एक शून्य ऑब्जेक्ट संदर्भ

Question

पर वर्चुअल विधि 'void android.widget.TextView.setText (java.lang.CharSequence)' का आह्वान करने का प्रयास इरादे का उपयोग करके एक टुकड़े से दूसरे में डेटा पास करने में असमर्थ। तर्क ठीक है। कृपया मुख्य गतिविधि के अंतिम भाग देखें जहां मैंने putExtra का उपयोग करके अन्य गतिविधियों में तार भेज दिए हैं।

Process: khurana.nikhil.lovemeter, PID: 4019 
java.lang.RuntimeException: Unable to start activity ComponentInfo{khurana.nikhil.lovemeter/khurana.nikhil.lovemeter.SecondActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference 
     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325) 
     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2390) 
     at android.app.ActivityThread.access$800(ActivityThread.java:151) 
     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303) 
     at android.os.Handler.dispatchMessage(Handler.java:102) 
     at android.os.Looper.loop(Looper.java:135) 
     at android.app.ActivityThread.main(ActivityThread.java:5257) 
     at java.lang.reflect.Method.invoke(Native Method) 
     at java.lang.reflect.Method.invoke(Method.java:372) 
     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) 
     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698) 
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference 
     at khurana.nikhil.lovemeter.SecondActivity.onCreate(SecondActivity.java:32) 
     at android.app.Activity.performCreate(Activity.java:5990) 
     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106) 
     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278) 

यहाँ:

public class SecondActivity extends Activity { 

    TextView tv7,tv8,tv9,tv10; 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_second); 


    Intent in = getIntent(); 

    String s1 = in.getStringExtra("k1"); 
    String s2 = in.getStringExtra("k2"); 
    String s3 = in.getStringExtra("k3"); 
    String s4 = in.getStringExtra("k4"); 
    tv7=(TextView)findViewById(R.id.textView3); 
    tv8=(TextView)findViewById(R.id.editText4); 
    tv9=(TextView)findViewById(R.id.editText5); 
    tv10=(TextView)findViewById(R.id.editText6); 

    tv7.setText("Hello "+s1); 
    tv8.setText("Your partner "+s2+" is really nice"); 
    tv9.setText("Your love percent based on name is "+s3); 
    tv10.setText("Your love percent based on age is "+s4); 
} 
} 

यहाँ त्रुटि मैं हो रही है:

public class MainActivity extends Activity implements View.OnClickListener { 
EditText ed1,ed2,ed3,ed4,ed5,ed6; 

Button bt1; 
TextView tv1,tv2; 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    ed1=(EditText)findViewById(R.id.editText); 
    ed2=(EditText)findViewById(R.id.editText2); 
    ed3=(EditText)findViewById(R.id.editText3); 
    ed4=(EditText)findViewById(R.id.editText4); 
    ed5=(EditText)findViewById(R.id.editText5); 
    ed6=(EditText)findViewById(R.id.editText6); 
    tv1=(TextView)findViewById(R.id.textView); 
    tv2=(TextView)findViewById(R.id.textView2); 
    bt1=(Button)findViewById(R.id.button); 
    bt1.setOnClickListener(this); 
} 
public void onClick(View v) 
{ 

    String str1=ed1.getText().toString(); 
    String str2=ed2.getText().toString(); 
    String str3=ed3.getText().toString(); 
    String str4=ed4.getText().toString(); 
    String str5=ed5.getText().toString(); 
    String str6=ed6.getText().toString(); 

    if(str1.matches("") || str2.matches("") || str3.matches("")) 
    { 
     tv1.setText("One or more fields missing"); 
     if(str4.matches("") || str5.matches("") || str6.matches("")) 
     { 
      tv2.setText("One or more fields missing"); 
     } 
    } 

    else { 
     int age1 = Integer.parseInt(ed2.getText().toString()); 
     int age2 = Integer.parseInt(ed5.getText().toString()); 

     int l1 = str1.length(); 
     str1 = str1.toLowerCase(); 
     str4 = str4.toLowerCase(); 
     int l2 = str4.length(); 

     int[] a = new int[26]; 
     int[] b = new int[26]; 

     for (int i = 0; i < l1; i++) { 

      char c = str1.charAt(i); 
      int x = (int) c - 97; 
      a[x]++; 
     } 
     for (int i = 0; i < l2; i++) { 

      char c = str4.charAt(i); 
      int x = (int) c - 97; 
      b[x]++; 
     } 
     int s=0,p; 
     for(int i=0;i<26;i++) 
     { 
      if(a[i]>b[i]) 
       p=a[i]; 
      else 
       p=b[i]; 

      s+=p; 
     } 
     if(l1>l2) 
      p=l1; 
     else 
      p=l2; 
     double love1=(double)(s/p)*100; 
     double love2=0.0,x; 

     if(age1>age2) { 
      p = age1; 
     x=age2; 
     } 
     else { 
      p = age2; 
      x=age1; 
     } 
     love2=(double)(x/p)*100; 

     Intent in=new Intent(MainActivity.this,SecondActivity.class); 
     String s1=""+love1; 
     String s2=""+love2; 



     in.putExtra("k1",str4); 
     in.putExtra("k2",str4); 
     in.putExtra("k3", love1); 
     in.putExtra("k4",love2); 
     startActivity(in); 
     finish(); 


    } 


} 


} 

यहाँ SecondActivity.java के लिए कोड है:

यहाँ MainActivity.java है गतिविधि_second.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" 
android:background="#cefcfd" 
tools:context="khurana.nikhil.lovemeter.SecondActivity"> 


<TextView 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="" 
    android:id="@+id/textView3" 
    android:layout_alignParentTop="true" 
    android:layout_centerHorizontal="true" 
    android:layout_marginTop="68dp" /> 

<TextView 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="" 
    android:id="@+id/textView4" 
    android:layout_below="@+id/textView3" 
    android:layout_centerHorizontal="true" 
    android:layout_marginTop="51dp" /> 

<TextView 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="" 
    android:id="@+id/textView5" 
    android:layout_above="@+id/textView6" 
    android:layout_alignStart="@+id/textView6" 
    android:layout_marginBottom="84dp" /> 

<TextView 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="" 
    android:id="@+id/textView6" 
    android:layout_alignParentBottom="true" 
    android:layout_centerHorizontal="true" 
    android:layout_marginBottom="51dp" /> 
</RelativeLayout> 

Answer 1

tv8=(TextView)findViewById(R.id.editText4); 
tv9=(TextView)findViewById(R.id.editText5); 
tv10=(TextView)findViewById(R.id.editText6); 

बदलें इन करने के लिए:

tv8=(TextView)findViewById(R.id.textView4); 
tv9=(TextView)findViewById(R.id.textView5); 
tv10=(TextView)findViewById(R.id.textView6); 

तुम बस गलत आईडी का इस्तेमाल किया।