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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