機器人：錯誤裝載上一個的LinearLayout

Question

我試圖加載一個背景到的LinearLayout當的NullPointerException錯誤可繪製背景：

的LinearLayout fondoSpinner =（的LinearLayout）findViewById（R.id.fondoSpinner）; fondoSpinner.setBackgroundResource（R.drawable.spinner_morado_gradiente）;

LinearLayout屬於自定義微調器。

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
android:id="@+id/fondoSpinner" 
android:layout_width="fill_parent" 
android:layout_height="wrap_content" 
android:background="@drawable/spinner_naranja_gradiente" 
android:orientation="horizontal" > 

<ImageView 
    android:id="@+id/imagenSpinner" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content"/> 

<TextView 
    android:id="@+id/textoSpinner" 
    style="@style/SpinnerText" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:ellipsize="marquee" 
    android:gravity="left"/> 

此代碼還收你的背景和它的作品確定。當我嘗試將它加載到主文件時發生錯誤。我必須做改變顏色動態

protected void onCreate(Bundle savedInstanceState) { 

    super.onCreate(savedInstanceState); 


    requestWindowFeature(Window.FEATURE_CUSTOM_TITLE); 
    setContentView(R.layout.activity_main); 
    getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.barra_titulo); 

cargarCombo(); 

    LinearLayout fondoSpinner = (LinearLayout)findViewById(R.id.fondoSpinner); 
    fondoSpinner.setBackgroundResource(R.drawable.spinner_morado_gradiente); 
} 

private void cargarCombo() { 

    Spinner spinner = (Spinner) findViewById(R.id.comboTipo_Vistos); 
    listaSpinner = new ArrayList<CountryInfo>(); 


     listaSpinner = cargarComboVistos(); 


    CountryAdapter myAdapter = new CountryAdapter 
      (this, android.R.layout.simple_spinner_item, listaSpinner); 

    spinner.setAdapter(myAdapter); 
} 

private ArrayList<CountryInfo> cargarComboVistos() { 

    ArrayList<CountryInfo> lista = new ArrayList<CountryInfo>(); 

    int imagen = R.drawable.mapanaranja; 

    lista.add(new CountryInfo("Todos", imagen)); 
    lista.add(new CountryInfo("Sí", imagen)); 
    lista.add(new CountryInfo("No", imagen)); 

    return lista; 
} 

public class CountryAdapter extends ArrayAdapter<CountryInfo> 
{ 
    private Activity context; 
    ArrayList<CountryInfo> data = null; 

    public CountryAdapter(Activity context, int resource, ArrayList<CountryInfo> data) 
    { 
     super(context, resource, data); 
     this.context = context; 
     this.data = data; 
    } 

    @Override 
    public View getView(int position, View convertView, ViewGroup parent) 
    { // Ordinary view in Spinner, we use android.R.layout.simple_spinner_item 
     return super.getView(position, convertView, parent); 
    } 

    @Override 
    public View getDropDownView(int position, View convertView, ViewGroup parent) 
    { // This view starts when we click the spinner. 
     View row = convertView; 
     if(row == null) 
     { 
      LayoutInflater inflater = context.getLayoutInflater(); 
      row = inflater.inflate(R.layout.spinner_row, parent, false); 
     } 

     CountryInfo item = data.get(position); 

     if(item != null) 
     { // Parse the data from each object and set it. 
      ImageView imagenSpinner = (ImageView) row.findViewById(R.id.imagenSpinner); 
      TextView textoSpinner = (TextView) row.findViewById(R.id.textoSpinner); 

      if(imagenSpinner != null) 
      { 
       imagenSpinner.setBackgroundResource(item.getCountryFlag()); 
      } 
      if(textoSpinner != null) 
       textoSpinner.setText(item.getCountryName()); 

     } 

     return row; 
    } 
} 

<selector xmlns:android="http://schemas.android.com/apk/res/android"> 
<item android:state_pressed="true" > 
    <shape> 
     <solid 
      android:color="#9933CC" /> 
     <stroke 
      android:width="3dp" 
      android:color="#AA66CC" /> 
     <padding 
      android:left="4dp" 
      android:top="4dp" 
      android:right="4dp" 
      android:bottom="4dp" /> 
    </shape> 
</item> 
<item> 
    <shape> 
     <gradient 
      android:startColor="#FFFFFF" 
      android:endColor="#FFFFFF" 
      android:angle="270" 
      android:type="linear" 
      /> 
     <stroke 
      android:width="1dp" 
      android:color="#9933CC" /> 
     <padding 
      android:left="4dp" 
      android:top="4dp" 
      android:right="4dp" 
      android:bottom="4dp" /> 
    </shape> 
</item> 
</selector> 

Answer 1

要定製微調項目佈局，這樣做在適配器getView()。例如：

@Override 
public View getView(int position, View convertView, ViewGroup parent) 
{ // Ordinary view in Spinner, we use android.R.layout.simple_spinner_item 
    View v = super.getView(position, convertView, parent); 
    v.setBackgroundResource(R.drawable.spinner_morado_gradiente); 
    return v; 
}