类微信界面 02

1、功能说明#

编辑功能
psLxi

删除功能
psD8L

查看详情页
ps4DC

2、核心代码#

xml 部分#

item.xml
psV1Y

<?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"
    android:id="@+id/linearLayout_item1"
    android:layout_width="match_parent"
    android:layout_height="80dp"
    android:background="@drawable/underline_list"
    android:orientation="horizontal">

    <ImageView
        android:id="@+id/imageView_item1"
        android:layout_width="72dp"
        android:layout_height="53dp"
        android:layout_gravity="center"
        app:srcCompat="@drawable/ic___wx_this" />

    <TextView
        android:id="@+id/textView_item1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="5dp"
        android:text="编号"
        android:textSize="16dp" />

    <TextView
        android:id="@+id/textView_item2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="5dp"

        android:text="内容"
        android:textSize="16dp" />

</LinearLayout>

tab02.xml

ps9xc

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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:background="@color/hui"
    android:layout_height="match_parent"
    android:orientation="horizontal">


    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerView1"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:overScrollMode="never"
        android:scrollbars="none"
        android:visibility="visible"

        />

    <com.google.android.material.floatingactionbutton.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_alignParentBottom="true"
        android:layout_gravity="end|bottom"
        android:layout_marginStart="16dp"
        android:layout_marginTop="16dp"
        android:layout_marginEnd="36dp"
        android:layout_marginBottom="41dp"
        android:contentDescription="add"
        android:src="@drawable/ic_action_name" />

    <androidx.constraintlayout.widget.ConstraintLayout
        android:id="@+id/constraintlayout_none"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentStart="true"
        android:layout_alignParentTop="true"
        android:layout_alignParentEnd="true"
        android:layout_alignParentBottom="true"
        android:layout_marginStart="2dp"
        android:layout_marginTop="48dp"
        android:layout_marginEnd="-2dp"
        android:layout_marginBottom="461dp"
        android:background="@color/hui"
        android:visibility="gone">

        <EditText
            android:id="@+id/text_add"
            android:layout_width="294dp"
            android:layout_height="58dp"
            android:layout_marginTop="4dp"
            android:ems="10"
            android:hint="请输入..."
            android:imeOptions="actionNext"
            android:inputType="text"
            android:minHeight="48dp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <Button
            android:id="@+id/button_cl"
            android:layout_width="117dp"
            android:layout_height="wrap_content"
            android:layout_marginTop="36dp"
            android:text="取消"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toStartOf="@+id/button_ok"
            app:layout_constraintHorizontal_bias="0.444"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/text_add"
            app:layout_constraintVertical_bias="0.0" />

        <Button
            android:id="@+id/button_ok"
            android:layout_width="137dp"
            android:layout_height="48dp"
            android:layout_marginTop="36dp"
            android:layout_marginEnd="32dp"
            android:text="确认"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/text_add"
            app:layout_constraintVertical_bias="0.0" />
    </androidx.constraintlayout.widget.ConstraintLayout>

</RelativeLayout>

输入框开始是隐藏状态

Java 部分#

onBindViewHolder 中设置 3 个组件内容

        holder.textView1.setText("" + position);//转字符串
        holder.textView2.setText(list.get(position));
        holder.imageView_item1.setImageResource(addimg(position));

