Ошибка приложений при переключении с экрана всплеска на MainActivity

Question

Итак, я постоянно получаю эту ошибку каждый раз, когда я запускаю свое приложение, оно запускается и запускает SplashActivity за правильное время, а затем пытается запустить MainActivity и немедленно сбой ,

Из того, что я могу сказать, это ошибка NullPointer, но я не могу для жизни понять, что.

Ошибка:

11-30 21:03:33.146 3216-3216/? D/dalvikvm: Not late-enabling CheckJNI (already on) 
11-30 21:03:34.646 3216-3216/edu.wmich.lab4aoneill3193 W/dalvikvm: VFY: unable to find class referenced in signature (Landroid/view/SearchEvent;) 
11-30 21:03:34.646 3216-3216/edu.wmich.lab4aoneill3193 I/dalvikvm: Could not find method android.view.Window$Callback.onSearchRequested, referenced from method android.support.v7.view.WindowCallbackWrapper.onSearchRequested 
11-30 21:03:34.656 3216-3216/edu.wmich.lab4aoneill3193 W/dalvikvm: VFY: unable to resolve interface method 14517: Landroid/view/Window$Callback;.onSearchRequested (Landroid/view/SearchEvent;)Z 
11-30 21:03:34.656 3216-3216/edu.wmich.lab4aoneill3193 D/dalvikvm: VFY: replacing opcode 0x72 at 0x0002 
11-30 21:03:34.656 3216-3216/edu.wmich.lab4aoneill3193 I/dalvikvm: Could not find method android.view.Window$Callback.onWindowStartingActionMode, referenced from method android.support.v7.view.WindowCallbackWrapper.onWindowStartingActionMode 
11-30 21:03:34.656 3216-3216/edu.wmich.lab4aoneill3193 W/dalvikvm: VFY: unable to resolve interface method 14521: Landroid/view/Window$Callback;.onWindowStartingActionMode (Landroid/view/ActionMode$Callback;I)Landroid/view/ActionMode; 
11-30 21:03:34.656 3216-3216/edu.wmich.lab4aoneill3193 D/dalvikvm: VFY: replacing opcode 0x72 at 0x0002 
11-30 21:03:34.856 3216-3216/edu.wmich.lab4aoneill3193 D/dalvikvm: GC_FOR_ALLOC freed 129K, 7% free 2772K/2972K, paused 57ms, total 59ms 
11-30 21:03:34.856 3216-3216/edu.wmich.lab4aoneill3193 I/dalvikvm-heap: Grow heap (frag case) to 5.308MB for 2658320-byte allocation 
11-30 21:03:34.916 3216-3225/edu.wmich.lab4aoneill3193 D/dalvikvm: GC_FOR_ALLOC freed <1K, 4% free 5367K/5572K, paused 48ms, total 48ms 
11-30 21:03:35.646 3216-3216/edu.wmich.lab4aoneill3193 I/dalvikvm: Could not find method android.content.res.TypedArray.getChangingConfigurations, referenced from method android.support.v7.widget.TintTypedArray.getChangingConfigurations 
11-30 21:03:35.646 3216-3216/edu.wmich.lab4aoneill3193 W/dalvikvm: VFY: unable to resolve virtual method 409: Landroid/content/res/TypedArray;.getChangingConfigurations()I 
11-30 21:03:35.646 3216-3216/edu.wmich.lab4aoneill3193 D/dalvikvm: VFY: replacing opcode 0x6e at 0x0002 
11-30 21:03:35.656 3216-3216/edu.wmich.lab4aoneill3193 I/dalvikvm: Could not find method android.content.res.TypedArray.getType, referenced from method android.support.v7.widget.TintTypedArray.getType 
11-30 21:03:35.656 3216-3216/edu.wmich.lab4aoneill3193 W/dalvikvm: VFY: unable to resolve virtual method 431: Landroid/content/res/TypedArray;.getType (I)I 
11-30 21:03:35.656 3216-3216/edu.wmich.lab4aoneill3193 D/dalvikvm: VFY: replacing opcode 0x6e at 0x0002 
11-30 21:03:35.866 3216-3216/edu.wmich.lab4aoneill3193 W/EGL_emulation: eglSurfaceAttrib not implemented 
11-30 21:03:35.886 3216-3216/edu.wmich.lab4aoneill3193 D/OpenGLRenderer: Enabling debug mode 0 
11-30 21:03:41.596 3216-3216/edu.wmich.lab4aoneill3193 D/AndroidRuntime: Shutting down VM 
11-30 21:03:41.596 3216-3216/edu.wmich.lab4aoneill3193 W/dalvikvm: threadid=1: thread exiting with uncaught exception (group=0xb3ac0ba8) 
11-30 21:03:41.666 3216-3216/edu.wmich.lab4aoneill3193 E/AndroidRuntime: FATAL EXCEPTION: main 
                     Process: edu.wmich.lab4aoneill3193, PID: 3216 
                     java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{edu.wmich.lab4aoneill3193/edu.wmich.lab4aoneill3193.MainActivity}: java.lang.NullPointerException 
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2121) 
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245) 
                      at android.app.ActivityThread.access$800(ActivityThread.java:135) 
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196) 
                      at android.os.Handler.dispatchMessage(Handler.java:102) 
                      at android.os.Looper.loop(Looper.java:136) 
                      at android.app.ActivityThread.main(ActivityThread.java:5017) 
                      at java.lang.reflect.Method.invokeNative(Native Method) 
                      at java.lang.reflect.Method.invoke(Method.java:515) 
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779) 
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595) 
                      at dalvik.system.NativeStart.main(Native Method) 
                      Caused by: java.lang.NullPointerException 
                      at android.app.Activity.findViewById(Activity.java:1884) 
                      at edu.wmich.lab4aoneill3193.MainActivity.<init>(MainActivity.java:36) 
                      at java.lang.Class.newInstanceImpl(Native Method) 
                      at java.lang.Class.newInstance(Class.java:1208) 
                      at android.app.Instrumentation.newActivity(Instrumentation.java:1061) 
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2112) 
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)  
                      at android.app.ActivityThread.access$800(ActivityThread.java:135)  
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)  
                      at android.os.Handler.dispatchMessage(Handler.java:102)  
                      at android.os.Looper.loop(Looper.java:136)  
                      at android.app.ActivityThread.main(ActivityThread.java:5017)  
                      at java.lang.reflect.Method.invokeNative(Native Method)  
                      at java.lang.reflect.Method.invoke(Method.java:515)  
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)  
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)  
                      at dalvik.system.NativeStart.main(Native Method)  
11-30 21:08:42.916 3216-3216/edu.wmich.lab4aoneill3193 I/Process: Sending signal. PID: 3216 SIG: 9 

