流式佈局+資料庫+刪除
阿新 • • 發佈：2018-12-01
1.佈局
<?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=".MainActivity"> <EditText android:id="@+id/ettext" android:layout_width="match_parent" android:layout_height="wrap_content" /> <Button android:id="@+id/button" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="搜尋"/> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="30sp" android:textFontWeight="500dp" android:layout_marginLeft="20dp" android:text="搜尋歷史"/> <com.bw.ymy.demo09.CurstomLayout android:id="@+id/fall" android:layout_width="match_parent" android:layout_height="wrap_content"/> <Button android:id="@+id/dell" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="清空" android:layout_gravity="center"/> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="30sp" android:layout_marginLeft="30dp" android:text="熱門"/> <com.bw.ymy.demo09.CurstomLayout android:id="@+id/hotview" android:layout_width="wrap_content" android:layout_height="wrap_content"/> </LinearLayout>
2.熱門展示資料佈局
<?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"> <TextView android:id="@+id/text" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="20sp" android:gravity="center" android:layout_weight="1"/> </LinearLayout>
3.主頁面
package com.bw.ymy.demo09; import android.graphics.Color; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.EditText; import android.widget.TextView; import org.w3c.dom.Text; import java.util.List; public class MainActivity extends AppCompatActivity { //向裡面新增熱門內容 private String[] desc=new String[]{"陳獨秀","李雲龍","和尚","秀芹","秀兒","是","陳獨秀","陳獨秀","陳獨秀","陳獨秀",}; CurstomLayout fall; CurstomLayout hotview; EditText et; Dao dao; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); //dao層 dao= new Dao(MainActivity.this); //獲取資源id fall=findViewById(R.id.fall); et=findViewById(R.id.ettext); hotview=findViewById(R.id.hotview); //迴圈新增熱門內容 for(String str:desc){ TextView textView=new TextView(MainActivity.this); textView.setText(str); textView.setTextSize(24); hotview.addView(textView); } //新增到資料庫 List<String> list=dao.selall(); if(list.size()!=0) { for (String string:list) { TextView tv=new TextView(MainActivity.this); tv.setText(et.getText()); tv.setTextColor(Color.GREEN); fall.addView(tv); } } //點選新增按鈕 findViewById(R.id.button).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { TextView tv=new TextView(MainActivity.this); tv.setText(et.getText()); tv.setTextColor(Color.GREEN); //判斷資料庫是否有重複的 重複的加不進去 boolean b=dao.sel(et.getText().toString()); if(!et.getText().toString().equals("")&&b) { dao.add(et.getText().toString()); //沒有重複的新增 fall.addView(tv); } } }); ///清空 findViewById(R.id.dell).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //刪除資料庫 dao.delall(); //刪除列表 fall.removeAllViews(); } }); } }
4.View
package com.bw.ymy.demo09;
import android.content.Context;
import android.graphics.Canvas;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.view.View;
import android.widget.LinearLayout;
public class CurstomLayout extends LinearLayout {
//孩子最高的一個
private int mChildMaxHeight;
//每一個左邊距20 px
private int mHSpace=20;
//上下間距 20 px
private int mVSpace=20;
public CurstomLayout(Context context) {
super(context);
}
public CurstomLayout(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
//拿到父容器的寬高和計算模式
int sizeWidth=MeasureSpec.getSize(widthMeasureSpec);
int sizeHeight=MeasureSpec.getSize(heightMeasureSpec);
//測量孩子大小，必須寫
measureChildren(widthMeasureSpec,heightMeasureSpec);
//尋找孩子最高的一個
//在下方
findMaxChildMaxHeight();
//初始化值
int left=0,top=0;
//開始迴圈
int childCount=getChildCount();
for (int i=0;i<childCount;i++)
{
View view=getChildAt(i);
//是否是一行的第一個
if(left!=0)
{
//換行，放不下
if((left +view.getMeasuredWidth())>sizeWidth)
{
top+=mChildMaxHeight+mVSpace;
left=0;
}
}
left+=view.getMeasuredWidth()+mHSpace;
}
setMeasuredDimension(sizeWidth,(top+mChildMaxHeight)>sizeHeight?sizeHeight:top+mChildMaxHeight);
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
super.onLayout(changed, l, t, r, b);
findMaxChildMaxHeight();
//
//開始
//初始化
int left=0,top=0;
//迴圈
int childCount=getChildCount();
for (int i=0;i<childCount;i++)
{
View view=getChildAt(i);
//是否第一個
if(left !=0)
{
if((left+ view.getMeasuredWidth())>getWidth())
{
//計算下一行top
top+=mChildMaxHeight+mVSpace;
//換行
left=0;
}
}
//安排位置
view.layout(left,top,left+view.getMeasuredWidth(),top+getMeasuredHeight());
left+=view.getMeasuredWidth()+mHSpace;
}
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
}
//z最高的孩子
private void findMaxChildMaxHeight() {
mChildMaxHeight=0;
int childCount =getChildCount();
for (int i=0;i<childCount;i++)
{
View view=getChildAt(i);
if(view.getMeasuredHeight()>mChildMaxHeight)
{
mChildMaxHeight=view.getMeasuredHeight();
}
}
}
}
5.Dao層
package com.bw.ymy.demo09;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import java.util.ArrayList;
import java.util.List;
public class Dao {
private SQLiteDatabase database;
public Dao(Context context) {
database=new Sqlitehelp(context).getWritableDatabase();
}
//新增到資料庫
public void add(String string)
{
ContentValues values=new ContentValues();
values.put("context",string);
database.insert("history",null,values);
}
//刪除
public void delall()
{
database.delete("history",null,null);
}
public boolean sel(String string)
{
Cursor query = database.query("history", null, "context=?", new String[]{string}, null, null, null);
return query.getCount()==0?true:false;
}
//查詢
public List<String> selall()
{
List<String> list=new ArrayList<>();
Cursor query = database.query("history", null, null, null, null, null, null);
while (query.moveToNext())
{
list.add(query.getString(query.getColumnIndex("context")));
}
return list;
}
}
6.sqlite建立資料庫
package com.bw.ymy.demo09;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class Sqlitehelp extends SQLiteOpenHelper {
public Sqlitehelp(Context context) {
super(context, "User.db", null, 1);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("create table history(id integer primary key autoincrement,"+"context text)");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
展示效果圖
#熱門的文字是死資料
