Android手机开发——通讯录

实现增加、查询、修改、删除的功能，输入联系人信息，点击“添加”按钮，可以添加联系人信息到数据库；点击“查询”按钮，会发现添加的联系人信息显示在界面中；重新输入联系人电话，点击“修改”按钮，可以修改该联系人的电话，再进行查询发现联系人电话已经修改；点击“删除”按钮，会将数据库中该联系人的所有记录删除。

主界面的布局文件代码

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:orientation="horizontal"

android:layout_marginTop="100dp">

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="姓名：" />

android:id="@+id/et_name"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:hint="请输入姓名"/>

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:orientation="horizontal">

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="电话：" />

android:id="@+id/et_tel"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:hint="请输入手机号码"/>

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:orientation="horizontal"

android:layout_marginTop="20dp">

android:id="@+id/btn_add"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="添加"

android:background="#b9b9ff"/>

android:id="@+id/btn_query"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="查询"

android:background="#dcb5ff"/>

android:id="@+id/btn_update"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="修改"

android:background="#e6caff"/>

android:id="@+id/btn_del"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="删除"

android:background="#acd6ff"/>

android:id="@+id/tv_show"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_marginTop="20dp" />

MyHelper.java

public class MyHelper extends SQLiteOpenHelper {

private  static  final  int DATABASE_VERSION=2;

private  static  final  String DATABASE_NAME="mydb";

private  static  final String sql="CREATE TABLE directory("+

"_id INTEGER PRIMARY KEY AUTOINCREMENT,name VARCHAR(20),"

+"phone VARCHAR(20))";

public MyHelper(Context context){

super(context,DATABASE_NAME,null,DATABASE_VERSION);

}

@Override

public void onCreate(SQLiteDatabase db) {

db.execSQL(sql);

}

@Override

public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {

}

}

MyDBManager.java

public class MyDBManager {

private  MyHelper myHelper;

private SQLiteDatabase sqLiteDatabase;

public MyDBManager(Context context){

myHelper=new MyHelper(context);

sqLiteDatabase=myHelper.getReadableDatabase();

}

public  void getConnect(){

sqLiteDatabase=myHelper.getWritableDatabase();

}

public  void releaseConnect(){

if(sqLiteDatabase!=null){

sqLiteDatabase.close();

}

}

public  void insert(Person data){

ContentValues values =new ContentValues();

values.put("name",data.getName());

values.put("phone",data.getPhone());

sqLiteDatabase.insert("directory",null,values);

}

public ArrayListfindAll(){

ArrayList list =new ArrayList<>();

Person person =null;

Cursor cursor=sqLiteDatabase.query("directory",null,null,null,null,null,null);

while(cursor.moveToNext()){

Person person1=new Person();

person1.setName(cursor.getString(1));

person1.setPhone(cursor.getString(2));

list.add(person1);

}

cursor.close();

return  list;

}

public  void updateBysql(String clause,String data,String[] args){

ContentValues values=new ContentValues();

values.put("phone",data);

sqLiteDatabase.update("directory",values,clause,args);

}

public void delete(String clause,String[] args){

sqLiteDatabase.delete("directory",clause,args);

}

}

MainActivity.java

public class MainActivity extends AppCompatActivity {

private EditText et_name,et_phone;

private Button btn_add,btn_find,btn_update,btn_del;

private TextView tv_show;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

et_name=(EditText)findViewById(R.id.et_name);

et_phone=(EditText)findViewById(R.id.et_tel);

btn_add=(Button)findViewById(R.id.btn_add);

btn_find=(Button)findViewById(R.id.btn_query);

tv_show=(TextView)findViewById(R.id.tv_show);

btn_update=(Button)findViewById(R.id.btn_update);

btn_del=(Button)findViewById(R.id.btn_del);

btn_add.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View view) {

String name =et_name.getText().toString().trim();

String phone=et_phone.getText().toString().trim();

if(TextUtils.isEmpty(name)&&TextUtils.isEmpty(phone)){

Toast.makeText(MainActivity.this,"姓名和电话号码不能为空",Toast.LENGTH_SHORT).show();

}else {

Person person=new Person();

person.setName(name);

person.setPhone(phone);

MyDBManager myDBManager=new MyDBManager(MainActivity.this);

myDBManager.getConnect();

myDBManager.insert(person);

myDBManager.releaseConnect();

Toast.makeText(MainActivity.this,"保存成功",Toast.LENGTH_SHORT).show();

}

}

});

btn_find.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View view) {

MyDBManager myDBManager=new MyDBManager(MainActivity.this);

ArrayList list =myDBManager.findAll();

tv_show.setText("");

for (Person p:list){

tv_show.append("姓名"+p.getName()+";"+"电话"+p.getPhone()+"\n");

}

myDBManager.releaseConnect();

}

});

btn_update.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View view) {

String name =et_name.getText().toString().trim();

String phone=et_phone.getText().toString();

MyDBManager myDBManager=new MyDBManager(MainActivity.this);

myDBManager.getConnect();

myDBManager.updateBysql("name=?",phone,new String[] {name});

myDBManager.releaseConnect();

Toast.makeText(MainActivity.this,"信息已修改",Toast.LENGTH_SHORT).show();

}

});

btn_del.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View view) {

String name =et_name.getText().toString().trim();

String phone =et_phone.getText().toString().trim();

MyDBManager myDBManager= new MyDBManager(MainActivity.this);

myDBManager.getConnect();

myDBManager.delete("name=?",new String[]{name});

myDBManager.releaseConnect();

Toast.makeText(MainActivity.this,"信息已删除",Toast.LENGTH_SHORT).show();

}

});

}

}