eventueel af garneren met een takje mint.",
    "auteur":"3",
    "timestamp":"2015-10-22 14:42:14"},
{"id":"2",
    "naam":"Vlindertjes met kip, spekjes en roomsaus",
    "beschrijving":"Lekker lekker!",
    "ingredienten":"Een beetje liefde\r\nEen beetje kip\r\nEen beetje spekjes\r\nEen beetje kruidenshit\r\nEen beetje creeemeee freeescheee\r\nEn vlindertjes",
    "bereiding":"In pan hop klaar!",
    "auteur":"1",
    "timestamp":"2015-11-02 09:50:54"}]

公共类主页扩展活动 

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

public void showReceptenScherm(View view){
    Intent intent = new Intent(Home.this, Recepten.class);
    startActivity(intent);
}

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

public void onRadioButtonClicked(View view) {
    Toast.makeText(getApplicationContext(), "Sending your vote..", Toast.LENGTH_LONG).show();


}

接收活动 

    ListView list;
ReceptenAdapter adapter;
ArrayList<ReceptenDefine> receptenList;

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

    list = (ListView)findViewById(R.id.receptenList);
    receptenList = new ArrayList<>();

    new ReceptenAsynTask().execute("http://janvandijk.me/zooi/receptenapp/getrecipes.php?type=request&datatype=recepten");
}


public class ReceptenAsynTask extends AsyncTask<String, Void, Boolean> {

    @Override
    protected Boolean doInBackground(String... params) {
        try {
            HttpClient client = new SystemDefaultHttpClient();
            HttpPost post = new HttpPost(params[0]);
            HttpResponse response = client.execute(post);

            int status = response.getStatusLine().getStatusCode();

            if (status == 200){
                HttpEntity entity = response.getEntity();
                String data = EntityUtils.toString(entity);

                JSONArray jArray = new JSONArray(data); //jArray.length()
                for (int i=0; i<jArray.length(); i++){
                    ReceptenDefine recept;
                    recept = new ReceptenDefine();

                    JSONObject jRealObject = jArray.getJSONObject(i);

                    recept.setReceptnaam(jRealObject.getString("naam"));
                    recept.setReceptauthor(jRealObject.getString("id"));
                    recept.setReceptimageurl("http://www.crossfitswarm.com/wp-content/uploads/2013/03/food-photo-200x200.png");
                    recept.setReceptrating(jRealObject.getString("ingredienten"));

                    receptenList.add(recept);

                }
                return true;


            }

        } catch (JSONException | IOException e) {
            e.printStackTrace();
        }
        return false;
    }

    @Override
    protected void onPostExecute(Boolean result){
        super.onPostExecute(result);

        if(!result){
            //Show message that data wasn't parsed
        } else {
            ReceptenAdapter adapter = new ReceptenAdapter(getApplicationContext(), R.layout.row, receptenList);
            list.setAdapter(adapter);
        }



    }
}

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

    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {

        return true;
    }

    return super.onOptionsItemSelected(item);
}

ReceptenDefine 

public class ReceptenDefine extends Recepten {
private String receptnaam;
private String receptauthor;
private String receptimageurl;
private String receptrating;

public ReceptenDefine(){

}

public String getReceptnaam() {
    return receptnaam;
}

public void setReceptnaam(String receptnaam) {
    this.receptnaam = receptnaam;
}

public String getReceptauthor() {
    return receptauthor;
}

public void setReceptauthor(String receptauthor) {
    this.receptauthor = receptauthor;
}

public String getReceptimageurl() {
    return receptimageurl;
}

public void setReceptimageurl(String receptimageurl) {
    this.receptimageurl = receptimageurl;
}

public String getReceptrating() {
    return receptrating;
}

public void setReceptrating(String receptrating) {
    this.receptrating = receptrating;
}

ReceptenAdapter 

public class ReceptenAdapter extends ArrayAdapter<ReceptenDefine>{

ArrayList<ReceptenDefine> ArrayListRecepten;
int Resource;
Context context;
LayoutInflater vi;


public ReceptenAdapter(Context context, int resource, ArrayList<ReceptenDefine> objects) {
    super(context, resource, objects);

    ArrayListRecepten = objects;
    Resource = resource;
    this.context = context;

    vi = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); //Verschillende items laten zien

}

@Override
public View getView(int position, View convertView, ViewGroup parent) {

    ViewHolder holder;

    if(convertView == null){
        //Eerste listview item wordt gemaakt
        convertView = vi.inflate(Resource, null);
        holder = new ViewHolder();

        //Set all textview and imageview dingen



        holder.listImage = (ImageView)convertView.findViewById(R.id.listImage);
        holder.listAuthor = (TextView)convertView.findViewById(R.id.listAuthor);
        holder.listName = (TextView)convertView.findViewById(R.id.listName);
        holder.listRating = (TextView)convertView.findViewById(R.id.listRating);

        //Zet het neer
        convertView.setTag(holder);
    } else {
        //volgende list items, doe alles opnieuw zetten
        holder = (ViewHolder)convertView.getTag();
    }

    new DownloadImageTask(holder.listImage).execute(ArrayListRecepten.get(position).getReceptimageurl());
    holder.listName.setText(ArrayListRecepten.get(position).getReceptnaam());
    holder.listAuthor.setText(ArrayListRecepten.get(position).getReceptauthor());
    holder.listRating.setText(ArrayListRecepten.get(position).getReceptrating());
    return convertView;
}

static class ViewHolder {
    public ImageView listImage;
    public TextView listName;
    public TextView listAuthor;
    public TextView listRating;
}

private class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
    ImageView bmImage;

    public DownloadImageTask(ImageView bmImage) {
        this.bmImage = bmImage;
    }
    protected Bitmap doInBackground(String... urls) {
        String urldisplay = urls[0];
        Bitmap mIcon = null;
        try {
            InputStream in = new java.net.URL(urldisplay).openStream();
            mIcon = BitmapFactory.decodeStream(in);
        } catch (Exception e) {
            Log.e("Error", e.getMessage());
            e.printStackTrace();
        }
        return mIcon;
    }

    protected void onPostExecute(Bitmap result) {
        bmImage.setImageBitmap(result);
    }
}

}

1 个答案:

答案 0 :(得分：0)

下面：

user_id
latest (nullable , integer)
recommend (nullable , integer)
follow (nullable , integer)
history (nullable , integer)
most_view (nullable , integer)

在导致问题的public class ReceptenDefine extends Recepten { ... ^^^^^^ } 类中扩展Recepten的{​​{1}}的子类。

因为Activity类只包含getter-setter方法，所以不需要为此类扩展ReceptenDefine或ReceptenDefine类。只需将它作为普通类使用。

要修复问题，请从Activity类扩展：

Recepten
相关问题
最新问题