我正在构建一个Android应用程序，我正在尝试构建一个用户可以登录，注销等用户管理系统。如果用户已注销，我想显示一个登录菜单项，如果是用户已登录。如何动态执行此操作？
这是现在的布局文件：
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
<item android:id="@+id/add" android:title="Add" android:icon="@drawable/ic_menu_add"/>
<item android:id="@+id/list" android:title="List" android:icon="@drawable/ic_menu_list"/>
<item android:id="@+id/refresh" android:title="Refresh" android:icon="@drawable/ic_menu_refresh"/>
<item android:id="@+id/login" android:title="Login" android:icon="@drawable/ic_menu_login"/>
</menu>
这是我的Java：
@Override
public boolean onCreateOptionsMenu(Menu menu) {
new MenuInflater(this).inflate(R.menu.activity_main, menu);
return(super.onCreateOptionsMenu(menu));
}
@Override
public boolean onOptionsItemSelected(MenuItem item)
{
System.out.println(item.getItemId()==R.id.add);
if (item.getItemId()==R.id.add)
{
//Cannot add spot unless we have obtained the users current location.
if((currentLat != 0) && (currentLng != 0))
{
System.out.println("loggedin? : " + auth.isLoggedIn());
if(!auth.isLoggedIn())
{
Toast.makeText(MainActivity.this, "You must be logged in to add a new spot",
Toast.LENGTH_LONG).show();
}
else
{
Intent addIntent = new Intent(MainActivity.this, AddSpot.class);
Bundle b = new Bundle();
b.putDouble("currentLat", currentLat);
b.putDouble("currentLng", currentLng);
addIntent.putExtras(b);
startActivity(addIntent);
return(true);
}
}
}
else if(item.getItemId()==R.id.list)
{
//Pointless showing them a blank screen if nothing is retrieved from the server
if(list != null)
{
Intent listIntent = new Intent(MainActivity.this, ListLocations.class);
listIntent.putExtra("list", list);
startActivity(listIntent);
return(true);
}
}
if(item.getItemId()==R.id.refresh)
{
finish();
startActivity(getIntent());
return(true);
}
if(item.getItemId()==R.id.login)
{
Intent loginIntent = new Intent(MainActivity.this, LoginActivity.class);
startActivity(loginIntent);
return(true);
}
return(super.onOptionsItemSelected(item));
}
答案 0 :(得分：101)
public class yourActivity extends Activity {
...
private static final int MENU_ADD = Menu.FIRST;
private static final int MENU_LIST = MENU.FIRST + 1;
private static final int MENU_REFRESH = MENU.FIRST + 2;
private static final int MENU_LOGIN = MENU.FIRST + 3;
/**
* Use if your menu is static (i.e. unchanging)
*/
/*
@Override
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
menu.add(0, MENU_ADD, Menu.NONE, R.string.your-add-text).setIcon(R.drawable.your-add-icon);
menu.add(0, MENU_LIST, Menu.NONE, R.string.your-list-text).setIcon(R.drawable.your-list-icon);
menu.add(0, MENU_REFRESH, Menu.NONE, R.string.your-refresh-text).setIcon(R.drawable.your-refresh-icon);
menu.add(0, MENU_LOGIN, Menu.NONE, R.string.your-login-text).setIcon(R.drawable.your-login-icon);
return true;
}
*/
/**
* Gets called every time the user presses the menu button.
* Use if your menu is dynamic.
*/
@Override
public boolean onPrepareOptionsMenu(Menu menu) {
menu.clear();
if(enableAdd)
menu.add(0, MENU_ADD, Menu.NONE, R.string.your-add-text).setIcon(R.drawable.your-add-icon);
if(enableList)
menu.add(0, MENU_LIST, Menu.NONE, R.string.your-list-text).setIcon(R.drawable.your-list-icon);
if(enableRefresh)
menu.add(0, MENU_REFRESH, Menu.NONE, R.string.your-refresh-text).setIcon(R.drawable.your-refresh-icon);
if(enableLogin)
menu.add(0, MENU_LOGIN, Menu.NONE, R.string.your-login-text).setIcon(R.drawable.your-login-icon);
return super.onPrepareOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
super.onOptionsItemSelected(item);
switch (item.getItemId()) {
case MENU_ADD: doAddStuff(); break;
case MENU_LIST: doListStuff(); break;
case MENU_REFRESH: doRefreshStuff(); break;
case MENU_LOGIN: doLoginStuff(); break;
}
return false;
}
以下具体示例在用户登录时添加了一个MENU_LOGOUT选项。
private static final int MENU_LOGOUT = MENU.FIRST + 4;
public boolean onPrepareOptionsMenu(Menu menu) {
...
if(auth.isLoggedIn()) {
menu.add(0, MENU_LOGOUT, Menu.NONE, R.string.your-logout-text).setIcon(R.drawable.your-logout-icon);
}
...
}
public boolean onOptionsItemSelected(MenuItem item) {
...
case MENU_LOGOUT:
if(auth.isLoggedIn()) {
doLogout();
} else {
Toast.makeText(this, "You must have somehow been logged out between the time the menu button was pressed and now.", Toast.DURATION_LONG).show();
}
break;
...
}
这就是它的全部内容。
答案 1 :(得分：7)
你可以调用invalidateOptionsMenu（）（注意：需要使用类似actionBarSherlock的兼容性库来访问，以防你需要支持低API版本），然后根据状态更新菜单项。
您可以隐藏登录操作项并显示注销操作项。
您也可以尝试更新图标本身但我从未尝试过。
答案 2 :(得分：5)
在我的情况下，菜单项位于ArrayList中， - 试试这个希望它会帮助你：）
public getAddress(autocomplete: google.maps.places.Autocomplete): void {
if (this._canGetAddress) {
var place: google.maps.places.PlaceResult = autocomplete.getPlace();
this.address = place['formatted_address'];
var location = place['geometry']['location'];
var lat = location.lat();
var lng = location.lng();
this.onAreaChanged.emit({areaEntered: true, place: place});
this.areaInput.nativeElement.setCustomValidity("");
}
}
答案 3 :(得分：0)
创建菜单项的简单方法：
Dynamic_PopUpMenu.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
PopupMenu menu = new PopupMenu(DialogCheckBox.this, v);
menu.getMenu().add("AGIL"); // menus items
menu.getMenu().add("AGILANBU"); // menus items
menu.getMenu().add("AGILarasan");
menu.getMenu().add("Arasan");
menu.show();
}
});
试试这个：）
答案 4 :(得分：0)
很简单
要创建菜单
@Override
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
for (int i = 0; i < list.size(); i++) {
menu.add(0, i, 0, "Menu Name").setShortcut('5', 'c');
}
return true;
}
从点击的菜单中获取详细信息
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId(); //to get the selected menu id
String name = item.getTitle(); //to get the selected menu name
return super.onOptionsItemSelected(item);
}
答案 5 :(得分：0)
private void getPopup(final TextView textView, ArrayList<String> arrayList) {
final PopupMenu popupMenu = new PopupMenu(sContext, textView);
for (int i = 0; i < arrayList.size(); i++) {
popupMenu.getMenu().add(arrayList.get(i));
}
popupMenu.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
@Override
public boolean onMenuItemClick(MenuItem item) {
textView.setText(item.getTitle());
return false;
}
});
popupMenu.show();
}