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Java 在android中将温度从Celcius转换为Farenheit时出现空指针异常

java android

Java 在android中将温度从Celcius转换为Farenheit时出现空指针异常,java,android,nullpointerexception,weather,Java,Android,Nullpointerexception,Weather,我正在尝试将天气应用程序设置页面中的温度从塞尔修斯转换为法伦海特（C到F）。一旦我点击切换按钮到“C”或“F”并按下“保存”按钮，应用程序就会崩溃并强制关闭，而不是在转换之后，它应该在MainActivity.java屏幕中显示结果。logcat中的错误表明这是由于“Null指针”异常引起的，但我已经正确地声明了所有变量。请帮我纠正这个问题。谢谢 这是密码。 这是获取空指针异常的行 String ccmin1 =data.getStringExtra("cmin1"); Logcat错误

我正在尝试将天气应用程序设置页面中的温度从塞尔修斯转换为法伦海特（C到F）。一旦我点击切换按钮到“C”或“F”并按下“保存”按钮，应用程序就会崩溃并强制关闭，而不是在转换之后，它应该在MainActivity.java屏幕中显示结果。logcat中的错误表明这是由于“Null指针”异常引起的，但我已经正确地声明了所有变量。请帮我纠正这个问题。谢谢

这是密码。 这是获取空指针异常的行

String ccmin1 =data.getStringExtra("cmin1");

Logcat错误

 01-15 13:37:25.287: E/AndroidRuntime(602): java.lang.RuntimeException: Failure  delivering result ResultInfo{who=null, request=2, result=1, data=Intent { (has extras) }}   to activity {com.weather/com.weather.MainActivity}: java.lang.NullPointerException
 01-15 13:37:25.287: E/AndroidRuntime(602):     at android.app.ActivityThread.deliverResults(ActivityThread.java:2532)
 01-15 13:37:25.287: E/AndroidRuntime(602):     at android.app.ActivityThread.handleSendResult(ActivityThread.java:2574)
 01-15 13:37:25.287: E/AndroidRuntime(602):     at android.app.ActivityThread.access$2000(ActivityThread.java:117)
 01-15 13:37:25.287: E/AndroidRuntime(602):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:961)
 01-15 13:37:25.287: E/AndroidRuntime(602):     at android.os.Handler.dispatchMessage(Handler.java:99)
 01-15 13:37:25.287: E/AndroidRuntime(602):     at android.os.Looper.loop(Looper.java:123)
 01-15 13:37:25.287: E/AndroidRuntime(602):     at android.app.ActivityThread.main(ActivityThread.java:3683)
 01-15 13:37:25.287: E/AndroidRuntime(602):     at java.lang.reflect.Method.invokeNative(Native Method)
 01-15 13:37:25.287: E/AndroidRuntime(602):     at java.lang.reflect.Method.invoke(Method.java:507)
 01-15 13:37:25.287: E/AndroidRuntime(602):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
 01-15 13:37:25.287: E/AndroidRuntime(602):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
 01-15 13:37:25.287: E/AndroidRuntime(602):     at dalvik.system.NativeStart.main(Native Method)
 01-15 13:37:25.287: E/AndroidRuntime(602): Caused by: java.lang.NullPointerException
  01-15 13:37:25.287: E/AndroidRuntime(602):    at com.weather.MainActivity.onActivityResult(MainActivity.java:922)
  01-15 13:37:25.287: E/AndroidRuntime(602):    at android.app.Activity.dispatchActivityResult(Activity.java:3908)
Settings.java代码

public class Settings extends SherlockActivity {
MainActivity mActivity;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.settings_activity);
    mActivity = new MainActivity();

