public class HomeActivity extends AppCompatActivity{ RecyclerView chillHits; RecyclerView coolSongs; HomeAdaptor homeAdaptor; SongCollection songCollection = new SongCollection(); ImageButton imageButton; ImageButton imageButton2; ImageButton imageButton3; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); imageButton = findViewById(R.id.imageButton2); imageButton2 = findViewById(R.id.imageButton3); imageButton3 = findViewById(R.id.imageButton4); imageButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { startActivity(new Intent(getApplicationContext(), SearchActivity.class)); finish(); } }); setContentView(R.layout.activity_home); LinearLayoutManager horizontalLayoutManager = new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false); LinearLayoutManager horizontalLayoutManager2 = new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false); chillHits = findViewById(R.id.chillHits); homeAdaptor = new HomeAdaptor(SongCollection.arrayChillHits); chillHits.setAdapter(homeAdaptor); chillHits.setLayoutManager(horizontalLayoutManager); coolSongs = findViewById(R.id.coolSongs); homeAdaptor = new HomeAdaptor(SongCollection.arrayCoolSongs); coolSongs.setAdapter(homeAdaptor); coolSongs.setLayoutManager(horizontalLayoutManager2); } }
Error: Caused by: java.lang.NullPointerException: Attempt to invoke virtual method ‘void android.widget.ImageButton.setOnClickListener(android.view.View$OnClickListener)’ on a null object reference
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Answer
1)You forgot about setContentView(R.layout.YOURLAYOUT)
after super.onCreate
2)Make sure, that your XML file have the same ImageView ID