我的应用崩溃了，但我不知道为什么？

问题描述：

当我运行我的应用程序时，它崩溃了，但我不知道为什么。登录猫正在给出致命的错误。我的应用崩溃了，但我不知道为什么？

Logcat

09-30 07:09:38.380: D/AndroidRuntime(1361): Shutting down VM 
09-30 07:09:38.380: W/dalvikvm(1361): threadid=1: thread exiting with uncaught exception (group=0xb4b06b90) 
09-30 07:09:38.410: E/AndroidRuntime(1361): FATAL EXCEPTION: main 
09-30 07:09:38.410: E/AndroidRuntime(1361): Process: shibli.sendDarood, PID: 1361 
09-30 07:09:38.410: E/AndroidRuntime(1361): java.lang.RuntimeException: Unable to start activity ComponentInfo{shibli.sendDarood/shibli.sendDarood.MainActivity}: java.lang.NullPointerException 
09-30 07:09:38.410: E/AndroidRuntime(1361):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2176) 
09-30 07:09:38.410: E/AndroidRuntime(1361):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2226) 
09-30 07:09:38.410: E/AndroidRuntime(1361):  at android.app.ActivityThread.access$700(ActivityThread.java:135) 
09-30 07:09:38.410: E/AndroidRuntime(1361):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1397) 
09-30 07:09:38.410: E/AndroidRuntime(1361):  at android.os.Handler.dispatchMessage(Handler.java:102) 
09-30 07:09:38.410: E/AndroidRuntime(1361):  at android.os.Looper.loop(Looper.java:137) 
09-30 07:09:38.410: E/AndroidRuntime(1361):  at android.app.ActivityThread.main(ActivityThread.java:4998) 
09-30 07:09:38.410: E/AndroidRuntime(1361):  at java.lang.reflect.Method.invokeNative(Native Method) 
09-30 07:09:38.410: E/AndroidRuntime(1361):  at java.lang.reflect.Method.invoke(Method.java:515) 
09-30 07:09:38.410: E/AndroidRuntime(1361):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777) 
09-30 07:09:38.410: E/AndroidRuntime(1361):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593) 
09-30 07:09:38.410: E/AndroidRuntime(1361):  at dalvik.system.NativeStart.main(Native Method) 
09-30 07:09:38.410: E/AndroidRuntime(1361): Caused by: java.lang.NullPointerException 
09-30 07:09:38.410: E/AndroidRuntime(1361):  at shibli.sendDarood.MainActivity.onCreate(MainActivity.java:143) 
09-30 07:09:38.410: E/AndroidRuntime(1361):  at android.app.Activity.performCreate(Activity.java:5243) 
09-30 07:09:38.410: E/AndroidRuntime(1361):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087) 
09-30 07:09:38.410: E/AndroidRuntime(1361):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2140) 
09-30 07:09:38.410: E/AndroidRuntime(1361):  ... 11 more 
09-30 07:14:39.150: I/Process(1361): Sending signal. PID: 1361 SIG: 9

代码

package shibli.sendDarood; 

import android.os.Bundle; 
import android.app.Activity; 
import android.content.Context; 
import android.content.SharedPreferences; 
import android.view.View; 
import android.widget.Button; 
import android.widget.EditText; 
import android.widget.TextView; 


public class MainActivity extends Activity { 
EditText dAmnt; 
TextView finmsg; 
Button enter, msg, bt3; 
int counter = 0; 
long total = 0; 

@Override 
protected void onSaveInstanceState(Bundle outState) { 
    // TODO Auto-generated method stub 
    super.onSaveInstanceState(outState); 

    outState.putLong("Value", total); 
} 
@Override 
protected void onRestoreInstanceState(Bundle savedInstanceState) { 
    // TODO Auto-generated method stub 
    super.onRestoreInstanceState(savedInstanceState); 
    total=savedInstanceState.getLong("Value"); 

} 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    SharedPreferences ob=getSharedPreferences("mydata", Context.MODE_PRIVATE); 
    total=ob.getLong("Total", total); 



    setContentView(R.layout.activity_main); 

    finmsg = (TextView) findViewById(R.id.finalmsg); 
    dAmnt = (EditText) findViewById(R.id.editText1); 
    enter = (Button) findViewById(R.id.button1); 
    msg = (Button) findViewById(R.id.button2); 
    enter.setOnClickListener(new View.OnClickListener() { 

