當我嘗試在模擬器上運行我的應用程序時，很不幸地說應用程序已停止

-3

我是Android新手。我剛剛製作了我的第一個應用程序。但是，當我在android模擬器上運行我的應用程序時，它無法運行。應用程序編譯沒有任何錯誤，但在模擬器上它顯示不幸的應用程序已停止。當我嘗試在模擬器上運行我的應用程序時，很不幸地說應用程序已停止

這是Java代碼：

package com.example.kartikeya; 

import android.graphics.Color; 
import android.os.Bundle; 
import android.support.v7.app.AppCompatActivity; 
import android.view.View; 
import android.widget.Button; 
import android.widget.TextView; 

public class MainActivity extends AppCompatActivity implements View.OnClickListener{ 
double x,y; 
static int op=0; 
double result; 
TextView textView = new TextView(this); 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(); 

    Button button = (Button) findViewById(R.id.button); 
    button.setOnClickListener(this); // calling onClick() method 
    Button button2 = (Button) findViewById(R.id.button2); 
    button2.setOnClickListener(this); 
    //Button button3 = (Button) findViewById(R.id.button3); 
    // button3.setOnClickListener(this); 


    textView = (TextView) findViewById(R.id.textView); 
    textView.setOnClickListener(this); 
} 

private void setContentView() { 
} 

@Override 
public void onClick(View v) { 

    switch (v.getId()) { 

     case R.id.button: 
      Button button = new Button(this); 
      button.setBackgroundColor(Color.CYAN); 
      textView.setText(textView.getText() +"" + 9); 
      break; 

     case R.id.button2: 
      Button button2 = new Button(this); 
      button2.setBackgroundColor(Color.CYAN); 
      textView.setText(textView.getText() +"" + 8); 
      break; 

     case R.id.button3: 
      Button button3 = new Button(this); 
      button3.setBackgroundColor(Color.CYAN); 
      textView.setText(textView.getText() +"" + 7); 
      break; 

     case R.id.button4: 
      Button button4 = new Button(this); 
      button4.setBackgroundColor(Color.CYAN); 
      textView.setText(textView.getText() +"" + 6); 
      break; 

     case R.id.button5: 
      Button button5 = new Button(this); 
      button5.setBackgroundColor(Color.CYAN); 
      textView.setText(textView.getText() +"" + 5); 
      break; 

     case R.id.button6: 
      Button button6 = new Button(this); 
      button6.setBackgroundColor(Color.CYAN); 
      textView.setText(textView.getText() +"" + 4); 
      break; 

     case R.id.button7: 
      Button button7 = new Button(this); 
      button7.setBackgroundColor(Color.CYAN); 
      textView.setText(textView.getText() +"" + 3); 
      break; 

     case R.id.button8: 
      Button button8 = new Button(this); 
      button8.setBackgroundColor(Color.CYAN); 
      textView.setText(textView.getText() +"" + 2); 
      break; 

     case R.id.button9: 
      Button button9 = new Button(this); 
      button9.setBackgroundColor(Color.CYAN); 
      textView.setText(textView.getText() +"" + 1); 
      break; 

     case R.id.button10: 
      Button button10 = new Button(this); 
      button10.setBackgroundColor(Color.CYAN); 
      textView.setText(textView.getText() +"" + 0); 
      break; 

     case R.id.button11: 
      Button button11 = new Button(this); 
      button11.setBackgroundColor(Color.CYAN); 
      textView.setText(textView.getText() +"" + '.'); 
      break; 



     case R.id.button13: 
      x=Double.parseDouble((String)textView.getText()); 
      op=1; 
      Button button13 = new Button(this); 
      button13.setBackgroundColor(Color.CYAN); 
      textView.setText(" "); 
      break; 

     case R.id.button14: 
      x=Double.parseDouble((String)textView.getText()); 
      op=2; 
      Button button14 = new Button(this); 
      button14.setBackgroundColor(Color.CYAN); 
      textView.setText(" "); 
      break; 

     case R.id.button15: 
      x=Double.parseDouble((String)textView.getText()); 
      op=3; 
      Button button15 = new Button(this); 
      button15.setBackgroundColor(Color.CYAN); 
      textView.setText(" "); 
      break; 