Android Manifest:

<?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=".SplashActivity"> 
     <intent-filter> 
      <action android:name="android.intent.action.MAIN" /> 

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

SplashActivity.java:

package edu.wmich.lab4aoneill3193; 

import android.content.Intent; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 

import java.util.Timer; 
import java.util.TimerTask; 

public class SplashActivity extends AppCompatActivity { 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_splash); 

     TimerTask splash = new TimerTask() { 
      @Override 
      public void run() { 
       finish(); 
       startActivity(new Intent(SplashActivity.this,MainActivity.class)); 
      } 
     }; 
     Timer opening = new Timer(); 
     opening.schedule(splash,5000); 
    } 
} 

MainActivity.Java:

package edu.wmich.lab4aoneill3193 

import android.app.DatePickerDialog; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.Button; 
import android.widget.DatePicker; 
import android.widget.RadioButton; 
import android.widget.TextView; 
import android.widget.Toast; 

import java.text.DateFormat; 
import java.util.Calendar; 

public class MainActivity extends AppCompatActivity { 

    private TextView reservation; 

    final RadioButton chcOne = (RadioButton) findViewById(R.id.choiceOne); 
    final RadioButton chcTwo = (RadioButton) findViewById(R.id.choiceTwo); 
    final RadioButton chcThree = (RadioButton) findViewById(R.id.choiceThree); 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 

     reservation = (TextView) findViewById(R.id.rsltText); 
     Button btnDate = (Button) findViewById(R.id.btnDate); 

     btnDate.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       new DatePickerDialog(MainActivity.this, date, cal.get(Calendar.YEAR), 
         cal.get(Calendar.MONTH), cal.get(Calendar.DAY_OF_MONTH)).show(); 
      } 
     }); 

    } 

    Calendar cal = Calendar.getInstance(); 
    DateFormat fmtDate = DateFormat.getDateInstance(); 
    DatePickerDialog.OnDateSetListener date = new DatePickerDialog.OnDateSetListener() { 

