如何在片段中添加它

Question

我正在尝试将片段与活动结合起来。但我最终得到了一个错误。

片段代码：

public class QFragment extends Fragment {@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    //returning our layout file
    //change R.layout.yourlayoutfilename for each of your fragments
    return inflater.inflate(R.layout.fragment_q, container, false);
}


    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        //you can set the title for your toolbar here for different fragments different titles
        getActivity().setTitle("QFragment");
    }
}

一个被用作活动，另一个是片段。我是片段概念的新手。

主要活动代码：

    public class SpinnerEx4Activity extends Activity implements
    OnItemSelectedListener{
    Spinner s1,s2;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            // TODO Auto-generated method stub
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_spinner_ex4);
            s1 = (Spinner)findViewById(R.id.spinner1);
            s2 = (Spinner)findViewById(R.id.spinner2);
            s1.setOnItemSelectedListener(this);
        }
        @Override
        public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2,
                long arg3) {
            // TODO Auto-generated method stub
            String sp1= String.valueOf(s1.getSelectedItem());
            Toast.makeText(this, sp1, Toast.LENGTH_SHORT).show();
            if(sp1.contentEquals("Income")) {
                List<String> list = new ArrayList<String>();
                list.add("Salary");
                list.add("Sales");
                list.add("Others");
                ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,
                    android.R.layout.simple_spinner_item, list);
                dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
                dataAdapter.notifyDataSetChanged();
                s2.setAdapter(dataAdapter);
            }
            if(sp1.contentEquals("Expense")) {
                List<String> list = new ArrayList<String>();
                list.add("Conveyance");
                list.add("Breakfast");
                list.add("Purchase");
                ArrayAdapter<String> dataAdapter2 = new ArrayAdapter<String>(this,
                    android.R.layout.simple_spinner_item, list);
                dataAdapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
                dataAdapter2.notifyDataSetChanged();
                s2.setAdapter(dataAdapter2);
            }

        }
        @Override
        public void onNothingSelected(AdapterView<?> arg0) {
            // TODO Auto-generated method stub

        }
    }

那么解决这个问题的方法是什么？我想在我的应用中使用底部导航栏。

Answer 1

您将把您的实现放在片段中，并让片段事务管理器从活动中调用它，这里是代码示例。 `

package com.bar.example.androidspinnerexample;

    import java.util.ArrayList;
    import java.util.List;

    import android.app.Activity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.AdapterView;
    import android.widget.ArrayAdapter;
    import android.widget.Spinner;
    import android.widget.AdapterView.OnItemSelectedListener;
    import android.widget.Toast;

    public class SpinnerEx4Activity extends Activity implements
    OnItemSelectedListener{
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            // TODO Auto-generated method stub
            super.onCreate(savedInstanceState);
            QFragment fragment = new QFragment();
            android.support.v4.app.FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
            //container id as first param for replace function
            fragmentTransaction.replace(R.id.activity_spinner_ex4, fragment, null);
            fragmentTransaction.addToBackStack(null);
            fragmentTransaction.commit();

        }
    }

对于片段

package com.blipclap.engineering_solution;

import android.content.Context;

import android.net.Uri;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;


public class QFragment extends Fragment implements
    OnItemSelectedListener{@Nullable
            Spinner s1,s2;

@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    //returning our layout file
    //change R.layout.yourlayoutfilename for each of your fragments
    View view = inflater.inflate(R.layout.fragment_q, container, false);
    s1 = (Spinner)view.findViewById(R.id.spinner1);
    s2 = (Spinner)view.findViewById(R.id.spinner2);
    s1.setOnItemSelectedListener(this);

    return view;
}


    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        //you can set the title for your toolbar here for different fragments different titles
        getActivity().setTitle("QFragment");
    }

        @Override
        public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2,
                long arg3) {
            // TODO Auto-generated method stub
            String sp1= String.valueOf(s1.getSelectedItem());
            Toast.makeText(this, sp1, Toast.LENGTH_SHORT).show();
            if(sp1.contentEquals("Income")) {
                List<String> list = new ArrayList<String>();
                list.add("Salary");
                list.add("Sales");
                list.add("Others");
                ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,
                    android.R.layout.simple_spinner_item, list);
                dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
                dataAdapter.notifyDataSetChanged();
                s2.setAdapter(dataAdapter);
            }
            if(sp1.contentEquals("Expense")) {
                List<String> list = new ArrayList<String>();
                list.add("Conveyance");
                list.add("Breakfast");
                list.add("Purchase");
                ArrayAdapter<String> dataAdapter2 = new ArrayAdapter<String>(this,
                    android.R.layout.simple_spinner_item, list);
                dataAdapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
                dataAdapter2.notifyDataSetChanged();
                s2.setAdapter(dataAdapter2);
            }

        }
        @Override
        public void onNothingSelected(AdapterView<?> arg0) {
            // TODO Auto-generated method stub

        }

}

Answer 2

对于您提到的 3 个错误，请将 this 替换为您的班级名称 SpinnerEx4Activity.this 用于所有三行这样的。

Toast.makeText(SpinnerEx4Activity.this, sp1, Toast.LENGTH_SHORT).show();



ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(SpinnerEx4Activity.this, android.R.layout.simple_spinner_item, list);



ArrayAdapter<String> dataAdapter2 = new ArrayAdapter<String>(SpinnerEx4Activity.this, android.R.layout.simple_spinner_item, list);