当我运行应用程序时，模拟器会启动，并显示一条消息＆＃39;不幸的是MyApplicationin停止工作。＆＃39;单击应用程序图标时会显示相同的消息。我甚至杀死并重新启动了adb服务器。但错误仍然存在。请帮忙！ 这是MainActivity.java的代码
> package com.computer.om.myapplicationin;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.util.ArrayMap;
public class MainActivity extends AppCompatActivity
{
int NoOfSubjects;
int i;
// int TotMarksTH[]=new int[10];
// int TotMarksPR[]=new int[10];
// int ObtMarksTH[]=new int[10];
// int ObtMarksPR[]=new int[10];
TextView Theory =
(TextView) findViewById(R.id.Theory);
TextView TheoryMarks =
(TextView) findViewById(R.id.TheoryMarks);
TextView Practical =
(TextView) findViewById(R.id.Practical);
TextView PracticalMarks =
(TextView) findViewById(R.id.PracticalMarks);
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button1 = (Button) findViewById(R.id.button1);
final Button button2 = (Button) findViewById(R.id.button2);
Theory.setVisibility(View.VISIBLE);
TheoryMarks.setVisibility(View.VISIBLE);
Practical.setVisibility(View.VISIBLE);
PracticalMarks.setVisibility(View.VISIBLE);
button1.setOnClickListener(
new Button.OnClickListener() {
public void onClick(View v) {
TextView NoSubject =
(TextView) findViewById(R.id.NoSubject);
//Copying the entererd number of subjects to character sequence and then converting it to integer
// CharSequence s=NoSubject.getText();
// NoOfSubjects=Integer.parseInt(s.toString());
button2.setVisibility(View.VISIBLE);
//the label number of subjects and the enter number will get visible when we click ok button
// NoSubject.setVisibility(View.INVISIBLE);
// TextView labelsubject =
// (TextView) findViewById(R.id.NoOfSubjectslbl);
// labelsubject.setVisibility(View.INVISIBLE);
}
}
);
/* button2.setOnClickListener(
new Button.OnClickListener()
{
public void onClick(View v1)
{
CharSequence totth,totpr,obtph,obtpr;
if(i<NoOfSubjects)
{
totth=Theory.getText();
TotMarksTH[i]=Integer.parseInt(totth.toString());
totpr=Theory.getText();
TotMarksPR[i]=Integer.parseInt(totpr.toString());
i++;
}
else
{
button2.setVisibility(View.INVISIBLE);
Theory.setVisibility(View.INVISIBLE);
TheoryMarks.setVisibility(View.INVISIBLE);
Practical.setVisibility(View.INVISIBLE);
PracticalMarks.setVisibility(View.INVISIBLE);
}
}
}
);*/
}
}
and this is the stack trace
> `
03/09 03:33:43: Launching app
$ adb push C:\Users\om\AndroidStudioProjects\MyApplicationin\app\build\outputs\apk\app-debug.apk /data/local/tmp/com.computer.om.myapplicationin
$
adb shell pm install -r "/data/local/tmp/com.computer.om.myapplicationin"
pkg: /data/local/tmp/com.computer.om.myapplicationin
Success
$ adb shell am start -n "com.computer.om.myapplicationin/com.computer.om.myapplicationin.MainActivity" -a android.intent.action.MAIN -c android.intent.category.LAUNCHER
Client not ready yet..Waiting for process to come online
Connected to process 2068 on device Nexus_6P_API_17 [emulator-5554]
D/dalvikvm: Not late-enabling CheckJNI (already on)
E/jdwp: Failed writing handshake bytes: Broken pipe (-1 of 14)
D/dalvikvm: Debugger has detached; object registry had 0 entries
E/Trace: error opening trace file: No such file or directory (2)
I/dalvikvm: Could not find method android.app.Application.registerOnProvideAssistDataListener, referenced from method com.android.tools.fd.runtime.BootstrapApplication.registerOnProvideAssistDataListener
W/dalvikvm: VFY: unable to resolve virtual method 232: Landroid/app/Application;.registerOnProvideAssistDataListener (Landroid/app/Application$OnProvideAssistDataListener;)V
D/dalvikvm: VFY: replacing opcode 0x6e at 0x0002
I/dalvikvm: Could not find method android.app.Application.unregisterOnProvideAssistDataListener, referenced from method com.android.tools.fd.runtime.BootstrapApplication.unregisterOnProvideAssistDataListener
W/dalvikvm: VFY: unable to resolve virtual method 235: Landroid/app/Application;.unregisterOnProvideAssistDataListener (Landroid/app/Application$OnProvideAssistDataListener;)V
D/dalvikvm: VFY: replacing opcode 0x6e at 0x0002
I/InstantRun: Instant Run Runtime started. Android package is com.computer.om.myapplicationin, real application class is null.
