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

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考高分网。