RecyclerView的使用、res下新建選單menu-main.xml
阿新 • • 發佈：2019-01-01
2.使用RecyclerView需要匯入support v7包：
在build.gradle(app)中設定：(和AndroidStudio設定的一樣就行了，哈哈)
compile 'com.android.support:recyclerview-v7:25.1.0'3.疑問：瀑布流中新增分割線操作？
4.程式碼如下：
MainActivity:
package com.ruru.recyclerview;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
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.Menu;
import android.view.MenuItem;
import com.ruru.recyclerview.adapter.DividerGridItemDecoration;
import com.ruru.recyclerview.adapter.DividerItemDecoration;
import com.ruru.recyclerview.adapter.MyAdapter;
import java.util.ArrayList;
import java.util.List;
/**
* RecycleView-回收與複用View 高度解耦 給予充分定製自由
*/
public class MainActivity extends AppCompatActivity {
//列印log語句
public static final String TAG = "info";
//UI控制元件
private RecyclerView recycleView;
//ListView集合
private List<String> list;
private MyAdapter mAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//初始化控制元件
initView();
//初始化list集合
initData();
//初始化佈局
initLayout();
}
/**
* 初始化RecycleView的佈局
*/
private void initLayout() {
/*設定佈局
RecyclerView.LayoutManager是一個抽象類 系統實現了三個實現類
LinearLayoutManager 現行管理器，支援橫向、縱向。
GridLayoutManager 網格佈局管理器
StaggeredGridLayoutManager 瀑布就式佈局管理器*/
//ListView
// recycleView.setLayoutManager(new LinearLayoutManager(this));
// recycleView.setAdapter(new MyAdapter(this, list));
//當我們呼叫recycleView.addItemDecoration()方法新增decoration的時候，RecycleView在繪製的時候，
// 會去繪製decorator,即呼叫該類的onDraw()和onDrawOver()方法
// recycleView.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL_LIST));
//GridView
// recycleView.setLayoutManager(new GridLayoutManager(this,4));
// recycleView.setAdapter(new MyAdapter(this, list));
// recycleView.addItemDecoration(new DividerGridItemDecoration(this));
// 瀑布流StaggeredGridLayoutManager
// 第二個引數傳一個orientation，
// 如果傳入的是StaggeredGridLayoutManager.VERTICAL代表有多少列；注：固定列上下混動
// 如果傳入的是StaggeredGridLayoutManager.HORIZONTAL就代表有多少行；注:固定行的話可能會左右滑動
//如果是橫向的時候，item的寬度需要注意去設定，畢竟橫向的寬度沒有約束了，應為控制元件可以橫向滾動了
recycleView.setLayoutManager(new StaggeredGridLayoutManager(4, StaggeredGridLayoutManager.VERTICAL));
mAdapter = new MyAdapter(this, list);
recycleView.setAdapter(mAdapter);
// 設定item動畫
recycleView.setItemAnimator(new DefaultItemAnimator());
}
/**
* 初始化list集合資料
*/
private void initData() {
list = new ArrayList<String>();
for (int i = 1; i < 10; i++) {
list.add("序號" + i);
}
}
/**
* 初始化控制元件
*/
private void initView() {
recycleView = (RecyclerView) findViewById(R.id.recycleView);
}
/**
* Activity中點選MenuItem觸發
* 注意，這裡更新資料集不是用adapter.notifyDataSetChanged()
* 而是notifyItemInserted(position)與notifyItemRemoved(position)
*/
@Override
public boolean onCreateOptionsMenu(Menu menu)
{
getMenuInflater().inflate(R.menu.main, menu);
return super.onCreateOptionsMenu(menu);
}
/**
* Activity中點選MenuItem觸發
*/
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.id_action_add:
mAdapter.addData(1);
break;
case R.id.id_action_delete:
mAdapter.removeData(1);
break;
}
return true;
}
}
package com.ruru.recyclerview.adapter;
import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import com.ruru.recyclerview.R;
import java.util.List;
/**
* Created by SophieLiang on 2017/2/28.
