解决listView.setAdapter()出现空指针异常

<!--这里是你的ListView-->
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ListView
        android:id="@+id/list_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</LinearLayout>

public class ToGoTravel1 extends AppCompatActivity {

    private static final String TAG = "ToGoTravel1";

    private List<String> data(){
        List<String> data = new ArrayList<>();
        data.add("梦游天子山");
        data.add("长沙橘子洲头和坡子街");
        return data;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_to_go_travel);//你的listView一定要是这个布局中的listViewID

        ArrayAdapter<String> adapter = new ArrayAdapter<>(
                this,android.R.layout.simple_list_item_1,data());
        ListView listView = (ListView) findViewById(R.id.list_view);
        listView.setAdapter(adapter);

其实就是粗心犯的小错误-。-