E/InstantRun: Could not find slices in APK; aborting.
W/InstantRun: No instant run dex files added to classpath
E/dalvikvm: Could not find class 'android.util.ArrayMap', referenced from method com.android.tools.fd.runtime.MonkeyPatcher.monkeyPatchExistingResources
W/dalvikvm: VFY: unable to resolve check-cast 1924 (Landroid/util/ArrayMap;) in Lcom/android/tools/fd/runtime/MonkeyPatcher;
D/dalvikvm: VFY: replacing opcode 0x1f at 0x025e
E/dalvikvm: Could not find class 'android.util.ArrayMap', referenced from method com.android.tools.fd.runtime.MonkeyPatcher.pruneResourceCache
W/dalvikvm: VFY: unable to resolve const-class 1924 (Landroid/util/ArrayMap;) in Lcom/android/tools/fd/runtime/MonkeyPatcher;
D/dalvikvm: VFY: replacing opcode 0x1c at 0x0060
D/AndroidRuntime: Shutting down VM
W/dalvikvm: threadid=1: thread exiting with uncaught exception (group=0xa649e908)
E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.computer.om.myapplicationin/com.computer.om.myapplicationin.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2106)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5041)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at android.support.v7.app.AppCompatDelegateImplBase.<init>(AppCompatDelegateImplBase.java:120)
at android.support.v7.app.AppCompatDelegateImplV9.<init>(AppCompatDelegateImplV9.java:151)
at android.support.v7.app.AppCompatDelegateImplV11.<init>(AppCompatDelegateImplV11.java:31)
at android.support.v7.app.AppCompatDelegateImplV14.<init>(AppCompatDelegateImplV14.java:55)
at android.support.v7.app.AppCompatDelegate.create(AppCompatDelegate.java:205)
at android.support.v7.app.AppCompatDelegate.create(AppCompatDelegate.java:185)
at android.support.v7.app.AppCompatActivity.getDelegate(AppCompatActivity.java:519)
at android.support.v7.app.AppCompatActivity.findViewById(AppCompatActivity.java:190)
at com.computer.om.myapplicationin.MainActivity.<init>(MainActivity.java:23)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1319)
at android.app.Instrumentation.newActivity(Instrumentation.java:1054)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2097)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5041)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
at dalvik.system.NativeStart.main(Native Method)
Application terminated.
答案 0 :(得分：1)
在onCreate之外，您可以将其声明为
TextView Theory;
和onCreate
Theory = (TextView) findViewById(R.id.Theory);
答案 1 :(得分：0)
from django.contrib.auth.models import User
from django.contrib.auth.models import Group
from django.db import models
from quiz.models import Quiz
# Create your models here.
class Organisation(models.Model):
name = models.CharField(max_length=255)
user = models.ForeignKey(User, on_delete=models.CASCADE)
quiz = models.ForeignKey(Quiz, on_delete=models.CASCADE)
group = models.ForeignKey(Group, on_delete=models.CASCADE)