 Intent intent = getIntent();

    final String YourtransferredData =intent.getStringExtra("YourValueKey");
    final String tempData =intent.getStringExtra("temp");
    final String WwindData =intent.getStringExtra("windspeed");
    final String tempfvalue = intent.getStringExtra("Tempf");
    final String PressureData = intent.getStringExtra("pressure");
    final String tempfmin1 = intent.getStringExtra("tempfmin1");
    final String tempfmax1 = intent.getStringExtra("tempfmax1");
    final String tempcmin1 = intent.getStringExtra("tempcmin1");
    final String tempcmax1 = intent.getStringExtra("tempcmax1");
    final String tempFFFmin1 = intent.getStringExtra("tempFFmin1");
    final String tempFFFmin2 = intent.getStringExtra("tempFFmin2");
    final String tempFFFmin3 = intent.getStringExtra("tempFFmin3");
    final String tempFFFmin4 = intent.getStringExtra("tempFFmin4");
    final String tempFFFmax1 = intent.getStringExtra("tempFFmax1");
    final String tempFFFmax2 = intent.getStringExtra("tempFFmax2");
    final String tempFFFmax3 = intent.getStringExtra("tempFFmax3");
    final String tempFFFmax4 = intent.getStringExtra("tempFFmax4");
    final String tempCCCmin1 = intent.getStringExtra("tempCCmin1");
    final String tempCCCmin2 = intent.getStringExtra("tempCCmin2");
    final String tempCCCmin3 = intent.getStringExtra("tempCCmin3");
    final String tempCCCmin4 = intent.getStringExtra("tempCCmin3");
    final String tempCCCmax1 = intent.getStringExtra("tempCCmax1");
    final String tempCCCmax2 = intent.getStringExtra("tempCCmax2");
    final String tempCCCmax3 = intent.getStringExtra("tempCCmax3");
    final String tempCCCmax4 = intent.getStringExtra("tempCCmax4");

    Log.d("tempfvalue111","welcome all "+getIntent().getStringExtra("YourValueKey")+tempData+WwindData+tempfvalue+PressureData);     
    //Log.d("tempfvalue","Value");     
    final Button mNotification_tempc=(Button)findViewById(R.id.tempc);
    final Button mNotification_tempf=(Button)findViewById(R.id.tempf);
    final Button mNotification_wmph=(Button)findViewById(R.id.wmph);
    final Button mNotification_wms=(Button)findViewById(R.id.wms);
    final Button mNotification_wkm=(Button)findViewById(R.id.wkm);
    /*final Button mNotification_pinches=(Button)findViewById(R.id.pinches);
    final Button mNotification_pmm=(Button)findViewById(R.id.pmm);
    final Button mNotification_pmbar=(Button)findViewById(R.id.pmbar);*/
    final Button done =(Button)findViewById(R.id.done);

    TextView header = (TextView)findViewById(R.id.textheader);
    header.setText("Please choose the Settings your personalized settings");

    mNotification_tempc.setOnClickListener(new OnClickListener() {
                public void onClick(View v) {
                   // mNotification_on_btn.setVisibility(View.GONE);
                    mNotification_tempc.setVisibility(View.VISIBLE);
                    String state =  mNotification_tempc.getText().toString(); 
                    Toast.makeText(Settings.this,
                            "Toggle State :" + state, Toast.LENGTH_LONG).show();
                    Log.d("OnCclick",tempData); 
                   // mNotification_tempc.setBackgroundColor(Color.CYAN);
                   // mNotification_tempf.setEnabled(false); 
                    Intent intent1=new Intent();  
                   intent1.putExtra("TEMPC",tempData); 
                   intent1.putExtra("cmin",tempcmin1);
                    intent1.putExtra("cmax",tempcmax1);
                    intent1.putExtra("cmin1",tempCCCmin1);
                    intent1.putExtra("cmin2",tempCCCmin2);
                    intent1.putExtra("cmin3",tempCCCmin3);
                    intent1.putExtra("cmin4",tempCCCmin4);
                    intent1.putExtra("cmax1",tempCCCmax1);
                    intent1.putExtra("cmax2",tempCCCmax2);
                    intent1.putExtra("cmax3",tempCCCmax3);
                    intent1.putExtra("cmax4",tempCCCmax4);
                   setResult(1,intent1);  


