我的片段每次重新选择时都会重新加载。我需要片段继续它离开的地方,好像片段在取消选择时被最小化了。我在我的网络浏览器应用程序中使用片段作为标签。
问题:
每次重新选择时,如何停止重新加载片段。
以下是MainActivity。谢谢。
public class MainActivity extends Activity {
private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
private ActionBarDrawerToggle mDrawerToggle;
private CharSequence mDrawerTitle;
private CharSequence mTitle;
private String[] navMenuTitles;
private TypedArray navMenuIcons;
private ArrayList<NavDrawerItem> navDrawerItems;
private NavDrawerListAdapter adapter;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mTitle = mDrawerTitle = getTitle();
navMenuTitles = getResources().getStringArray(R.array.nav_drawer_items);
navMenuIcons = getResources()
.obtainTypedArray(R.array.nav_drawer_icons);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerList = (ListView) findViewById(R.id.list_slidermenu);
navDrawerItems = new ArrayList<NavDrawerItem>();
navDrawerItems.add(new NavDrawerItem(navMenuTitles[0], navMenuIcons.getResourceId(0, -1)));
navDrawerItems.add(new NavDrawerItem(navMenuTitles[1], navMenuIcons.getResourceId(1, -1)));
navDrawerItems.add(new NavDrawerItem(navMenuTitles[2], navMenuIcons.getResourceId(2, -1)));
navDrawerItems.add(new NavDrawerItem(navMenuTitles[3], navMenuIcons.getResourceId(3, -1)));
navDrawerItems.add(new NavDrawerItem(navMenuTitles[4], navMenuIcons.getResourceId(4, -1)));
navDrawerItems.add(new NavDrawerItem(navMenuTitles[5], navMenuIcons.getResourceId(5, -1)));
navMenuIcons.recycle();
mDrawerList.setOnItemClickListener(new SlideMenuClickListener());
adapter = new NavDrawerListAdapter(getApplicationContext(),
navDrawerItems);
mDrawerList.setAdapter(adapter);
getActionBar().setDisplayHomeAsUpEnabled(true);
getActionBar().setHomeButtonEnabled(true);
mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,
R.drawable.ic_drawer,
R.string.app_name,
R.string.app_name
) {
public void onDrawerClosed(View view) {
getActionBar().setTitle(mTitle);
invalidateOptionsMenu();
}
public void onDrawerOpened(View drawerView) {
getActionBar().setTitle(mDrawerTitle);
invalidateOptionsMenu();
}
};
mDrawerLayout.setDrawerListener(mDrawerToggle);
if (savedInstanceState == null) {
displayView(0);
}
}
private class SlideMenuClickListener implements
ListView.OnItemClickListener {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
displayView(position);
}
}
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
switch (item.getItemId()) {
case R.id.action_settings:
return true;
default:
return super.onOptionsItemSelected(item);
}
}
@Override
public boolean onPrepareOptionsMenu(Menu menu) {
boolean drawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList);
menu.findItem(R.id.action_settings).setVisible(!drawerOpen);
return super.onPrepareOptionsMenu(menu);
}
private void displayView(int position) {
Fragment fragment = null;
switch (position) {
case 0:
fragment = new HomeFragment();
break;
case 1:
fragment = new Fragment2();
break;
case 2:
fragment = new Fragment3();
break;
case 3:
fragment = new Fragment4();
break;
case 4:
fragment = new Fragment5();
break;
case 5:
fragment = new Fragment6();
break;
default:
break;
}
if (fragment != null) {
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.frame_container, fragment).commit();
mDrawerList.setItemChecked(position, true);
mDrawerList.setSelection(position);
setTitle(navMenuTitles[position]);
mDrawerLayout.closeDrawer(mDrawerList);
} else {
Log.e("MainActivity", "Error in creating fragment");
}
}
@Override
public void setTitle(CharSequence title) {
mTitle = title;
getActionBar().setTitle(mTitle);
}
@Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
mDrawerToggle.syncState();
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
mDrawerToggle.onConfigurationChanged(newConfig);
}
}
答案 0 :(得分:1)
您需要改进TabListener。
这就是每次切换后再次加载标签的原因:
.replace(R.id.frame_container, fragment).commit();
最佳解决方案是here.
答案 1 :(得分:0)
这是我的一个应用程序中的MyTabsListener.java类的示例:
class MyTabsListener<T extends Fragment> implements ActionBar.TabListener {
private Fragment mFragment;
private final Activity mActivity;
private final String mTag;
private final Class<T> mClass;
EditText mEditText;
public MyTabsListener(Activity activity, String tag, Class<T> clz){
mActivity = activity;
mTag = tag;
mClass = clz;
}
@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
// Check if the fragment is already initialized
if (mFragment == null) {
// If not, instantiate and add it to the activity
mFragment = Fragment.instantiate(mActivity, mClass.getName());
ft.add(android.R.id.content, mFragment, mTag);
} else {
// If it exists, simply attach it in order to show it
ft.show(mFragment);
}
}
@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
if (mFragment != null) {
// Detach the fragment, because another one is being attached
ft.hide(mFragment);
}
}
@Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}
}
在MainActivity.java中:
- 你的onCreate(Bundle savedInstanceState)
至少需要这样做:
ActionBar actionbar = getSupportActionBar();
actionbar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
ActionBar.Tab Animals = actionbar.newTab().setText("Animals");
ActionBar.Tab Frag2Tab = actionbar.newTab().setText("Favorites");
ActionBar.Tab Frag3Tab = actionbar.newTab().setText("Settings");
Fragment Fragment1 = new Fragment1();
// new Fragment1()是片段的//类的名称,依此类推......
Fragment Fragment2 = new Fragment2();
Fragment Fragment3 = new Fragment3();
Animals.setTabListener(new MyTabsListener<Fragment1>(
this, "Animals", Fragment1.class));
Frag2Tab.setTabListener(new MyTabsListener<Fragment2>(
this, "Favorites", Fragment2.class));
Frag3Tab.setTabListener(new MyTabsListener<Fragment3>(
this, "Settings", Fragment3.class));
actionbar.addTab(Animals);
actionbar.addTab(Frag2Tab);
actionbar.addTab(Frag3Tab);
如果您有任何问题,请询问