package com.example.zuoye3;
import android.app.Activity;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
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 Activity implements View.OnClickListener {
MyHelper myHelper;
private EditText mEtName;
private EditText mEtPhone;
private TextView mTvShow;
private Button mBtnAdd;
private Button mBtnQuery;
private Button mBtnUpdate;
private Button mBtnDelete;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myHelper=new MyHelper(this);
init();
}
private void init(){
mEtName=(EditText)findViewById(R.id.et_name);
mEtPhone=(EditText)findViewById(R.id.et_phone);
mTvShow=(TextView)findViewById(R.id.tv_show);
mBtnAdd=(Button)findViewById(R.id.add);
mBtnQuery=(Button)findViewById(R.id.query);
mBtnUpdate=(Button)findViewById(R.id.update);
mBtnDelete=(Button)findViewById(R.id.delete);
mBtnAdd.setOnClickListener(this);
mBtnQuery.setOnClickListener(this);
mBtnUpdate.setOnClickListener(this);
mBtnDelete.setOnClickListener(this);
}
public void onClick(View view){
String name,phone;
SQLiteDatabase db;
ContentValues values;
switch (view.getId()){
case R.id.add:
name=mEtName.getText().toString();
phone=mEtPhone.getText().toString();
db=myHelper.getWritableDatabase();
values=new ContentValues();
values.put("name",name);
values.put("phone",phone);
db.insert("information",null,values);
Toast.makeText(this,"信息已添加",Toast.LENGTH_LONG).show();
db.close();
break;
case R.id.query:
db=myHelper.getReadableDatabase();
Cursor cursor=db.query("information",null,null,null,null,null,null);
if (cursor.getCount()==0){
mTvShow.setText("");
Toast.makeText(this,"没有数据",Toast.LENGTH_LONG).show();
}else {
cursor.moveToFirst();
mTvShow.setText("Name:"+cursor.getString(1)+"Tel:"+cursor.getString(2));
}
while (cursor.moveToNext()){
mTvShow.append("\n"+"Name:"+cursor.getString(1)+"Tel:"+cursor.getString(2));
}
cursor.close();
db.close();
break;
case R.id.update:
db=myHelper.getWritableDatabase();
values=new ContentValues();
values.put("phone",phone=mEtPhone.getText().toString());
db.update("information",values,"name=?",new String[]{mEtName.getText().toString()});
Toast.makeText(this,"信息已修改",Toast.LENGTH_LONG).show();
db.close();
break;
case R.id.delete:
db=myHelper.getWritableDatabase();
db.delete("information","name=?",new String[]{mEtName.getText().toString()});
Toast.makeText(this,"信息已删除",Toast.LENGTH_LONG).show();
mTvShow.setText("");
db.close();
break;
}
}
class MyHelper extends SQLiteOpenHelper{
public MyHelper(Context context){
super(context,"itcast.db",null,1);
}
public void onCreate(SQLiteDatabase db){
db.execSQL("CREATE TABLE information(_id INTEGER PRIMARY KEY AUTOINCREMENT,name VARCHAR(20),phone VARCHAR(20))");
}
public void onUpgrade(SQLiteDatabase db,int oldVersion,int newVersion){
}
}
}
<?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"
tools:context=".MainActivity"
android:padding="16dp"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="130dp"
android:orientation="horizontal"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="姓 名:"
android:textSize="18sp"
/>
<EditText
android:id="@+id/et_name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="请输入姓名"
android:textSize="16sp" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_marginTop="15dp"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="电 话:"
android:textSize="18sp"
/>
<EditText
android:id="@+id/et_phone"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="请输入手机号码"
android:textSize="16sp" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="15dp"
>
<Button
android:id="@+id/add"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginRight="2dp"
android:layout_weight="1"
android:text="添加"
android:textSize="18sp"/>
<Button
android:id="@+id/query"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginRight="2dp"
android:layout_weight="1"
android:text="查询"
android:textSize="18sp"/>
<Button
android:id="@+id/update"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginRight="2dp"
android:layout_weight="1"
android:text="修改"
android:textSize="18sp"/>
<Button
android:id="@+id/delete"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginRight="2dp"
android:layout_weight="1"
android:text="删除"
android:textSize="18sp"/>
</LinearLayout>
<TextView
android:id="@+id/tv_show"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="25dp"
android:textSize="20sp"
/>
</LinearLayout>
![](https://img2018.cnblogs.com/common/1701021/201911/1701021-20191107202343565-800780232.png)
![](https://img2018.cnblogs.com/common/1701021/201911/1701021-20191107202350565-2040083576.png)
![](https://img2018.cnblogs.com/common/1701021/201911/1701021-20191107202359174-777693933.png)