安卓学习之SQLite+ListView完成一个通讯录

activity_main.xml  含有ListView布局

<?xml version="1.0" encoding="utf-8"?><RelativeLayout    xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    xmlns:app="http://schemas.android.com/apk/res-auto"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context="com.example.sqlite.MainActivity">    <ListView        android:id="@+id/user_list"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentTop="true"        android:layout_alignParentBottom="true"        android:layout_alignParentLeft="true"        android:layout_alignParentStart="true"        android:layout_marginBottom="50dp" />    <LinearLayout        android:id="@+id/bottom"        android:layout_width="match_parent"        android:layout_height="50dp"        android:layout_alignParentBottom="true"        android:layout_alignParentLeft="true"        android:layout_alignParentStart="true">        <Button            android:id="@+id/addUser"            android:text="添加联系人"            android:textSize="18dp"            android:layout_weight="1"            android:layout_width="match_parent"            android:layout_height="match_parent" />        <Button            android:id="@+id/searchUser"            android:text="查询联系人"            android:textSize="18dp"            android:layout_weight="1"            android:layout_width="match_parent"            android:layout_height="match_parent" />    </LinearLayout></RelativeLayout>

user_item.xml

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent">    <ImageView        android:id="@+id/user_img"        android:layout_marginLeft="10dp"        android:layout_width="wrap_content"        android:layout_height="wrap_content" />    <TextView        android:id="@+id/user_name"        android:textSize="18dp"        android:layout_marginLeft="10dp"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_toRightOf="@+id/user_img"/>    <TextView        android:id="@+id/telnumber"        android:layout_marginTop="15dp"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_below="@+id/user_name"        android:layout_alignLeft="@+id/user_name"        android:layout_alignStart="@+id/user_name"/></RelativeLayout>

MainActivity.java Main活动，显示联系人ListView,各种点击事件操作

public class MainActivity extends AppCompatActivity implements View.OnClickListener{    private MyDatabaseHelper dbHelper;    private List<User> UserList = new ArrayList<>();    private Button addUser;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        addUser = (Button) findViewById(R.id.addUser);        addUser.setOnClickListener(this);        dbHelper = new MyDatabaseHelper(this,"User.db",null,1);        //初始化数据        initUser();        UserAdapter adapter = new UserAdapter(MainActivity.this,                R.layout.user_item,UserList);        ListView listView = (ListView) findViewById(R.id.user_list);        listView.setAdapter(adapter);        listView.setOnItemClickListener(new AdapterView.OnItemClickListener(){            @Override            public void onItemClick(AdapterView<?> parent,View view,                                    int position,long id){                User user = UserList.get(position);                String name = user.getName();                String telnumber = user.getTelnumber();                Intent intent = new Intent(MainActivity.this,UserActivity.class);                intent.putExtra("name",name);                intent.putExtra("telnumber",telnumber);                startActivity(intent);            }        });    }    private void initUser(){        SQLiteDatabase db = dbHelper.getWritableDatabase();        Cursor cursor = db.query("User",null,null,null,null,null,null);        if(cursor.moveToFirst()){            do{                //遍历                String name = cursor.getString(cursor.getColumnIndex("name"));                String telnumber = cursor.getString(cursor.getColumnIndex("telnumber"));                User user = new User(name,telnumber,R.mipmap.ic_launcher);                UserList.add(user);            }while(cursor.moveToNext());        }        cursor.close();    }    @Override    public void onClick(View view) {        switch (view.getId()){            case R.id.addUser:{                Intent intent = new Intent(MainActivity.this,AddUserActivity.class);                startActivity(intent);                this.finish();            }                break;        }    }}

User.java 联系人类

public class User {    private int imgId;    private String name;    private String telnumber;    public User(String name,String telnumber,int imgId){        this.name = name;        this.telnumber = telnumber;        this.imgId = imgId;    }    public int getImgId(){        return imgId;    }    public String getName(){        return name;    }    public String getTelnumber(){        return telnumber;    }}

UserAdapter.java  ListView的适配器

public class UserAdapter extends ArrayAdapter<User>{    private int resourceId;    public UserAdapter(Context context, int textViewResourceId,List<User> objects){        super(context,textViewResourceId,objects);        resourceId = textViewResourceId;    }    @Override    public View getView(int position,View converView,ViewGroup parent){        User user = getItem(position);//获取当前User实例        View view = LayoutInflater.from(getContext()).inflate(resourceId,parent,false);        ImageView userimg = (ImageView) view.findViewById(R.id.user_img);        TextView username = (TextView) view.findViewById(R.id.user_name);        TextView telphone = (TextView) view.findViewById(R.id.telnumber);        userimg.setImageResource(user.getImgId());        username.setText(user.getName());        telphone.setText(user.getTelnumber());        return view;    }}

