Android 3.0平板系统的重要特性Fragment示例代码今天Android123给大家两个例子，一起来看下Fragment的实战代码:
一、通过Fragment实现简单的上下文菜单
public class FragmentContextMenu extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ContextMenuFragment content = new ContextMenuFragment();
getFragmentManager().beginTransaction().add(android.R.id.content, content).commit(); //在Activity中通过这个与Fragment通讯
}
下面ContextMenuFragment是我们从Fragment派生的子类，里面重写了onCreateView来布局自己的Fragment
public static class ContextMenuFragment extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View root = inflater.inflate(R.layout.fragment_context_menu, container, false);
registerForContextMenu(root.findViewById(R.id.long_press));
return root;
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
menu.add(Menu.NONE, R.id.a_item, Menu.NONE, "菜单1");
menu.add(Menu.NONE, R.id.b_item, Menu.NONE, "菜单2");
}
@Override
public boolean onContextItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.a_item:
Log.i("CWJ", "Item 1a was chosen");
return true;
case R.id.b_item:
Log.i("CWJ", "Item 1b was chosen");
return true;
}
return super.onContextItemSelected(item);
}
}
}
涉及到的布局文件fragment_context_menu.xml源码
<?xml version="1.0" encoding="utf-8"?><TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="@string/fragment_context_menu_msg" />
<Button android:id="@+id/long_press"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="@string/long_press">
<requestFocus />
</Button>
二、控制Fragment的显示或隐藏同时包含淡入淡出效果
public class FragmentHideShow extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_hide_show);
FragmentManager fm = getFragmentManager();
addShowHideListener(R.id.frag1hide, fm.findFragmentById(R.id.fragment1));
addShowHideListener(R.id.frag2hide, fm.findFragmentById(R.id.fragment2));
//上面的两行代码是在Activity中为Fragment中的按钮添加监听事件
}
void addShowHideListener(int buttonId, final Fragment fragment) {
final Button button = (Button)findViewById(buttonId);
button.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
FragmentTransaction ft = getFragmentManager().beginTransaction();
ft.setCustomAnimations(android.R.animator.fade_in,
android.R.animator.fade_out); //为Fragment设置淡入淡出效果，Android开发网提示这里这两个动画资源是android内部资源无需我们手动定义。
if (fragment.isHidden()) {
ft.show(fragment);
button.setText("隐藏");
} else {
ft.hide(fragment);
button.setText("显示");
}
ft.commit();
}
});
}
public static class FirstFragment extends Fragment {
TextView mTextView;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.labeled_text_edit, container, false);
View tv = v.findViewById(R.id.msg);
((TextView)tv).setText("The fragment saves and restores this text.");
mTextView = (TextView)v.findViewById(R.id.saved);
if (savedInstanceState != null) {
mTextView.setText(savedInstanceState.getCharSequence("text"));
}
return v;
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putCharSequence("text", mTextView.getText());
}
}
public static class SecondFragment extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.labeled_text_edit, container, false);
View tv = v.findViewById(R.id.msg);
((TextView)tv).setText("The TextView saves and restores this text.");
((TextView)v.findViewById(R.id.saved)).setSaveEnabled(true);
return v;
}
}
}
涉及资源布局文件fragment_hide_show.xml代码:
<?xml version="1.0" encoding="utf-8"?><TextView android:layout_width="match_parent" android:layout_height="wrap_content"
android:gravity="center_vertical|center_horizontal"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="Demonstration of hiding and showing fragments." />
<LinearLayout android:orientation="horizontal" android:padding="4dip"
android:gravity="center_vertical" android:layout_weight="1"
android:layout_width="match_parent" android:layout_height="wrap_content">
<Button android:id="@+id/frag1hide"
android:layout_width="wrap_content" android:layout_height="wrap_content"
android:text="Hide" />
<fragment android:name="com.android123.FragmentHideShow$FirstFragment"
android:id="@+id/fragment1" android:layout_weight="1"
android:layout_width="0px" android:layout_height="wrap_content" />
</LinearLayout>
<LinearLayout android:orientation="horizontal" android:padding="4dip"
android:gravity="center_vertical" android:layout_weight="1"
android:layout_width="match_parent" android:layout_height="wrap_content">
<Button android:id="@+id/frag2hide"
android:layout_width="wrap_content" android:layout_height="wrap_content"
android:text="Hide" />
<fragment android:name="com.android123.FragmentHideShow$SecondFragment"
android:id="@+id/fragment2" android:layout_weight="1"
android:layout_width="0px" android:layout_height="wrap_content" />
</LinearLayout>
有关布局文件labeled_text_edit.xml的代码为
<?xml version="1.0" encoding="utf-8"?><TextView android:id="@+id/msg"
android:layout_width="match_parent" android:layout_height="wrap_content"
android:layout_weight="0"
android:paddingBottom="4dip" />
<EditText android:id="@+id/saved"
android:layout_width="match_parent" android:layout_height="wrap_content"
android:layout_weight="1"
android:background="@drawable/green"
android:text="@string/initial_text"
android:freezesText="true">
<requestFocus />
</EditText>