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MainActivity.java
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends AppCompatActivity {
public static final String TYPE_VERTICAL_LIST= "Vertical List";
public static final String TYPE_HORIZONTAL_LIST= "Horizontal List";
public static final String TYPE_GRID_VIEW = "Grid View";
public static final String TYPE_HORIZONTAL_GRID_VIEW_STAGGERED = "HorizontalStaggeredGridView";
public static final String TYPE_VERTICAL_GRID_VIEW_STAGGERED = "VerticalStaggeredGridView";
public static final String TYPE = "TYPE";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
attachFragment(TYPE_VERTICAL_LIST);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_main, menu);
/** Return false so that we can capture {@link PlaceholderFragment#onOptionsItemSelected(android.view.MenuItem)} events in {@link PlaceholderFragment} Fragment*/
return false;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()){
case R.id.action_vertical_list:
attachFragment(TYPE_VERTICAL_LIST);
break;
case R.id.action_horizontal_list:
attachFragment(TYPE_HORIZONTAL_LIST);
break;
case R.id.action_grid_view:
attachFragment(TYPE_GRID_VIEW);
break;
case R.id.action_vertical_grid_view_staggered:
attachFragment(TYPE_VERTICAL_GRID_VIEW_STAGGERED);
break;
case R.id.action_horizontal_grid_view_staggered:
attachFragment(TYPE_HORIZONTAL_GRID_VIEW_STAGGERED);
break;
}
return super.onOptionsItemSelected(item);
}
/** Attach placeholder fragment here and show different kind of RecyclerView flavours eg List or grid based on user selection in the options menu.*/
private void attachFragment(String type){
Bundle bundle = new Bundle();
bundle.putString(TYPE, type);
PlaceholderFragment placeholderFragment = new PlaceholderFragment();
placeholderFragment.setArguments(bundle);
getSupportFragmentManager().beginTransaction().replace(R.id.container, placeholderFragment).commit();
}
}
PlaceholderFragment.java
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.view.LayoutInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import java.util.ArrayList;
public class PlaceholderFragment extends Fragment {
private static final String TAG = "PlaceholderFragment";
/*Number of columns in the grid view*/
private static final int NUM_OF_COLUMNS = 2;
/*Total number of items in the RecyclerView*/
private static final int NUM_OF_ITEMS = 100;
private ArrayList<DataModel> mDataModels;
private RecyclerView recyclerView;
private RecyclerViewAdapter recyclerViewAdapter;
private int addItemCount = 0;
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
//Must be set in order to capture menu item click events. If you don't set it, it will not show the menu items set in the Activity holding this fragment.
setHasOptionsMenu(true);
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
recyclerView = (RecyclerView)rootView.findViewById(R.id.recyclerview);
RecyclerView.LayoutManager layoutManager = null;
String type = getArguments().getString(MainActivity.TYPE);
if( type.equals(MainActivity.TYPE_VERTICAL_LIST)){
/*LinearLayoutManager to show a vertical list view*/
layoutManager = new LinearLayoutManager(getActivity(), LinearLayoutManager.VERTICAL, false);
}else if(type.equals(MainActivity.TYPE_HORIZONTAL_LIST)){
/*LinearLayoutManager to show a horizontal list view*/
layoutManager = new LinearLayoutManager(getActivity(), LinearLayoutManager.HORIZONTAL, false);
}else if(type.equals(MainActivity.TYPE_GRID_VIEW)){
/*LinearLayoutManager to show a grid view. We can specify number of columns in the grid.*/
layoutManager = new GridLayoutManager(getActivity(), NUM_OF_COLUMNS);
}else if(type.equals(MainActivity.TYPE_HORIZONTAL_GRID_VIEW_STAGGERED)){
/*LinearLayoutManager to show a staggered grid view. We can specify number of columns in the grid.*/
//spanCount: If orientation is vertical, spanCount is number of columns. If orientation is horizontal, spanCount is number of rows.
//orientation: StaggeredGridLayoutManager.HORIZONTAL or StaggeredGridLayoutManager.HORIZONTAL
layoutManager = new StaggeredGridLayoutManager(3/*span count*/, StaggeredGridLayoutManager.HORIZONTAL/* orientation*/);
}else if(type.equals(MainActivity.TYPE_VERTICAL_GRID_VIEW_STAGGERED)){
/*LinearLayoutManager to show a staggered grid view. We can specify number of columns in the grid.*/
//spanCount: If orientation is vertical, spanCount is number of columns. If orientation is horizontal, spanCount is number of rows.
//orientation: StaggeredGridLayoutManager.HORIZONTAL or StaggeredGridLayoutManager.HORIZONTAL
layoutManager = new StaggeredGridLayoutManager(2/*span count*/, StaggeredGridLayoutManager.VERTICAL/* orientation*/);
}
recyclerView.setLayoutManager(layoutManager);
mDataModels = getDataModelList();
recyclerViewAdapter = new RecyclerViewAdapter(mDataModels, type);
/*Third party ItemDecoration found from https://gist.github.com/alexfu/0f464fc3742f134ccd1e*/
RecyclerView.ItemDecoration verticalDivider = new DividerItemDecoration(getActivity(), DividerItemDecoration.VERTICAL_LIST);
RecyclerView.ItemDecoration horizontalDivider = new DividerItemDecoration(getActivity(), DividerItemDecoration.HORIZONTAL_LIST);
recyclerView.addItemDecoration(horizontalDivider);
recyclerView.addItemDecoration(verticalDivider);
// this is the default;
// this call is actually only necessary with custom ItemAnimators
recyclerView.setItemAnimator(new DefaultItemAnimator());
recyclerView.setAdapter(recyclerViewAdapter);
return rootView;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()){
case R.id.action_add_item:
addItem();
break;
case R.id.action_delete_item:
deleteItem();
break;
}
return super.onOptionsItemSelected(item);
}
/** Creates and returns the data items to be shown in the Recycler View*/
private ArrayList<DataModel> getDataModelList(){
ArrayList<DataModel> dataModels = new ArrayList<>();
for (int i = 0; i < NUM_OF_ITEMS; i++) {
dataModels.add(new DataModel("Title:"+i));
}
return dataModels;
}
/** Adds a single item in the existing list*/
private final void addItem(){
//Adding item at top second position(i.e. at index 1).
