更改TextView的背景顏色

Question

我想知道如何更改文本視圖的背景，因為我要從網站parse.com提取數據，但是我卻做不到，我想做的就是這樣。

碼

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();
    }
}
}

埃羅

04-30 11：56：59.156 28388-28691 / com.example.ronysueliton.patospizzas E / AndroidRuntime：致命異常：AsyncTask＃2進程：com.example.ronysueliton.patospizzas，PID：28388 java.lang.RuntimeException：錯誤在java.util.concurrent.FutureTask.finishCompletion（FutureTask.java:355）處android.os.AsyncTask $ 3.done（AsyncTask.java:300）處執行doInBackground（）時發生在java.util.concurrent.FutureTask.setException（ FutureTask.java:222），位於java.util.concurrent.FutureTask.run（FutureTask.java:242），位於android.os.AsyncTask $ SerialExecutor $ 1.run（AsyncTask.java:231），位於java.util.concurrent.ThreadPoolExecutor。 java.util.concurrent.ThreadPoolExecutor $ Worker.run（ThreadPoolExecutor.java:587）的java.lang.Thread.run（Thread.java:818）的runWorker（ThreadPoolExecutor.java:1112）原因：java.lang.NullPointerException ：嘗試在com.example.ronysueliton.patospizzas.Pizzarias $ RemoteDataTask.doIn上的空對象引用上調用虛擬方法'void android.widget.TextView.setTextColor（int）' 背景（Pizzarias.java:111）在com.example.ronysueliton.patospizzas.Pizzarias $ RemoteDataTask.doInBackground（Pizzarias.java:78）在android.os.AsyncTask $ 2.call（AsyncTask.java:288）在java.util。 android.os.AsyncTask $ SerialExecutor $ 1.run（AsyncTask.java:231）處的java.util.concurrent.ThreadPoolExecutor.runWorker（ThreadPoolExecutor.java:1112）處並發.FutureTask.run（FutureTask.java:237）。 util.concurrent.ThreadPoolExecutor $ Worker.run（ThreadPoolExecutor.java:587）at java.lang.Thread.run（Thread.java:818）04-30 11：56：59.590 28388-28388 / com.example.ronysueliton.patospizzas E / WindowManager：android.view.WindowLeaked：活動com.example.ronysueliton.patospizzas.Pizzarias泄漏了com.android.internal.policy.impl.PhoneWindow $ DecorView {3dc64751 VE .... R ...... D 0,0-513,248}，最初是在android.view.ViewRootImpl。（ViewRootImpl.java:375）在android.view.WindowManagerGlobal.addView（WindowManagerGlobal.java:261）處添加的 在android.app.Dialog.show（Dialog.java:298）在android.view.WindowManagerImpl.addView（WindowManagerImpl.java:69）在com.example.ronysueliton.patospizzas.Pizzarias $ RemoteDataTask.onPreExecute（Pizzarias.java:90） ）在android.os.AsyncTask.executeOnExecutor（AsyncTask.java:587）在android.os.AsyncTask.execute（AsyncTask.java:535）在com.example.ronysueliton.patospizzas.Pizzarias.onCreate（Pizzarias.java:47）在android.app.Activity.performCreate（Activity.java:5953）在android.app.Instrumentation.callActivityOnCreate（Instrumentation.java:1128）在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2267）在android.app。 android.app.ActivityThread.access $ 800（ActivityThread.java:148）的ActivityThread.handleLaunchActivity（ActivityThread.java:2388）android.app.Activ.Thread的$ H.handleMessage（ActivityThread.java:1292）。 Java的android.app.ActivityThread.main（ActivityThread.java:5312）的android.os.Looper.loop（Looper.java:135）的dispatchMessage（Handler.java:102）。 com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:901）處java.lang.reflect.Method.invoke（Method.java:372）處的lang.reflect.Method.invoke（本機方法） com.android.internal.os.ZygoteInit.main（ZygoteInit.java:696）04-30 12：01：59.260 28388-28691 / com.example.ronysueliton.patospizzas I / Process：發送信號。 PID：28388 SIG：9

有人可以幫忙嗎？

Answer 1

看起來您正在嘗試在后台線程上處理UI元素。 您的變量status在doInBackground()將為null。 設置這些顏色將需要在onPostExecute()或調用runOnUiThread(Runnable action) 。