onBindViewHolder 中的监听

holder.linearLayout_item1.setOnTouchListener(new View.OnTouchListener() {
            private int X;
            private int lastX;
            private int Y;
            @SuppressLint("ResourceAsColor")
            @Override
            public boolean onTouch(View view, MotionEvent event) {
                switch (event.getAction() & MotionEvent.ACTION_MASK) {
                    case MotionEvent.ACTION_DOWN://当屏幕检测到第一个触点按下之后就会触发到这个事件。
                        lastX = (int) event.getRawX();
                        Y = (int) event.getRawY();
                        X = (int) event.getRawX();
                        break;
                    case MotionEvent.ACTION_UP://当触点松开时被触发。
                        if (Math.abs((int) event.getRawX() - X)<2){//单击，点击坐标没发生变化
                            Intent intent = new Intent(holder.itemView.getContext(), MainActivity2.class);
                            intent.putExtra("msg","position:"+position+"\n"+list.get(position));
                            context.startActivity(intent);
                        }
                        if(Math.abs(((int) event.getRawX() - X))<200){
                            holder.linearLayout_item1.setLeft(0);
                        }else{
                            onSwiped(position);
                            holder.linearLayout_item1.setLeft(0);
                        }
                        break;
                    case MotionEvent.ACTION_MOVE:
                        int dx = (int) event.getRawX() - lastX;
                        int left = view.getLeft() + dx;
                        holder.linearLayout_item1.setLeft(left);
                        lastX = (int) event.getRawX();
                        break;
                }
                return true;
            }
        });

MotionEvent 的几种触发的事件，目前存在 bug. 竖直滚动与左右滑动的判断
拖动还是点击的判断：根据触摸与抬起的坐标差在一定范围

删除数据

//  删除数据
    @SuppressLint("NotifyDataSetChanged")
    public void onSwiped(int p) {
        list.remove(p);
        notifyItemRemoved(p);
        notifyDataSetChanged();
    }

Fragment.java 中Viewinit()函数

private void Viewinit() {
        context = this.getActivity();
        //fullview=getView();
        myadapter = new Adapter(context);
        //设置LayoutManager
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(context);
        linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
        recyclerView.setLayoutManager(linearLayoutManager);
        recyclerView.setHasFixedSize(true);
        recyclerView.setAdapter(myadapter);
        myadapter.list(list);

    }

列表的添加

@SuppressLint("NotifyDataSetChanged")
    @Override
    public void onStart() {
        super.onStart();
        fab=getActivity().findViewById(R.id.fab);
        ConstraintLayout constraintlayout_none=getActivity().findViewById(R.id.constraintlayout_none);
        EditText text_add=getActivity().findViewById(R.id.text_add);
        Button button_cl=getActivity().findViewById(R.id.button_cl);
        Button button_ok=getActivity().findViewById(R.id.button_ok);
        InputMethodManager imm = (InputMethodManager) context.getSystemService(Context.INPUT_METHOD_SERVICE);   ;
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                constraintlayout_none.setVisibility(View.VISIBLE);
                recyclerView.setVisibility(View.INVISIBLE);
                imm.showSoftInput(text_add, 0);
                text_add.setText("");
                button_ok.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        String s=text_add.getText().toString();
                        constraintlayout_none.setVisibility(View.GONE);
                        list.add(s);
                        Log.d("add","+1");
                        imm.hideSoftInputFromWindow(text_add.getWindowToken(), 0);
                        myadapter.notifyDataSetChanged();
                        recyclerView.scrollToPosition(myadapter.getItemCount() - 1);
                        Toast.makeText(context, "添加成功", Toast.LENGTH_SHORT).show();
                        recyclerView.setVisibility(View.VISIBLE);
                    }
                });
                button_cl.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        constraintlayout_none.setVisibility(View.GONE);
                        Toast.makeText(context, "取消添加", Toast.LENGTH_SHORT).show();
                        recyclerView.setVisibility(View.VISIBLE);
                        imm.hideSoftInputFromWindow(text_add.getWindowToken(), 0);
                    }
                });
                //list.add("111111");
                //Log.d("add",list.toString());


            }
        });


    }

思路是点击添加按钮后显示输入的 layout, 隐藏 Reclyview, 打开键盘

如果点击确认则获取输入的值添加到列表，刷新 reclyview，隐藏输入 layout, 软键盘，显示 Reclyview
如果点击取消直接还原视图（即隐藏输入 layout, 显示 Reclyview...）

