如何使用OnTabChangeListener？

我有一个带有3个选项卡的android程序。 当我点击“地图选项卡”时，我希望它显示“地图被选中”消息，如下图所示。 但是，如果我单击“名称”选项卡，然后第二次返回“地图选项卡”，则“再次选择地图”消息将不会显示在屏幕上。 每次选择该选项卡时，如何使“地图”选项卡显示“再次选择地图”消息？ 您可以编辑以下代码并显示有关如何使用OnTabChangeListener的示例吗？

public class MapsActivity extends MapActivity implements OnTabChangeListener { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main4); Toast.makeText(getApplicationContext(),"Map is Selected", Toast.LENGTH_LONG).show(); } public void onTabChanged(String tabId) { Toast.makeText(getApplicationContext(),"Map Selected Again", Toast.LENGTH_LONG).show(); } @Override protected boolean isRouteDisplayed() { return false; } } 

更新。 但以下方法不输出消息。

 `public class HelloTabWidget extends TabActivity implements OnTabChangeListener{` private TabHost mTabHost; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); Resources res = getResources(); TabHost tabHost = getTabHost(); TabHost.TabSpec spec; Intent intent; intent = new Intent().setClass(this, BarActivity.class); spec = tabHost.newTabSpec("Name").setIndicator("Name",res.getDrawable(R.drawable.ic_tab_name)).setContent(intent); tabHost.addTab(spec); intent = new Intent().setClass(this, CityActivity.class); spec = tabHost.newTabSpec("city").setIndicator("City",res.getDrawable(R.drawable.ic_tab_city)).setContent(intent); tabHost.addTab(spec); intent = new Intent().setClass(this, MapsActivity.class); spec = tabHost.newTabSpec("Map").setIndicator("Map",res.getDrawable(R.drawable.ic_tab_map)).setContent(intent); tabHost.addTab(spec); tabHost.setCurrentTab(2); } public void onTabChanged(String tabId) { mTabHost = getTabHost(); mTabHost.setOnTabChangedListener(this); Toast.makeText(getApplicationContext(), "To check for Display", Toast.LENGTH_LONG).show(); Log.i("selected tab index", "Current index - "+ mTabHost.getCurrentTab()); }} 

Answer 1

您应该将OnTabChangeListener实现为TabActivity类而不是Tab的内容。

在TabActivity中实现OnTabChangeListener

然后设置mTabHost.setOnTabChangedListener(this);的监听器mTabHost.setOnTabChangedListener(this);

 @Override public void onTabChanged(String tabId) { Log.i("selected tab ", tabId); } 

UPDATE

 public class HelloTabWidget extends TabActivity implements OnTabChangeListener{` private TabHost mTabHost; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); Resources res = getResources(); TabHost tabHost = getTabHost(); TabHost.TabSpec spec; Intent intent; mTabHost = getTabHost(); intent = new Intent().setClass(this, BarActivity.class); spec = tabHost.newTabSpec("Name").setIndicator("Name",res.getDrawable(R.drawable.ic_tab_name)).setContent(intent); tabHost.addTab(spec); intent = new Intent().setClass(this, CityActivity.class); spec = tabHost.newTabSpec("city").setIndicator("City",res.getDrawable(R.drawable.ic_tab_city)).setContent(intent); tabHost.addTab(spec); intent = new Intent().setClass(this, MapsActivity.class); spec = tabHost.newTabSpec("Map").setIndicator("Map",res.getDrawable(R.drawable.ic_tab_map)).setContent(intent); tabHost.addTab(spec); tabHost.setCurrentTab(2); mTabHost.setOnTabChangedListener(this); } public void onTabChanged(String tabId) { Toast.makeText(getApplicationContext(), "Selected Tab "+tabId, Toast.LENGTH_LONG).show(); Log.i("selected tab index", "Current index - "+ mTabHost.getCurrentTab()); }}