Android实现通讯录功能

本文实例为大家分享了Android通讯录案例，供大家参考，具体内容如下

实战演练——通讯录

1、功能描述：通过SQLite实现数据库的增删改查

2、技术要点：SQLite的基本操作

3、实现步骤：

① 创建一个类继承SQLiteOpenHelper
② 重写父类构造方法、onCreate()、onUpgrade()
③ 增删改查

4、效果图

5、案例代码

MyHelper.java

package com.example.sqlite;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;import androidx.annotation.Nullable;public class MyHelper extends SQLiteOpenHelper {  public MyHelper(@Nullable Context context) {    super(context, "test.db", null, 1);  }  //当数据库第一次创建的时候执行  @Override  public void onCreate(SQLiteDatabase db) {    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) {  }}

MainActivity.java

package com.example.sqlite;import androidx.appcompat.app.AppCompatActivity;import android.content.ContentValues;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.TextView;import android.widget.Toast;public class MainActivity extends AppCompatActivity implements View.OnClickListener {  private TextView name;  private TextView phone;  private Button btnAdd;  private Button btnDel;  private Button btnUqd;  private Button btnSel;  private String uPhone;  private String uName;  private MyHelper myHelper;  private SQLiteDatabase db;  private TextView show;  private ContentValues contentValues;  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    myHelper = new MyHelper(this);    init();  }  private void init() {    show = findViewById(R.id.show);    name = findViewById(R.id.name);    phone = findViewById(R.id.phone);    btnAdd = findViewById(R.id.insert);    btnDel = findViewById(R.id.delete);    btnUqd = findViewById(R.id.update);    btnSel = findViewById(R.id.select);    btnAdd.setOnClickListener(this);    btnDel.setOnClickListener(this);    btnUqd.setOnClickListener(this);    btnSel.setOnClickListener(this);  }  @Override  public void onClick(View v) {    switch (v.getId()) {      case R.id.select:        db = myHelper.getReadableDatabase();        Cursor cursor = db.query("information", null, null, null, null, null, null);        if (cursor.getCount() == 0) {          Toast.makeText(this, "没有数据", Toast.LENGTH_LONG).show();        } else {          cursor.moveToFirst();          show.setText("Name:" + cursor.getString(1) + "Tel:" + cursor.getString(2));        }        while (cursor.moveToNext()) {          show.append("\n" + "Name" + cursor.getString(1) + "Tel" + cursor.getString(2));        }        cursor.close();        db.close();        break;      case R.id.insert:        uName = name.getText().toString();        uPhone = phone.getText().toString();        db = myHelper.getReadableDatabase();        contentValues = new ContentValues();        contentValues.put("name", uName);        contentValues.put("phone", uPhone);        db.insert("information", null, contentValues);        db.close();        break;      case R.id.update:        db = myHelper.getReadableDatabase();        contentValues = new ContentValues();        contentValues.put("phone", uPhone = phone.getText().toString());        db.update("information", contentValues, "name=?", new String[]{name.getText().toString()});        db.close();        break;      case R.id.delete:        db = myHelper.getReadableDatabase();        db.delete("information", null, null);        Toast.makeText(this, "信息已经删除", Toast.LENGTH_LONG).show();        show.setText("");        db.close();        break;    }  }}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。

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