在适配器中创建三个元素

Question

我已经用ImageView和TextView制作了抽屉菜单，它可以run.However，当我想用两个ImageView和一个TextView创建抽屉菜单时，它会用我的第二个ImageView显示错误（“尝试调用虚拟方法”）（我代码中的变量名称是“img”）

我的代码如下：

public class MenuListAdapter extends BaseAdapter {

//...

public View getView(int position, View convertView, ViewGroup parent) {
    View v = convertView;
    
    TextView Title = null;
    ImageView Icon = null;
    ImageView img = null;

    if (v == null) {
        
        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        v = inflater.inflate(R.layout.drawer, parent, false);

        // Locate the TextViews in drawer_list_item.xml
        Title = (TextView) convertView.findViewById(R.id.title);

        // Locate the ImageView in drawer_list_item.xml
        Icon = (ImageView) convertView.findViewById(R.id.icon);

        // Locate the ImageView in drawer_list_item.xml
        img = (ImageView) convertView.findViewById(R.id.img);

    }

    Title.setText(mTitle[position]);
    
    Icon.setImageResource(mIcon[position]);
    img.setImageResource(mimg[position]);

    return v;
}

这是我的日志：

09-16 22:25:38.458：E/AndroidRuntime（14966）：致命例外：主

09-16 22:25:38.458:E/Android runtime(14966):Java . lang . nullpointerexception:尝试在空对象引用上调用虚拟方法“Android . view . view Android . view . view . findviewbyid(int)”09-16 22:25:38.458:E/Android runtime(14966):at com . test . adapter . menulistadapter . get view(menulistadapter . Java:84) 09-16 22:25:38.458:E/Android runtime(14966):at Android . widget . frame layout . onlayout(frame layout . Java:508)09-16 22:25:38.458:E/Android runtime(14966):at Android . view . view . layout(view . Java:15686)09-16 22:25:38.458:E/Android runtime(14966 09-16 22:25:38.458:E/Android runtime(14966):at Android . view . choreographer . do frame(choreographer . Java:550)09-16 22:25:38.458:E/Android runtime(14966):at Android . view . choreographer $ framedisplayeventreceiver . run(choreographer . Java:753)09-16 22:25:38.458:E/Android

Answer 1

   <ImageView
       android:id="@+id/icon"
       android:layout_width="30dp"
       android:layout_height="30dp"
       android:layout_marginLeft="22dp"
       android:layout_marginRight="20dp"
       android:adjustViewBounds="true"
       android:scaleType="fitCenter" />



   <TextView
       android:id="@+id/title"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:textColor="#848484"
       android:textSize="15dp" />

   <TextView
       android:id="@+id/textABC"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:text="TextView" />

Answer 2

您已将膨胀视图分配给 v，但您正在使用 convertView 来查找膨胀视图小部件。摆脱v并使用只转换视图

public View getView(int position, View convertView, ViewGroup parent) {

    if (convertView == null) {
        LayoutInflater inflater = (LayoutInflater) context
              .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
       convertView = inflater.inflate(R.layout.drawer, parent, false);
    }

    // Locate the TextViews in drawer_list_item.xml
    TextView title = (TextView) convertView.findViewById(R.id.title);
    // Locate the ImageView in drawer_list_item.xml
    ImageView icon = (ImageView) convertView.findViewById(R.id.icon);
    // Locate the ImageView in drawer_list_item.xml
    ImageView img = (ImageView) convertView.findViewById(R.id.img);

    title.setText(mTitle[position]);
    icon.setImageResource(mIcon[position]);
    img.setImageResource(mimg[position]);

   return convertView;
}