从导航抽屉中打开新片段时，将content_main替换为

Question

我已经搜索了这个，还没有找到答案，我使用Android导航抽屉模板，当从导航菜单点击时，我有一些片段相互替换，当应用程序第一次打开时，它在Content_Main布局上打开，当我点击我的一个片段时，它打开了，但Content_Main的内容仍然显示，我需要隐藏，而我使用其他片段，也做了一个主页按钮，让我从菜单上回到这个内容，有什么帮助吗？

问题是当我打开应用程序时，Content_main布局出现了，当我滑动导航抽屉并在菜单中选择nav_gallery时，音乐片段打开了，但内容main没有被替换。

package com.justmikey.justmik;

 import android.media.MediaPlayer;
 import android.os.Bundle;
 import android.support.design.widget.FloatingActionButton;
 import android.support.design.widget.Snackbar;
 import android.support.v4.app.FragmentManager;
 import android.support.v7.internal.widget.ButtonBarLayout;
 import android.text.method.ScrollingMovementMethod;
 import android.view.View;
 import android.support.design.widget.NavigationView;
 import android.support.v4.view.GravityCompat;
 import android.support.v4.widget.DrawerLayout;
 import android.support.v7.app.ActionBarDrawerToggle;
 import android.support.v7.app.AppCompatActivity;
 import android.support.v7.widget.Toolbar;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.widget.Button;
 import android.widget.TextView;

 import JustMikey.Fragments.MainFragment;
 import JustMikey.Fragments.MusicFragment;

 public class MainActivity extends AppCompatActivity
    implements NavigationView.OnNavigationItemSelectedListener {

//create a media player object called mp
MediaPlayer mp;
//declare my buttons play, pause and stop
Button play, pause,stop;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    //Set the textView scrollMain to scrollable
    TextView tv = (TextView) findViewById(R.id.scrollMain);
    tv.setMovementMethod(new ScrollingMovementMethod());

    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
            this, drawer, toolbar, R.string.navigation_drawer_open,      R.string.navigation_drawer_close);
    drawer.setDrawerListener(toggle);
    toggle.syncState();

    NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
    navigationView.setNavigationItemSelectedListener(this);
     }




@Override
public void onBackPressed() {
    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    if (drawer.isDrawerOpen(GravityCompat.START)) {
        drawer.closeDrawer(GravityCompat.START);
    } else {
        super.onBackPressed();
    }
     }

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
     }

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
    android.app.FragmentManager fm = getFragmentManager();

    int id = item.getItemId();

    if (id == R.id.nav_camara) {

   fm.beginTransaction().replace(R.id.content_frame, new MainFragment()).commit();


    } else if (id == R.id.nav_gallery) {

        fm.beginTransaction().replace(R.id.content_frame, new MusicFragment()).commit();


    } else if (id == R.id.nav_slideshow) {

    } else if (id == R.id.nav_manage) {

    } else if (id == R.id.nav_share) {

    } else if (id == R.id.nav_send) {

    }

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

<FrameLayout
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:id="@+id/content_frame">

    <ImageView
        android:layout_width="355dp"
        android:layout_height="wrap_content"
        android:src="@drawable/jmmain"
        android:id="@+id/imageView2"
        android:layout_gravity="center_horizontal|top"
        android:layout_alignRight="@+id/content_frame"
        android:layout_alignEnd="@+id/content_frame" />

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="274dp"
        android:text="hello hello hello hello hello hello hello hello hello  hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello "
        android:id="@+id/scrollMain"
        android:layout_gravity="center_horizontal|bottom"
        android:layout_alignBottom="@+id/scrollView"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginBottom="28dp"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true"
        android:background="#ffffff"
        android:padding="10dp" />

    <ScrollView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:id="@+id/scrollView"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_gravity="center"></ScrollView>


</FrameLayout>

</RelativeLayout>

package JustMikey.Fragments;

import android.app.Fragment;
import android.graphics.LightingColorFilter;
import android.graphics.PorterDuff;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;

import com.justmikey.justmik.R;

 /**
  *     Created by James on 24/02/2016.
  */
public class MusicFragment extends Fragment implements View.OnClickListener {

//create a media player object called mp
MediaPlayer mp;
//declare my buttons play, pause and stop
Button play, pause,stop;




@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle  savedInstanceState) {

    View rootView = inflater.inflate(R.layout.fragmentmusic, container,  false);


    //call my button views in by using the ID tag
    play = (Button) rootView.findViewById(R.id.play);
    pause = (Button) rootView.findViewById(R.id.pause);
    stop = (Button) rootView.findViewById(R.id.stop);

    //set an onClickListener to make my buttons clickable
    play.setOnClickListener(this);
    pause.setOnClickListener(this);
    stop.setOnClickListener(this);

    //Change the colour of the pause button for a nice design effect
    pause.getBackground().setColorFilter(new LightingColorFilter(0x00000000,  0xFFAA0000));
    //return the view
    return rootView;
}
// onClick Method for the play, pause and stop buttons
public void onClick(View v) {
    switch(v.getId()) {
        case R.id.play : if(mp == null) {
            mp = MediaPlayer.create(getActivity(), R.raw.holdmytong);
        }
            mp.start();
            break;
        case R.id.pause : mp.pause();break;

        case R.id.stop : mp.stop();mp = null;break;
    }

    }



}

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

<ImageView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:adjustViewBounds="true"
    android:scaleType="fitCenter"
    android:id="@+id/imageView3"
    android:src="@drawable/jmholdmy"
    android:layout_gravity="center_horizontal|top" />

<Button
    style="?android:attr/buttonStyleSmall"
    android:layout_width="100dp"
    android:layout_height="74dp"
    android:id="@+id/pause"
    android:layout_alignTop="@+id/play"
    android:layout_toRightOf="@+id/play"
    android:layout_toEndOf="@+id/play"
    android:layout_gravity="center_horizontal|bottom"
    android:background="@drawable/pausebtnimg" />

<Button
    style="?android:attr/buttonStyleSmall"
    android:layout_width="113dp"
    android:layout_height="72dp"
    android:id="@+id/stop"
    android:layout_alignTop="@+id/play"
    android:layout_toRightOf="@+id/pause"
    android:layout_toEndOf="@+id/pause"
    android:layout_gravity="right|bottom"
    android:background="@drawable/stopbtnimg" />

<Button
    style="?android:attr/buttonStyleSmall"
    android:layout_width="114dp"
    android:layout_height="72dp"
    android:id="@+id/play"
    android:layout_marginTop="170dp"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_gravity="left|bottom"
    android:background="@drawable/playbtnimg" />

<TextView
    android:layout_width="match_parent"
    android:layout_height="258dp"
    android:id="@+id/textView4"
    android:layout_gravity="left|bottom"
    android:text="Taking from our debut EP Hold my tongue was our first released song, it won play at the Picnic competition which brought Just Mikey to the stage at the largest festivil in Europe Electric Picnic, This is the first of many to come so enjoy.  " />

<TextView
    android:layout_width="314dp"
    android:layout_height="156dp"
    android:text="Buy Track: https://www.facebook.com/search/top/?q=just%20mikey%20google%20play"
    android:id="@+id/textView5"
    android:layout_gravity="center_horizontal|bottom"
    android:backgroundTint="#000000"
    android:backgroundTintMode="screen" />

Answer 1

appcompatactivity应该使用通过getsupportfragmentManager()检索的fragmentManager。