我现在已经完成了所有脚本和设计，没有编译时错误但是没有出现这个运行时错误，我的应用程序闪烁而且没有启动。 我有它需要的所有文件，一切都完成了， 请立即建议，
这是我的MainActivity.java代码，可能会抛出这些异常
package com.example.dell.demologin;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import java.util.HashMap;
import activity.LoginActivity;
import helper.SQLiteHandler;
import helper.SessionManager;
public class MainActivity extends Activity {
private TextView txtName;
private TextView txtEmail;
private Button btnLogout;
private SQLiteHandler db;
private SessionManager session;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_register);
txtName = (TextView) findViewById(R.id.name);
txtEmail = (TextView) findViewById(R.id.email);
btnLogout = (Button) findViewById(R.id.btnLogout);
// SqLite database handler
db = new SQLiteHandler(getApplicationContext());
// session manager
session = new SessionManager(getApplicationContext());
if (!session.isLoggedIn()) {
logoutUser();
}
// Fetching user details from sqlite
HashMap<String, String> user = db.getUserDetails();
String name = user.get("name");
String email = user.get("email");
// Displaying the user details on the screen
txtName.setText(name);
txtEmail.setText(email);
// Logout button click event
btnLogout.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
logoutUser();
}
});
}
/**
* Logging out the user. Will set isLoggedIn flag to false in shared
* preferences Clears the user data from sqlite users table
* */
private void logoutUser() {
session.setLogin(false);
db.deleteUsers();
// Launching the login activity
Intent intent = new Intent(MainActivity.this, LoginActivity.class);
startActivity(intent);
finish();
}
}
这是我的logcat，
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.dell.demologin, PID: 15578
java.lang.RuntimeException: Unable to instantiate application com.android.tools.fd.runtime.BootstrapApplication: java.lang.IllegalStateException: java.lang.ClassNotFoundException: com.example.dell.demologin.AppController
at android.app.LoadedApk.makeApplication(LoadedApk.java:601)
at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4757)
at android.app.ActivityThread.access$1600(ActivityThread.java:159)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1445)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:152)
at android.app.ActivityThread.main(ActivityThread.java:5507)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.IllegalStateException: java.lang.ClassNotFoundException: com.example.dell.demologin.AppController
at com.android.tools.fd.runtime.BootstrapApplication.createRealApplication(BootstrapApplication.java:220)
at com.android.tools.fd.runtime.BootstrapApplication.attachBaseContext(BootstrapApplication.java:239)
at android.app.Application.attach(Application.java:187)
at android.app.Instrumentation.newApplication(Instrumentation.java:1001)
at android.app.Instrumentation.newApplication(Instrumentation.java:985)
at android.app.LoadedApk.makeApplication(LoadedApk.java:586)
at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4757)
at android.app.ActivityThread.access$1600(ActivityThread.java:159)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1445)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:152)
at android.app.ActivityThread.main(ActivityThread.java:5507)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.ClassNotFoundException: com.example.dell.demologin.AppController
at java.lang.Class.classForName(Native Method)
at java.lang.Class.forName(Class.java:324)
at java.lang.Class.forName(Class.java:285)
at com.android.tools.fd.runtime.BootstrapApplication.createRealApplication(BootstrapApplication.java:209)
at com.android.tools.fd.runtime.BootstrapApplication.attachBaseContext(BootstrapApplication.java:239)
at android.app.Application.attach(Application.java:187)
at android.app.Instrumentation.newApplication(Instrumentation.java:1001)
at android.app.Instrumentation.newApplication(Instrumentation.java:985)
at android.app.LoadedApk.makeApplication(LoadedApk.java:586)
at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4757)
at android.app.ActivityThread.access$1600(ActivityThread.java:159)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1445)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:152)
at android.app.ActivityThread.main(ActivityThread.java:5507)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.ClassNotFoundException: Didn't find class "com.example.dell.demologin.AppController" on path: DexPathList[[zip file "/data/app/com.example.dell.demologin-2/base.apk"],nativeLibraryDirectories=[/data/app/com.example.dell.demologin-2/lib/arm64, /vendor/lib64, /system/lib64]]
at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
at java.lang.Class.classForName(Native Method)
at java.lang.Class.forName(Class.java:324)
at java.lang.Class.forName(Class.java:285)
at com.android.tools.fd.runtime.BootstrapApplication.createRealApplication(BootstrapApplication.java:209)
at com.android.tools.fd.runtime.BootstrapApplication.attachBaseContext(BootstrapApplication.java:239)
at android.app.Application.attach(Application.java:187)
at android.app.Instrumentation.newApplication(Instrumentation.java:1001)
at android.app.Instrumentation.newApplication(Instrumentation.java:985)
at android.app.LoadedApk.makeApplication(LoadedApk.java:586)
at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4757)
at android.app.ActivityThread.access$1600(ActivityThread.java:159)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1445)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:152)
at android.app.ActivityThread.main(ActivityThread.java:5507)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Suppressed: java.lang.ClassNotFoundException: Didn't find class "com.example.dell.demologin.AppController" on path: DexPathList[[dex file "/data/data/com.example.dell.demologin/files/instant-run/dex/slice-support-annotations-23.4.0_2f85958e3577c0887206665b958d529f2917b10d-classes.dex", dex file "/data/data/com.example.dell.demologin/files/instant-run/dex/slice-slice_9-classes.dex", dex file "/data/data/com.example.dell.demologin/files/instant-run/dex/slice-slice_8-classes.dex", dex file "/data/data/com.example.dell.demologin/files/instant-run/dex/slice-slice_7-classes.dex", dex file "/data/data/com.example.dell.demologin/files/instant-run/dex/slice-slice_6-classes.dex", dex file "/data/data/com.example.dell.demologin/files/instant-run/dex/slice-slice_5-classes.dex", dex file "/data/data/com.example.dell.demologin/files/instant-run/dex/slice-slice_4-classes.dex", dex file "/data/data/com.example.dell.demologin/files/instant-run/dex/slice-slice_3-classes.dex", dex file "/data/data/com.example.dell.demologin/files/instant-run/dex/slice-slice_2-classes.dex", dex file "/data/data/com.example.dell.demologin/files/instant-run/dex/slice-slice_1-classes.dex", dex file "/data/data/com.example.dell.demologin/files/instant-run/dex/slice-slice_0-classes.dex", dex file "/data/data/com.example.dell.demologin/files/instant-run/dex/slice-mysql-connector-java_910883ba1d0637ad761451367a22e76261a44141-classes.dex", dex file "/data/data/com.example.dell.demologin/files/instant-run/dex/slice-jtds_dd6bef0a517729fc55f6897f784dfc3379233a03-classes.dex", dex file "/data/data/com.example.dell.demologin/files/instant-run/dex/slice-internal_impl-23.4.0_acbefc0422230ccc1164ab
E/AndroidRuntime: Error reporting crash
java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.Context android.app.Application.getApplicationContext()' on a null object reference
at com.android.internal.os.RuntimeInit$UncaughtHandler.uncaughtException(RuntimeInit.java:96)
at java.lang.ThreadGroup.uncaughtException(ThreadGroup.java:693)
at java.lang.ThreadGroup.uncaughtException(ThreadGroup.java:690)
I/Process: Sending signal. PID: 15578 SIG: 9
Application terminated.