好的，所以我已经用键盘敲打我的头大约 2 天了。当我运行程序时，它会强制关闭，并且 log cat 告诉我一个空指针。当我将按钮放在评论中时，程序将打开。（更新）现在它在没有空指针的情况下运行，但 onclick() 不起作用。也许这是我如何为按钮充气的问题。
好的，所以我编辑了按钮，现在它看起来像这样，
Button b;
View v1 = getLayoutInflater().inflate(R.layout.current, null);
b = (Button) v1.findViewById(R.id.okbutton);
b.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
result.setText("Test");
}
});
但是，我认为问题可能在于我如何连接主 xml 中的选项卡。
所以这是我的代码的完整部分。
import java.util.*;
import android.app.*;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.*;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends FragmentActivity implements
ActionBar.TabListener {
/**
* 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;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Set up the action bar.
final ActionBar actionBar = getActionBar();
final TextView result = (TextView) findViewById(R.id.TextView);
//final GameEventHandler object = new GameEventHandler();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// 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);
// When swiping between different sections, select the corresponding
// tab. We can also use ActionBar.Tab#select() to do this if we have
// a reference to the Tab.
mViewPager
.setOnPageChangeListener(new
ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
});
// For each of the sections in the app, add a tab to the action bar.
for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) {
// Create a tab with text corresponding to the page title defined by
// the adapter. Also specify this Activity object, which implements
// the TabListener interface, as the callback (listener) for when
// this tab is selected.
actionBar.addTab(actionBar.newTab()
.setText(mSectionsPagerAdapter.getPageTitle(i))
.setTabListener(this));
}
Button b;
View v1 = getLayoutInflater().inflate(R.layout.current, null);
b = (Button) v1.findViewById(R.id.okbutton);
b.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
result.setText("Test");
}
});
}
@Override
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;
}
@Override
public void onTabSelected(ActionBar.Tab tab,
FragmentTransaction fragmentTransaction) {
// When the given tab is selected, switch to the corresponding page in
// the ViewPager.
mViewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(ActionBar.Tab tab,
FragmentTransaction fragmentTransaction) {
}
@Override
public void onTabReselected(ActionBar.Tab tab,
FragmentTransaction fragmentTransaction) {
}
/**
* 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 4 total pages.
return 4;
}
@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);
case 3:
return getString(R.string.title_section4).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() {
}
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.current,
container, false);
TextView dummyTextView = (TextView) rootView
.findViewById(R.id.textView1);
dummyTextView.setText(Integer.toString(getArguments().getInt(
ARG_SECTION_NUMBER)));
if(dummyTextView.getText().equals("1") ){
rootView = inflater.inflate(R.layout.current,
container, false);
}
if(dummyTextView.getText().equals("2")){
rootView = inflater.inflate(R.layout.stats,
container, false);
}
if(dummyTextView.getText().equals("3")){
rootView = inflater.inflate(R.layout.inventory,
container, false);
}
if(dummyTextView.getText().equals("4")){
rootView = inflater.inflate(R.layout.options,
container, false);
}
return rootView;
}
}
}
这是包含按钮的 xml 的 xml；
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center_vertical" >
<Button
android:id="@+id/okbutton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/Yesbutton"
android:layout_alignBottom="@+id/Yesbutton"
android:layout_alignLeft="@+id/RollButton"
android:text="ok" />
<Button
android:id="@+id/nobutton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/RollButton"
android:layout_toRightOf="@+id/okbutton"
android:text="no" />
<Button
android:id="@+id/Yesbutton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/textView1"
android:layout_toLeftOf="@+id/okbutton"
android:text="Yes" />
<Button
android:id="@+id/RollButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/okbutton"
android:layout_centerHorizontal="true"
android:text="Roll" />
<TextView
android:id="@+id/RollResult"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/RollButton"
android:layout_centerHorizontal="true"
android:text="0"
android:textAppearance="?android:attr/textAppearanceLarge" />
<TextView
android:id="@+id/text2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/RollButton"
android:layout_toLeftOf="@+id/RollResult"
android:text="Current Roll:"
android:textAppearance="?android:attr/textAppearanceLarge" />
<TextView
android:id="@+id/TextView"
android:layout_width="200dp"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:text="Welcome to the dungeon! press ok to start!"
android:textAppearance="?android:attr/textAppearanceLarge" />
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:text="1"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textSize="1px" />
</RelativeLayout>
</LinearLayout>
抱歉，如果我不够具体，这是我第一次不得不寻求帮助。