AddUserActivity.java 添加联系人信息的活动

public class AddUserActivity extends AppCompatActivity implements View.OnClickListener{    private MyDatabaseHelper dbHelper;    private EditText username,telnumber;    private Button ok_add,create_database;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_add_user);        dbHelper = new MyDatabaseHelper(this,"User.db",null,1);        username = (EditText) findViewById(R.id.add_user_name);        telnumber = (EditText) findViewById(R.id.add_user_telnumber);        ok_add = (Button) findViewById(R.id.ok_add);        ok_add.setOnClickListener(this);        create_database = (Button) findViewById(R.id.create_database);        create_database.setOnClickListener(this);    }    @Override    public void onClick(View view) {        switch (view.getId()){            case R.id.create_database:{                dbHelper.getWritableDatabase();            }                break;            case R.id.ok_add:{                String name = username.getText().toString();                String tel_number = telnumber.getText().toString();                if(name == null || tel_number == null){                    Toast.makeText(this,"用户名和电话不能为空！",Toast.LENGTH_SHORT).show();                }else{                    SQLiteDatabase db = dbHelper.getWritableDatabase();                    ContentValues values = new ContentValues();                    values.put("name",name);                    values.put("telnumber",tel_number);                    db.insert("User",null,values);                    values.clear();                    Toast.makeText(this,"添加成功!",Toast.LENGTH_SHORT).show();                    Intent intent = new Intent(AddUserActivity.this,MainActivity.class);                    startActivity(intent);                    this.finish();                }            }        }    }}

MyDatabaseHelper.java  MyDatabaseHelper类，用来帮助管理数据库，建立数据库、更新数据库

public class MyDatabaseHelper extends SQLiteOpenHelper{    public static final String Create_User_Table = "create table User ("            + "id integer primary key autoincrement,"            + "name text,"            + "telnumber text)";    private Context mContext;    public MyDatabaseHelper(Context context,String name,SQLiteDatabase.CursorFactory factory,                            int version){        super(context,name,factory,version);        mContext = context;    }    @Override    public void onCreate(SQLiteDatabase db) {        db.execSQL(Create_User_Table);        Toast.makeText(mContext,"创建成功",Toast.LENGTH_SHORT).show();    }    @Override    public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {    }}

UserActivity.java用来显示用户详细信息的活动

public class UserActivity extends AppCompatActivity {    private TextView name,telnumber;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_user);        name = (TextView) findViewById(R.id.text_name);        telnumber = (TextView) findViewById(R.id.text_number);        Intent intent = getIntent();        String user_name = intent.getStringExtra("name");        name.setText(user_name);        String telephone = intent.getStringExtra("telnumber");        telnumber.setText(telephone);    }}

activity_add_user.xml添加联系人信息的布局

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:app="http://schemas.android.com/apk/res-auto"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context="com.example.sqlite.AddUserActivity">    <EditText        android:id="@+id/add_user_name"        android:hint="姓名"        android:layout_marginTop="20dp"        android:layout_width="match_parent"        android:layout_height="wrap_content" />    <EditText        android:id="@+id/add_user_telnumber"        android:hint="电话号码"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_below="@+id/add_user_name"/>    <Button        android:id="@+id/ok_add"        android:text="添加"        android:textSize="18dp"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_below="@+id/add_user_telnumber"/>    <Button        android:id="@+id/create_database"        android:text="创建数据库"        android:textSize="18dp"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_below="@+id/ok_add"/></RelativeLayout>

activity_user.xml 点击ListView后显示联系人详细信息的

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:app="http://schemas.android.com/apk/res-auto"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context="com.example.sqlite.UserActivity">    <TextView        android:id="@+id/textView"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_marginTop="92dp"        android:text="姓名"        android:textSize="20dp"        android:layout_marginLeft="70dp"        android:layout_marginStart="39dp"        android:layout_alignParentTop="true"        android:layout_alignParentLeft="true"        android:layout_alignParentStart="true" />    <TextView        android:id="@+id/textView2"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignEnd="@+id/textView"        android:layout_alignRight="@+id/textView"        android:layout_below="@+id/textView"        android:layout_marginTop="29dp"        android:text="电话"        android:textSize="20dp"/>    <TextView        android:id="@+id/text_name"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignTop="@+id/textView"        android:layout_marginLeft="49dp"        android:layout_marginStart="49dp"        android:layout_toEndOf="@+id/textView"        android:layout_toRightOf="@+id/textView"        android:textSize="20dp"/>    <TextView        android:id="@+id/text_number"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignBottom="@+id/textView2"        android:layout_alignStart="@+id/text_name"        android:layout_alignLeft="@+id/text_name"        android:layout_alignRight="@+id/text_name"        android:textSize="20dp"/></RelativeLayout>