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android - 使用 onNavigationItemSelected() 在抽屉导航中切换 fragment

转载 作者:行者123 更新时间:2023-11-30 01:31:51 25 4
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所以我在 StackOverFlow 上浏览了很多答案,但无法正常工作。我想在抽屉导航项目点击时切换 fragment 。我在 Android Studio 1.5 中使用默认的抽屉导航。

我关注了this回答,我已经确定我已经创建了所有 fragment 。问题是每当我单击任何菜单项时,应用程序都会停止工作。这是我到目前为止所拥有的。

主 Activity .java

import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTransaction;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);

FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});

DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();

NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);

displayView(R.id.twitter);
}

@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();

//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}

return super.onOptionsItemSelected(item);
}

@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
displayView(item.getItemId());
return true;
}

public void displayView(int viewId) {

Fragment fragment = null;
String title = getString(R.string.app_name);

switch (viewId) {
case R.id.facebook:
fragment = new FacebookFragment();
title = "Facebook";
break;
case R.id.twitter:
fragment = new TwitterFragment();
title = "Twitter";
break;
case R.id.googleplus:
fragment = new GooglePlusFragment();
title = "Google Plus";
break;
case R.id.settings:
fragment = new SettingsFragment();
title = "Settings";
break;
}

if (fragment != null) {
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.content_frame, fragment);
ft.commit();
}

// set the toolbar title
if (getSupportActionBar() != null) {
getSupportActionBar().setTitle(title);
}

DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);

}
}

FacebookFragment.java

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


/**
* A simple {@link Fragment} subclass.
* Activities that contain this fragment must implement the
* {@link FacebookFragment.OnFragmentInteractionListener} interface
* to handle interaction events.
* Use the {@link FacebookFragment#newInstance} factory method to
* create an instance of this fragment.
*/
public class FacebookFragment extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";

// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;

private OnFragmentInteractionListener mListener;

public FacebookFragment() {
// Required empty public constructor
}

/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* @param param1 Parameter 1.
* @param param2 Parameter 2.
* @return A new instance of fragment FacebookFragment.
*/
// TODO: Rename and change types and number of parameters
public static FacebookFragment newInstance(String param1, String param2) {
FacebookFragment fragment = new FacebookFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_facebook, container, false);
}

// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}

@Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}

@Override
public void onDetach() {
super.onDetach();
mListener = null;
}

/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
* <p/>
* See the Android Training lesson <a href=
* "http://developer.android.com/training/basics/fragments/communicating.html"
* >Communicating with Other Fragments</a> for more information.
*/
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(Uri uri);
}
}

我已将 FrameLayout 添加到 content_main.xml 文件中,正如我提到的问题中所建议的那样。感谢您的帮助。

最佳答案

根据你的 logcat,错误是:

com.internetwarz.sploon.MainActivity@3caae0bc 必须实现 OnFragmentInteractionListener

我认为发生错误是因为您的父 Activity (MainActivity.java) 没有实现此方法:OnFragmentInteractionListener

通过评论可以看到:

/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
*/
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(Uri uri);
}

所以,解决方案是:

public class MainActivity extends AppCompatActivity 
implements NavigationView.OnNavigationItemSelectedListener,
FacebookFragment.OnFragmentInteractionListener {

....

// Add the method below to MainActivity.java
private void onFragmentInteraction(Uri uri) {
// Do something or just return
Toast.makeText(this, "Success", Toast.LENGTH_SHORT).show();
}
}

关于android - 使用 onNavigationItemSelected() 在抽屉导航中切换 fragment ,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/35642055/

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