我们正在编写一个基于android的应用程序，它跟踪几个手机传感器，现在我试图在突然发生这种情况时编译代码
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.max.pswi, PID: 14291
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.max.pswi/com.example.max.pswi.MainActivity}:
java.lang.ClassNotFoundException: Didn't find class "com.example.max.pswi.MainActivity" on path: DexPathList[[zip file "/data/app/com.example.max.pswi-1/base.apk"],nativeLibraryDirectories=[/vendor/lib, /system/lib]]
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2555)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2767)
at android.app.ActivityThread.access$900(ActivityThread.java:177)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1449)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:5951)
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:1388)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1183)
Caused by: java.lang.ClassNotFoundException: Didn't find class "com.example.max.pswi.MainActivity" on path: DexPathList[[zip file "/data/app/com.example.max.pswi-1/base.apk"],nativeLibraryDirectories=[/vendor/lib, /system/lib]]
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 android.app.Instrumentation.newActivity(Instrumentation.java:1079)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2545)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2767)
at android.app.ActivityThread.access$900(ActivityThread.java:177)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1449)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:5951)
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:1388)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1183)
Suppressed: java.lang.ClassNotFoundException: com.example.max.pswi.MainActivity
at java.lang.Class.classForName(Native Method)
at java.lang.BootClassLoader.findClass(ClassLoader.java:781)
at java.lang.BootClassLoader.loadClass(ClassLoader.java:841)
at java.lang.ClassLoader.loadClass(ClassLoader.java:504)
... 13 more
Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack available
我不知道为什么会出现这种错误
我在Android Studio上编程
以下是创建错误的MainActivity-Code：
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
setContentView(R.layout.activity_main);
int currentVersionCode = 0;
try {
currentVersionCode = this.getPackageManager().getPackageInfo(this.getPackageName(), 0).versionCode;
} catch (PackageManager.NameNotFoundException e1) {
e1.printStackTrace();
}
final ImageButton export = (ImageButton) findViewById(R.id.export);
final ImageButton clear = (ImageButton) findViewById(R.id.clear);
final ToggleButton toggle = (ToggleButton) findViewById(R.id.anaus);
final ImageButton settingsBtn = (ImageButton) findViewById(R.id.settings);
final ImageButton aktualisieren = (ImageButton) findViewById(R.id.aktualisieren);
final ListView liste = (ListView)findViewById(R.id.infos);
if (CheckIfServiceIsRunning())
toggle.setChecked(true);
Boolean status = CheckIfServiceIsRunning();
aktualisieren.setVisibility(View.VISIBLE);
export.setVisibility(View.VISIBLE);
toggle.setVisibility(View.VISIBLE);
settingsBtn.setVisibility(View.VISIBLE);
/* clear.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
SensorManager.getInstance().clearValues(SensorManager.getInstance().getContext());
}
});
export.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
SensorManager.getInstance().exportValues(SensorManager.getInstance().getContext());
}
});
settingsBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent("android.settings.ACTION_NOTIFICATION_LISTENER_SETTINGS");
startActivity(intent);
}
});
toggle.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
Boolean status = CheckIfServiceIsRunning();
ComponentName cn = new ComponentName(getApplicationContext(), NLService.class);
String flat = Settings.Secure.getString(getApplicationContext().getContentResolver(), "enabled_notification_listeners");
final boolean enabled = (flat != null && flat.contains(cn.flattenToString()));
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (isChecked) {
// The toggle is enabled
if (!enabled) {
final AlertDialog alertDialog = new AlertDialog.Builder(MainActivity.this).create();
alertDialog.setCancelable(false);
alertDialog.setTitle("Notificationlistener aktivieren");
alertDialog.setMessage("Bitte aktivieren sie den Notificationlistener für die App PSWI");
alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "Aktivieren", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
alertDialog.cancel();
Intent intent = new Intent("android.settings.ACTION_NOTIFICATION_LISTENER_SETTINGS");
startActivity(intent);
Intent i = new Intent(getApplicationContext(), MainService.class);
i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
getApplicationContext().startService(i);
status = true;
}
});
alertDialog.setButton(AlertDialog.BUTTON_NEGATIVE, "zurueck", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
alertDialog.cancel();
}
});
alertDialog.show();
} else {
Intent i = new Intent(getApplicationContext(), MainService.class);
i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
getApplicationContext().startService(i);
status = true;
}
} else {
// The toggle is disabled
Intent i = new Intent(getApplicationContext(), MainService.class);
getApplicationContext().stopService(i);
status = false;
}
}
});
// SensorManager.getInstance().populateListView(liste);
settings = PreferenceManager.getDefaultSharedPreferences(this);
if (settings.getBoolean("first_start", true)) {
// set initial version code, set first_start true and create ID
SharedPreferences.Editor editor = settings.edit();
editor.putBoolean("first_start", false);
editor.putBoolean("SMSSensor:ObserverStarted", false);
editor.putString("CallSensor:lastIntent", null);
editor.putBoolean("serviceStarted", false);
editor.putString("version", "" + currentVersionCode);
editor.putString("ID", ""
+ ((TelephonyManager) getApplicationContext()
.getSystemService(TELEPHONY_SERVICE))
.getDeviceId().hashCode());
editor.apply();
}
// getLoaderManager().initLoader(0, null, (android.app.LoaderManager.LoaderCallbacks<Cursor>) this);
*/
}
如果有人能看一眼我会变得绝望，我会很高兴的。
答案 0 :(得分：0)
您是否在AndroidManifest文件中声明了此MainActivity？
答案 1 :(得分：0)
检查AndroidManifest.xml
您应该在application标记中看到您的活动，如下所示：
<activity android:name="com.example.max.pswi.MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>