我遵循了一个在线教程，该教程展示了如何在 Android 应用程序中实现滑动，但是当我在我的设备上测试它时它没有滑动。有人能发现这个实现有什么问题吗？
我的主要课程如下所示：
public class MainActivity extends FragmentActivity implements OnClickListener{
/**
* The {@link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {@link android.support.v4.app.FragmentPagerAdapter} derivative, which
* will keep every loaded fragment in memory. If this becomes too memory
* intensive, it may be best to switch to a
* {@link android.support.v4.app.FragmentStatePagerAdapter}.
*/
SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {@link ViewPager} that will host the section contents.
*/
ViewPager mViewPager;
EditText offsetLength,offsetDepth,ductDepth;
Button calculate;
//DemoCollectionPagerAdapter mDemoCollectionPagerAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final Intent intent1=new Intent(this,AboutActivity.class);
final Intent intent2=new Intent(this,MainActivity.class);
offsetLength = (EditText)findViewById(R.id.offLength);
offsetDepth = (EditText)findViewById(R.id.offDepth);
ductDepth = (EditText)findViewById(R.id.ductDepth);
calculate = (Button)findViewById(R.id.calc);
calculate.setOnClickListener(this);
final ViewGroup actionBarLayout = (ViewGroup) getLayoutInflater().inflate(R.layout.a,null);
// Create the adapter that will return a fragment for each of the three
// primary sections of the app.
mSectionsPagerAdapter = new SectionsPagerAdapter(
getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
try {
String getoffsetlength = offsetLength.getText().toString();
String getoffsetdepth = offsetDepth.getText().toString();
String getductdepth = ductDepth.getText().toString();
double tri1,tri2;
double marking1,marking2,marking3;
double off1 = Double.parseDouble(getoffsetlength);
double off2 = Double.parseDouble(getoffsetdepth);
double off3 = Double.parseDouble(getductdepth);
Intent myIntent = new Intent(MainActivity.this, CalcResult.class);
myIntent.putExtra("number1", marking1);
myIntent.putExtra("number2", marking2);
myIntent.putExtra("number3", marking3);
startActivity(myIntent);
Toast.makeText(getBaseContext(), "Calculating!", Toast.LENGTH_SHORT).show();
} catch (NumberFormatException e) {
// TODO: handle exception
System.out.println("Must enter a numeric value!");
}
//
}
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
/**
* A {@link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a DummySectionFragment (defined as a static inner class
// below) with the page number as its lone argument.
Fragment fragment = new DummySectionFragment();
Bundle args = new Bundle();
args.putInt(DummySectionFragment.ARG_SECTION_NUMBER, position + 1);
fragment.setArguments(args);
return fragment;
}
@Override
public int getCount() {
// Show 3 total pages.
return 3;
}
@Override
public CharSequence getPageTitle(int position) {
Locale l = Locale.getDefault();
switch (position) {
case 0:
return getString(R.string.title_section1).toUpperCase(l);
case 1:
return getString(R.string.title_section2).toUpperCase(l);
case 2:
return getString(R.string.title_section3).toUpperCase(l);
}
return null;
}
}
/**
* A dummy fragment representing a section of the app, but that simply
* displays dummy text.
*/
public static class DummySectionFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
public static final String ARG_SECTION_NUMBER = "section_number";
public DummySectionFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main_dummy,
container, false);
TextView dummyTextView = (TextView) rootView
.findViewById(R.id.section_label);
dummyTextView.setText(Integer.toString(getArguments().getInt(
ARG_SECTION_NUMBER)));
return rootView;
}
}
}