     case R.id.button16: 
      x=Double.parseDouble((String)textView.getText()); 
      op=4; 
      Button button16 = new Button(this); 
      button16.setBackgroundColor(Color.CYAN); 
      textView.setText(" "); 
      break; 
     case R.id.button12: 
      y=Double.parseDouble((String) textView.getText()); 
      Button button12 = new Button(this); 
      button12.setBackgroundColor(Color.CYAN); 
      switch(op) 
      { 
       case 1: 
       { 
        result=x+y; 
        break; 
       } 
       case 2: 
       { 
        result=x-y; 
        break; 
       } 
       case 3: 
       { 
        result=x*y; 
        break; 
       } 
       case 4: 
       { 
        result=x/y; 
        break; 
       } 
       default : 
        break; 
      } 
      if(result-Math.floor(result)==0) 
      { 
       result=Math.floor(result); 
      } 
      textView.setText(result+""); 
      break; 

     default: 
      break; 
    } 

}

}

這是xml文件

<?xml version="1.0" encoding="utf-8"?>

<Button 
    android:text="@string/button0" 
    android:id="@+id/button" 
    android:textColor="#0A0A0A" 
    android:textSize="25sp" 

    android:layout_width="80dp" 
    android:layout_height="80dp" 
    android:background="@drawable/buttonshape" 
    android:shadowColor="#A8A8A8" 
    android:shadowDx="0" 
    android:shadowDy="0" 

    android:layout_below="@+id/textView" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentStart="true" 
    android:layout_marginTop="10dp" 
    android:clickable="true" 
    android:contentDescription="@string/click1" 
    android:contextClickable="true" /> 

<TextView 
    android:layout_width="350dp" 
    android:layout_height="100dp" 
    android:textAppearance="?android:attr/textAppearanceLarge" 
    android:text="@string/text1" 
    android:id="@+id/textView" 
    android:layout_alignParentTop="true" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentStart="true" 
    android:background="#ffffff" /> 

<Button 
    android:textColor="#0A0A0A" 
    android:textSize="25sp" 

    android:layout_width="80dp" 
    android:layout_height="80dp" 
    android:background="@drawable/buttonshape" 
    android:shadowColor="#A8A8A8" 
    android:shadowDx="0" 
    android:shadowDy="0" 
    android:text="@string/button" 
    android:id="@+id/button2" 
    android:layout_alignTop="@+id/button" 
    android:layout_toRightOf="@+id/button" 
    android:layout_toEndOf="@+id/button" 
    android:layout_marginLeft="2.5dp"/> 

    <Button 
     android:textColor="#0A0A0A" 
     android:textSize="25sp" 

     android:layout_width="80dp" 
     android:layout_height="80dp" 
     android:background="@drawable/buttonshape" 
     android:shadowColor="#A8A8A8" 
     android:shadowDx="0" 
     android:shadowDy="0" 
     android:text="@string/button7" 
     android:id="@+id/button3" 
     android:layout_alignTop="@+id/button13" 
     android:layout_toRightOf="@+id/button5" /> 

    <Button 
     android:textColor="#0A0A0A" 
     android:textSize="25sp" 

     android:layout_width="80dp" 
     android:layout_height="80dp" 
     android:background="@drawable/buttonshape" 
     android:shadowColor="#A8A8A8" 
     android:shadowDx="0" 
     android:shadowDy="0" 
     android:text="@string/button6" 
     android:id="@+id/button4" 
     android:layout_centerVertical="true" 
     android:layout_alignParentLeft="true" 
     android:layout_alignParentStart="true" 
     android:layout_marginTop="10dp"/> 

    <Button 
     android:textColor="#0A0A0A" 
     android:textSize="25sp" 

     android:layout_width="80dp" 
     android:layout_height="80dp" 
     android:background="@drawable/buttonshape" 
     android:shadowColor="#A8A8A8" 
     android:shadowDx="0" 
     android:shadowDy="0" 
     android:text="@string/button5" 
     android:id="@+id/button5" 
     android:layout_alignTop="@+id/button4" 
     android:layout_toRightOf="@+id/button4" 
     android:layout_toEndOf="@+id/button4" 
     android:layout_marginLeft="2.5dp"/> 

    <Button 
     android:textColor="#0A0A0A" 
     android:textSize="25sp" 

     android:layout_width="80dp" 
     android:layout_height="80dp" 
     android:background="@drawable/buttonshape" 
     android:shadowColor="#A8A8A8" 
     android:shadowDx="0" 
     android:shadowDy="0" 
     android:text="@string/button4" 
     android:id="@+id/button6" 
     android:layout_alignTop="@+id/button5" 
     android:layout_toRightOf="@+id/button5" /> 

    <Button 
     android:textColor="#0A0A0A" 
     android:textSize="25sp" 

     android:layout_width="80dp" 
     android:layout_height="80dp" 
     android:background="@drawable/buttonshape" 
     android:shadowColor="#A8A8A8" 
     android:shadowDx="0" 
     android:shadowDy="0" 
     android:text="@string/button3" 
     android:id="@+id/button7" 
     android:layout_below="@+id/button4" 
     android:layout_alignParentLeft="true" 
     android:layout_alignParentStart="true" 
     android:layout_marginTop="10dp"/> 

