Question

例如，当我按下列表视图上的一个项目的长按，其实际按钮将变为删除按钮。我试着像next_sign.setBackgroundResource(R.drawable.delete);但是，它强行关闭。

lv.setOnItemLongClickListener(new OnItemLongClickListener() {

            @Override
            public boolean onItemLongClick(AdapterView<?> parent, View view,
                    int position, long id) {
                //next_sign.setBackgroundResource(R.drawable.delete);
                return true;
            }
        });

12-28 13:44:34.251: E/AndroidRuntime(9108): FATAL EXCEPTION: main
12-28 13:44:34.251: E/AndroidRuntime(9108): java.lang.NullPointerException
12-28 13:44:34.251: E/AndroidRuntime(9108):     at com.mycos.cycleborg.PreviousActivity$3.onItemLongClick(MenuListActivity.java:129)

Answer 1

您必须声明第一个项目的两个按钮并删除布局中相同位置的按钮使原始按钮可见

android:visibility="visible"

并使用

使删除按钮的可见性在布局中消失

android:visibility="gone"

编程中的

lv.setOnItemLongClickListener(new OnItemLongClickListener() {

            @Override
            public boolean onItemLongClick(AdapterView<?> parent, View view,
                    int position, long id) {
              Original_Button.setVisibility(View.Gone);
               delete_Button.setVisibility(View.Visible); 
                return true;
            }
        });

Answer 2

public boolean onItemLongClick(AdapterView<?> arg0, View view, int arg2, long arg3) {
   Button mButton = (Button)view.findViewById(R.id.button);
   mButton.setVisibility(View.Visible); 
   return true;
}

长按时如何更改列表视图上的图像按钮

2 个答案: