Make Alert dailog with buttons open another app - android studio

Button open = findViewById(R.id.open); open.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { }); Button open = findViewById(R.id.open); open.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { AlertDialog.Builder builder = new AlertDialog.Builder( loadgame.this ); builder.setTitle("OPEN GAME"); String[] animals = {"OPEN PUBG GLOBAL", "OPEN PUBG KOREA", "OPEN PUBG BGMI", "OPEN PUBG TAIWAN", "OPEN PUBG VIETNAM"}; builder.setItems(animals, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { switch (which) { case 0: /// startActivity(new Intent(getApplicationContext(), about.class)); Intent GlIntent = getPackageManager().getLaunchIntentForPackage("com.tencent.ig"); if (GlIntent != null) { startActivity(GlIntent); } else { Toast.makeText(loadgame.this, "Game Not Found", Toast.LENGTH_SHORT).show(); } break; case 1: Intent KrIntent = getPackageManager().getLaunchIntentForPackage("com.pubg.krmobile"); if (KrIntent != null) { startActivity(KrIntent); } else { Toast.makeText(loadgame.this, "Game Not Found", Toast.LENGTH_SHORT).show(); } break; case 2: Intent BgIntent = getPackageManager().getLaunchIntentForPackage("com.pubg.imobile"); if (BgIntent != null) { startActivity(BgIntent); } else { Toast.makeText(loadgame.this, "Game Not Found", Toast.LENGTH_SHORT).show(); } break; case 3: Intent TwIntent = getPackageManager().getLaunchIntentForPackage("com.rekoo.pubgm"); if (TwIntent != null) { startActivity(TwIntent); } else { Toast.makeText(loadgame.this, "Game Not Found", Toast.LENGTH_SHORT).show(); } break; case 4: Intent VnIntent = getPackageManager().getLaunchIntentForPackage("com.vng.pubgmobile"); if (VnIntent != null) { startActivity(VnIntent); } else { Toast.makeText(loadgame.this, "Game Not Found", Toast.LENGTH_SHORT).show(); } break; } } }); AlertDialog dialog = builder.create(); dialog.show(); } });