                }
            });

        mNotification_tempf.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {
                   // mNotification_off_btn.setVisibility(View.GONE);
                    mNotification_tempf.setVisibility(View.VISIBLE);
                    String state =  mNotification_tempf.getText().toString(); 
                    Toast.makeText(Settings.this,
                            "Toggle State :" + state, Toast.LENGTH_LONG).show();
                    Intent intent=new Intent();  
                    intent.putExtra("MESSAGE",tempfvalue);  
                    intent.putExtra("fmin",tempfmin1);
                    intent.putExtra("fmax",tempfmax1);
                    intent.putExtra("fmin1",tempFFFmin1);
                    intent.putExtra("fmin2",tempFFFmin2);
                    intent.putExtra("fmin3",tempFFFmin3);
                    intent.putExtra("fmin4",tempFFFmin4);
                    intent.putExtra("fmax1",tempFFFmax1);
                    intent.putExtra("fmax2",tempFFFmax2);
                    intent.putExtra("fmax3",tempFFFmax3);
                    intent.putExtra("fmax4",tempFFFmax4);
                    setResult(2,intent);  
                   // mNotification_tempf.setBackgroundColor(Color.LTGRAY);
                  //  mNotification_tempc.setPressed(true);; 
                        //  mActivity.setTextView3(tempfvalue); 
                   // mActivity.temp1.setText(tempfvalue+"\u00B0"+"F");;


                }
            });
    done.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
            finish();
            }
        });
            }
onActivityResult代码

@Override  
   protected void onActivityResult(int requestCode, int resultCode, Intent data)  
   {  
             super.onActivityResult(requestCode, resultCode, data);  

              // check if the request code is same as what is passed  here it is 2  



    if(resultCode==2)  

               {   
                    String message=data.getStringExtra("MESSAGE");   
                    String fminv= data.getStringExtra("fmin");
                    String fmaxv= data.getStringExtra("fmax");
                    String ffmin1 =data.getStringExtra("fmin1");
                    String ffmin2 =data.getStringExtra("fmin2");
                    String ffmin3 =data.getStringExtra("fmin3");
                    String ffmin4 =data.getStringExtra("fmin4");
                    String ffmax1 =data.getStringExtra("fmax1");
                    String ffmax2 =data.getStringExtra("fmax2");
                    String ffmax3 =data.getStringExtra("fmax3");
                    String ffmax4 =data.getStringExtra("fmax4");
                    temp1.setText(message);  
                    minvalue.setText(fminv); 
                    maxvalue.setText(fmaxv);  
                    tempmin1.setText(ffmin1);   
                    Log.d("jesus",ffmin1);
                    tempmin2.setText(ffmin2);
                    Log.d("jesus2",ffmin2);
                    tempmin3.setText(ffmin3);
                    tempmin4.setText(ffmin4);
                    tempmax1.setText(ffmax1);
                    tempmax2.setText(ffmax2);
                    tempmax3.setText(ffmax3);
                    tempmax4.setText(ffmax4);
                    Log.d("jesus4",ffmin2);
              }  

if( resultCode==1)
{
String message1=data.getStringExtra("TEMPC");
String cminv= data.getStringExtra("cmin");
String cmaxv= data.getStringExtra("cmax");
String ccmin1 =data.getStringExtra("cmin1");
String ccmin2 =data.getStringExtra("cmin2");
String ccmin3 =data.getStringExtra("cmin3");
String ccmin4 =data.getStringExtra("cmin4");
String ccmax1= data.getStringExtra("cmax1");
String ccmax2= data.getStringExtra("cmax2");
String ccmax3= data.getStringExtra("cmax3");
String ccmax4= data.getStringExtra("cmax4");

temp1.setText(message1);
minvalue.setText(cminv); 
maxvalue.setText(cmaxv);
tempmin1.setText(ccmin1);
tempmin2.setText(ccmin2);
tempmin3.setText(ccmin3);
tempmin4.setText(ccmin4);
tempmax1.setText(ccmax1);
tempmax2.setText(ccmax2);
tempmax3.setText(ccmax3);
tempmax4.setText(ccmax4);

