Question

我有一个导航抽屉，在点击我需要打开特定片段的菜单时包含n个菜单。首先，我尝试了活动和意图。在使用碎片的情况下，它看起来不太好。我正在通过id选择它们并从活动中调用片段。在片段中，我正在使用饼图，其中它抛出空指针异常。我尝试从get视图更改，因为它仅在Oncreate View之后进行了实例化。但没有结果。

/** UI Automator Google GPS dialog box */
UiDevice mDevice = UiDevice.getInstance(InstrumentationRegistry.getInstrumentation());
UiObject uiObject = mDevice.findObject(new UiSelector().text("OK"));
try {
  uiObject.click();
}catch (UiObjectNotFoundException e) {
  e.printStackTrace();
}

Answer 1

以下是有助于理解的示例代码。首先使用OnCreate（）中的片段替换activity_main.xml内容：

 FragmentManager fm = getFragmentManager();
        fm.beginTransaction().replace(R.id.content_frame, new HomeFragment()).commit();

然后将此HomeFragment替换为onNavigationItemSelected（）中的其他人：

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

    if (id == R.id.nav_home) {
        // Handle the camera action
        FragmentManager fm = getFragmentManager();
        fm.beginTransaction().replace(R.id.content_frame, new HomeFragment()).commit();
    } else if (id == R.id.nav_current_order) {
        FragmentManager fm = getFragmentManager();
        fm.beginTransaction().replace(R.id.content_frame, new MyCurrentOrderFragment(),"Tag").commit();
    } else if (id == R.id.nav_received_images) {
        FragmentManager fm = getFragmentManager();
        fm.beginTransaction().replace(R.id.content_frame, new HistoryFragment()).commit();
    } else if (id == R.id.nav_rate_app) {
        FragmentManager fm = getFragmentManager();
        fm.beginTransaction().replace(R.id.content_frame, new RateOurAppFragment()).commit();
    } else if (id == R.id.nav_help) {
        FragmentManager fm = getFragmentManager();
        fm.beginTransaction().replace(R.id.content_frame, new HelpFragment()).commit();
    } else if (id == R.id.nav_settings) {
        FragmentManager fm = getFragmentManager();
        fm.beginTransaction().replace(R.id.content_frame, new SettingsFragment()).commit();
    }

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

在您的content_main.xml中添加一个FrameLayout，并将其ID设置为＆＃34; content_frame＆＃34;

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="bd.com.chalo.dsstudio.MainActivity"
    tools:showIn="@layout/app_bar_main">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Hello World!"
    android:visibility="gone" />
<FrameLayout
    android:id="@+id/content_frame"
    android:layout_width="match_parent"
    android:layout_height="match_parent"></FrameLayout>

</RelativeLayout>

从Navigational Drawer调用片段

1 个答案: