Android(安卓)与SQlite 数据库操作（新手步骤）
16lz
2021-01-26
Android 与SQlite 数据库操作（新手步骤）
- 一、搭建简易的界面
- 1 新建shape xml文件，定义一个圆角和边框
- 1.1 创建shape文件 tv_corner.xml
- 1.2 创建shape文件 tv_stroke.xml
- 2 搭建简易页面 activity_main.xml
- 2.1 界面截图
- 2.2 控件id截图
- 二、新建MyHelper.java
- 1 构造方法，调用SQLiteOpenHelper的构造方法，创建数据库“contacter”
- 2 重写方法
- 三.搭建MainActivity.java框架
- 1.定义控件，创建点击事件框架
- 2.创建MyHelper 对象
- 3.实现增，改，删，查功能
- 3.1 插入功能
- 3.2 查询功能
- 3.3 更新功能
- 3.4 删除功能
- 3.5 button按钮点击事件（插入，查询，更新，删除）
- 四.整体代码
- 五.演示效果
- 六.表格显示数据（改进）
- 6.1 TableLayout替换原来的TextView
- 6.2 替换原来的查找数据代码
一、搭建简易的界面
1 新建shape xml文件，定义一个圆角和边框
1.1 创建shape文件 tv_corner.xml
<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="http://schemas.android.com/apk/res/android"> <corners android:radius="20dp"/> <stroke android:color="@color/colorPrimaryDark" android:width="3dp"/></shape>1.2 创建shape文件 tv_stroke.xml
<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="http://schemas.android.com/apk/res/android"> <corners android:radius="3dp"/> <stroke android:color="#28A62D" android:width="3dp"/></shape>2 搭建简易页面 activity_main.xml
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" tools:context=".MainActivity"> <TextView android:id="@+id/textView" android:layout_width="match_parent" android:layout_height="80dp" android:text="简易通讯录" android:textSize="40sp" android:textColor="#1051DD" android:gravity="center"/> <LinearLayout android:layout_width="match_parent" android:layout_height="84dp" android:orientation="horizontal"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="用户名：" android:textSize="30sp" /> <EditText android:id="@+id/ed_name" android:layout_width="260dp" android:layout_height="wrap_content" android:background="@drawable/tv_stroke" android:hint="请输入用户名" android:textSize="30sp" /> </LinearLayout> <LinearLayout android:layout_width="match_parent" android:layout_height="80dp" android:orientation="horizontal"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="手机号：" android:textSize="30sp"/> <EditText android:id="@+id/ed_phonenum" android:layout_width="260dp" android:layout_height="wrap_content" android:background="@drawable/tv_stroke" android:hint="请输入手机号" android:textSize="30sp"/> </LinearLayout> <LinearLayout android:layout_width="match_parent" android:layout_height="80dp" android:orientation="horizontal" tools:layout_editor_absoluteX="0dp"> <Button android:id="@+id/bt_insert" android:layout_width="0dp" android:layout_height="60dp" android:layout_weight="1" android:textSize="20sp" android:background="@drawable/tv_corner" android:text="插入" />2.1 界面截图
2.2 控件id截图
二、新建MyHelper.java
1 构造方法，调用SQLiteOpenHelper的构造方法，创建数据库“contacter”
public MyHelper(Context context){ super(context,"contacter",null,2); }2 重写方法
package com.maaa.sqlite;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;public class MyHelper extends SQLiteOpenHelper { public MyHelper(Context context){ //创建数据库 super(context,"contacter.db",null,2); } @Override public void onCreate(SQLiteDatabase db) { //创建表名 db.execSQL("CREATE TABLE information (_id INTEGER PRIMARY KEY AUTOINCREMENT,name VARCHAR(20),phone VARCHAR(20))"); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { }}三.搭建MainActivity.java框架
1.定义控件，创建点击事件框架
public class MainActivity extends AppCompatActivity implements View.OnClickListener { private EditText name,phonenum; private Button insert,query,updata,delete; private TextView show; private void init(){ name = findViewById(R.id.ed_name); phonenum = findViewById(R.id.ed_phonenum); show = findViewById(R.id.tv_show); insert= findViewById(R.id.bt_insert); query = findViewById(R.id.bt_query); updata = findViewById(R.id.bt_updata); delete = findViewById(R.id.bt_delete); insert.setOnClickListener(this); query.setOnClickListener(this); updata.setOnClickListener(this); delete.setOnClickListener(this); } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); init(); } @Override public void onClick(View v) { switch (v.getId()){ case R.id.bt_insert: break; case R.id.bt_query: break; case R.id.bt_updata: break; case R.id.bt_delete: break; } }}2.创建MyHelper 对象
//创建MyHelp对象MyHelper myHelper =new MyHelper(this);3.实现增，改，删，查功能
3.1 插入功能
name = edname.getText().toString().trim(); phone = edphonenum.getText().toString().trim(); db = myHelper.getWritableDatabase(); values = new ContentValues(); values.put("name",name); values.put("phone",phone); db.insert("information",null,values); show.setText("数据"+name+"插入成功"); Toast.makeText(this,"插入成功",Toast.LENGTH_SHORT).show(); db.close(); break;3.2 查询功能
Integer i =1; //定义显示信息的序号 db = myHelper.getReadableDatabase(); Cursor cursor = db.query("information", null, null, null, null, null, null); if(cursor.getCount() == 0){ show.setText("没有数据"); }else { cursor.moveToFirst(); show.setText("序号 姓名 电话"); show.append("\n"+i+" "+cursor.getString(cursor.getColumnIndex("name"))+" "+cursor.getString(2)); } while (cursor.moveToNext()){ i++; //每增加一行数据，显示序号加1 show.append("\n"+i+" "+cursor.getString(cursor.getColumnIndex("name"))+" "+cursor.getString(2)); } cursor.close(); db.close(); break;3.3 更新功能
name = edname.getText().toString().trim(); phone = edphonenum.getText().toString().trim(); db = myHelper.getWritableDatabase(); values = new ContentValues(); values.put("phone",phone); db.update("information",values,"name = ?",new String[]{name}); show.setText(name+"电话更新成功"); db.close(); break;3.4 删除功能
name = edname.getText().toString().trim();db = myHelper.getWritableDatabase();values = new ContentValues();values.put("name",name);db.delete("information","name=?",new String[]{name});show.setText(name+"删除成功");db.close();break;3.5 button按钮点击事件（插入，查询，更新，删除）
@Override public void onClick(View v) { String name; String phone; SQLiteDatabase db; ContentValues values; switch (v.getId()){ case R.id.bt_insert://插入数据 name = edname.getText().toString().trim(); phone = edphonenum.getText().toString().trim(); db = myHelper.getWritableDatabase(); values = new ContentValues(); values.put("name",name); values.put("phone",phone); db.insert("information",null,values); show.setText("数据"+name+"插入成功"); Toast.makeText(this,"插入成功",Toast.LENGTH_SHORT).show(); db.close(); break; case R.id.bt_query://查找数据 Integer i =1; //定义显示信息的序号 db = myHelper.getReadableDatabase(); Cursor cursor = db.query("information", null, null, null, null, null, null); if(cursor.getCount() == 0){ show.setText("没有数据"); }else { cursor.moveToFirst(); show.setText("序号 姓名 电话"); show.append("\n"+i+" "+cursor.getString(cursor.getColumnIndex("name"))+" "+cursor.getString(2)); } while (cursor.moveToNext()){ i++; //每增加一行数据，显示序号加1 show.append("\n"+i+" "+cursor.getString(cursor.getColumnIndex("name"))+" "+cursor.getString(2)); } cursor.close(); db.close(); break; case R.id.bt_updata://更新数据 name = edname.getText().toString().trim(); phone = edphonenum.getText().toString().trim(); db = myHelper.getWritableDatabase(); values = new ContentValues(); values.put("phone",phone); db.update("information",values,"name = ?",new String[]{name}); show.setText(name+"电话更新成功"); db.close(); break; case R.id.bt_delete://删除数据 name = edname.getText().toString().trim(); db = myHelper.getWritableDatabase(); values = new ContentValues(); values.put("name",name); db.delete("information","name=?",new String[]{name}); show.setText(name+"删除成功"); db.close(); break; } }四.整体代码
package com.maaa.sqlite;import androidx.appcompat.app.AppCompatActivity;import android.content.ContentValues;import android.content.Intent;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.TextView;import android.widget.Toast;public class MainActivity extends AppCompatActivity implements View.OnClickListener { private EditText edname,edphonenum; private Button insert,query,updata,delete; private TextView show; MyHelper myHelper; private void init(){ edname = findViewById(R.id.ed_name); edphonenum = findViewById(R.id.ed_phonenum); show = findViewById(R.id.tv_show); insert= findViewById(R.id.bt_insert); query = findViewById(R.id.bt_query); updata = findViewById(R.id.bt_updata); delete = findViewById(R.id.bt_delete); insert.setOnClickListener(this); query.setOnClickListener(this); updata.setOnClickListener(this); delete.setOnClickListener(this); } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); init(); //创建MyHelp对象 myHelper =new MyHelper(this); } @Override public void onClick(View v) { String name; String phone; SQLiteDatabase db; ContentValues values; switch (v.getId()){ case R.id.bt_insert://插入数据 name = edname.getText().toString().trim(); phone = edphonenum.getText().toString().trim(); db = myHelper.getWritableDatabase(); values = new ContentValues(); values.put("name",name); values.put("phone",phone); db.insert("information",null,values); show.setText("数据"+name+"插入成功"); Toast.makeText(this,"插入成功",Toast.LENGTH_SHORT).show(); db.close(); break; case R.id.bt_query://查找数据 Integer i =1; //定义显示信息的序号 db = myHelper.getReadableDatabase(); Cursor cursor = db.query("information", null, null, null, null, null, null); if(cursor.getCount() == 0){ show.setText("没有数据"); }else { cursor.moveToFirst(); show.setText("序号 姓名 电话"); show.append("\n"+i+" "+cursor.getString(cursor.getColumnIndex("name"))+" "+cursor.getString(2)); } while (cursor.moveToNext()){ i++; //每增加一行数据，显示序号加1 show.append("\n"+i+" "+cursor.getString(cursor.getColumnIndex("name"))+" "+cursor.getString(2)); } cursor.close(); db.close(); break; case R.id.bt_updata://更新数据 name = edname.getText().toString().trim(); phone = edphonenum.getText().toString().trim(); db = myHelper.getWritableDatabase(); values = new ContentValues(); values.put("phone",phone); db.update("information",values,"name = ?",new String[]{name}); show.setText(name+"电话更新成功"); db.close(); break; case R.id.bt_delete://删除数据 name = edname.getText().toString().trim(); db = myHelper.getWritableDatabase(); values = new ContentValues(); values.put("name",name); db.delete("information","name=?",new String[]{name}); show.setText(name+"删除成功"); db.close(); break; } }}五.演示效果
六.表格显示数据（改进）
6.1 TableLayout替换原来的TextView
TableLayout android:id="@+id/table" android:layout_width="match_parent" android:layout_height="match_parent" android:stretchColumns="2" ></TableLayout><!-- <TextView--><!-- android:id="@+id/tv_show"--><!-- android:layout_width="match_parent"--><!-- android:layout_height="match_parent"--><!-- android:textSize="20sp"--><!-- android:background="@drawable/tv_corner"--><!-- android:padding="10dp"--><!-- android:text="此处为显示内容区"/>-->6.2 替换原来的查找数据代码
case R.id.bt_query://查找数据 /* 没有表格的显示，比较乱 Integer i =1; //定义显示信息的序号 db = myHelper.getReadableDatabase(); Cursor cursor = db.query("information", null, null, null, null, null, null); if(cursor.getCount() == 0){ show.setText("没有数据"); }else { cursor.moveToFirst(); show.setText("序号 姓名 电话"); show.append("\n"+i+" "+cursor.getString(cursor.getColumnIndex("name"))+" "+cursor.getString(2)); } while (cursor.moveToNext()){ i++; //每增加一行数据，显示序号加1 show.append("\n"+i+" "+cursor.getString(cursor.getColumnIndex("name"))+" "+cursor.getString(2)); } cursor.close(); db.close(); */ /* 显示区域设为表格样式*/ db = myHelper.getReadableDatabase(); Cursor cursor = db.query("information",null,null,null,null,null,null); if (cursor.getCount() == 0){ show.setText("没有数据"); }else{ Integer row =cursor.getCount()+1; Integer column = cursor.getColumnCount(); //清除表格所有行 tableLayout.removeAllViews(); //全部列自动填充空白处 tableLayout.setStretchAllColumns(true); TableRow tableRow = new TableRow(MainActivity.this); tableRow.setGravity(Gravity.CENTER); TextView tv1 =new TextView(MainActivity.this); TextView tv2 =new TextView(MainActivity.this); TextView tv3 =new TextView(MainActivity.this); tv1.setText("序号"); tv1.setGravity(Gravity.CENTER); tv1.setBackgroundResource(R.drawable.tv_stroke); tv1.setTextSize(20); tableRow.addView(tv1); tv2.setText("姓名"); tv2.setGravity(Gravity.CENTER); tv2.setBackgroundResource(R.drawable.tv_stroke); tv2.setTextSize(20); tableRow.addView(tv2); tv3.setText("电话"); tv3.setGravity(Gravity.CENTER); tv3.setBackgroundResource(R.drawable.tv_stroke); tv3.setTextSize(20); tableRow.addView(tv3); tableLayout.addView(tableRow, new TableLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT,1)); int i=1; while (cursor.moveToNext()){ TableRow tableRow1 = new TableRow(MainActivity.this); for (int j=0;j<cursor.getColumnCount();j++){ TextView tv =new TextView(MainActivity.this); tv.setGravity(Gravity.CENTER); tv.setBackgroundResource(R.drawable.tv_stroke); tv.setTextSize(20); if(j==0){ tv.setText(String.valueOf(i)); tableRow1.addView(tv); }else{ tv.setText(cursor.getString(j)); tableRow1.addView(tv); } } tableLayout.addView(tableRow1, new TableLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT,1)); i++; }更多相关文章
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