     @Override 
     public void onClick(View v) { 

      if (dAmnt.getText().toString().equalsIgnoreCase("")) { 




      } else { 


       if (dAmnt.getText() != null 
         && Integer.parseInt(dAmnt.getText().toString()) <= 1000) { 
        counter = Integer.parseInt(dAmnt.getText().toString()); 
        total += counter; 
        dAmnt.getText().clear(); 


       } else if (Integer.parseInt(dAmnt.getText().toString()) > 1000) { 
        finmsg.setText("hey Dude Plz Enter value Less than 1000"); 
        dAmnt.getText().clear(); 

        total += 0; 


       } 

      } 
     } 

    }); 
    msg.setOnClickListener(new View.OnClickListener() { 

     @Override 
     public void onClick(View v) { 
      // TODO Auto-generated method stub 

      if (total < 1) { 
       finmsg.setText("No Darood you have Recited Yet :" + total); 



      } 

      else if (total >= 1 && total <= 1000) { 
       finmsg.setText("Total Darood Shareef Recited :" + total); 

      } 

      else if (total > 1000) { 
       finmsg.setText("SubhanAllah !!SubhanAllah!!SubhanAllah!! ..Total Number of Darood         you have Recited is: "+ total); 

      } 

     } 
    }); 
    bt3.setOnClickListener(new View.OnClickListener() { 

     @Override 
     public void onClick(View v) { 

      total=0; 



     } 
    }); 



} 




@Override 
protected void onDestroy() { 
    // TODO Auto-generated method stub 
    super.onDestroy(); 
    SharedPreferences ob=getSharedPreferences("mydata", Context.MODE_PRIVATE); 
    SharedPreferences.Editor ed= ob.edit(); 
    ed.putLong("Total",total); 
    ed.commit(); 
} 

}

XML代码

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent"> 

    <TextView 
    android:id="@+id/tvArabicText" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentRight="true" 
    android:layout_alignParentTop="true" 
    android:layout_margin="7dp" 
    android:gravity="center" 
    android:text="@string/arabicText" 
    android:textColor="#FF0707" 
    android:textStyle="bold" 
    /> 

<TextView 
    android:id="@+id/tvEngText" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentRight="true" 
    android:layout_below="@+id/tvArabicText" 
    android:layout_margin="7dp" 
    android:background="#00E00E" 
    android:gravity="center" 
    android:text="@string/engText" 
    /> 

<Button 
    android:id="@+id/button1" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentRight="true" 
    android:layout_below="@+id/editText1" 
    android:layout_margin="7dp" 
    android:text="@string/submit" /> 

<TextView 
    android:id="@+id/finalmsg" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_alignParentBottom="true" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentRight="true" 
    android:layout_below="@+id/button2" 
    android:layout_margin="7dp" 
    android:text="@string/FinalMsg" 
    android:textColor="#FF940A" 
    android:textSize="15sp" /> 

<EditText 
    android:id="@+id/editText1" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentRight="true" 
    android:layout_centerVertical="true" 
    android:layout_margin="7dp" 
    android:ems="10" 
    android:hint="@string/hin" 
    android:inputType="number" 
    android:maxLength="7" > 
</EditText> 

<Button 
    android:id="@+id/button2" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentRight="true" 
    android:layout_below="@+id/button1" 
    android:layout_margin="7dp" 
    android:text="@string/Button" /> 

<TextView 
    android:id="@+id/textView1" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:layout_alignLeft="@+id/tvEngText" 
    android:layout_below="@+id/tvEngText" 
    android:layout_margin="7dp" 
    android:background="#00E00E" 
    android:gravity="center" 
    android:text="@string/msg" /> 
    </RelativeLayout>

我的清单文件是

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
package="shibli.sendDarood" 
android:versionCode="1" 
android:versionName="1.0" > 

<uses-sdk 
    android:minSdkVersion="8" 
    android:targetSdkVersion="19" /> 

<application 

    android:allowBackup="true" 
    android:icon="@drawable/gumbad_ekhizra" 
    android:label="@string/app_name" 
    android:theme="@style/AppTheme" > 

    <activity 
     android:name="shibli.sendDarood.MainActivity" 
     android:label="@string/app_name" > 
     <intent-filter> 
      <action android:name="android.intent.action.MAIN" /> 