mDataModels.set(1, new DataModel("Added Item "+String.valueOf(++addItemCount)));
//See for similar methods to know more item insertion options
recyclerViewAdapter.notifyItemInserted(1);
}
/** Deletes a single item from the existing list*/
private void deleteItem(){
//Removing top item
mDataModels.remove(0);
//See for similar methods to know more item removing options
recyclerViewAdapter.notifyItemRemoved(0);
}
}
ListItemViewHolder.java
public class ListItemViewHolder extends ViewHolder {
ImageView imgView;
TextView title;
public ListItemViewHolder(View itemView) {
super(itemView);
title = (TextView) itemView.findViewById(R.id.textview_title);
imgView = (ImageView) itemView.findViewById(R.id.imageview_icon);
}
}
DividerItemDecoration.java
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
public class DividerItemDecoration extends RecyclerView.ItemDecoration {
private static final int[] ATTRS = new int[]{
android.R.attr.listDivider
};
public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;
public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;
private Drawable mDivider;
private int mOrientation;
public DividerItemDecoration(Context context, int orientation) {
final TypedArray a = context.obtainStyledAttributes(ATTRS);
mDivider = a.getDrawable(0);
a.recycle();
setOrientation(orientation);
}
public void setOrientation(int orientation) {
if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST) {
throw new IllegalArgumentException("invalid orientation");
}
mOrientation = orientation;
}
@Override
public void onDraw(Canvas c, RecyclerView parent) {
if (mOrientation == VERTICAL_LIST) {
drawVertical(c, parent);
} else {
drawHorizontal(c, parent);
}
}
public void drawVertical(Canvas c, RecyclerView parent) {
final int left = parent.getPaddingLeft();
final int right = parent.getWidth() - parent.getPaddingRight();
final int childCount = parent.getChildCount();
for (int i = 0; i < childCount; i++) {
final View child = parent.getChildAt(i);
final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
.getLayoutParams();
final int top = child.getBottom() + params.bottomMargin;
final int bottom = top + mDivider.getIntrinsicHeight();
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}
public void drawHorizontal(Canvas c, RecyclerView parent) {
final int top = parent.getPaddingTop();
final int bottom = parent.getHeight() - parent.getPaddingBottom();
final int childCount = parent.getChildCount();
for (int i = 0; i < childCount; i++) {
final View child = parent.getChildAt(i);
final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
.getLayoutParams();
final int left = child.getRight() + params.rightMargin;
final int right = left + mDivider.getIntrinsicHeight();
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}
@Override
public void getItemOffsets(Rect outRect, int itemPosition, RecyclerView parent) {
if (mOrientation == VERTICAL_LIST) {
outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
} else {
outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
}
}
}
RecyclerViewAdapter.java
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import java.util.ArrayList;
public class RecyclerViewAdapter extends RecyclerView.Adapter<ListItemViewHolder> {
private ArrayList<DataModel> mDataModels;
private String mType;
public RecyclerViewAdapter(ArrayList<DataModel> mDataModels, String mType) {
this.mDataModels = mDataModels;
this.mType = mType;
}
@Override
public ListItemViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_recycler_view, parent, false);
return new ListItemViewHolder(itemView);
}
@Override
public void onBindViewHolder(ListItemViewHolder holder, int position) {
DataModel model = mDataModels.get(position);
holder.title.setText(model.getTitle());
if(position % 2 == 0){
if(mType.equals(MainActivity.TYPE_VERTICAL_GRID_VIEW_STAGGERED)){
holder.imgView.setImageResource(R.drawable.lollipop);
}else{
holder.imgView.setImageResource(R.drawable.lollipop_h1);
}
}else if(position % 3 == 0){
if(mType.equals(MainActivity.TYPE_VERTICAL_GRID_VIEW_STAGGERED)){
holder.imgView.setImageResource(R.drawable.lollipop1);
}else{
holder.imgView.setImageResource(R.drawable.lollipop_h2);
}
}else{
if(mType.equals(MainActivity.TYPE_VERTICAL_GRID_VIEW_STAGGERED)){
holder.imgView.setImageResource(R.drawable.lollipop2);
}else{
holder.imgView.setImageResource(R.drawable.lollipop_h3);
}
}
}
@Override
public int getItemCount() {
return mDataModels.size();
}
}
数据模型.java
public class DataModel {
private String title;
public DataModel(String title) {
this.title = title;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
}
activity_main.xml
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity"
tools:ignore="MergeRootFrame" />
fragment_main.xml
<android.support.v7.widget.RecyclerView
android:id="@+id/recyclerview"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity"
tools:listitem="@layout/item_recycler_view"
/>
</RelativeLayout>
item_recycler_view.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center_vertical"
android:padding="8dp"
android:background="@android:color/holo_green_dark">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/imageview_icon"
android:src="@drawable/lollipop"
android:scaleType="centerCrop"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="New Text"
android:id="@+id/textview_title"
android:background="@android:color/darker_gray"/>
</LinearLayout>
