Android Fragment实现底部通知栏

<?xml version="1.0" encoding="utf-8"? 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
   
<LinearLayout
  android:id="@+id/ll_content_part"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
   
</LinearLayout 
<LinearLayout
  android:id="@+id/ll_function"
  android:layout_alignParentBottom="true"
  android:orientation="horizontal"
  android:layout_width="match_parent"
  android:layout_height="wrap_content" 

<Button
  android:id="@+id/btn_msg_list"
  android:layout_width="0dp"
  android:layout_height="wrap_content"
  android:layout_weight="1"
  android:textSize="13dp"
  android:onClick="click"
  android:text="msg"/ 
  <Button
    android:id="@+id/btn_contact"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:layout_weight="1"
    android:textSize="13dp"
    android:onClick="click"
    android:text="contact"/ 
  <Button
    android:id="@+id/btn_disc"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:layout_weight="1"
    android:textSize="13dp"
    android:onClick="click"
    android:text="disc"/ 
  <Button
    android:id="@+id/btn_me"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:layout_weight="1"
    android:textSize="13dp"
    android:onClick="click"
    android:text="me"/ 
</LinearLayout 
</RelativeLayout 

public class MainActivity extends AppCompatActivity {
private Button btn_contact;
private Button btn_disc;
private Button btn_me;
private Button btn_msg_list;
private FragmentManager fragmentManager;
private MsgListFragment msgListFragment;
private ContactFragment contactFragment;
private DiscoveryFragment discoveryFragment;
private MeFragment meFragment;
private final int STATE_MSG =1;
private final int STATE_CON =2;
private final int STATE_DIS =3;
private final int STATE_ME =4;
private int currentState;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
initData();
chageButtonColor(currentState,STATE_MSG);
}
private void initData() {
fragmentManager = getFragmentManager();
switchFragment(this.STATE_MSG);
}
private void initView() {
btn_contact = (Button) findViewById(R.id.btn_contact);
btn_disc = (Button) findViewById(R.id.btn_disc);
btn_me = (Button) findViewById(R.id.btn_me);
btn_msg_list = (Button) findViewById(R.id.btn_msg_list);
}
public void click(View view) {
switch (view.getId()){
case R.id.btn_msg_list:
switchFragment(this.STATE_MSG);
break;
case R.id.btn_contact:
switchFragment(this.STATE_CON);
break;
case R.id.btn_disc:
switchFragment(this.STATE_DIS);
break;
case R.id.btn_me:
switchFragment(this.STATE_ME);
break;
}
}
private void switchFragment(int toState) {
if (toState == currentState)
return;
chageButtonColor(currentState,toState);
this.currentState=toState;
FragmentTransaction transaction = this.fragmentManager.beginTransaction();
Fragment fragment=msgListFragment;
switch (toState){
case STATE_DIS:
if (discoveryFragment == null)
discoveryFragment= new DiscoveryFragment();
fragment= discoveryFragment;
break;
case STATE_ME:
if (meFragment == null)
meFragment= new MeFragment();
fragment= meFragment;
break;
case STATE_CON:
if (contactFragment == null)
contactFragment= new ContactFragment();
fragment= contactFragment;
break;
case STATE_MSG:
if (msgListFragment == null)
msgListFragment= new MsgListFragment();
fragment= msgListFragment;
break;
}
transaction.replace(R.id.ll_content_part,fragment);
transaction.commit();
}
private void chageButtonColor(int currentState,int toState){
switch (currentState){
case STATE_DIS:
this.btn_disc.setTextColor(Color.BLACK);
break;
case STATE_ME:
this.btn_me.setTextColor(Color.BLACK);
break;
case STATE_CON:
this.btn_contact.setTextColor(Color.BLACK);
break;
case STATE_MSG:
this.btn_msg_list.setTextColor(Color.BLACK);
break;
}
switch (toState){
case STATE_DIS:
this.btn_disc.setTextColor(Color.GREEN);
break;
case STATE_ME:
this.btn_me.setTextColor(Color.GREEN);
break;
case STATE_CON:
this.btn_contact.setTextColor(Color.GREEN);
break;
case STATE_MSG:
this.btn_msg_list.setTextColor(Color.GREEN);
break;
}
}
}