我對Android開發相當陌生,所以遇到了onResume()方法的問題。從onResume()方法訪問Viewpager中的TextView.setText()方法
當我嘗試從onResume()方法中寫入Name.setText()時,我的代碼崩潰。 從onPause()方法中編寫TextView令人驚訝地沒有任何問題。
如何從onResume()方法訪問此TextView?
public class Main extends Activity {
private ViewPager awesomePager;
private static int NUM_AWESOME_VIEWS = 2;
private Context cxt;
private AwesomePagerAdapter awesomeAdapter;
View v;
TextView Name;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
cxt = this;
awesomeAdapter = new AwesomePagerAdapter();
awesomePager = (ViewPager) findViewById(R.id.awesomepager);
awesomePager.setAdapter(awesomeAdapter);
}
@Override
protected void onResume() {
super.onResume();
Name.setText("1");
}
@Override
protected void onPause() {
super.onPause();
}
private class AwesomePagerAdapter extends PagerAdapter{
@Override
public int getCount() {
return NUM_AWESOME_VIEWS;
}
@Override
public Object instantiateItem(View collection, int position) {
View v = new View(cxt.getApplicationContext());
final LayoutInflater inflater = (LayoutInflater) cxt
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
switch (position) {
case 0:
v = inflater.inflate(R.layout.subpage1, null, false);
Name = (TextView) v.findViewById(R.id.name);
break;
case 1:
v = inflater.inflate(R.layout.subpage2, null, false);
break;
default:
break;
}
((ViewPager) collection).addView(v, 0);
return v;
}
@Override
public void destroyItem(View collection, int position, Object view) {
((ViewPager) collection).removeView(v);
}
@Override
public boolean isViewFromObject(View view, Object object) {
return view == object;
}
@Override
public void finishUpdate(View arg0) {}
@Override
public void restoreState(Parcelable arg0, ClassLoader arg1) {}
@Override
public Parcelable saveState() {
return null;
}
@Override
public void startUpdate(View arg0) {}
}
}
嗨! onCreate()方法中的初始化給了我以下錯誤:java.lang.RuntimeException:無法恢復活動{...}:java.lang.NullPointerException ... 引起:java.lang.NullPointerException at Main.onResume(...) ... – user1023851
我們需要更多的信息。 –
嗨寇蒂斯!這是在啓動時的完整錯誤日誌:http://pastebin.com/Hiu1evmd – user1023851