}
确保从上一个活动中传递字符串“cmin1”，同时检查拼写

String ccmin1=data.getStringExtra（“cmin1”）

如果任何标签
fmin2
fmin3
未从以前的活动中传递，则将导致
NPE

更新
我认为您在
resultCode
和
requestCode

始终检查
if（resultCode==RESULT\u OK）


而
requestCode
是您传递的代码
查看com.weather.MainActivity.onActivityResult（MainActivity.java:922），调试并设置断点。发布onActivityResult
String ccmin1=data.getStringExtra（“cmin1”）的代码块
您在这行中说您得到了
NullPointerException
。。如果它是一个对象，那么这里的
data
是什么？它的值为null。很可能
tempcmin1
为null，意思是
intent.getStringExtra（“tempcmin1”）
为null，这意味着您在调用Settingsupdated onActivityResult代码时从不额外添加TempcMin1@阿朱

@Override  
   protected void onActivityResult(int requestCode, int resultCode, Intent data)  
   {  
             super.onActivityResult(requestCode, resultCode, data);  

              // check if the request code is same as what is passed  here it is 2  



    if(resultCode==2)  

               {   
                    String message=data.getStringExtra("MESSAGE");   
                    String fminv= data.getStringExtra("fmin");
                    String fmaxv= data.getStringExtra("fmax");
                    String ffmin1 =data.getStringExtra("fmin1");
                    String ffmin2 =data.getStringExtra("fmin2");
                    String ffmin3 =data.getStringExtra("fmin3");
                    String ffmin4 =data.getStringExtra("fmin4");
                    String ffmax1 =data.getStringExtra("fmax1");
                    String ffmax2 =data.getStringExtra("fmax2");
                    String ffmax3 =data.getStringExtra("fmax3");
                    String ffmax4 =data.getStringExtra("fmax4");
                    temp1.setText(message);  
                    minvalue.setText(fminv); 
                    maxvalue.setText(fmaxv);  
                    tempmin1.setText(ffmin1);   
                    Log.d("jesus",ffmin1);
                    tempmin2.setText(ffmin2);
                    Log.d("jesus2",ffmin2);
                    tempmin3.setText(ffmin3);
                    tempmin4.setText(ffmin4);
                    tempmax1.setText(ffmax1);
                    tempmax2.setText(ffmax2);
                    tempmax3.setText(ffmax3);
                    tempmax4.setText(ffmax4);
                    Log.d("jesus4",ffmin2);
              }  

if( resultCode==1)
{
String message1=data.getStringExtra("TEMPC");
String cminv= data.getStringExtra("cmin");
String cmaxv= data.getStringExtra("cmax");
String ccmin1 =data.getStringExtra("cmin1");
String ccmin2 =data.getStringExtra("cmin2");
String ccmin3 =data.getStringExtra("cmin3");
String ccmin4 =data.getStringExtra("cmin4");
String ccmax1= data.getStringExtra("cmax1");
String ccmax2= data.getStringExtra("cmax2");
String ccmax3= data.getStringExtra("cmax3");
String ccmax4= data.getStringExtra("cmax4");

temp1.setText(message1);
minvalue.setText(cminv); 
maxvalue.setText(cmaxv);
tempmin1.setText(ccmin1);
tempmin2.setText(ccmin2);
tempmin3.setText(ccmin3);
tempmin4.setText(ccmin4);
tempmax1.setText(ccmax1);
tempmax2.setText(ccmax2);
tempmax3.setText(ccmax3);
tempmax4.setText(ccmax4);

}