1.RecyclerView
<1>知识点介绍
RecyclerView 比 ListView 更高级且更具灵活性。 它是一个用于显示庞大数据集的容器，可通过保持有限数量的视图进行非常有效的滚动操作。 如果您有数据集合，其中的元素将因用户操作或网络事件而在运行时发生改变，请使用 RecyclerView 。
RecyclerView代表的意义是，我只管Recycler View，也就是说RecyclerView只管回收与复用View，其他的你可以自己去设置。可以看出其高度的解耦，给予你充分的定制*（所以你才可以轻松的通过这个控件实现ListView,GirdView，瀑布流等效果）
要实现一个RecyclerView，会接触到它的几个小伙伴，其中1、2是必须的。剩下的3、4、5三项，可以让RecyclerView更好看、效果更好。
(1)想要控制其item们的排列方式，请使用布局管理器LayoutManager
(2)如果要创建一个适配器，请使用RecyclerView.Adapter
(3)想要控制Item间的间隔，请使用RecyclerView.ItemDecoration
(4)想要控制Item增删的动画，请使用RecyclerView.ItemAnimator
(5)CardView 扩展 FrameLayout 类并让您能够显示卡片内的信息，这些信息在整个平台中拥有一致的呈现方式。CardView 小部件可拥有阴影和圆角。
2. 实际案例
<1>先将RecyclerView拖入界面
<2>源码（对应工程名为test17）
使用RecyclerView需在build.gradle中添加声明
implementation 'com.android.support:design:28.0.0'
(1)XML页面布局
<?xml version="1.0" encoding="utf-8"?> <LinearLayout 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:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" tools:context=".recyclerview.Recycler2Activity"> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal"> <Button android:id="@+id/button_add" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_weight="1" android:text="添加" /> <Button android:id="@+id/button_delete" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_weight="1" android:text="删除" /> <Button android:id="@+id/button_list" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_weight="1" android:text="list" /> <Button android:id="@+id/button_grid" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_weight="1" android:text="grid" /> <Button android:id="@+id/button_flow" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_weight="1" android:text="flow" /> </LinearLayout> <android.support.v7.widget.RecyclerView android:id="@+id/recycler_test1" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_weight="1" /> </LinearLayout>
(2)适配器源码
package com.lucky.test17.recyclerview; import android.content.Context; import android.support.annotation.NonNull; import android.support.v7.widget.RecyclerView; import android.view.View; import android.view.ViewGroup; import android.widget.ImageView; import android.widget.TextView; import android.widget.Toast; import com.lucky.test17.R; import java.util.ArrayList; public class MyRecyclerViewAdapter extends RecyclerView.Adapter<MyRecyclerViewAdapter.MyViewHolder> { private final Context content; private final ArrayList<String> datas; //构造方法 public MyRecyclerViewAdapter(Context content, ArrayList<String> datas) { this.content=content; this.datas=datas; } @NonNull @Override public MyViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) { View viewItem=View.inflate(content, R.layout.item_recycle,null); return new MyViewHolder(viewItem); } //数据与view绑定 @Override public void onBindViewHolder(@NonNull MyViewHolder myViewHolder, int i) { //根据位置得到对应的数据 String str=datas.get(i); myViewHolder.textView.setText(str); } //得到总条数 @Override public int getItemCount() { return datas.size(); } class MyViewHolder extends RecyclerView.ViewHolder{ ImageView imageView; TextView textView; public MyViewHolder(@NonNull View itemView) { super(itemView); imageView=itemView.findViewById(R.id.image1); textView=itemView.findViewById(R.id.test1); itemView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Toast.makeText(content,"data=="+datas.get(getLayoutPosition()),Toast.LENGTH_SHORT).show(); } }); } } }
(3)分割线源码(直接调用即可)
package com.lucky.test17.recyclerview; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.Rect; import android.graphics.drawable.Drawable; import android.support.v4.content.ContextCompat; import android.support.v7.widget.LinearLayoutManager; import android.support.v7.widget.RecyclerView; import android.view.View; /** * @DateTime: 2016-07-21 17:55 * @Author: duke * @Deacription: recyclerview万能分割线 */ public class RecycleViewDivider extends RecyclerView.ItemDecoration { private Paint mPaint;//如果需要用画笔手绘 private Drawable mDrawableDivider;//如果需要绘制给定的drawable private int mPaintDividerLength = 2;//分割线宽度或高度 private DrawType drawType;//用画笔绘制颜色，还是绘制特定的drawable /** * 注意：列表的方向 * LinearLayoutManager.VERTICAL或LinearLayoutManager.HORIZONTAL */ private int mOrientation; //系统默认的分割线 private static final int[] ATTRS = new int[]{android.R.attr.listDivider}; /** * 自定义分割线 * * @param context * @param orientation 列表方向 * @param drawableId 分割线图片 */ public RecycleViewDivider(Context context, int orientation, int drawableId) { if (orientation != LinearLayoutManager.VERTICAL && orientation != LinearLayoutManager.HORIZONTAL) { throw new IllegalArgumentException("请输入正确的参数！"); } mOrientation = orientation; if (drawableId == -100) { //获取系统的样式 final TypedArray a = context.obtainStyledAttributes(ATTRS); mDrawableDivider = a.getDrawable(0); a.recycle(); } else { mDrawableDivider = ContextCompat.getDrawable(context, drawableId); } //表明绘制drawable drawType = DrawType.USEDRAWABLE; } /** * @param context 上下文 * @param orientation 列表方向 */ public RecycleViewDivider(Context context, int orientation) { this(context, orientation, -100); } /** * 自定义分割线 * @param orientation 列表方向 * @param dividerHeight 分割线高度 * @param dividerColor 分割线颜色 */ public RecycleViewDivider(int orientation, int dividerHeight, int dividerColor) { if (orientation != LinearLayoutManager.VERTICAL && orientation != LinearLayoutManager.HORIZONTAL) { throw new IllegalArgumentException("请输入正确的参数！"); } mOrientation = orientation; if (dividerHeight != -100) { //分割线高度 mPaintDividerLength = dividerHeight; } //创建特定画笔 mPaint = new Paint(Paint.ANTI_ALIAS_FLAG); mPaint.setColor(dividerColor); mPaint.setStyle(Paint.Style.FILL); //表明绘制用paint drawType = DrawType.USEPAINT; } /** * 自定义分割线 * * @param orientation 列表方向 * @param dividerColor 分割线颜色 */ public RecycleViewDivider(int orientation, int dividerColor) { this(orientation, -100, dividerColor); } /** * 看图说话：get Item Offsets,获得item的偏移量。此方法用来控制item的偏移 * @param outRect * @param view * @param parent * @param state */ @Override public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) { super.getItemOffsets(outRect, view, parent, state); /** * 列表的方向为横向，画分割线就是纵向的，需要确定的是child的右边偏移值 * 留出空间画分割线 */ if (this.mOrientation == LinearLayoutManager.HORIZONTAL) switch (drawType) { case USEPAINT: outRect.set(0, 0, mPaintDividerLength, 0); break; case USEDRAWABLE: outRect.set(0, 0, mDrawableDivider.getIntrinsicWidth(), 0); break; } /** * 列表的方向为纵向，画分割线就是横向的，需要确定的是child的下边偏移值 * 留出空间画分割线 */ else if (this.mOrientation == LinearLayoutManager.VERTICAL) switch (drawType) { case USEPAINT: outRect.set(0, 0, 0, mPaintDividerLength); break; case USEDRAWABLE: outRect.set(0, 0, 0, mDrawableDivider.getIntrinsicHeight()); break; } } /** * 绘制分割线 * @param c * @param parent * @param state */ @Override public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) { super.onDraw(c, parent, state); if (mOrientation == LinearLayoutManager.VERTICAL) { //列表是纵向的，需要绘制横向的分割线 drawHorizontal(c, parent); } else { //列表是横向的，需要绘制纵向的分割线 drawVertical(c, parent); } } /** * 绘制横向 item 分割线。左、上、右都是可计算的，下需要获取给定的高度值 * @param canvas * @param parent */ private void drawHorizontal(Canvas canvas, RecyclerView parent) { //左边：到父容器的left内间距位置值 final int left = parent.getPaddingLeft(); //右边：到父容器的right内间距位置值 final int right = parent.getMeasuredWidth() - parent.getPaddingRight(); final int childSize = parent.getChildCount(); //循环绘制每条分割线 for (int i = 0; i < childSize; i++) { final View child = parent.getChildAt(i); RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams) child.getLayoutParams(); //上边：具体的某条分割线的左边以child的(bottom+bottomMargin)位置值 final int top = child.getBottom() + layoutParams.bottomMargin; //下边：根据类型判断 int bottom; switch (drawType){ case USEPAINT://构造方法声明使用画笔绘制 //下边：top加上指定的高度 bottom = top + mPaintDividerLength; if (mPaint != null) { canvas.drawRect(left, top, right, bottom, mPaint); } break; case USEDRAWABLE://构造方法声明使用drawable if (mDrawableDivider != null) { //下边：top加上指定的高度 bottom = top + mDrawableDivider.getIntrinsicHeight(); mDrawableDivider.setBounds(left, top, right, bottom); mDrawableDivider.draw(canvas); } break; } } } /** * 绘制纵向 item 分割线。上、下、左都是可计算的，右侧需要获取给定的宽度值 * @param canvas * @param parent */ private void drawVertical(Canvas canvas, RecyclerView parent) { //上边：到父容器的top内间距位置值 final int top = parent.getPaddingTop(); //下边：到父容器的bottom内间距位置值 final int bottom = parent.getMeasuredHeight() - parent.getPaddingBottom(); final int childSize = parent.getChildCount(); //循环绘制每条分割线 for (int i = 0; i < childSize; i++) { final View child = parent.getChildAt(i); RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams) child.getLayoutParams(); //左边：具体的某条分割线的左边以child的(right+rightMargin)位置值 final int left = child.getRight() + layoutParams.rightMargin; //右边：根据类型判断 int right; switch (drawType){ case USEPAINT://构造方法声明使用画笔绘制 //右边：left加上指定的宽度 right = left + mPaintDividerLength; if (mPaint != null) { canvas.drawRect(left, top, right, bottom, mPaint); } break; case USEDRAWABLE://构造方法声明使用drawable if (mDrawableDivider != null) { //右边：left加上指定的宽度 right = left + mDrawableDivider.getIntrinsicWidth(); mDrawableDivider.setBounds(left, top, right, bottom); mDrawableDivider.draw(canvas); } break; } } } public static enum DrawType { USEPAINT(1),//用画笔画 USEDRAWABLE(2); //画特定的drawable private final int type; DrawType(int type) { this.type = type; } public int getType() { return type; } } }
(4)主屏幕源码
package com.lucky.test17.recyclerview; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; 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.View; import android.widget.Button; import android.widget.LinearLayout; import com.lucky.test17.R; import java.util.ArrayList; public class Recycler2Activity extends AppCompatActivity { private Button button_add; private Button button_delete; private Button button_list; private Button button_grid; private Button button_flow; private RecyclerView recyclerView; private ArrayList<String> datas; private MyRecyclerViewAdapter myAdapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_recycler2); initview(); initdata(); //设置RecyclerView的适配器 myAdapter=new MyRecyclerViewAdapter(Recycler2Activity.this,datas); recyclerView.setAdapter(myAdapter); //设置分割线 recyclerView.addItemDecoration(new RecycleViewDivider(Recycler2Activity.this,LinearLayout.VERTICAL)); } //设置数据集合 private void initdata() { datas=new ArrayList<>(); for (int i = 0; i <100 ; i++) { datas.add("content_"+i); } } private void initview() { button_add=findViewById(R.id.button_add); button_delete=findViewById(R.id.button_delete); button_list=findViewById(R.id.button_list); button_grid=findViewById(R.id.button_grid); button_flow=findViewById(R.id.button_flow); recyclerView=findViewById(R.id.recycler_test1); button_add.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { } }); button_delete.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { } }); button_list.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //使用布局管理器LayoutManager,实现list效果 recyclerView.setLayoutManager(new LinearLayoutManager(Recycler2Activity.this,LinearLayoutManager.VERTICAL,false)); } }); button_grid.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //使用布局管理器LayoutManager，实现Grid效果 recyclerView.setLayoutManager(new GridLayoutManager(Recycler2Activity.this,3,GridLayoutManager.VERTICAL,false)); } }); button_flow.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //使用布局管理器LayoutManager，实现瀑布流效果 recyclerView.setLayoutManager(new StaggeredGridLayoutManager(4,StaggeredGridLayoutManager.VERTICAL)); } }); } }
<3>效果图：
2.ListView组件(了解，可以用RecyclerView 组件替换)
<1>介绍
<2>XML属性
3.Spinner(下拉列表框)
<1>简介
<2>xml 文件配置
(1)列表下拉框里的内容可以写在strings.xml文件中
<resources> <string name="app_name">zjzyhq</string> <string-array name="riskrank"> <item>----</item> <item>红</item> <item>橙</item> <item>黄</item> <item>蓝</item> </string-array> </resources>
(2)在屏幕布局文件中
<Spinner android:entries="@array/riskrank" android:layout_width="wrap_content" android:layout_height="wrap_content">