首先澄清一下，我是Java和Android的新手，我仍然处于沉重的学习过程中。
总之...
我正在开发一个简单的停车短信应用程序，而且我遇到了Spinner和TextView。
基本上，我正在尝试这样做：当我从Spinner中选择一个停车区域（它有五个停车区域）时，我想在停车区域描述中填充Spinner下面的TextView。
Spinner有自己的StringArray，而停车区描述各自都在自己的字符串中。
所以它看起来像这样：
activity_glavni.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".Glavni">
<ScrollView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/scrollView" >
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"></LinearLayout>
</ScrollView>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="@string/txGrad"
android:id="@+id/txOdaberiteGrad"
android:layout_alignParentTop="true"
android:layout_alignParentStart="true" />
<Spinner
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/spinnergradovi"
android:layout_below="@+id/txOdaberiteGrad"
android:layout_alignParentStart="true"
android:layout_marginTop="23dp" />
<Space
android:layout_width="20px"
android:layout_height="20px"
android:id="@+id/space" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:id="@+id/txZona"
android:text="@string/txZona"
android:layout_below="@+id/spinnergradovi"
android:layout_alignParentStart="true" />
<Spinner
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/spinnerZona"
android:layout_below="@+id/txZona"
android:layout_alignParentStart="true"
android:layout_marginTop="23dp" />
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:id="@+id/txPrikazZone"
android:layout_below="@+id/spinnerZona" />
<EditText
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/editTextRegistracija"
android:layout_below="@+id/txPrikazZone"
android:layout_alignParentStart="true"
android:hint="Unesite broj registracije" />
<Button
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/btn_posalji"
android:id="@+id/btn_posalji"
android:layout_below="@+id/editTextRegistracija"
android:layout_alignParentStart="true"
android:layout_marginTop="33dp"
android:layout_alignParentEnd="false"
/>
的strings.xml
<resources>
<string name="app_name">ParkingZagreb</string>
<string name="action_settings">Settings</string>
<string name="txGrad">Odaberite grad</string>
<string name="txZona">Odaberite zonu</string>
<string name="btn_posalji">Pošalji SMS!</string>
<string-array name="gradovi">
<item>Zagreb</item>
<item>Velika Gorica</item>
<item>Zaprešić</item>
</string-array>
<string-array name="zone">
<item>Prva zona</item>
<item>Druga zona</item>
<item>Treća zona</item>
<item>Četvrta zona (1)</item>
<item>Četvrta zona (2)</item>
</string-array>
<string-array name="opisi_zona">
<item>6 kn/h, maksimalno 2 h</item>
<item>3 kn/h, maksimalno 3 h</item>
<item>1,5 kn/h, bez ograničenja</item>
<item>5 kn/dan, 7-16 h</item>
<item>10 kn/dan, 7-20 h</item>
</string-array>
Glavni.java
public class Glavni extends ActionBarActivity {
public TextView txPrikazZone;
private Button btn_posalji;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_glavni);
this.getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);
btn_posalji = (Button) findViewById(R.id.btn_posalji);
btn_posalji.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
AlertDialog alertDialog = new AlertDialog.Builder(Glavni.this).create();
alertDialog.setTitle("SMS poslan!");
alertDialog.setMessage("Provjerite SMS aplikaciju. Poruka bi trebala doći za nekoliko trenutaka.");
alertDialog.setButton("OK", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
}
});
alertDialog.show();
}
});
// the first city selection Spinner
Spinner spinner_gradovi = (Spinner) findViewById(R.id.spinnergradovi);
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
this, R.array.gradovi, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(
android.R.layout.simple_spinner_dropdown_item);
spinner_gradovi.setAdapter(adapter);
// the second Spinner with parking zones
final Spinner spinner_zona = (Spinner) findViewById(R.id.spinnerZona);
ArrayAdapter<CharSequence> adapter2 = ArrayAdapter.createFromResource(
this, R.array.zone, android.R.layout.simple_spinner_item);
adapter2.setDropDownViewResource(
android.R.layout.simple_spinner_dropdown_item);
spinner_zona.setAdapter(adapter2);
// this is where I'm trying to populate the TextView with the String-Array by selecting an item from the second Spinner
final String[] opisi_zona = getResources().getStringArray(R.array.opisi_zona);
spinner_zona.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
txPrikazZone.setText(opisi_zona[position]);
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
}
@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_glavni, 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);
}
}
感谢您的帮助......
答案 0 :(得分：0)
适用于两个Spinners的适配器
修改
首先尝试将ZonaX字符串包装成字符串数组
<string-array name="zonas">
...
</string-array>
现在在代码中更改了ItemSelectedListener
的集合final String[] zonas = getResources().getStringArray(R.array.zonas);
spinner_zona.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
txPrikazZone.setText(zonas[position]);
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
}
答案 1 :(得分：0)
空指针的原因是您尚未初始化txPrikazZone而您正试图调用setText。
您需要在onCreate方法中对其进行初始化，如下所示：
txPrikazZone = (TextView) findViewById(R.id.txPrikazZone);
我希望这会有所帮助。