[英]How do I start a new activity when a tab is clicked?
我有這個課:
public class MainActivity extends ActionBarActivity implements TabListener{
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Set up the action bar.
final ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
ActionBar.Tab TestTab = actionBar.newTab().setText("The test");
ActionBar.Tab chatTab = actionBar.newTab().setText("Chat");
TestTab.setTabListener(this);
chatTab.setTabListener(this);
actionBar.addTab(TestTab);
actionBar.addTab(chatTab);
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment()).commit();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater actionMenue = getMenuInflater();
actionMenue.inflate(R.menu.main_activity_bar, menu);
return super.onCreateOptionsMenu(menu);
}
@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();
if (id == R.id.action_settings) {
return true;
}
if (id == R.id.mapIcon) {
Intent displayTheMap = new Intent(this, Map.class);
startActivity(displayTheMap);
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
return rootView;
}
}
public void showTheMap(View mainView){
Intent displayTheMap = new Intent(this, Map.class);
startActivity(displayTheMap);
}
@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub
}
@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub
}
@Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub
}
}
如您所見,我在操作欄下放置了2個標簽。 現在一切看起來都很好,但是,當單擊選項卡時,如何執行一對代碼? 我的意思是,很明顯,我必須在這里編寫代碼:
@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub
}
但是我怎么知道選擇了“ wich”選項卡? 有人可以給我一個線索,因為作為一個初學者,這似乎很難理解。 我知道我在這里缺少一小部分。
使用下面的代碼
請給我們下面的代碼。
@Override
public void onTabSelected(Tab tab, FragmentTransaction arg1) {
int position = tab.getPosition();
switch(position){
case 0:
//code for test
break;
case 1:
//code for chat
break;
}
}
你可以試試這個:
public class MainActivity extends TabActivity {
static TabHost mytabs;
mytabs = getTabHost();
mytabs.setOnTabChangedListener(new OnTabChangeListener() {
@Override
public void onTabChanged(String arg0) {
Log.i("***Selected Tab", "Im currently in tab with index::" + mytabs.getCurrentTab());
}
});
通常,我會像在官方文檔中一樣解決此問題。 這是一個鏈接
建議在這里實現一個單獨的TabListener
如下所示:
public static class TabListener<T extends Fragment> implements ActionBar.TabListener {
private Fragment mFragment;
private final Activity mActivity;
private final String mTag;
private final Class<T> mClass;
/** Constructor used each time a new tab is created.
* @param activity The host Activity, used to instantiate the fragment
* @param tag The identifier tag for the fragment
* @param clz The fragment's Class, used to instantiate the fragment
*/
public TabListener(Activity activity, String tag, Class<T> clz) {
mActivity = activity;
mTag = tag;
mClass = clz;
}
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.attach(mFragment);
}
}
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
if (mFragment != null) {
// Detach the fragment, because another one is being attached
ft.detach(mFragment);
}
}
public void onTabReselected(Tab tab, FragmentTransaction ft) {
// User selected the already selected tab. Usually do nothing.
}
}
然后添加如下標簽:
Tab tab = actionBar.newTab()
.setText(R.string.artist)
.setTabListener(new TabListener<ArtistFragment>(this, "artist", ArtistFragment.class));
您在構造函數中提供給偵聽器的類確定了Fragment
的類,如果選擇了選項卡,它將打開。
試試這個代碼
@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub
if(tab.getText().equals("The test"){
//the test tab is selected
}
else if(tab.getText().equals("Chat"){
// the chat tab is selected
}
}
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