完整代码#

Adapter.java

package com.example.applicationtest;

import android.annotation.SuppressLint;
import android.content.Context;
import android.content.Intent;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import java.util.List;

public class Adapter extends RecyclerView.Adapter<Adapter.Myholder> {
    private View itemview;
    private Context context;

    private List<String> list;


    public int addimg(int i) {
        if (i % 4 == 0) {
            return R.drawable.num_a;
        } else if (i % 4 - 1 == 0) {
            return R.drawable.num_b;
        } else if (i % 4 - 2 == 0) {
            return R.drawable.num_c;
        } else if (i % 4 - 3 == 0) {
            return R.drawable.num_d;
        } else {
            return R.drawable.ic___fx;
        }
    }
    public Adapter(Context context) {

        this.context = context;
    }

    public void list(List<String> list) {
        this.list = list;
        notifyDataSetChanged();

    }
    
    @NonNull
    @Override
    public Myholder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        itemview = LayoutInflater.from(context).inflate(R.layout.item1, parent, false);
        Myholder holder;

        holder = new Myholder(itemview);
        return holder;
    }

    @SuppressLint({"SetTextI18n", "ClickableViewAccessibility"})
    @Override
    public void onBindViewHolder(@NonNull Myholder holder, @SuppressLint("RecyclerView") int position) {
        holder.textView1.setText("" + position);//转字符串
        holder.textView2.setText(list.get(position));
        holder.imageView_item1.setImageResource(addimg(position));
//        holder.linearLayout_item1.setOnClickListener(new View.OnClickListener() {
//            @Override
//            public void onClick(View view) {
//                //Toast.makeText(itemview.getContext(), position + "号:" + list.get(position), Toast.LENGTH_SHORT).show();
//                Intent intent = new Intent(holder.itemView.getContext(), MainActivity2.class);
//                intent.putExtra("msg","position:"+position+"\n"+list.get(position));
//                context.startActivity(intent);
//                //onSwiped(position);
//            }
//        });
        holder.linearLayout_item1.setOnTouchListener(new View.OnTouchListener() {
            private int X;
            private int lastX;
            private int Y;
            @SuppressLint("ResourceAsColor")
            @Override
            public boolean onTouch(View view, MotionEvent event) {
                switch (event.getAction() & MotionEvent.ACTION_MASK) {
                    case MotionEvent.ACTION_DOWN://当屏幕检测到第一个触点按下之后就会触发到这个事件。
                        lastX = (int) event.getRawX();
                        Y = (int) event.getRawY();
                        X = (int) event.getRawX();
                        break;
                    case MotionEvent.ACTION_UP://当触点松开时被触发。
                        if (Math.abs((int) event.getRawX() - X)<2){//单击，点击坐标没发生变化
                            Intent intent = new Intent(holder.itemView.getContext(), MainActivity2.class);
                            intent.putExtra("msg","position:"+position+"\n"+list.get(position));
                            context.startActivity(intent);
                        }
                        if(Math.abs(((int) event.getRawX() - X))<200){
                            holder.linearLayout_item1.setLeft(0);
                        }else{
                            onSwiped(position);
                            holder.linearLayout_item1.setLeft(0);
                        }
                        break;
                    case MotionEvent.ACTION_MOVE:
                        int dx = (int) event.getRawX() - lastX;
                        int left = view.getLeft() + dx;
                        holder.linearLayout_item1.setLeft(left);
                        lastX = (int) event.getRawX();
                        break;
                }
                return true;
            }
        });
    }
    //  删除数据
    @SuppressLint("NotifyDataSetChanged")
    public void onSwiped(int p) {
        list.remove(p);
        notifyItemRemoved(p);
        notifyDataSetChanged();
    }


    @Override
    public int getItemCount() {
        return list.size();
    }

    public static class Myholder extends RecyclerView.ViewHolder {

        private TextView textView1, textView2;
        private ImageView imageView_item1;
        private LinearLayout linearLayout_item1;

        public Myholder(@NonNull View itemView) {
            super(itemView);
            textView1 = itemView.findViewById(R.id.textView_item1);
            textView2 = itemView.findViewById(R.id.textView_item2);
            imageView_item1 = itemView.findViewById(R.id.imageView_item1);
            linearLayout_item1 = itemView.findViewById(R.id.linearLayout_item1);


