概述
翻译:碎片
优点:适用于不同的屏幕尺寸和分辨率的UI布局,提高了代码的重用率。
创建
1.通过xml文件
— 1.创建main布局
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<fragment
android:id="@+id/center_fragment"
android:name="com.example.fragmenttest.FragmentCenter"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="5" >
</fragment>
<fragment
android:id="@+id/bottom_fragment"
android:name="com.example.fragmenttest.FragmentBottom"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1" >
</fragment>
</LinearLayout>
— 2.定义两个fragment类
public class FragmentCenter extends Fragment{
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// TODO Auto-generated method stub
View view = inflater.inflate(R.layout.center_fragment, container, false);
return view;
}
}
public class FragmentBottom extends Fragment{
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// TODO Auto-generated method stub
View view = inflater.inflate(R.layout.bottom_fragment, container,false);
return view;
}
}
注意:这里的两个布局文件R.layout.center_fragment
和R.layout.bottom_fragment
是自定义的普通的布局文件
— 3.MainActivity
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
}
2.通过java代码动态创建
@SuppressLint("NewApi") public class FragmentTest2Activity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_fragment_test2);
//获取碎片管理器
FragmentManager fragmentManager = getFragmentManager();
//碎片的显示需要使用FragmentTransaction类操作
FragmentTransaction transaction = fragmentManager.beginTransaction();
//获取屏幕管理器和默认的显示
Display display = getWindowManager().getDefaultDisplay();
if(display.getWidth() > display.getHeight()){ //判断横屏
FragmentCenter fragmentCenter = new FragmentCenter(); //获取java类
transaction.replace(android.R.id.content, fragmentCenter);
}else {
FragmentBottom fragmentBottom = new FragmentBottom();
transaction.replace(android.R.id.content, fragmentBottom);
}
transaction.commit(); //使用FragmentTransaction必须要commit
}
}
fragment仿qq界面(fragment的切换)
MainActivity中的相关代码
功能:
— 1、创建fragment
— 2、点击相应的按钮时,会切换不同的fragment(在切换的过程中,首先需要判断该fragment是隐藏了还是没有创建过;如果是隐藏了就直接show,如果没有创建过就new,最后调用fragmentTransaction.commit();进行切换
)
public class MainActivity extends Activity implements View.OnClickListener {
private ImageView contactImage;
private ImageView msgImage;
private ImageView trendImage;
private ImageView title_head;
private TextView title_center;
private Button title_button;
private ContactFragment contactFragment;
private MsgFragment msgFragment;
private TrendFragment trendFragment;
private FragmentManager fragmentManager;
private FragmentTransaction fragmentTransaction;
//表示是哪个Fragment
int fragment_tag = 0; //默认是消息
static final int FRAGMENT_TAB_MSG = 0;
static final int FRAGMENT_TAB_CONTACT = 1;
static final int FRAGMENT_TAB_PLUGIN = 2;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_main);
initViews();
fragmentManager = getFragmentManager();
// 第一次启动时选中第0个tab
setTabSelection(0);
}
private void initViews() {
//消息
contactImage = (ImageView) findViewById(R.id.tab_contact);
//联系人
msgImage = (ImageView) findViewById(R.id.tab_conversation);
//动态
trendImage = (ImageView) findViewById(R.id.tab_plugin);
//标题栏
title_head = (ImageView) findViewById(R.id.title_head);
title_center = (TextView) findViewById(R.id.title_center);
title_button = (Button) findViewById(R.id.title_button);
contactImage.setOnClickListener(this);
msgImage.setOnClickListener(this);
trendImage.setOnClickListener(this);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.tab_conversation:
// 当点击了消息tab时,选中第1个tab
setTabSelection(0);
break;
case R.id.tab_contact:
// 当点击了联系人tab时,选中第2个tab
setTabSelection(1);
break;
case R.id.tab_plugin:
// 当点击了动态tab时,选中第3个tab
setTabSelection(2);
break;
default:
break;
}
}
/**
* 根据传入的index参数来设置选中的tab页。
*
* @param index 每个tab页对应的下标。0表示消息,1表示联系人,2表示动态
*/
private void setTabSelection(int index) {
// 开启一个Fragment事务
fragmentTransaction = fragmentManager.beginTransaction();
// 先隐藏掉所有的Fragment,以防止有多个Fragment显示在界面上的情况
hideFragments(fragmentTransaction);
/*--------------------------------------------------
* 改变底层栏(bottom panel)
* 改变标题栏
*-------------------------------------------------*/
switch (index) {
case 0: // 当点击了消息tab时,改变控件的图片和文字颜色
//“消息”
msgImage.setImageResource(R.drawable.skin_tab_icon_conversation_selected);
//normal
contactImage.setImageResource(R.drawable.skin_tab_icon_contact_normal);
trendImage.setImageResource(R.drawable.skin_tab_icon_plugin_normal);
//标记为“消息”的fragment
fragment_tag = FRAGMENT_TAB_MSG;
break;
case 1:
//联系人
contactImage.setImageResource(R.drawable.skin_tab_icon_contact_selected);
//消息和动态 normal
msgImage.setImageResource(R.drawable.skin_tab_icon_conversation_normal);
trendImage.setImageResource(R.drawable.skin_tab_icon_plugin_normal);
//标记为“联系人”的fragment
fragment_tag = FRAGMENT_TAB_CONTACT;
break;
case 2:
//动态
trendImage.setImageResource(R.drawable.skin_tab_icon_plugin_selected);
//normal
contactImage.setImageResource(R.drawable.skin_tab_icon_contact_normal);
msgImage.setImageResource(R.drawable.skin_tab_icon_conversation_normal);
fragment_tag = FRAGMENT_TAB_PLUGIN; //标记为“动态”的fragment
break;
}
//切换fragment
switchFragment(fragment_tag);
}
private void switchFragment(int tag) {
/*--------------------------------------------------
* Fragment不存在则新建
*-------------------------------------------------*/
Fragment fragment = null;
if (tag == FRAGMENT_TAB_MSG) {
//不存在则新建
if (msgFragment == null) {
msgFragment = new MsgFragment();
}
fragment = msgFragment;
} else if (tag == FRAGMENT_TAB_CONTACT) {
if (contactFragment == null) {
contactFragment = new ContactFragment();
}
fragment = contactFragment;
} else if (tag == FRAGMENT_TAB_PLUGIN) {
if (trendFragment == null) {
trendFragment = new TrendFragment();
}
fragment = trendFragment;
}
/*--------------------------------------------------
* 显示或者绑定Fragment
* 1.如果隐藏,则显示
* 2.如果第一次使用,add
*-------------------------------------------------*/
if (fragment != null) {
if (fragment.isHidden()) {
fragmentTransaction.show(fragment);
} else if (!fragment.isAdded()) {
fragmentTransaction.add(R.id.content, fragment, tag + "");
}
}
//不为空,切换
if (fragmentTransaction != null && !fragmentTransaction.isEmpty()) {
fragmentTransaction.commit();
}
}
/**
* 将所有的Fragment都置为隐藏状态。
*
* @param transaction 用于对Fragment执行操作的事务
*/
private void hideFragments(FragmentTransaction transaction) {
if (contactFragment != null) {
transaction.hide(contactFragment);
}
if (msgFragment != null) {
transaction.hide(msgFragment);
}
if (trendFragment != null) {
transaction.hide(trendFragment);
}
}
}