瀑布流实现历史记录的展示（根据字符串的长度来设置换行）和添加到数据库

效果图
在这里插入图片描述
1主页面的布局

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
    <EditText
        android:id="@+id/edit"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        app:layout_constraintLeft_toLeftOf="parent"
       app:layout_constraintRight_toLeftOf="@id/btn"
        app:layout_constraintTop_toTopOf="parent"
        android:hint="输入"
        />
    <Button
        android:id="@+id/btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintTop_toTopOf="@id/edit"
        app:layout_constraintBottom_toBottomOf="@id/edit"
        app:layout_constraintLeft_toRightOf="@id/edit"
        app:layout_constraintRight_toRightOf="parent"
        android:text="搜索"
        />
    <com.example.day04_water_fall01.WaterFall
        android:id="@+id/water_fall"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@id/edit"
        />
    <Button
        android:id="@+id/clear"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@id/water_fall"
        app:layout_constraintBottom_toBottomOf="parent"
        android:text="清空历史"
        />
</android.support.constraint.ConstraintLayout>

2.自定义view引入的布局页面
2.1这是一个横向的布局

<?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="match_parent"
    android:orientation="horizontal"
    >

</LinearLayout>

2.2这是一个竖向布局里面包含要展示的textview文本

<?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="match_parent"
    android:orientation="vertical"
    >
<TextView
    android:id="@+id/water_text"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/textshape"
    android:gravity="center"
    android:textSize="20sp"
    android:layout_marginLeft="5dp"
    android:layout_marginRight="5dp"
    android:layout_marginTop="10dp"
    />
</LinearLayout>

3.MainActivity主页面

package com.example.day04_water_fall01;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

import com.example.day04_water_fall01.db.WaterDao;

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

public class MainActivity extends AppCompatActivity {

    private EditText editText;
    private Button button;
    private WaterFall waterFall;
    private List<String> list = new ArrayList<>();
    private Button button1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //获取资源id
        editText = findViewById(R.id.edit);
        button = findViewById(R.id.btn);
        waterFall = findViewById(R.id.water_fall);
        button1 = findViewById(R.id.clear);
        //点击
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //获取输入框的值
                String str = editText.getText().toString();
                //添加到数据库
                WaterDao.getIntance(MainActivity.this).add(str);
                //存入集合
                list.add(str);
                //List<String> select = WaterDao.getIntance(MainActivity.this).select();
                //设置数据
                waterFall.setList(list);
            }
        });
        //第二次进入从数据库查询展示页面
        List<String> select = WaterDao.getIntance(MainActivity.this).select();
        waterFall.setList(select);
        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                waterFall.removeAllViews();
                WaterDao.getIntance(MainActivity.this).delAll();
            }
        });
    }

}

4.自定义view的页面

package com.example.day04_water_fall01;

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;

import com.example.day04_water_fall01.db.WaterDao;

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

public class WaterFall extends LinearLayout {
    //定义常量允许字符串最大长度
    private final int mMaxSize = 20;
    //定义集合
    private List<String> list = new ArrayList<>();
    private Context mContext;

    public WaterFall(Context context) {
        super(context);
        mContext = context;
        init();
    }

    public WaterFall(Context context, AttributeSet attrs) {
        super(context, attrs);
        mContext = context;
        init();
    }

    private void init() {
        //设置最外层的LinearLayout为垂直
        setOrientation(VERTICAL);
    }

    public void setList(List<String> list) {
        this.list = list;
        showData();
    }

    private void showData() {
        //因为每一次都要新画，所以要先移除
        removeAllViews();
        //优先向跟布局添加一条横向布局
        LinearLayout linearLayout_h = (LinearLayout) View.inflate(mContext,
                R.layout.water_fall_h, null);
        addView(linearLayout_h);
        //定义临时变量来计算最后一行已有的字符串长度
        int len = 0;
        //遍历
        for (int i = 0; i < list.size(); i++) {
            final String str = list.get(i);
            //将此字符串长度与记录的已有字符串长度相加
            len += str.length();
            //如果长度大于规定最大长度，说明这一行放不下，需要换行
            if(len>mMaxSize){
                //向跟布局添加一条横向布局
                linearLayout_h = (LinearLayout) View.inflate(mContext,
                        R.layout.water_fall_h,null);
                addView(linearLayout_h);
                //因为换行，所有这个字符串的长度就是最后一行长度
                len = str.length();
            }
            //添加textview并赋值
            View view = View.inflate(mContext,R.layout.water_fall_t,null);
            TextView textView = view.findViewById(R.id.water_text);
            textView.setText(str);
            linearLayout_h.addView(view);
            //设置权重
            LinearLayout.LayoutParams params = (LayoutParams) view.getLayoutParams();
            params.weight = 1;
            view.setLayoutParams(params);
            //点击
            final int index = i;
            view.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {
                    Toast.makeText(mContext,"点击了"+list.get(index),Toast.LENGTH_SHORT).show();
                }
            });
            //长按删除
            view.setOnLongClickListener(new OnLongClickListener() {
                @Override
                public boolean onLongClick(View v) {
                    //删除集合
                    list.remove(index);
                    //删除数据库
                    WaterDao.getIntance(mContext).del(str);
                    //刷新重新画
                    showData();
                    return false;
                }
            });
        }
    }
}

5.数据库创建表页面

package com.example.day04_water_fall01.db;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class SqlitHelper extends SQLiteOpenHelper {
    public SqlitHelper(Context context) {
        super(context, "Water.db", null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("create table waters(id integer primary key autoincrement," +
                "name text)");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }
}

6.数据库增删改查方法页面即dao包

package com.example.day04_water_fall01.db;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

import com.example.day04_water_fall01.Bean.WateBean;

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

public class WaterDao {
    private static WaterDao intance;
    private Context context;
    private final SqlitHelper sqlitHelper;
    private final SQLiteDatabase sb;

    public WaterDao(Context context) {
        this.context = context;
        sqlitHelper = new SqlitHelper(context);
        sb = sqlitHelper.getWritableDatabase();
    }

    public static WaterDao getIntance(Context context) {
        if (intance==null){
            intance = new WaterDao(context);
        }
        return intance;
    }
    //添加
    public void add(String name){
        ContentValues values = new ContentValues();
        values.put("name",name);
        sb.insert("waters",null,values);
    }
    //删除
    public void del(String name ){
        sb.delete("waters","name = ?",new String[]{name});
    }
    //删除所有
    public void delAll(){
        sb.delete("waters",null,null);
    }
    //查询
    public List<String> select(){
        List<String> list = new ArrayList<>();
        Cursor waters = sb.query("waters", null, null, null, null, null, null, null);
        if(waters!=null){
            while (waters.moveToNext()){
                String name = waters.getString(waters.getColumnIndex("name"));
                list.add(name);
            }
        }
        return list;
    }
}

瀑布流实现历史记录的展示（根据字符串的长度来设置换行）和添加到数据库

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