我的代码工作得很完美:每次单击导航抽屉中的项目时，项目就会被选中。
当然，我想启动应用程序与默认片段(家)，但导航抽屉没有选择的项目。如何以编程方式选择该项目?
public class BaseApp extends AppCompatActivity {
//Defining Variables
protected String LOGTAG = "LOGDEBUG";
protected Toolbar toolbar;
protected NavigationView navigationView;
protected DrawerLayout drawerLayout;
private DateManager db = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.base_layout);
navigationView = (NavigationView) findViewById(R.id.navigation_view);
// set the home/dashboard at startup
FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.frame, new DashboardFragment());
fragmentTransaction.commit();
setNavDrawer();
}
private void setNavDrawer(){
// Initializing Toolbar and setting it as the actionbar
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
//Initializing NavigationView
//Setting Navigation View Item Selected Listener to handle the item click of the navigation menu
navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
// This method will trigger on item Click of navigation menu
@Override
public boolean onNavigationItemSelected(MenuItem menuItem) {
//Checking if the item is in checked state or not, if not make it in checked state
// I THINK THAT I NEED EDIT HERE...
if (menuItem.isChecked()) menuItem.setChecked(false);
else menuItem.setChecked(true);
//Closing drawer on item click
drawerLayout.closeDrawers();
//Check to see which item was being clicked and perform appropriate action
switch (menuItem.getItemId()) {
//Replacing the main content with ContentFragment
case R.id.home:
DashboardFragment dashboardFragment = new DashboardFragment();
FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.frame, dashboardFragment,"DASHBOARD_FRAGMENT");
fragmentTransaction.commit();
return true;
[...]
我认为我需要在这里进行编辑:
if (menuItem.isChecked()) menuItem.setChecked(false);
else menuItem.setChecked(true);
或者在onCreate中在App启动时使用FragmentTransaction。
谢谢你的支持。
使用下面的代码:
navigationView.getMenu().getItem(0).setChecked(true);
在调用setNavDrawer()之后调用此方法;
getItem(int index)方法获取MenuItem，然后你可以调用setChecked(true);在这个MenuItem上，剩下要做的就是找出默认的元素索引，并用该索引替换0。
您可以通过调用来选择(突出显示)项目
onNavigationItemSelected(navigationView.getMenu().getItem(0));
这里有一个参考链接:http://thegeekyland.blogspot.com/2015/11/navigation-drawer-how-set-selected-item.html
编辑
在nexus 4上无法使用，支持库版本24.0.0。我推荐使用
navigationView.setCheckedItem（R.id.nav_item）;
下面是@kingston的回复。
首先，为选定的项目创建颜色。这里https://stackoverflow.com/a/30594875/1462969很好的例子。它可以帮助你改变图标的颜色。为了改变所有选定项目的背景添加到您的价值\style.xml文件this
<item name="selectableItemBackground">@drawable/selectable_item_background</item>
在drawable/selectable_item_background.xml中应该声明selectable_item_background
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="@color/accent_translucent"
android:state_pressed="true" />
<item android:drawable="@android:color/transparent" />
</selector>
哪里可以在style.xml中声明颜色
<color name="accent_translucent">#80FFEB3B</color>
在这之后
// The main navigation menu with user-specific actions
mainNavigationMenu_ = (NavigationView) findViewById(R.id.main_drawer);
mainNavigationMenu_.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(MenuItem menuItem) {
mainNavigationMenu_.getMenu().findItem(itemId).setChecked(true);
return true;
}
});
正如你看到的，我用了这个
.setChecked mainNavigationMenu_.getMenu () .findItem (itemId)(真正的);
设置所选项目。
这里navigationView
<android.support.design.widget.NavigationView
android:id="@+id/main_drawer"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
app:headerLayout="@layout/header_main_navigation_menu"
app:itemIconTint="@color/state_list"
app:itemTextColor="@color/primary"
app:menu="@menu/main_menu_drawer"/>
API 23提供了以下方法:
navigationView.setCheckedItem(R.id.nav_item_id);
但是，由于某种原因，这个函数没有导致导航项后面的代码运行。该方法当然会突出显示导航抽屉中的项目，或“检查”它，但它似乎不会调用OnNavigationItemSelectedListener，导致启动时出现空白屏幕，如果您的启动屏幕依赖于导航抽屉的选择。可以手动调用监听器，但看起来很俗气:
if (savedInstanceState == null) this.onNavigationItemSelected(navigationView.getMenu().getItem(0));
上面的代码假设:
你已经实现了
NavigationView。OnNavigationItemSelectedListener在你的活动
您已经呼叫过:
navigationView.setNavigationItemSelectedListener(这个);
您要选择的项目位于位置0
关于你的活动(在抽屉后面):
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
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.addDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
navigationView.setCheckedItem(R.id.nav_portfolio);
onNavigationItemSelected(navigationView.getMenu().getItem(0));
}
and
@Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
Fragment fragment = null;
if (id == R.id.nav_test1) {
fragment = new Test1Fragment();
displaySelectedFragment(fragment);
} else if (id == R.id.nav_test2) {
fragment = new Test2Fragment();
displaySelectedFragment(fragment);
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
在菜单中:
<group android:checkableBehavior="single">
<item
android:id="@+id/nav_test1"
android:title="@string/test1" />
<item
android:id="@+id/nav_test2"
android:title="@string/test2" />
</group>
第一个菜单被高亮显示为默认菜单。
package com.example.projectdesign;
import androidx.annotation.NonNull;
import androidx.appcompat.app.ActionBarDrawerToggle;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.view.GravityCompat;
import androidx.drawerlayout.widget.DrawerLayout;
import androidx.fragment.app.Fragment;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.MenuItem;
import android.widget.Toast;
import com.google.android.material.navigation.NavigationView;
public class MenuDrawer extends AppCompatActivity implements
NavigationView.OnNavigationItemSelectedListener{
public DrawerLayout drawerLayout;
public ActionBarDrawerToggle actionBarDrawerToggle;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_menu_drawer);
drawerLayout = findViewById(R.id.my_drwaer_layout);
actionBarDrawerToggle = new ActionBarDrawerToggle(this, drawerLayout,
R.string.nav_open, R.string.nav_close);
drawerLayout.addDrawerListener(actionBarDrawerToggle);
actionBarDrawerToggle.syncState();
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
NavigationView navigationView = findViewById(R.id. nav_view ) ;
navigationView.setNavigationItemSelectedListener( this ) ;
}
@SuppressLint("ResourceType")
@SuppressWarnings ( "StatementWithEmptyBody" )
@Override
public boolean onNavigationItemSelected (MenuItem item){
int id=item.getItemId();
switch (id){
case R.id.nav_account:
Intent intent= new Intent(MenuDrawer.this, UsingBackKey.class);
startActivity(intent);
break;
case R.id.women:
getSupportFragmentManager().beginTransaction().replace(R.id.my_drwaer_layout,new
Fragment2()).commit();
break;
case R.id.men:
Toast.makeText(getApplicationContext(),"Soon",
Toast.LENGTH_SHORT).show();
break;
case R.id.kids:
Toast.makeText(getApplicationContext(),"Welcome to Kids",
Toast.LENGTH_SHORT).show();
break;
}
drawerLayout.closeDrawer(GravityCompat.START);
return super.onContextItemSelected(item);
}
@Override
public boolean onOptionsItemSelected(@NonNull MenuItem item) {
if (actionBarDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onBackPressed() {
if (drawerLayout.isDrawerOpen(GravityCompat.START)) {
drawerLayout.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
super.onBackPressed();
}
}
