android联系人的简易通讯录

android简易的通讯录代码  主要用到了 数据库存储的知识点  还有menu

package com.example.song.lx_day13_contact;

import android.content.ContentValues;
import android.content.DialogInterface;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.CursorAdapter;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    private ListView listView;
    private TextView empty;
    private SQLiteDatabase db;
    private Cursor cursor;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        //设置空视图
        listView.setEmptyView(empty);
        registerForContextMenu(listView);
        initDataBase();
        initData();//listview赋值
    }

    private void initData() {
        cursor = db.rawQuery("select * from contact", null);
        SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, R.layout.list_item, cursor, new String[]{ "name", "sex", "number"}, new int[]{ R.id.tv_name, R.id.tv_sex, R.id.tv_phoneNumber}, CursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER);
        listView.setAdapter(adapter);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        //true 带自己创建菜单
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
        builder.setIcon(R.mipmap.icon);
        builder.setTitle("添加联系人");
        View view = LayoutInflater.from(MainActivity.this).inflate(R.layout.dialog_view, null);
        builder.setView(view);
        final EditText nameEditText = (EditText) view.findViewById(R.id.et_name);
        final EditText sexEditText = (EditText) view.findViewById(R.id.et_sex);
        final EditText phoneEditText = (EditText) view.findViewById(R.id.et_phone);
        builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                ContentValues values = new ContentValues();
                values.put("name", nameEditText.getText() + "");
                values.put("sex", sexEditText.getText() + "");
                values.put("number", phoneEditText.getText() + "");
                long insert = db.insert("contact", null, values);
                if (insert != -1) {//判断是否添加上联系人
                    initData();//跟新一下数据
                    Toast.makeText(MainActivity.this, "添加成功", Toast.LENGTH_SHORT).show();
                }
            }
        });
        builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss();
            }
        });
        builder.show();
        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
        super.onCreateContextMenu(menu, v, menuInfo);
        getMenuInflater().inflate(R.menu.contextmenu_listview_main, menu);
        AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) menuInfo;
//        menu.setHeaderTitle("id:" + info.id);
    }

    @Override
    public boolean onContextItemSelected(MenuItem item) {
        AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) item.getMenuInfo();
        final long id = info.id;//单条对应的数据库
        switch (item.getItemId()) {
            case R.id.action_delete:
                db.execSQL("delete from contact where _id =?", new Object[]{id});
                initData();
                break;
            case R.id.action_update:
                AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
                builder.setTitle("更新联系人");
                builder.setIcon(R.mipmap.icon);
                View view = LayoutInflater.from(MainActivity.this).inflate(R.layout.dialog_view, null);
                builder.setView(view);
                final EditText nameEditText = (EditText) view.findViewById(R.id.et_name);
                final EditText sexEditText = (EditText) view.findViewById(R.id.et_sex);
                final EditText phoneEditText = (EditText) view.findViewById(R.id.et_phone);
                Cursor cursor = db.rawQuery("select * from contact where _id = ?", new String[]{"" + id});
                cursor.moveToFirst();
                nameEditText.setText(cursor.getString(cursor.getColumnIndex("name")));
                sexEditText.setText(cursor.getString(cursor.getColumnIndex("sex")));
                phoneEditText.setText(cursor.getString(cursor.getColumnIndex("number")));
                builder.setPositiveButton("修改", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        ContentValues contentValues = new ContentValues();
                        contentValues.put("name", nameEditText.getText()+"");
                        contentValues.put("sex", sexEditText.getText()+"");
                        contentValues.put("number", phoneEditText.getText()+"");
                        db.update("contact", contentValues, "_id=?", new String []{id+""});
                        initData();
                    }
                });
                builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                    }
                });
                builder.show();
                break;
        }

        return super.onContextItemSelected(item);
    }

    private void initDataBase() {
        OpenHelper helper = new OpenHelper(this);
        db = helper.getReadableDatabase();
    }

    private void initView() {
        listView = ((ListView) findViewById(R.id.lv));
        empty = ((TextView) findViewById(R.id.tv_empty));
    }
}

package com.example.song.lx_day13_contact;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

/**
 * Created by song on 2017/1/18.
 */

public class OpenHelper extends SQLiteOpenHelper {
    public static final String NAME = "contacts.db";
    public static final int VERSION = 1;
    public OpenHelper(Context context) {
        super(context, NAME, null, VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("create table if not exists contact(_id integer primary key autoincrement,name,sex,number)");

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        if (newVersion > oldVersion) {
            db.execSQL("drop table if exists contact");
            onCreate(db);
        }
    }
}

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