您好我正在创建将从微调器中选择数据的应用程序（在列表视图中）并希望选择值。所以这是我的日志猫信息
08-25 09:13:28.786: W/dalvikvm(580): threadid=1: thread exiting with uncaught exception (group=0x40015560)
08-25 09:13:28.892: E/AndroidRuntime(580): FATAL EXCEPTION: main
08-25 09:13:28.892: E/AndroidRuntime(580): java.lang.NullPointerException
08-25 09:13:28.892: E/AndroidRuntime(580): at com.example.dcsd.Result$1.onClick(Result.java:44)
08-25 09:13:28.892: E/AndroidRuntime(580): at android.view.View.performClick(View.java:2485)
08-25 09:13:28.892: E/AndroidRuntime(580): at android.view.View$PerformClick.run(View.java:9080)
08-25 09:13:28.892: E/AndroidRuntime(580): at android.os.Handler.handleCallback(Handler.java:587)
08-25 09:13:28.892: E/AndroidRuntime(580): at android.os.Handler.dispatchMessage(Handler.java:92)
08-25 09:13:28.892: E/AndroidRuntime(580): at android.os.Looper.loop(Looper.java:123)
08-25 09:13:28.892: E/AndroidRuntime(580): at android.app.ActivityThread.main(ActivityThread.java:3683)
08-25 09:13:28.892: E/AndroidRuntime(580): at java.lang.reflect.Method.invokeNative(Native Method)
08-25 09:13:28.892: E/AndroidRuntime(580): at java.lang.reflect.Method.invoke(Method.java:507)
08-25 09:13:28.892: E/AndroidRuntime(580): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
08-25 09:13:28.892: E/AndroidRuntime(580): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
08-25 09:13:28.892: E/AndroidRuntime(580): at dalvik.system.NativeStart.main(Native Method)
这是我的Result.java类
package com.example.dcsd;
import java.util.ArrayList;
import java.util.List;
import android.app.ListActivity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.View.OnClickListener;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Spinner;
import android.widget.TextView;
public class Result extends ListActivity{
Spinner sp;
SpinnerWrapper wrapper=new SpinnerWrapper();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.result);
MyAdapter adap=new MyAdapter(this, android.R.layout.simple_list_item_1,R.id.textView1, getResources().getStringArray(R.array.modules));
setListAdapter(adap);
Button b=(Button) findViewById(R.id.button12);
final Spinner sp=(Spinner) findViewById(R.id.spinner1);
b.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
Intent intent=new Intent(Result.this,Cal.class);
for(int i=0;i<15;i++){
//String text= sp.getSelectedItem().toString();
//Log.d("This", "huu");
}
sp.setOnItemSelectedListener(wrapper);
//intent.putExtra("values", sp.getSelectedItem().toString());
//intent.putExtra("values", sp.setOnItemSelectedListener(wrapper));
startActivity(intent);
}
});
}
private class MyAdapter extends ArrayAdapter<String>{
public MyAdapter(Context context, int resource, int textViewResourceId,
String[] strings) {
super(context, resource, textViewResourceId, strings);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater=(LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View row=inflater.inflate(R.layout.item_layout, parent,false);
String[] items=getResources().getStringArray(R.array.modules);
TextView tv=(TextView) row.findViewById(R.id.textView1);
tv.setText(items[position]);
sp=(Spinner)row.findViewById(R.id.spinner1);
ArrayAdapter<CharSequence> adapter=ArrayAdapter.createFromResource(Result.this, R.array.grades, android.R.layout.simple_spinner_dropdown_item);
sp.setAdapter(adapter);
//sp.setOnItemSelectedListener(wrapper);
//int dd=row.getId();
return row;
}
}
}
我的SpinnerWrapper.java类就像这样lokks
package com.example.dcsd;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
public class SpinnerWrapper implements OnItemSelectedListener {
public SpinnerWrapper() {
}
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position,
long id) {
String tex=parent.getItemAtPosition(position).toString();
Log.d("Selected", tex);
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
}
我如何解决这个问题？
答案 0 :(得分：0)
试试这个..
import java.util.ArrayList;
import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.Toast;
public class MainActivity extends Activity {
ArrayList<String> spinner_items;
Spinner spinner_from;
Button btn;
ArrayAdapter<String> from_adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
spinner_items = new ArrayList<String>();
spinner_items.add("Select");
spinner_items.add("One");
spinner_items.add("Two");
spinner_items.add("Three");
spinner_items.add("Four");
spinner_from = (Spinner) findViewById(R.id.spinner_from);
btn = (Button) findViewById(R.id.btn);
from_adapter = new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item, spinner_items);
from_adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner_from.setAdapter(from_adapter);
btn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
Toast.makeText(getBaseContext(), ""+spinner_from.getSelectedItem().toString().trim(), Toast.LENGTH_SHORT).show();
}
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}