      <category android:name="android.intent.category.LAUNCHER" /> 
     </intent-filter> 
    </activity> 
    </application> 
</manifest>

你能张贴的内容是符合143的你'MainActivity'很可能与布局或不成立又一个参考的一个问题。 – ScouseChris 2014-09-30 11:41:58

变量bt3未在onCreate（）方法中初始化 – Neji 2014-09-30 11:43:16

@Syed [be polite]（http://stackoverflow.com/help/how-to-ask） – Gattsu 2014-09-30 11:46:51

答

我只能看到两个布局文件按钮..
但你已经声明了三个按钮

public class MainActivity extends Activity { 
EditText dAmnt; 
TextView finmsg; 
Button enter, msg, bt3; // three buttons 
int counter = 0; 
long total = 0; 


setContentView(R.layout.activity_main); 

finmsg = (TextView) findViewById(R.id.finalmsg); 
dAmnt = (EditText) findViewById(R.id.editText1); 
enter = (Button) findViewById(R.id.button1); 
msg = (Button) findViewById(R.id.button2); 

bt3 = (Button) findViewById(R.id.id_of_your_button)     //Add this line 
enter.setOnClickListener(new View.OnClickListener() {

非常感谢...其作品4我... – 2014-09-30 11:55:27

我已经点击刻度线标记...我可以在多个答案上打勾 – 2014-09-30 11:59:49

您可以将任何一个标记为接受答案 – Pooja 2014-09-30 12:01:02

答

在调用方法之前，您需要初始化bt3。

答

您的代码会因为崩溃：

java.lang.NullPointerException

这异常的代码是在MainActivity.java在143行代码。

快速的解决方法是：

Button bt3 = (Button) findViewById(R.id.button3);

你忘了在xml文件中设置此按钮为好。

<Button 
    android:id="@+id/button3" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentRight="true" 
    android:layout_below="@+id/button2" 
    android:layout_margin="7dp" 
    android:text="@string/Button" />

帽子的家伙...其作品4我... – 2014-09-30 11:56:10

答

有2只在您的布局首先的按钮创建的第三个按钮布局，然后像其他人一样初始化该按钮。如果你没有初始化的NPE来

@Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     SharedPreferences ob=getSharedPreferences("mydata", Context.MODE_PRIVATE); 
     total=ob.getLong("Total", total); 



     setContentView(R.layout.activity_main); 

     bt3=(Button)findViewById(R.id.xyz_button); //Here you find the new button 

     finmsg = (TextView) findViewById(R.id.finalmsg); 
     dAmnt = (EditText) findViewById(R.id.editText1); 
     enter = (Button) findViewById(R.id.button1); 
     msg = (Button) findViewById(R.id.button2); 
     enter.setOnClickListener(new View.OnClickListener() { 

      @Override 
      public void onClick(View v) { 

       if (dAmnt.getText().toString().equalsIgnoreCase("")) { 




       } else { 


        if (dAmnt.getText() != null 
          && Integer.parseInt(dAmnt.getText().toString()) <= 1000) { 
         counter = Integer.parseInt(dAmnt.getText().toString()); 
         total += counter; 
         dAmnt.getText().clear(); 


        } else if (Integer.parseInt(dAmnt.getText().toString()) > 1000) { 
         finmsg.setText("hey Dude Plz Enter value Less than 1000"); 
         dAmnt.getText().clear(); 

         total += 0; 


        } 

       } 
      } 

     }); 
     msg.setOnClickListener(new View.OnClickListener() { 

      @Override 
      public void onClick(View v) { 
       // TODO Auto-generated method stub 

       if (total < 1) { 
        finmsg.setText("No Darood you have Recited Yet :" + total); 



       } 

       else if (total >= 1 && total <= 1000) { 
        finmsg.setText("Total Darood Shareef Recited :" + total); 

       } 

       else if (total > 1000) { 
        finmsg.setText("SubhanAllah !!SubhanAllah!!SubhanAllah!! ..Total Number of Darood         you have Recited is: "+ total); 

       } 

      } 
     }); 
     bt3.setOnClickListener(new View.OnClickListener() { 

      @Override 
      public void onClick(View v) { 

       total=0; 



      } 
     }); 



    }

我的应用崩溃了，但我不知道为什么？

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