*/
//注意要加後面的<MyAdapter.MyViewHolder>
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> {
private Context context;
private List<String> list;
public MyAdapter(Context context, List<String> list) {
this.context = context;
this.list = list;
}
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
MyViewHolder holder = new MyViewHolder(LayoutInflater.from(context).inflate(R.layout.item, parent, false));
return holder;
}
@Override
public void onBindViewHolder(MyViewHolder holder, int position) {
holder.tv_name.setText(list.get(position));
//如果是瀑布流的話，為item設計個隨機的高度
}
@Override
public int getItemCount() {
return list.size();
}
class MyViewHolder extends RecyclerView.ViewHolder {
TextView tv_name;//不要寫成private static
public MyViewHolder(View itemView) {
super(itemView);
tv_name = (TextView) itemView.findViewById(R.id.tv_name);
}
}
/**
* 新增動畫更新資料集
*/
public void addData(int position) {
list.add(position, "Insert One");
notifyItemInserted(position);
}
/**
* 刪除動畫更新資料集
*/
public void removeData(int position) {
list.remove(position);
notifyItemRemoved(position);
}
}
package com.ruru.recyclerview;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.support.v7.widget.RecyclerView;
import android.view.View;
/**
* Created by SophieLiang on 2017/2/28.
*/
public abstract class ItemDecoration {
//onDraw方法先於drawChildren
public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
onDraw(c, parent, state);
}
//onDrawOver在drawChildren之後，一般我們選擇複寫其中一個即可。
public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
onDrawOver(c, parent, state);
}
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
getItemOffsets(outRect, ((RecyclerView.LayoutParams) view.getLayoutParams()).getViewLayoutPosition(),
parent);
}
//getItemOffsets 可以通過outRect.set()為每個Item設定一定的偏移量，主要用於繪製Decorator。
@Deprecated
public void getItemOffsets(Rect outRect, int itemPosition, RecyclerView parent) {
outRect.set(0, 0, 0, 0);
}
}
/**
* Created by SophieLiang on 2017/2/28.
* 新增分割線操作
*/
public class DividerItemDecoration extends RecyclerView.ItemDecoration {
private static final String TAG = "info";
/**
* 通過讀取系統主題中的 Android.R.attr.listDivider作為Item間的分割線,並且支援橫向和縱向
*/
private static final int[] ATTRS = new int[]{
android.R.attr.listDivider
};
//定義了兩個方法中的orientation
public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;
public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;
//獲取到listDivider以後，該屬性的值是個Drawable
private Drawable mDivider;
private int mOrientation;
public DividerItemDecoration(Context context, int orientation) {
//自定義屬性
final TypedArray a = context.obtainStyledAttributes(ATTRS);
mDivider = a.getDrawable(0);
a.recycle();
//設定分割線的方向
setOrientation(orientation);
}
/**
* 設定分割線方向
*/
public void setOrientation(int orientation) {
if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST) {
throw new IllegalArgumentException("invalid orientation");
}
mOrientation = orientation;
}
/**
* 畫分割線:一個item只有一個children
*/
@Override
public void onDraw(Canvas c, RecyclerView parent) {
Log.i(TAG, "onDraw:+++ ");
if (mOrientation == VERTICAL_LIST) {
drawVertical(c, parent);
} else {
drawHorizontal(c, parent);
}
}
/**
* 畫垂直分割線
*/
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);
android.support.v7.widget.RecyclerView v = new android.support.v7.widget.RecyclerView(parent.getContext());
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);//左上右下
mDivider.draw(c);
}
}
/**
* 畫水平分割線
*/
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);
}
}
/**
* 在getItemOffsets中，outRect去設定了繪製的範圍。onDraw中實現了真正的繪製
*/
@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);
}
}
}public class DividerGridItemDecoration extends RecyclerView.ItemDecoration {
private static final int[] ATTRS = new int[]{android.R.attr.listDivider};
private Drawable mDivider;
public DividerGridItemDecoration(Context context) {
final TypedArray a = context.obtainStyledAttributes(ATTRS);
mDivider = a.getDrawable(0);
a.recycle();
}
@Override
public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
drawHorizontal(c, parent);
drawVertical(c, parent);
}
private int getSpanCount(RecyclerView parent) {
// 列數
int spanCount = -1;
RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
if (layoutManager instanceof GridLayoutManager) {