    <Button 
     android:textColor="#0A0A0A" 
     android:textSize="25sp" 

     android:layout_width="80dp" 
     android:layout_height="80dp" 
     android:background="@drawable/buttonshape" 
     android:shadowColor="#A8A8A8" 
     android:shadowDx="0" 
     android:shadowDy="0" 
     android:text="@string/button10" 
     android:id="@+id/button8" 
     android:layout_below="@+id/button5" 
     android:layout_alignLeft="@+id/button5" 
     android:layout_alignStart="@+id/button5" 
     android:layout_marginTop="10dp"/> 

    <Button 
     android:textColor="#0A0A0A" 
     android:textSize="25sp" 

     android:layout_width="80dp" 
     android:layout_height="80dp" 
     android:background="@drawable/buttonshape" 
     android:shadowColor="#A8A8A8" 
     android:shadowDx="0" 
     android:shadowDy="0" 
     android:text="@string/button11" 
     android:id="@+id/button9" 
     android:layout_alignTop="@+id/button15" 
     android:layout_toRightOf="@+id/button8" /> 

    <Button 
     android:textColor="#0A0A0A" 
     android:textSize="25sp" 

     android:layout_width="80dp" 
     android:layout_height="80dp" 
     android:background="@drawable/buttonshape" 
     android:shadowColor="#A8A8A8" 
     android:shadowDx="0" 
     android:shadowDy="0" 
     android:text="@string/button12" 
     android:id="@+id/button10" 
     android:layout_below="@+id/button9" 
     android:layout_alignParentLeft="true" 
     android:layout_alignParentStart="true" 
     android:layout_marginTop="10dp"/> 

    <Button 
     android:textColor="#0A0A0A" 
     android:textSize="25sp" 

     android:layout_width="80dp" 
     android:layout_height="80dp" 
     android:background="@drawable/buttonshape" 
     android:shadowColor="#A8A8A8" 
     android:shadowDx="0" 
     android:shadowDy="0" 
     android:text="@string/button13" 
     android:id="@+id/button11" 
     android:layout_below="@+id/button9" 
     android:layout_alignLeft="@+id/button8" 
     android:layout_alignStart="@+id/button8" 
     android:layout_marginTop="10dp"/> 

    <Button 
     android:textColor="#0A0A0A" 
     android:textSize="25sp" 

     android:layout_width="80dp" 
     android:layout_height="80dp" 
     android:background="@drawable/buttonshape" 
     android:shadowColor="#A8A8A8" 
     android:shadowDx="0" 
     android:shadowDy="0" 
     android:text="@string/button18" 
     android:id="@+id/button12" 
     android:layout_alignTop="@+id/button16" 
     android:layout_toRightOf="@+id/button11" /> 



    <Button 
     android:textColor="#0A0A0A" 
     android:textSize="25sp" 

     android:layout_width="80dp" 
     android:layout_height="80dp" 
     android:background="@drawable/buttonshape" 
     android:shadowColor="#A8A8A8" 
     android:shadowDx="0" 
     android:shadowDy="0" 
     android:text="@string/button14" 
     android:id="@+id/button13" 
     android:layout_above="@+id/button4" 
     android:layout_alignParentRight="true" /> 

    <Button 
     android:textColor="#0A0A0A" 
     android:textSize="25sp" 
     android:layout_width="80dp" 
     android:layout_height="80dp" 
     android:background="@drawable/buttonshape" 
     android:shadowColor="#A8A8A8" 
     android:shadowDx="0" 
     android:shadowDy="0" 
     android:text="@string/button15" 
     android:id="@+id/button14" 
     android:layout_alignTop="@+id/button6" 
     android:layout_alignParentRight="true" /> 

    <Button 
     android:textColor="#0A0A0A" 
     android:textSize="25sp" 
     android:layout_width="80dp" 
     android:layout_height="80dp" 
     android:background="@drawable/buttonshape" 
     android:shadowColor="#A8A8A8" 
     android:shadowDx="0" 
     android:shadowDy="0" 
     android:text="@string/button16" 
     android:id="@+id/button15" 
     android:layout_alignTop="@+id/button8" 
     android:layout_alignRight="@+id/textView" 
     android:layout_alignEnd="@+id/textView" /> 

