I am using TabbedActivity in android 3.0.1 i like'd to display grid view in tab 1 of fragment java class whose name is fragment_simple.java all three tabs works fine but when i tried to display grid view for tab 1 my app just crashes and i set up some xml file and custom Grid Adapter .Here is following files
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/main_content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context="com.mobdev.birthdaycakesquotes.MainActivity">
<android.support.design.widget.AppBarLayout
android:id="@+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="@dimen/appbar_padding_top"
android:theme="@style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:layout_weight="1"
android:background="?attr/colorPrimary"
app:layout_scrollFlags="scroll|enterAlways"
app:popupTheme="@style/AppTheme.PopupOverlay"
app:title="@string/app_name">
</android.support.v7.widget.Toolbar>
<android.support.design.widget.TabLayout
android:id="@+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.design.widget.TabItem
android:id="@+id/tabItem"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/tab_text_1" />
<android.support.design.widget.TabItem
android:id="@+id/tabItem2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/tab_text_2" />
<android.support.design.widget.TabItem
android:id="@+id/tabItem3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/tab_text_3" />
</android.support.design.widget.TabLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="501dp"
app:layout_behavior="@string/appbar_scrolling_view_behavior" />
</android.support.design.widget.CoordinatorLayout>
fragment_simple_cake.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.mobdev.birthdaycakesquotes.Simple_cakes">
<GridView android:id="@+id/MyGrid"
android:stretchMode="columnWidth"
android:horizontalSpacing="10dp"
android:verticalSpacing="10dp"
android:numColumns="auto_fit"
android:columnWidth="150dp"
android:layout_height="fill_parent"
android:layout_width="fill_parent"
xmlns:android="http://schemas.android.com/apk/res/android"/>
</LinearLayout>
custom_layout.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<FrameLayout android:layout_height="200dp"
android:layout_width="fill_parent" android:layout_margin="1dp">
<!--150-->
<FrameLayout android:layout_height="fill_parent"
android:layout_width="fill_parent">
<ImageView
android:id="@+id/imageView"
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:scaleType="fitCenter"
android:layout_gravity="center"
android:contentDescription="@string/cake"
android:src="@mipmap/birthday_cake_01" />
</FrameLayout>
</FrameLayout>
</LinearLayout>
GridAdapter.java
package com.mobdev.birthdaycakesquotes;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import static android.content.Context.LAYOUT_INFLATER_SERVICE;
public class GridAdapter extends ArrayAdapter {
private Integer[] Image;
private int resource;
private LayoutInflater inflater;
public GridAdapter(Context context, int resource, Integer[] image) {
super(context, resource, image);
Image = image;
this.resource = resource;
inflater = (LayoutInflater)context.getSystemService(LAYOUT_INFLATER_SERVICE);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder Holder = null;
if (convertView == null) {
Holder = new ViewHolder();
convertView = inflater.inflate(resource, null);
Holder.IMAGE = (ImageView) convertView.findViewById(R.id.imageView);
convertView.setTag(Holder);
} else {
Holder = (ViewHolder)convertView.getTag();
}
Holder.IMAGE.setImageResource(Image[position]);
Holder.IMAGE.setScaleType(ImageView.ScaleType.CENTER_CROP);
return convertView;
}
class ViewHolder {
private ImageView IMAGE;
}
}
Simple_cakes.java
package com.mobdev.birthdaycakesquotes;
import android.content.Context;
import android.net.Uri;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import static android.content.Context.LAYOUT_INFLATER_SERVICE;
public class Simple_cakes extends Fragment {
GridView gridView;
GridAdapter adapter;
TextView textView;
Integer[] image = new Integer[]{R.mipmap.birthday_cake_01,
R.mipmap.birthday_cake_02, R.mipmap.birthday_cake_03,
R.mipmap.birthday_cake_04, R.mipmap.birthday_cake_05,R.mipmap.birthday_cake_04};
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view =inflater.inflate(R.layout.fragment_supreme_cakes,container,false);
//view.setBackgroundColor(getResources().getColor(android.R.color.holo_green_light));
gridView=(GridView) view.findViewById(R.id.MyGrid);
adapter = new GridAdapter(getActivity(),R.layout.custom_layout,image);
/* gridView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
Toast.makeText(getActivity(),"Clicked",Toast.LENGTH_LONG).show();
}
});*/
gridView.setAdapter(adapter);
return view;
}
}
MainActivity.java
package com.mobdev.birthdaycakesquotes;
import android.app.TaskStackBuilder;
import android.support.design.widget.TabLayout;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.GridView;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
/**
* The {@link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {@link 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}.
*/
private SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {@link ViewPager} that will host the section contents.
*/
private ViewPager mViewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
mViewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.addOnTabSelectedListener(new TabLayout.ViewPagerOnTabSelectedListener(mViewPager));
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
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 PlaceholderFragment (defined as a static inner class below).
//return PlaceholderFragment.newInstance(position + 1);
switch (position){
case 0:
Simple_cakes simple_cakes=new Simple_cakes();
return simple_cakes;
case 1:
Special_cakes special_cakes=new Special_cakes();
return special_cakes;
case 2:
Supreme_cakes supreme_cakes=new Supreme_cakes();
return supreme_cakes;
default:
return null;
}
}
@Override
public int getCount() {
// Show 3 total pages.
return 3;
}
@Override
public CharSequence getPageTitle(int position) {
switch (position){
case 0:
return "Simple";
case 1:
return "Special";
case 2:
return "Supreme";
default:
return null;
}
}
}
}
Null pointer Exception Error
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.mobdev.birthdaycakesquotes, PID: 25821
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.GridView.setAdapter(android.widget.ListAdapter)' on a null object reference
at com.mobdev.birthdaycakesquotes.Simple_cakes.onCreateView(Simple_cakes.java:49)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:2354)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1419)
at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1740)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1809)
at android.support.v4.app.BackStackRecord.executeOps(BackStackRecord.java:799)
at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2580)
at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2367)
at android.support.v4.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2322)
at android.support.v4.app.FragmentManagerImpl.execSingleAction(FragmentManager.java:2199)
at android.support.v4.app.BackStackRecord.commitNowAllowingStateLoss(BackStackRecord.java:651)
at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:145)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1236)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1084)
at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1614)
at android.view.View.measure(View.java:19147)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6113)
at android.support.design.widget.CoordinatorLayout.onMeasureChild(CoordinatorLayout.java:714)
at android.support.design.widget.CoordinatorLayout.onMeasure(CoordinatorLayout.java:786)
at android.view.View.measure(View.java:19147)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6113)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:223)
at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:139)
at android.view.View.measure(View.java:19147)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6113)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1723)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:788)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:648)
at android.view.View.measure(View.java:19147)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6113)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:223)
at android.view.View.measure(View.java:19147)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6113)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1723)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:788)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:648)
at android.view.View.measure(View.java:19147)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6113)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:223)
at com.android.internal.policy.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2693)
at android.view.View.measure(View.java:19147)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2481)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1440)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1694)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1321)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6708)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:894)
at android.view.Choreographer.doCallbacks(Choreographer.java:696)
at android.view.Choreographer.doFrame(Choreographer.java:631)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:880)
at android.os.Handler.handleCallback(Handler.java:815)
at android.os.Handler.dispatchMessage(Handler.java:104)
at android.os.Looper.loop(Looper.java:2
I/System: FinalizerDaemon: finalize objects = 1
I/Process: Sending signal. PID: 25821 SIG: 9
Application terminated.
