Android更改屏幕旋转

Question

Hello I am having a problem when the screen is normal the image looks okay on the android phone but when i shift to landscape it occupy the space of the Navigation header bar. Also when i rotate phone it takes me back to the home or Main Activity i don't what that. the following is the Main-fragment.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"
    tools:context="com.example.fred.yeno.MainFragment">


    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical">
        <ImageView
            android:id="@+id/puAdd"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@drawable/dice" />
    </LinearLayout>
</LinearLayout>

MAnifest.XML

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.fred.yeu">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name"
            android:theme="@style/AppTheme.NoActionBar">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

The following is the MainFragment.java

package com.example.fred.yenu;


import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;


/**
 * A simple {@link Fragment} subclass.
 */
public class MainFragment extends Fragment {


    public MainFragment() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_main, container, false);
    }

}

Answer 1

I think that you don't have defined the Toolbar to your Fragment , and you don't know how and when use Fragment . I suggest you to Download Android studio (if you had it, update SDK and IDE at last version).

After that crete a new project with Blank Activity and start you project from there.

After if you want/need, you can add 1,2 or N Fragments to your Activity .

I Suggest you to read the official documents that i link to you below:

Build your first app

Activitys

Fragments

Build dynamic UI with Fragments

If you read this Documents you have the basic for start your App and you can see that the problem that you have disappear.