    <Button 
     android:textColor="#0A0A0A" 
     android:textSize="25sp" 
     android:layout_width="80dp" 
     android:layout_height="80dp" 
     android:background="@drawable/buttonshape" 
     android:shadowColor="#A8A8A8" 
     android:shadowDx="0" 
     android:shadowDy="0" 
     android:text="@string/button17" 
     android:id="@+id/button16" 
     android:layout_below="@+id/button9" 
     android:layout_alignParentRight="true" 
     android:layout_alignParentEnd="true" 
     android:layout_marginTop="10dp"/>

這是AndroidManifest文件：

<?xml version="1.0" encoding="utf-8"?>

<application 
    android:allowBackup="true" 
    android:icon="@mipmap/ic_launcher" 
    android:label="@string/app_name" 
    android:supportsRtl="true" 
    android:theme="@style/AppTheme" > 
    <activity android:name=".MainActivity" > 
     <intent-filter> 
      <action android:name="android.intent.action.MAIN" /> 

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

這是logcat的

12-21 22:15:23.620 1425-1425/com.example.kartikeya.calc D/dalvikvm: Not late-enabling CheckJNI (already on) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc D/AndroidRuntime: Shutting down VM 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc W/dalvikvm: threadid=1: thread exiting with uncaught exception (group=0xb2fed180) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime: FATAL EXCEPTION: main 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime: java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.kartikeya.calc/com.example.kartikeya.calc.MainActivity}: java.lang.NullPointerException 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1880) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at android.app.ActivityThread.access$600(ActivityThread.java:123) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at android.os.Handler.dispatchMessage(Handler.java:99) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at android.os.Looper.loop(Looper.java:137) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at android.app.ActivityThread.main(ActivityThread.java:4424) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at java.lang.reflect.Method.invokeNative(Native Method) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at java.lang.reflect.Method.invoke(Method.java:511) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at dalvik.system.NativeStart.main(Native Method) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime: Caused by: java.lang.NullPointerException 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at android.content.ContextWrapper.getResources(ContextWrapper.java:81) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at android.view.View.<init>(View.java:2696) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at android.view.View.<init>(View.java:2744) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at android.widget.TextView.<init>(TextView.java:449) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc `E/AndroidRuntime:  at android.widget.TextView.<init>(TextView.java:442) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at android.widget.TextView.<init>(TextView.java:437) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at com.example.kartikeya.calc.MainActivity.<init>(MainActivity.java:14) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at java.lang.Class.newInstanceImpl(Native Method) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at java.lang.Class.newInstance(Class.java:1319) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at android.app.Instrumentation.newActivity(Instrumentation.java:1023) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1871) 
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)  
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at android.app.ActivityThread.access$600(ActivityThread.java:123)  
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)  
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at android.os.Handler.dispatchMessage(Handler.java:99)  
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at android.os.Looper.loop(Looper.java:137)  
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at android.app.ActivityThread.main(ActivityThread.java:4424)  
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at java.lang.reflect.Method.invokeNative(Native Method)  
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at java.lang.reflect.Method.invoke(Method.java:511)  
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)  
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)  
12-21 22:15:23.640 1425-1425/com.example.kartikeya.calc E/AndroidRuntime:  at dalvik.system.NativeStart.main(Native Method)  
12-21 22:15:24.140 1425-1431/com.example.kartikeya.calc I/dalvikvm: threadid=3: reacting to signal 3 
12-21 22:15:24.140 1425-1431/com.example.kartikeya.calc I/dalvikvm: Wrote stack traces to '/data/anr/traces.txt' 
12-21 22:15:24.160 1425-1431/com.example.kartikeya.calc I/dalvikvm: threadid=3: reacting to signal 3 
12-21 22:15:24.160 1425-1431/com.example.kartikeya.calc I/dalvikvm: Wrote stack traces to '/data/anr/traces.txt' 
12-21 22:15:27.801 1425-1425/? I/Process: Sending signal. PID: 1425 SIG: 9

來源

2015-12-21 Kartikeya Garg

' TextView textView = new TextView（this）;'在這一點上不能這樣做，上下文尚未初始化。等到onCreate被調用。此外，你沒有顯示它，所以我不知道你怎麼用 – njzk2

你的問題是此行TextView textView = new TextView(this);

您正試圖在onClick方法中的此視圖上致電setText()，但此視圖並未誇大。你有誇大的觀點之前，你可以操縱它，就像你與Button button = (Button) findViewById(R.id.button);

因此，在沒有你的onCreate()你會希望把textView = (TextView) findViewById(R.id.your_text_view_id);和擺脫你的TextView textView = new TextView(this);行 - 只是讓TextView textView;

來源

2015-12-21 17:09:30 NoChinDeluxe

我已經使用你的方法，但沒有發生。 –

當我嘗試在模擬器上運行我的應用程序時，很不幸地說應用程序已停止

回答

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