[英]android tabs not working
我正在關注有關android中的標簽的教程,並且所做的一切都與視頻中的完全一樣。 有很多代碼,但是我在其中一行tab1.setTabListener(new ActionBar.TabListener(fragment1))上遇到錯誤。 它說“ TabListener”是抽象的; 無法實例化。 我該如何解決?
這是活動的完整代碼,其中包含錯誤:
import android.app.ActionBar;
import android.app.Fragment;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.TextView;
public class ProjectCreateScreen extends ActionBarActivity {
@SuppressWarnings("deprecation")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.secondary_layout1);
Toolbar toolbar = (Toolbar) findViewById(R.id.AwesomeBar);
setSupportActionBar(toolbar);
ActionBar.Tab tab1, tab2, tab3;
// Fragments that will load when the tabs are clicked
Fragment fragment1 = new TabFragment1();
Fragment fragment2 = new TabFragment2();
Fragment fragment3 = new TabFragment3();
ActionBar actionBar = getActionBar();
// Set the current navigation mode to tabs
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// Add titles to tabs
tab1 = actionBar.newTab().setText("Tab1");
tab2 = actionBar.newTab().setText("Tab2");
tab3 = actionBar.newTab().setText("Tab3");
// Set tab listeners which provide callbacks for tab events
// A callback informs another class when an action occurs
tab1.setTabListener(new ActionBar.TabListener(fragment1));
tab2.setTabListener(new ActionBar.TabListener(fragment2));
tab3.setTabListener(new ActionBar.TabListener(fragment3));
// Adds tabs to the actionbar
actionBar.addTab(tab1);
actionBar.addTab(tab2);
actionBar.addTab(tab3);
}
}
創建一個實現ActionBar.TabListener
的類,然后在setTabListener
調用該類。
有兩種解決方法:
創建一個實現ActionBar.TabListener
的新類。 例如:
protected class MyTabListener implements ActionBar.TabListener { private Fragment fragment; public MyTabListener(Fragment fragment){ this.fragment = fragment; } public void onTabSelected(Tab tab, FragmentTransaction ft){ ft.add(R.id.layout, fragment, null); } public void onTabReselected(Tab tab, FragmentTransaction ft) { } public void onTabUnselected(Tab tab, FragmentTransaction ft) { ft.remove(fragment); } }
然后設置TabListener
:
tab1.setTabListener(new MyTabListener(fragment1));
讓您的MainActivity
實現ActionBar.TabListener
並覆蓋所需的方法。 例如:
public class MainActivity extends FragmentActivity implements ActionBar.TabListener { @Override public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) { // When the given tab is selected, show the tab contents in the // container view. Fragment fragment = new Fragment(); getFragmentManager().beginTransaction().replace(R.id.container, fragment).commit(); } @Override public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) { } @Override public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) { } }
您必須創建一個實現TabListener接口的類
protected class MyTabsListener implements ActionBar.TabListener{
private Fragment fragment;
public MyTabsListener(Fragment fragment){
this.fragment = fragment;
}
public void onTabSelected(Tab tab, FragmentTransaction ft){
ft.add(R.id.layout2, fragment, null);
}
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
ft.remove(fragment);
}
}
然后設置tabListener
tab1.setTabListener(new MyTabsListener(fragment1));
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