Question

我输入了这一行：lv1.setOnItemClickListener（（OnItemClickListener）this）;因为它会产生一条红色的波浪线。我是否正确使用onItemClick功能？

 public class MainActivity extends Activity {

private ListView lv1;
private String lv_arr[] = {
        "Android",
        "iPhone",
        "Blackberry",
        "AndroidPeople"
};


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    lv1 = (ListView) findViewById(R.id.ListView01);
    lv1.setOnItemClickListener((OnItemClickListener) this);
    //by using setAdapter method in ListView, we can add string array in list

    lv1.setAdapter(new ArrayAdapter<String>(
            this, android.R.layout.simple_list_item_1, lv_arr));

}

public void onItemClick(AdapterView arg0, View v, int position, long arg3){

    Toast.makeText(this, "You clicked" + lv_arr[position],       Toast.LENGTH_LONG).show();

}



 }

Answer 1

您的MainActivity没有实施OnItemClickListener，这就是为什么它会给您“红色线条”。

您应该将类声明更改为：

public class MainActivity extends Activity implements OnItemClickListener {

这意味着，在将MainActivity设置为OnItemClickListener

时，您无需将ListView投射到{{1}}

Answer 2

你需要实现OnItemClickListener，或者只是你可以编写

 lv1.setOnItemClickListener(new OnItemClickListener() {
        public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {
            Toast.makeText(this, "You clicked" + lv_arr[position],       Toast.LENGTH_LONG).show();
        }
    });

Answer 3

如果您尝试使用自定义onClickListener()的每一行，则需要扩展ArrayAdapter（例如）并为其中的每一行实施onClickListener() getView()方法。

@Override
public View getView(final int position, View convertView, final ViewGroup parent) {
  // Speaking very vaguely, convertView represents each of your rows
  if (convertView == null) {
    ...
    convertView.setOnClickListener(new View.OnClickListener() {
      public void onClick(final View v) {
        // Whetever you need
        ...
      }
    }
  });
  else
    ...

  // Rest of your implementation
  ...

  return convertView; 
}

我的ListView不起作用。我在这里错过了一些东西

3 个答案: