【发布时间】：2017-12-25 17:52:36
【问题描述】：
我是第一次使用 Fragments，如果我确实很愚蠢，很抱歉：D
我有一个导航抽屉活动。当我在第一个项目上单击它时，我想打开一个片段。打开的时候，不仅有Fragment的Layout，还有我的MainActivity的layout，看起来很奇怪。
[1]: https://i.stack.imgur.com/iqTAq.png MainActivity
[2]: https://i.stack.imgur.com/kULQY.png Navigation Drawer
[3]: https://i.stack.imgur.com/T2vDJ.png First Fragment
我该如何解决这个问题？
如果你需要，这是我的代码：
MainActivity(Navigation Drawer Templated，我只写在onNavigationItemSelected中，这样点击第一个item的时候就到fragment了：
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
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) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.nav_camera) {
setTitle("First Fragment");
first first = new first();
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction().replace(R.id.fragment, first).commit();
} else if (id == R.id.nav_gallery) {
} 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;
}
}
content_main（应该属于MainActivity）
<?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"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="com.gsr.fragmenttest.MainActivity"
tools:showIn="@layout/app_bar_main">
<FrameLayout
android:id="@+id/fragment"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="This is the Mainactivity, no fragemnt"/>
</FrameLayout>
</RelativeLayout>
第一个片段活动
public class first extends Fragment {
Button btn;
TextView textView;
public first() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_first, container, false);
btn=(Button)v.findViewById(R.id.button);
textView=(TextView)v.findViewById(R.id.textView);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
textView.setText("Nice, it works !!");
}
});
// Inflate the layout for this fragment
return v;
}
}
至少还有片段布局文件
<FrameLayout 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.gsr.fragmenttest.first">
<!-- TODO: Update blank fragment layout -->
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/textView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:text="Hello Fragment"
android:textSize="50dp"/>
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true"/>
</RelativeLayout>
</FrameLayout>
我希望有人可以帮助我:)
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标签： java android xml android-layout android-fragments