如何将临时片段设置到我的“主屏幕”Android 工作室

Question

I have started coding and I really like it, I have been on/off on diffrent project (to learn diffrent things) But now i got a problem, I "app"reciate all the help i can get.

I am using the navigation drawer and got three fragments installed. I can navigate through the navigation drawer and select a fragment and it loads on my screen. But when i start my app the screen is just white and the navigation drawer is on the left and i can pick a fragment. Is it possible to have a fragment on my "home screen" so when I start the app there is a fragment already placed on the screen BUT! when i chosse another fragment in the navigation drawer i would like to have my fragment who loaded at the beginning to disappear. Otherwise both fragments will show on eachother (Text on text). Maybe to have the temporary fragment to "finish" itself somehow. Please look at my imgur image to get my idea. Imgur image press here to view

Answer 1

Here is a generic solution on how to use the FragmentManager . It should give a good idea on how to display a Fragment . Besides that you could include a static Fragment in your layout. It's up to you how to approach it.
So the FragmentManager solution looks like this:

YourActivity.java

 @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        FragmentManager fragmentManager = getFragmentManager();
        Fragment fragment = AnyFragment.instantiate(this, AnyFragment.class.getName());
        fragmentManager.beginTransaction().add(R.id.fragment_placeholder, fragment).addToBackStack(null).commit();
    }

The target id is defined in your activity layout.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <FrameLayout
        android:id="@+id/fragment_placeholder"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"></FrameLayout>
</LinearLayout>

---

Later if you want to replace the current Fragment you can use the remove and add method of the FragmentManager (the replace method is kinda buggy).

Fragment currentFragment = fragmentManager.findFragmentById(R.id.fragment_placeholder))
fragmentManager.beginTransaction().remove(currentFragment).add(R.id.fragment_placeholder, yourNewFragment).addToBackStack(null).commit();