     @Override 
     public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) { 
      cal.set(Calendar.YEAR, year); 
      cal.set(Calendar.MONTH, monthOfYear); 
      cal.set(Calendar.DAY_OF_MONTH, dayOfMonth); 
      if (chcOne.isChecked()) { 
       reservation.setText("A Massive Asteroid Will Impact The Earth on " 
         + fmtDate.format(cal.getTime())); 
      } else {Toast.makeText(MainActivity.this, "Choose Something!",Toast.LENGTH_LONG).show(); 
      } 
      if (chcTwo.isChecked()){ 
       reservation.setText("Massive Tsunamis Will Engulf The World on " 
         + fmtDate.format(cal.getTime())); 
      } else {Toast.makeText(MainActivity.this, "Choose Something!",Toast.LENGTH_LONG).show(); 
      } 
      if (chcThree.isChecked()) { 
       reservation.setText("A Fatal Disease Will OverWhelm The World on " 
         + fmtDate.format(cal.getTime())); 
      } else {Toast.makeText(MainActivity.this, "Choose Something!",Toast.LENGTH_LONG).show(); 
      } 
     } 
    }; 
} 

Answer 1

findViewById(int) должен быть вызван только после того, как макет активности установлен на setContentView(int). Если вы раздуваете свои взгляды, вы можете вызвать findViewById(int) на этом объекте вида.

Так изменить код

MainActivity.Java: общественного класса MainActivity расширяет AppCompatActivity {

private TextView reservation; 

RadioButton chcOne; 
RadioButton chcTwo; 
RadioButton chcThree; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 

    reservation = (TextView) findViewById(R.id.rsltText); 
    Button btnDate = (Button) findViewById(R.id.btnDate); 
    chcOne = (RadioButton) findViewById(R.id.choiceOne); 
    chcTwo = (RadioButton) findViewById(R.id.choiceTwo); 
    chcThree = (RadioButton) findViewById(R.id.choiceThree); 

    btnDate.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      new DatePickerDialog(MainActivity.this, date, cal.get(Calendar.YEAR), 
        cal.get(Calendar.MONTH), cal.get(Calendar.DAY_OF_MONTH)).show(); 
     } 
    }); 

} 

Calendar cal = Calendar.getInstance(); 
DateFormat fmtDate = DateFormat.getDateInstance(); 
DatePickerDialog.OnDateSetListener date = new DatePickerDialog.OnDateSetListener() { 

    @Override 
    public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) { 
     cal.set(Calendar.YEAR, year); 
     cal.set(Calendar.MONTH, monthOfYear); 
     cal.set(Calendar.DAY_OF_MONTH, dayOfMonth); 
     if (chcOne.isChecked()) { 
      reservation.setText("A Massive Asteroid Will Impact The Earth on " 
        + fmtDate.format(cal.getTime())); 
     } else {Toast.makeText(MainActivity.this, "Choose Something!",Toast.LENGTH_LONG).show(); 
     } 
     if (chcTwo.isChecked()){ 
      reservation.setText("Massive Tsunamis Will Engulf The World on " 
        + fmtDate.format(cal.getTime())); 
     } else {Toast.makeText(MainActivity.this, "Choose Something!",Toast.LENGTH_LONG).show(); 
     } 
     if (chcThree.isChecked()) { 
      reservation.setText("A Fatal Disease Will OverWhelm The World on " 
        + fmtDate.format(cal.getTime())); 
     } else {Toast.makeText(MainActivity.this, "Choose Something!",Toast.LENGTH_LONG).show(); 
     } 
    } 
}; 
} 

Надеется, что это помогает ...

Answer 2

привет вы закончите вашу деятельность первого после того, как вы начать свою следующую деятельность попытаться изменить этот путь,

TimerTask splash = new TimerTask() { 
     @Override 
     public void run() { 

      startActivity(new Intent(SplashActivity.this,MainActivity.class)); 
finish(); 
     } 
    }; 
    Timer opening = new Timer(); 
    opening.schedule(splash,5000); 

Answer 3

Попробуйте открыть непосредственно Основную активность первой в эмуляторе если его запуск затем попробует это во всплеске

Thread timer= new Thread() { 
    public void run() { 
    try{sleep(2000);}catch (InteruptedException e) {e.printstacktrace() ;} 
    finally {Intent intent=new Intent(splash.this, MainActivity.class)  startActivity(intent) ;} 
} 
}; 
timer.start(); 
@Override 
public void onPause() { 
super.onPause() ; 
finish() ; 
    }