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in Technique[技术] by (71.8m points)

not able to launch the app on android studio is it showing java.lang.NullPointerException:

app is not launching. i have seen the the splash screen tutorial from youtube

<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    android:background="#fece2f">

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="10dp"
        android:layout_marginTop="104dp"
        android:layout_marginEnd="10dp"
        android:contentDescription="@string/todo"
        android:src="@drawable/logo"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="496dp"
        android:fontFamily="@font/bangers"
        android:text="@string/TARZERA"
        android:textAlignment="center"
        android:textSize="70sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="1.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"/>

    <TextView
        android:id="@+id/textView3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:fontFamily="@font/antic"
        android:text="@string/Manifacturer_of_Scarves_Stoles"
        android:textAlignment="center"
        android:textSize="18sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.502"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView2" />

here is the main activity

</androidx.constraintlayout.widget.ConstraintLayout>


    {
   private static int SPLASH_SCREEN = 5000;

    //variables
    Animation topAnim, bottomAnim;
    ImageView imageView;
    TextView logo, slogan;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.activity_main);

        //Animations
        topAnim  = AnimationUtils.loadAnimation(this,R.anim.top_animation);
        bottomAnim = AnimationUtils.loadAnimation(this,R.anim.bottom_animation);

        //Hooks

        imageView = findViewById(R.id.imageView);
        logo = findViewById(R.id.textView);
        slogan = findViewById(R.id.textView2);

        imageView.setAnimation(topAnim);
         logo.setAnimation(bottomAnim);
        slogan.setAnimation(bottomAnim);

        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                Intent intent = new Intent(MainActivity.this,Dashboard.class);
                startActivity(intent);
                finish();
            }
        },SPLASH_SCREEN);
    }
}


    <?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">

    <translate
        android:fromXDelta="0%"
        android:fromYDelta="-50%"
        android:duration="2000"/>
    <alpha
        android:fromAlpha="0.1"
        android:toAlpha="1.0"
        android:duration="1500"/>
</set>




  <?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">

    <translate
        android:fromXDelta="0%"
        android:fromYDelta="100%"
        android:duration="1500"/>
    <alpha
        android:fromAlpha="0.1"
        android:toAlpha="1.0"
        android:duration="1500"/>
</set>

the main problem is that i am not able to now launch the app in the emulator also tried everything to makke it work but still not able to make it. while launching the app it is showing a long list of errors but non of them is any coding error but launching problem


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1 Answer

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by (71.8m points)

In your xml file you gave id of textviews as textView2 and textView3. But in your java file you are setting id's as textView and textView2. So, change that 2 lines.

logo = findViewById(R.id.textView2);
slogan = findViewById(R.id.textView3);

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
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