Android:从所选的NavigationMenu项目调用上下文菜单

时间:2016-04-18 05:01:29

标签: java android contextmenu

抱歉我的英语。

尝试在Android中调用ContextMenu时遇到问题。

Android Studio在一个float小部件中设置一个侦听器,它可以工作:

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
    registerForContextMenu(fab);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
            openContextMenu(fab);
        }
    });

但是当用户按下NavigationMenu的项目时尝试调用它,我不确定正确的声明方式:

NavigationMenuItemView navigationItemView = (NavigationMenuItemView) findViewById(R.id.nav_call);

然后使用:

openContextMenu(navigationItemView);

我有这个:

    @SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
    NavigationMenuItemView navigationItemView = (NavigationMenuItemView) findViewById(R.id.nav_call); //Declare view maybe like this?

    // Handle navigation view item clicks here.
    int id = item.getItemId();

    if (id == R.id.nav_home) {
        //home
    } else if (id == R.id.nav_call) {
        //Here is my problem
        openContextMenu(navigationItemView);

    }

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

activity_main_drawer.xml

<?xml version="1.0" encoding="utf-8"?>

<group android:checkableBehavior="single">
    <item
        android:id="@+id/nav_home"
        android:icon="@drawable/ic_home_24dp"
        android:title="Home" />
    <item
        android:id="@+id/nav_call"
        android:icon="@drawable/ic_call_24dp"
        android:title="Call" />
</group>

当然,它不起作用,因为当我按下按钮应用程序将崩溃并给我Null指针异常:

日志:

  

04-18 00:40:45.561 27548-27548 / com.android.test01 E / eglCodecCommon:**** ERROR unknown type 0xb8a05080(glSizeof,80)   04-18 00:40:45.593 27548-27548 / com.android.test01 D / AndroidRuntime:关闭VM   04-18 00:40:45.593 27548-27548 / com.android.test01 W / dalvikvm:threadid = 1:线程退出未捕获的异常(组= 0xa4d14b20)   04-18 00:40:45.593 27548-27548 / com.android.test01 E / AndroidRuntime:FATAL EXCEPTION:main                                                                             处理:com.android.test01,PID:27548                                                                             显示java.lang.NullPointerException                                                                                 在android.app.Activity.openContextMenu(Activity.java:2933)                                                                                 在com.android.test01.MainActivity.onNavigationItemSelected(MainActivity.java:109)                                                                                 在android.support.design.widget.NavigationView $ 1.onMenuItemSelected(NavigationView.java:151)                                                                                 在android.support.v7.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:811)                                                                                 在android.support.v7.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:152)                                                                                 在android.support.v7.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:958)                                                                                 在android.support.design.internal.NavigationMenuPresenter $ 1.onClick(NavigationMenuPresenter.java:318)                                                                                 在android.view.View.performClick(View.java:4438)                                                                                 在android.view.View $ PerformClick.run(View.java:18422)                                                                                 在android.os.Handler.handleCallback(Handler.java:733)                                                                                 在android.os.Handler.dispatchMessage(Handler.java:95)                                                                                 在android.os.Looper.loop(Looper.java:136)                                                                                 在android.app.ActivityThread.main(ActivityThread.java:5001)                                                                                 at java.lang.reflect.Method.invokeNative(Native Method)                                                                                 在java.lang.reflect.Method.invoke(Method.java:515)                                                                                 在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:785)                                                                                 在com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)                                                                                 在dalvik.system.NativeStart.main(本地方法)

使用导航项调用ContextMenu的正确方法是什么?

感谢阅读!问候。

1 个答案:

答案 0 :(得分:0)

好吧,我认为这是不可能的,正如另一位用户所说,这没有意义。

然后我使用了一个子菜单。

我刚刚编辑了菜单XML文件:

activity_main_drawer.xml

<?xml version="1.0" encoding="utf-8"?>

<group android:checkableBehavior="single">
    <item
        android:id="@+id/nav_home"
        android:icon="@drawable/ic_home_24dp"
        android:title="Home" />
    <item
        android:id="@+id/nav_call"
        android:icon="@drawable/ic_call_24dp"
        android:title="Call">
        <menu>
            <item
                android:id="@+id/nav_call1"
                android:icon="@drawable/ic_call_24dp"
                android:title="Call to A" />
            <item
                android:id="@+id/nav_call2"
                android:icon="@drawable/ic_call_24dp"
                android:title="Call to B" />
            <item
                android:id="@+id/nav_call3"
                android:icon="@drawable/ic_call_24dp"
                android:title="Call to C" />
        </menu>
        </item>
</group>

并在Activity.java文件中进行验证:

    @SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
    // Handle navigation view item clicks here.
    int id = item.getItemId();

    if (id == R.id.nav_home) {
        //Home activity
    } else if (id == R.id.nav_call1) {
        //foo CallNumber(1);
    } else if (id == R.id.nav_call2) {
        //foo CallNumber(2);
    } else if (id == R.id.nav_call3) {
        //foo CallNumber(3);
    }

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

感谢阅读,问候!