        }
    }

}

Fragment2.java

package com.example.applicationtest;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.text.InputType;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.inputmethod.InputMethodManager;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import androidx.constraintlayout.widget.ConstraintLayout;
import androidx.fragment.app.Fragment;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import com.google.android.material.floatingactionbutton.FloatingActionButton;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import javax.security.auth.PrivateCredentialPermission;


public class Fragment2 extends Fragment {

    private RecyclerView recyclerView;
    private Context context;
    private FloatingActionButton fab;
    private Adapter myadapter;
    private List<String> list = new ArrayList<>();


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View view;
        view = inflater.inflate(R.layout.tab02, container, false);

        recyclerView = view.findViewById(R.id.recyclerView1);
        listdata();
        Viewinit();
        return view;



    }

    @SuppressLint("NotifyDataSetChanged")
    @Override
    public void onStart() {
        super.onStart();
        fab=getActivity().findViewById(R.id.fab);
        ConstraintLayout constraintlayout_none=getActivity().findViewById(R.id.constraintlayout_none);
        EditText text_add=getActivity().findViewById(R.id.text_add);
        Button button_cl=getActivity().findViewById(R.id.button_cl);
        Button button_ok=getActivity().findViewById(R.id.button_ok);
        InputMethodManager imm = (InputMethodManager) context.getSystemService(Context.INPUT_METHOD_SERVICE);   ;
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                constraintlayout_none.setVisibility(View.VISIBLE);
                recyclerView.setVisibility(View.INVISIBLE);
                imm.showSoftInput(text_add, 0);
                text_add.setText("");
                button_ok.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        String s=text_add.getText().toString();
                        constraintlayout_none.setVisibility(View.GONE);
                        list.add(s);
                        Log.d("add","+1");
                        imm.hideSoftInputFromWindow(text_add.getWindowToken(), 0);
                        myadapter.notifyDataSetChanged();
                        recyclerView.scrollToPosition(myadapter.getItemCount() - 1);
                        Toast.makeText(context, "添加成功", Toast.LENGTH_SHORT).show();
                        recyclerView.setVisibility(View.VISIBLE);
                    }
                });
                button_cl.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        constraintlayout_none.setVisibility(View.GONE);
                        Toast.makeText(context, "取消添加", Toast.LENGTH_SHORT).show();
                        recyclerView.setVisibility(View.VISIBLE);
                        imm.hideSoftInputFromWindow(text_add.getWindowToken(), 0);
                    }
                });
                //list.add("111111");
                //Log.d("add",list.toString());


            }
        });


    }

    private void Viewinit() {
        context = this.getActivity();
        //fullview=getView();
        myadapter = new Adapter(context);
        //设置LayoutManager
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(context);
        linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
        recyclerView.setLayoutManager(linearLayoutManager);
        recyclerView.setHasFixedSize(true);
        recyclerView.setAdapter(myadapter);
        myadapter.list(list);

    }

    private void listdata() {
        list.add("明媚的阳光和明媚的少女······是不是很相衬呢？");
        list.add("别动哦，借你的眼睛照照镜子。是不是觉得很怀念？");
        list.add("我的眼睛漂亮吗？这可不是美瞳哦，是美少女的魔法。");
        ...

    }


}

3、实验小结#

继承于RecyclerView.ViewHolder，编写自己的ViewHolder
实现onCreateViewHolder(ViewGroup parent, int viewType)
当 RecyclerView 需要我们提供类型为 viewType 的新 ViewHolder 时，会回调这个方法。实例化出了Item的根布局，并返回一个和它绑定的ViewHolder。
实现onBindViewHolder(VH viewHolder, int position)
当 RecyclerView 需要展示对应 position 位置的数据时会回调这个方法。
通过 viewHolder 中持有的对应 position 上的 View，更新视图。
实现 getItemCount ()
返回 Item 的总数。

代码仓库：#

2412322029/Applicationtest

安卓作业

Java10