Android 如何截取片段中的后退按钮?
我是android编程新手,需要帮助:我需要截取片段中的后退按钮以显示退出警报对话框。我用onBackPressed和onKeyDown都试过了,但都不起作用,我不知道为什么。。。 下面是一些代码:Android 如何截取片段中的后退按钮?,android,android-viewpager,fragment,back-button,android-fragmentactivity,Android,Android Viewpager,Fragment,Back Button,Android Fragmentactivity,我是android编程新手,需要帮助:我需要截取片段中的后退按钮以显示退出警报对话框。我用onBackPressed和onKeyDown都试过了,但都不起作用,我不知道为什么。。。 下面是一些代码: public class Home extends Fragment { private Dialog dialog; // onAttach : set activity listener @Override public void onAttach(Activity a
public class Home extends Fragment {
private Dialog dialog;
// onAttach : set activity listener
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
// if implemented by activity, set listener
// else create local listener (code never executed in this example)
}
// onCreateView :
@Override
public View onCreateView(LayoutInflater inflater,ViewGroup container,Bundle savedInstanceState) {
// fragment not when container null
if (container == null) {
return null;
}
// inflate view from layout
final View view = inflater.inflate(R.layout.home,container,false);
...
//onBackPressed(); doesn't work, alertDialog comes up only the first time without touching back button
return view;
}
我的背压
public void onBackPressed() {
new AlertDialog.Builder(getActivity())
.setIcon(android.R.drawable.ic_dialog_alert)
.setTitle("Hey!")
.setMessage("Exit?")
.setPositiveButton("Yes", new DialogInterface.OnClickListener()
{
@Override
public void onClick(DialogInterface dialog, int which) {
FragmentActivity i=getActivity();
i.finish();
}
})
.setNegativeButton("No", null)
.show();
}
}
这里为您提供PagerTabsActivity和PagerDapter,如果您需要。。。
PagerTab活动:
public class PagerTabsActivity extends FragmentActivity {
private static int i=0;
private static View pagerStrip;
// list contains fragments to instantiate in the viewpager
List<Fragment> fragments = new Vector<Fragment>();
List<String> fragmentTitles = new Vector<String>();
// page adapter between fragment list and view pager
private PagerAdapter mPagerAdapter;
// view pager
private ViewPager mViewPager;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// creating fragments and adding to list
fragments.add(Fragment.instantiate(this, Home.class.getName()));
fragmentTitles.add(Home.class.getSimpleName());
fragments.add(Fragment.instantiate(this, Second.class.getName()));
fragmentTitles.add(Second.class.getSimpleName());
fragments.add(Fragment.instantiate(this, Third.class.getName()));
fragmentTitles.add(Third.class.getSimpleName());
//
mViewPager = (ViewPager) findViewById(R.id.pager);
pagerStrip = findViewById(R.id.pagerTabStrip);
if (pagerStrip instanceof PagerTabStrip) {
PagerTabStrip pagerTabStrip = (PagerTabStrip) pagerStrip;
pagerTabStrip.setDrawFullUnderline(true);
pagerTabStrip.setTabIndicatorColorResource(android.R.color.white);
// pagerTabStrip.setTextColor(color.white);
} else if (pagerStrip instanceof PagerTitleStrip) {
PagerTitleStrip pagerTitleStrip = (PagerTitleStrip) pagerStrip;
pagerTitleStrip.setTextColor(getResources().getColor(android.R.color.white));
}
this.mPagerAdapter = new PagerAdapter(super.getSupportFragmentManager(), fragments);
mViewPager.setAdapter(this.mPagerAdapter);
mViewPager.setCurrentItem(0);
}
}
PagerAdapter:
public class PagerAdapter extends FragmentPagerAdapter {
// private String titles[] = new String[] { "Tab1", "Tab2", "Tab3" };
private List<String> fragmentTitles;
private List<Fragment> fragments;
public PagerAdapter(FragmentManager fm, List<Fragment> fragments) {
super(fm);
this.fragments = fragments;
}
@Override
public CharSequence getPageTitle(int position) {
if (null == fragmentTitles || fragmentTitles.size() <= position) {
return " ";
}
String fragTitle = fragmentTitles.get(position);
if (null == fragTitle || fragTitle.trim().length() == 0) {
return "No Title";
}
// Log.v("TitleAdapter - getPageTitle=", fragmentTitles.get(position));
return fragmentTitles.get(position);
}
@Override
public Fragment getItem(int position) {
// Log.v("TitleAdapter - getItem=", String.valueOf(position));
return this.fragments.get(position);
}
@Override
public int getCount() {
return this.fragments.size();
}
}
任何帮助都将不胜感激!: 您需要重写该方法。。请尝试以下代码:
@Override
public void onBackPressed() {
new AlertDialog.Builder(this)
.setTitle("Exit")
.setMessage("Are you sure you want to exit?")
.setNegativeButton("No", null)
.setPositiveButton("Get me out!", new OnClickListener() {
public void onClick(DialogInterface arg0, int arg1) {
FragmentActivity i=getActivity();
i.finish();
}
}).create().show();
}
显示退出警报对话框-这是个坏主意,因为您试图在此处保存的任何数据都可能以其他方式丢失,例如,用户按HOME键。请不要用此类对话框打断用户。相反,如果您认为任何未完成的数据尚未准备好应用到主数据存储,请将其保存到临时位置,并在用户返回到您的应用程序时告知该临时数据。非常感谢您的建议:我会记住它!顺便说一句,我只做了一个非常简单的应用程序与互动样机,所以现在我只想知道如何解决这个问题!是的,我已经试过了,我已经发布了一个非常类似的代码…我将编辑第一篇文章以更好地展示它!