//di activity_main.xml:

<ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/soal" android:id="@+id/soal0" android:layout_gravity="center" android:visibility="invisible" /><Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/answer" android:onClick="answer_click" android:layout_alignParentBottom="true" android:layout_centerInParent="true"/>

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//di MainActivity.java:

public boolean soal_ada=false; public void answer_click(View view) { if(!soal_ada) { ImageView imageView = (ImageView) findViewById(R.id.soal0); imageView.setVisibility(View.VISIBLE); soal_ada=true; }else{ ImageView imageView = (ImageView) findViewById(R.id.soal0); imageView.setVisibility(View.INVISIBLE); soal_ada=false; } }