Question

我的片段（称为＆＃34;购买＆＃34;）列表视图。所以当然我有一个适配器。问题是我的适配器中有一个数学过程，我需要将结果发送到我的txtview。但不幸的是，我的文本观点在我的片段中。那么我该如何发送这个变量呢？有些像

((FragmentBuy) Fragment).send(prize);

但当然这不起作用。谢谢你的帮助！

我有一个MainActivity

public class MainActiviry extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_tabs);


        TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
        tabLayout.addTab(tabLayout.newTab().setText("Buy"));
        tabLayout.addTab(tabLayout.newTab().setText("Sell"));
        tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);

        final ViewPager viewPager = (ViewPager) findViewById(R.id.pager);
        final PagerAdapter adapter = new PagerAdapter
                (getSupportFragmentManager(), tabLayout.getTabCount());
        viewPager.setAdapter(adapter);
        viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
        tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                viewPager.setCurrentItem(tab.getPosition());
            }

            @Override
            public void onTabUnselected(TabLayout.Tab tab) {

            }

            @Override
            public void onTabReselected(TabLayout.Tab tab) {

            }
        });
    }

当然还有我的寻呼机

        public class PagerAdapter extends FragmentStatePagerAdapter {
        int mNumOfTabs;
        public PagerAdapter(FragmentManager fm, int NumOfTabs) {
            super(fm);
            this.mNumOfTabs = NumOfTabs;
        }

        @Override
        public Fragment getItem(int position) {
            switch (position) {
                case 0:
                    FragmentCompras tab1 = new FragmentBuy();
                    return tab1;
                case 1:
                    FragmentDespensa tab2 = new FragmentSell();
                    return tab2;
                default:
                    return null;
            }
        }

        @Override
        public int getCount() {
            return mNumOfTabs;
        }
    }

我的适配器

    public class ListViewAdapter extends BaseAdapter{

public ArrayList<HashMap<String, String>> list;

Activity activity;
int contador = 0;
public ListViewAdapter(Activity activity, ArrayList<HashMap<String, String>> list){
    super();
    this.activity = activity;
    this.list = list;

}
@Override
public int getCount() {
    return list.size();
}

@Override
public Object getItem(int position) {
    return list.get(position);
}

@Override
public long getItemId(int position) {
    return 0;
}
private class ViewHolder {
TextView name;
TextView marc, cant, prec;}

@Override

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

    final ViewHolder holder;
    LayoutInflater inflater = activity.getLayoutInflater();
    if (convertView == null){
        convertView = inflater.inflate(R.layout.list_colum, null);
        holder = new ViewHolder();

        holder.name = (TextView) convertView.findViewById(R.id.name);
        holder.marc = (TextView) convertView.findViewById(R.id.marc);
        holder.cant = (TextView) convertView.findViewById(R.id.cant);
        holder.prec = (TextView) convertView.findViewById(R.id.prec);
        convertView.setTag(holder);
    }
    else{

        holder=(ViewHolder) convertView.getTag();

    }

    HashMap<String, String> map = list.get(position);
    holder.name.setText(map.get(FIRST_COLUMN));
    holder.marc.setText(map.get(SECOND_COLUMN));
    holder.prec.setText(map.get(THIRD_COLUMN));
    holder.cant.setText(map.get(FOURTH_COLUMN));



    return convertView;

}

我的片段

public class FragmentBuy extends android.support.v4.app.Fragment implements View.OnClickListener{
    private ArrayList<HashMap<String, String>> list;
    //HashMap<String, String> temp = new HashMap<String, String>();
    private Button scanBtn;
    static boolean guardar;
    private TextView txttotal, formatTxt, contentTxt, lblmx, textView, cantidadproducto;
    ListView listView;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.activy_micompra, container, false);
        final DbHelper admin = new DbHelper(view.getContext(), null);
        list = new ArrayList<HashMap<String, String>>();
        setHasOptionsMenu(true);
        guardar = false;

        txttotal = (TextView)view.findViewById(R.id.total); //this is my textview
        textView = (TextView) view.findViewById(R.id.mxcompra);
        cantidadproducto = (TextView)view.findViewById(R.id.cantidadproducto);
        return view;
    }

Answer 1

因此，直接的方法是直接在Activity中为数学计算创建变量。以下是步骤：

创建一个接口回调，它将数据从ListAdapter
为您的片段创建实例变量，该变量包含MainActivity中的公共方法发送（奖品）
通过接口回调中的fragmentBuy.send（prize）直接从活动中调用您的方法

Answer 2

您可以使用事件总线与适配器类中的片段进行通信。它简化了组件之间的通信。它还可以很好地处理活动，片段和后台线程。对于简单的通信过程，您可以使用Otto事件总线..

有关详情，请访问此处.. Otto event bus

Answer 3

您可以使用界面在Listview适配器和Fragment之间进行通信。

步骤：

1.使用send方法创建一个接口。 2.在Fragment中实现该方法。 3.当crating适配器传递接口的引用（即实现类的接口..这是当前片段。） 4）在使用该Interface对象调用send方法的适配器中。

如何在ListViewAdapter和Fragment之间发送变量。

3 个答案: