一、GridView
1、简介：GridView是一个在二维可滚动的网格中展示内容的控件。网格中的内容通过使用adapter2自动插入到布局中。
2、案例：手机的功能菜单界面
3、GridView的xml文件：
<?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">
<GridView android:id="@+id/menu_grid" android:layout_width="match_parent" android:layout_height="match_parent" android:numColumns="3" android:layout_margin="20dp"
/>
</LinearLayout>
4、适配器的xml文件：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical">
<ImageView android:id="@+id/menu_img" android:layout_width="90dp" android:layout_height="90dp" android:layout_margin="5dp"/>
<TextView android:id="@+id/menu_text" android:layout_width="wrap_content" android:layout_height="60dp" android:textSize="24dp" android:layout_margin="5dp"/>
</LinearLayout>
5、GridView的逻辑代码：
package com.me.androidstudy; import android.app.Activity; import android.os.Bundle; import android.widget.GridView; import androidx.annotation.Nullable; import com.me.adapter.MenuAdapter; import com.me.domain.MenuItem; import java.util.ArrayList; import java.util.List; public class Activity_grid extends Activity { GridView menu_gridView; MenuAdapter menuAdapter; List<MenuItem> data = new ArrayList<>(); public void initView(){ menu_gridView = findViewById(R.id.menu_grid); menuAdapter = new MenuAdapter(); } public void action(){ data.add(new MenuItem("二手车",R.drawable.car)); data.add(new MenuItem("彩票",R.drawable.cp)); data.add(new MenuItem("日历",R.drawable.data)); data.add(new MenuItem("记事本",R.drawable.jsb)); data.add(new MenuItem("新闻热点",R.drawable.news)); data.add(new MenuItem("网络设置",R.drawable.wf)); data.add(new MenuItem("天气",R.drawable.tq)); data.add(new MenuItem("视频",R.drawable.tv)); data.add(new MenuItem("应用市场",R.drawable.yysc)); menuAdapter.setData(data); menu_gridView.setAdapter(menuAdapter); } @Override protected void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_grid); initView(); action(); } }
6、适配器数据项实体：
package com.me.domain; public class MenuItem { private String menuTitle; private int res_id; public MenuItem(String menuTitle, int res_id) { this.menuTitle = menuTitle; this.res_id = res_id; } public String getMenuTitle() { return menuTitle; } public void setMenuTitle(String menuTitle) { this.menuTitle = menuTitle; } public int getRes_id() { return res_id; } public void setRes_id(int res_id) { this.res_id = res_id; } }
7、适配器的逻辑代码：（baseAdapter）
package com.me.adapter; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.ImageView; import android.widget.TextView; import com.me.androidstudy.R; import com.me.domain.MenuItem; import java.util.ArrayList; import java.util.List; public class MenuAdapter extends BaseAdapter { List<MenuItem> data = new ArrayList<>(); public void setData(List<MenuItem> data) { this.data = data; } @Override public int getCount() { return data.size(); } @Override public Object getItem(int position) { return data.get(position); } @Override public long getItemId(int position) { return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { View menuItem = LayoutInflater.from(parent.getContext()).inflate(R.layout.menu_adapter, null); ImageView menu_img = menuItem.findViewById(R.id.menu_img); TextView menu_text = menuItem.findViewById(R.id.menu_text); menu_img.setBackgroundResource(data.get(position).getRes_id()); menu_text.setText(data.get(position).getMenuTitle()); return menuItem; } }
二、RecycleView
1、简介：RecyclerView是Android一个更强大的控件,其不仅可以实现和ListView同样的效果,还有优化了ListView中的各种不足。其可以实现数据纵向滚动,也可以实现横向滚动(ListView做不到横向滚动)。接下来讲解RecyclerView的用法。
2、案例：学生信息列表（图片+文字）
3、依赖：
dependencies
{ implementation 'androidx.recyclerview:recyclerview:1.1.0' }
4、RecycleView的xml文件：
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent">
<androidx.recyclerview.widget.RecyclerView android:id="@+id/students" android:layout_width="match_parent" android:layout_height="wrap_content" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent"
/>
</androidx.constraintlayout.widget.ConstraintLayout>
5、适配器的xml文件：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="wrap_content" android:background="#1DEBE6E6" android:orientation="horizontal">
<ImageView android:id="@+id/sex" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_margin="5dp"/>
<TextView android:id="@+id/cuo" android:layout_width="wrap_content" android:layout_height="60dp" android:textSize="24dp" android:layout_margin="5dp"/>
</LinearLayout>
6、RecycleView的逻辑代码：
package com.me.androidstudy; import android.app.Activity; import android.os.Bundle; import androidx.annotation.Nullable; import androidx.recyclerview.widget.LinearLayoutManager; import androidx.recyclerview.widget.RecyclerView; import com.me.domain.Student; import java.util.ArrayList; import java.util.List; import com.me.adapter.StudentAdapter; public class Activity_Rec extends Activity { RecyclerView studentRec ; List<Student> data = new ArrayList<>(); StudentAdapter adapter = new StudentAdapter(); public void initView(){ studentRec = findViewById(R.id.students); } public void action(){ for (int i = 0; i < 50; i++) { Student student = new Student(); student.setName("笑天"+i); student.setId(20180001+i); student.setSex(i%2==0?"男":"女"); data.add(student); } adapter.setData(data); /** * * 必须加 studentRec.setLayoutManager(new LinearLayoutManager(this)); * */ studentRec.setLayoutManager(new LinearLayoutManager(this)); studentRec.setAdapter( adapter); } @Override protected void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.student_rec); initView(); action(); } }
7、适配器数据项实体：
package com.me.domain; public class Student { private int id; private String name; private String sex; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getSex() { return sex; } public void setSex(String sex) { this.sex = sex; } @Override public String toString() { return "学号：" + id +
"\n姓名：" + name +
"\n性别：" + sex + "\n"; } }
8、适配器的逻辑代码：(RecyclerView.Adapter)
package com.me.adapter; import android.util.Log; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.ImageView; import android.widget.TextView; import androidx.annotation.NonNull; import androidx.recyclerview.widget.RecyclerView; import com.me.androidstudy.R; import com.me.domain.Student; import java.util.ArrayList; import java.util.List; public class StudentAdapter extends RecyclerView.Adapter<com.me.adapter.StudentAdapter.MyViewHolder> { List<Student> data = new ArrayList<>(); public void setData(List<Student> data) { this.data = data; Log.e("rec",data.size()+""); } @NonNull @Override public com.me.adapter.StudentAdapter.MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) { LayoutInflater layoutInflater = LayoutInflater.from(parent.getContext()); View itemView = layoutInflater.inflate(R.layout.student_adapter,parent,false); return new MyViewHolder(itemView); } @Override public void onBindViewHolder(@NonNull com.me.adapter.StudentAdapter.MyViewHolder holder, int position) { Log.e("rec",data.get(position).getName()+"p"); String text = data.get(position).getName()+" "+data.get(position).getId()+" "+data.get(position).getSex(); holder.info.setText(text); if(data.get(position).getSex().equals("男")){ holder.sex.setBackgroundResource(R.drawable.m1); }else{ holder.sex.setBackgroundResource(R.drawable.f1); } } @Override public int getItemCount() { return data.size(); } class MyViewHolder extends RecyclerView.ViewHolder{ TextView info ; ImageView sex; public MyViewHolder(@NonNull View itemView) { super(itemView); info = itemView.findViewById(R.id.cuo); sex = itemView.findViewById(R.id.sex); Log.e("rec",data.get(0).getName()); Log.e("rec","1234"); } } }