spanCount = ((GridLayoutManager) layoutManager).getSpanCount();
} else if (layoutManager instanceof StaggeredGridLayoutManager) {
spanCount = ((StaggeredGridLayoutManager) layoutManager)
.getSpanCount();
}
return spanCount;
}
public void drawHorizontal(Canvas c, RecyclerView parent) {
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.getLeft() - params.leftMargin;
final int right = child.getRight() + params.rightMargin
+ mDivider.getIntrinsicWidth();
final int top = child.getBottom() + params.bottomMargin;
final int bottom = top + mDivider.getIntrinsicHeight();
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}
public void drawVertical(Canvas c, RecyclerView parent) {
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.getTop() - params.topMargin;
final int bottom = child.getBottom() + params.bottomMargin;
final int left = child.getRight() + params.rightMargin;
final int right = left + mDivider.getIntrinsicWidth();
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}
private boolean isLastColum(RecyclerView parent, int pos, int spanCount, int childCount) {
RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
if (layoutManager instanceof GridLayoutManager) {
if ((pos + 1) % spanCount == 0)// 如果是最後一列，則不需要繪製右邊
{
return true;
}
} else if (layoutManager instanceof StaggeredGridLayoutManager) {
int orientation = ((StaggeredGridLayoutManager) layoutManager)
.getOrientation();
if (orientation == StaggeredGridLayoutManager.VERTICAL) {
if ((pos + 1) % spanCount == 0)// 如果是最後一列，則不需要繪製右邊
{
return true;
}
} else {
childCount = childCount - childCount % spanCount;
if (pos >= childCount)// 如果是最後一列，則不需要繪製右邊
return true;
}
}
return false;
}
private boolean isLastRaw(RecyclerView parent, int pos, int spanCount,
int childCount) {
RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
if (layoutManager instanceof GridLayoutManager) {
childCount = childCount - childCount % spanCount;
if (pos >= childCount)// 如果是最後一行，則不需要繪製底部
return true;
} else if (layoutManager instanceof StaggeredGridLayoutManager) {
int orientation = ((StaggeredGridLayoutManager) layoutManager)
.getOrientation();
// StaggeredGridLayoutManager 且縱向滾動
if (orientation == StaggeredGridLayoutManager.VERTICAL) {
childCount = childCount - childCount % spanCount;
// 如果是最後一行，則不需要繪製底部
if (pos >= childCount)
return true;
} else
// StaggeredGridLayoutManager 且橫向滾動
{
// 如果是最後一行，則不需要繪製底部
if ((pos + 1) % spanCount == 0) {
return true;
}
}
}
return false;
}
/**
* 主要在getItemOffsets方法中，去判斷如果是最後一行，則不需要繪製底部；如果是最後一列，則不需要繪製右邊，
* 整個判斷也考慮到了StaggeredGridLayoutManager的橫向和縱向
* 一般如果僅僅是希望有空隙，還是去設定item的margin方便
*/
@Override
public void getItemOffsets(Rect outRect, int itemPosition, RecyclerView parent) {
int spanCount = getSpanCount(parent);
int childCount = parent.getAdapter().getItemCount();
if (isLastRaw(parent, itemPosition, spanCount, childCount))// 如果是最後一行，則不需要繪製底部
{
outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
} else if (isLastColum(parent, itemPosition, spanCount, childCount))// 如果是最後一列，則不需要繪製右邊
{
outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
} else {
outRect.set(0, 0, mDivider.getIntrinsicWidth(),
mDivider.getIntrinsicHeight());
}
}
}<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<gradient
android:centerColor="#ff00ff00"
android:endColor="#ff0000ff"
android:startColor="#ffff0000"
android:type="linear" />
<size android:height="4dp" />
</shape><?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
<item
android:id="@+id/id_action_add"
android:title="新增動畫"/>
<item
android:id="@+id/id_action_delete"
android:title="刪除動畫"/>
</menu><?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.ruru.recyclerview.MainActivity">
<!--RecycleView中divider這樣的屬性不會起作用-->
<android.support.v7.widget.RecyclerView
android:id="@+id/recycleView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:divider="#ffff0000"
android:dividerHeight="10dp"></android.support.v7.widget.RecyclerView>
</RelativeLayout>item.xml:ListView有一個item,GridView有好多個ChildView
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="50dp"
android:background="#44ff0000">
<TextView
android:id="@+id/tv_name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:gravity="center" />
</FrameLayout>