有很多与之相关的问题，我搜索过它们并尝试使用提供的解决方案，但无法解决我的问题，这就是我发布新问题的原因。
我正在研究spinner。在我的应用中，我使用dropdown作为local JSON。所有数据都是从我的资产文件夹中的JSON文件生成的。以下是我的{"reference":
[
{"ref_no":"11111111111111","Name":"Faisal"},
{"ref_no":"22222222222222","Name":"Salman"},
{"ref_no":"33333333333333","Name":"Asim"},
{"ref_no":"44444444444444","Name":"Asad"},
{"ref_no":"55555555555555","Name":"Mateen"},
{"ref_no":"66666666666666","Name":"Omar"},
{"ref_no":"77777777777777","Name":"Usama"}
]}
文件
ref.json
Spinner dd_ref, dd_m_type,dd_site_status, dd_pole_type;
String refr_no, meter_type, latitude, longitude, site_status, comm_status, pole_type;
ArrayList<String> refList, m_type_List, site_status_List, pole_type_List;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
try {
loadData();
} catch (JSONException e) {
e.printStackTrace();
}
}
public void loadData() throws JSONException {
//////////////// Below method is for reference number call
JSONArray RefjsonArray;
JSONObject Ref_obj;
refList = new ArrayList<String>();
try
{
Ref_obj = new JSONObject(loadRefJSONFromAssest());
RefjsonArray = Ref_obj.getJSONArray("reference");
for(int i = 0; i<RefjsonArray.length();i++)
{
Ref_obj = RefjsonArray.getJSONObject(i);
Log.d("Details-->", Ref_obj.getString("ref_no"));
String ref = Ref_obj.getString("ref_no");
refList.add(ref);
}
refList.add(0,"Select a reference number");
} catch (JSONException e)
{
e.printStackTrace();
}
dd_ref = (Spinner)findViewById(R.id.dd_ref);
dd_ref.setAdapter(new ArrayAdapter<String>(MainActivity.this, android.R.layout.simple_spinner_dropdown_item, refList));
dd_ref.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
refr_no = String.valueOf(refList.get(position));
//text_pos.setText("Hi " + refr_no);
// Log.d(" out ",refr_no);
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
});//// end reference spinner
///////// start of method meter type dropdown
JSONArray m_type_Array;
JSONObject m_type_obj;
m_type_List = new ArrayList<String>();
try{
m_type_obj = new JSONObject(loadMeterTypeJSONFromAssest());
m_type_Array = m_type_obj.getJSONArray("meter");
for(int i = 0; i<m_type_Array.length(); i++)
{
m_type_obj = m_type_Array.getJSONObject(i);
Log.d("Details-->", m_type_obj.getString("m_type"));
String m_type = m_type_obj.getString("m_type");
m_type_List.add(m_type);
}
m_type_List.add(0,"Select Meter Type");
}catch (JSONException e)
{
e.printStackTrace();
}
dd_m_type = (Spinner)findViewById(R.id.dd_m_type);
dd_m_type.setAdapter(new ArrayAdapter<String>(MainActivity.this, android.R.layout.simple_spinner_dropdown_item, m_type_List));
dd_ref.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
meter_type = String.valueOf(m_type_List.get(position));
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
});// end dropdown meter type
}
////// method for loading meter type data
public String loadMeterTypeJSONFromAssest() {
String json = " ";
try{
InputStream is = getAssets().open("meter.json");
int size = is.available();
byte[] buffer = new byte[size];
is.read(buffer);
is.close();
json = new String(buffer, "UTF-8");
} catch (IOException e) {
e.printStackTrace();
return null;
}
return json;
}
//// load reference # data
public String loadRefJSONFromAssest() {
String json = " ";
try{
InputStream is = getAssets().open("ref.json");
int size = is.available();
byte[] buffer = new byte[size];
is.read(buffer);
is.close();
json = new String(buffer, "UTF-8");
} catch (IOException e) {
e.printStackTrace();
return null;
}
return json;
}
MainActivity.java
spinner当我运行我的应用时，它会将数据加载到JSON。我的列表中有7个参考号，如33333333333333文件中所示。应用程序运行正常，选择参考号44444444444444，当我选择logcat或更多时，应用程序崩溃，同时在java.lang.ArrayIndexOutOfBoundsException: length=12; index=-1
at java.util.ArrayList.get(ArrayList.java:310)
at com.example.accurat.application.MainActivity$2.onItemSelected(MainActivity.java:131)
at android.widget.AdapterView.fireOnSelected(AdapterView.java:931)
at android.widget.AdapterView.dispatchOnItemSelected(AdapterView.java:920)
at android.widget.AdapterView.-wrap1(AdapterView.java)
at android.widget.AdapterView$SelectionNotifier.run(AdapterView.java:890)
at android.os.Handler.handleCallback(Handler.java:746)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5491)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:728)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
meter_type = String.valueOf(m_type_List.get(position));它正在点meter type，我不知道为什么它会在这一点上发生，因为它与{{1}}没有任何联系。
我进行了搜索并找到了delimiter，但它无法解决我的问题。
任何帮助都将受到高度赞赏。
答案 0 :(得分：1)
变化
dd_ref.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
到
dd_m_type.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
以米型下拉方式
答案 1 :(得分：1)
您正在添加错误的微调器项目单击侦听器，将dd_ref更改为dd_m_type微调器。
dd_m_type = (Spinner)findViewById(R.id.dd_m_type);
dd_m_type.setAdapter(new ArrayAdapter<String>(MainActivity.this, android.R.layout.simple_spinner_dropdown_item, m_type_List));
dd_m_type.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
meter_type = String.valueOf(m_type_List.get(position));
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
});// end dropdown meter type
答案 2 :(得分：0)
我认为从Spinner获取所选项目存在问题，请尝试以下方法获取所选项目。
String Text = dd_m_type.getSelectedItem().toString();
OR
dd_m_type.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
String item = parent.getItemAtPosition(position);
}
public void onNothingSelected(AdapterView<?> parent) {
}
});