更改文本视图的背景色

Question

我想知道如何更改文本视图的背景，因为我正在从站点解析中提取数据。com，但我不能这样做，我正在尝试这样做。

代码

public class Pizzarias extends ActionBarActivity {

// Declare Variables
Boolean bColorStatus = true;
TextView status;
ListView listview;
List<ParseObject> ob;
ProgressDialog mProgressDialog;
ListViewAdapterPizzarias adapter;
private List<WorldPopulation> worldpopulationlist = null;

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


    new RemoteDataTask().execute();
    //getSupportActionBar().setDisplayHomeAsUpEnabled(true);

    status = (TextView) findViewById(R.id.status);
   // status.setBackgroundColor(Color.BLUE);


}

@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_pizzarias, menu);

    //Os metodos abaixo são para mostrar o icone do aplicativo na action bar
    getSupportActionBar().setDisplayShowHomeEnabled(true);
    getSupportActionBar().setLogo(R.drawable.ic_launcher);
    getSupportActionBar().setDisplayUseLogoEnabled(true);

    return true;
}


/*@Override
public boolean onOptionsItemSelected(MenuItem item) {
    onBackPressed();
    return true;
}*/


//RemoteDataTask AsyncTask
private class RemoteDataTask extends AsyncTask<Void, Void, Void> {
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        // Create a progressdialog
        mProgressDialog = new ProgressDialog(Pizzarias.this);
        // Set progressdialog title
        mProgressDialog.setTitle("Carregando Pizzarias");
        // Set progressdialog message
        mProgressDialog.setMessage("Aguarde...");
        mProgressDialog.setIndeterminate(false);
        // Show progressdialog
        mProgressDialog.show();
    }

    @Override
    protected Void doInBackground(Void... params) {
        // Create the array
        worldpopulationlist = new ArrayList<WorldPopulation>();
        try {
            // Locate the class table named "Country" in Parse.com
            ParseQuery<ParseObject> query = new ParseQuery<ParseObject>(
                    "GerenciarPizzariasPatos");
            // Locate the column named "ranknum" in Parse.com and order list
            // by ascending,


//here is the implementation to search for the word "closed" and change the background color.
            query.whereStartsWith ( "status" , "fechado" );
            ob = query.find();
            if(query.equals("fechado")){
                status.setTextColor(getResources().getColor(R.color.red));
                bColorStatus = false;
            }
            else {
                status.setTextColor(getResources().getColor(R.color.green));
                bColorStatus = true;
            }

            query.orderByAscending("nome");
            query.equals("status");
            ob = query.find();
            for (ParseObject country : ob) {
                WorldPopulation map = new WorldPopulation();
                map.setNome((String) country.get("nome"));
                map.setEndereco((String) country.get("endereco"));
                map.setTelefone((String) country.get("telefone"));
                map.setStatus((String) country.get("status"));
                worldpopulationlist.add(map);
            }
        } catch (ParseException e) {
            Log.e("Error", e.getMessage());
            e.printStackTrace();
        }
        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        // Locate the listview in listview_main.xml
        listview = (ListView) findViewById(R.id.listviewpizzarias);
        // Pass the results into ListViewAdapter.java
        adapter = new ListViewAdapterPizzarias(Pizzarias.this,
                worldpopulationlist);
        // Binds the Adapter to the ListView
        listview.setAdapter(adapter);
        // Close the progressdialog
        mProgressDialog.dismiss();
    }
}
}

错误

04-30 11:56:59.156 28388-28691/com。实例ronysueliton。patospizzas E/AndroidRuntime﹕ 致命异常：AsyncTask#2进程：com。实例ronysueliton。patospizzas，PID:28388爪哇。lang.RuntimeException：在android上执行doInBackground（）时出错。操作系统。异步任务3美元。在java上完成（AsyncTask.java:300）。util。同时发生的未来任务。在java完成（FutureTask.java:355）。util。同时发生的未来任务。java上的setException（FutureTask.java:222）。util。同时发生的未来任务。在android上运行（FutureTask.java:242）。操作系统。AsyncTask$SerialExecutor$1。在java上运行（AsyncTask.java:231）。util。同时发生的线程池执行器。java上的runWorker（ThreadPoolExecutor.java:1112）。util。同时发生的ThreadPoolExecutor$工作者。在java上运行（ThreadPoolExecutor.java:587）。lang.Thread。运行（Thread.java:818）由：java引起。lang.NullPointerException：尝试调用虚拟方法“void android”。小装置。文本视图。com上的空对象引用上的setTextColor（int）“”。实例ronysueliton。帕托斯皮萨斯。Pizzarias$RemoteDataTask。com上的doInBackground（Pizzarias.java:111）。实例ronysueliton。帕托斯皮萨斯。Pizzarias$RemoteDataTask。android上的doInBackground（Pizzarias.java:78）。操作系统。异步任务2美元。在java上调用（AsyncTask.java:288）。util。同时发生的未来任务。运行（FutureTask.java:237）

有人能帮忙吗？

Answer 1

看起来您正在尝试在后台线程上处理UI元素。在doInBackground（）中，变量的状态将为空。需要在onPostExecute（）中设置这些颜色，或者调用RunUnuithRead（Runnable操作）。