android - getActivity().runOnUiThreadnew Runnable() 中的错误
问题描述
显示错误
致命异常:Timer-0 进程:com.example.tanis.myapplication,PID:9918 java.lang.NullPointerException:尝试调用虚拟方法 'void android.support.v4.app.FragmentActivity.runOnUiThread(java.lang.Runnable) ' 在 java.util.TimerThread.mainLoop(Timer.java:555) 在 java.util.TimerThread 的 com.example.tanis.myapplication.MenuItems.Home$Mytime.run(Home.java:158) 的空对象引用.run(Timer.java:505)
它在 getActivity().runOnUiThread(new Runnable() 中显示错误我不知道为什么会出现错误请帮助谢谢
主页.java
package com.example.tanis.myapplication.MenuItems;
import android.content.Context;
import android.content.Intent;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.design.widget.FloatingActionButton;
import android.support.v4.app.Fragment;
import android.support.v4.content.res.ResourcesCompat;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;
import com.example.tanis.myapplication.Adapters.CardItemString;
import com.example.tanis.myapplication.Adapters.CardPagerAdapterS;
import com.example.tanis.myapplication.Adapters.ViewPagerAdapter;
import com.example.tanis.myapplication.R;
import com.example.tanis.myapplication.Services.website_designing;
import java.util.Timer;
import java.util.TimerTask;
public class Home extends Fragment {
ViewPager mViewPager;
CardPagerAdapterS mCardAdapter;
ShadowTransformer mCardShadowTransformer;
private Context context;
ViewPager viewPager;
String titlesText [] = {" Website Design", " Digital Marketing", " Domain Registration", "Graphics Design", " Mobile Apps", " Server Hosting",
" Software Development", " Content Marketing", " Security (SSl)"};
String detailsArray [] = {
"Your website is your digital home. We create, design, redesign, develop, improvise, and implement. We make beautiful websites",
"We help your business reach potential customers on every possible digital device through all possible media channels ",
"To launch your website the first thing you need is the domain name. You can choose your domain name with us here ",
"We generate creative solutions and can create a wide range of graphic for your clients which match their business ",
"We are mobile. And we make you mobile. We make responsive websites and mobile apps which compliment your business ",
"When you are hosting your website in the India you will benefit from a higher ping rate and lowest latency ",
"Our team is competent at coding web apps with keen attention to detail & intuitive functionality that is high on design & creativity",
"Content is the heart of your digital presence. We create the right content with the right focus for your business",
"Secure your site with the world's leading provider of online security and get these exclusive features at no added cost",
};
int[] images = {R.drawable.website_design, R.drawable.digita,R.drawable.domain_registration,R.drawable.gric,
R.drawable.mob,R.drawable.server,R.drawable.software_development,R.drawable.ontent,R.drawable.ssl};
private static final String KEY_MOVIE_TITLE = "key_title";
public Home() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment.
*
* @return A new instance of fragment FragmentAction.
*/
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
{
View v = inflater.inflate(R.layout.home,container,false);
TextView txt = (TextView)v.findViewById( R.id.textView12 );
txt.setText("\u25BA Creative & Dedicated Team");
TextView txt1 = (TextView)v.findViewById( R.id.textView13 );
txt1.setText("\u25BA Affordable Cost");
TextView txt2 = (TextView)v.findViewById( R.id.textView14 );
txt2.setText("\u25BA Maintain Long Relationship");
TextView txt3 = (TextView)v.findViewById( R.id.textView15 );
txt3.setText("\u25BA Timely Deliverly ");
context = this.getContext();
Button b = (Button) v.findViewById( R.id.button7 ) ;
b.setOnClickListener( new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent=new Intent( getActivity(), website_designing.class);
}
} );
mViewPager = (ViewPager)v.findViewById(R.id.viewpager1);
mCardAdapter = new CardPagerAdapterS();
for (int i=0; i<titlesText.length; i++){
mCardAdapter.addCardItemS(new CardItemString( titlesText[i], detailsArray[i],images[i]));
}
mCardShadowTransformer = new ShadowTransformer(mViewPager, mCardAdapter);
mViewPager.setAdapter(mCardAdapter);
mViewPager.setPageTransformer(false, mCardShadowTransformer);
mViewPager.setOffscreenPageLimit(3);
viewPager = (ViewPager)v.findViewById( R.id.viewpager );
ViewPagerAdapter viewPagerAdapter = new ViewPagerAdapter( this.getContext() );
viewPager.setAdapter( viewPagerAdapter );
Timer timer = new Timer( );
timer.scheduleAtFixedRate( new Mytime(),2000,4000 );
FloatingActionButton floatingActionButton = (FloatingActionButton)v.findViewById( R.id.floatingActionButton );
floatingActionButton.setOnClickListener( new View.OnClickListener() {
@Override
public void onClick(View view) {
startActivity( new Intent( getActivity(),Registration.class ) );
}
} );
return v;
}
public class Mytime extends TimerTask {
@Override
public void run() {
//here it is showing me error//
**getActivity().runOnUiThread( new Runnable() {
@Override
public void run() {
if(viewPager.getCurrentItem() == 0) {
viewPager.setCurrentItem( 1 );
}
else if (viewPager.getCurrentItem()== 1){
viewPager.setCurrentItem( 2 );
}
else if (viewPager.getCurrentItem()== 2){
viewPager.setCurrentItem( 3 );
}
else if (viewPager.getCurrentItem()== 3){
viewPager.setCurrentItem( 4 );
}
else {
viewPager.setCurrentItem(0);
}
}
} );
}
}
@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
}
}
解决方案
java.lang.NullPointerException:尝试调用虚拟方法“void android.support.v4.app.FragmentActivity.runOnUiThread(java.lang.Runnable)”
NullPointerException
当应用程序尝试使用具有空值的对象引用时抛出。
您应该在下面添加检查。
if (getActivity()!=null)
演示
if (getActivity()!=null)
{
getActivity().runOnUiThread( new Runnable() {
@Override
public void run() {
......
}
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