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package com.example.myapplication; import androidx.appcompat.app.AppCompatActivity; import android.os.Bundle; import androidx.appcompat.app.AlertDialog; import android.content.DialogInterface; import android.view.View; import android.widget.AdapterView; import android.widget.EditText; import android.widget.ImageView; import android.widget.ListView; import android.widget.Toast; import java.util.List; public class MainActivity extends AppCompatActivity{ private ImageView iv_add; private ListView lv_show; private EditText et_name,et_phone; private MyAdapter myAdapter; private DBHelper dbHelper; private List<User> userList; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); iv_add = findViewById(R.id.iv_add); lv_show = findViewById(R.id.lv_show); if (userList != null) { userList.clear(); } dbHelper = new DBHelper(MainActivity.this, "user.db", null, 1); updateListView(); iv_add.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { addData(); } }); lv_show.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { updateData(position); } }); lv_show.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() { @Override public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) { deleteData(position); return true; } }); } private void addData() { AlertDialog.Builder builder=new AlertDialog.Builder(MainActivity.this); View dialogView=View.inflate(MainActivity.this,R.layout.dialog,null); builder.setIcon(R.drawable.icon) .setTitle("添加联系人") .setView(dialogView); builder.setPositiveButton("确定", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { et_name=dialogView.findViewById(R.id.et_name); et_phone=dialogView.findViewById(R.id.et_pwd); String name=et_name.getText().toString(); String phone=et_phone.getText().toString(); if (phone.length()!=11){ showToast("电话号码长度不符合要求"); }else { User user=dbHelper.get(name); if (user.getName()==null){ if (dbHelper.insert(name,phone)){ showToast("添加成功"); updateListView(); }else{ showToast("添加失败"); } }else { showToast("该联系人已存在"); } } } }) .setNegativeButton("取消", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.dismiss(); } }); AlertDialog alertDialog=builder.create(); alertDialog.show(); } private void deleteData(int position) { AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this); builder.setIcon(R.drawable.icon) .setTitle("提示") .setMessage("是否删除该联系人？") .setPositiveButton("确定", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { User user = (User) myAdapter.getItem(position); String deleteId = user.getId(); if (dbHelper.delete(deleteId)) { updateListView(); showToast("删除成功"); } else { showToast("删除失败"); } } }) .setNegativeButton("取消", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.dismiss(); } }); AlertDialog alertDialog = builder.create(); alertDialog.show(); } private void updateData(int position) { View dialogView = View.inflate(MainActivity.this, R.layout.dialog, null); User user = (User) myAdapter.getItem(position); et_name = dialogView.findViewById(R.id.et_name); et_phone = dialogView.findViewById(R.id.et_pwd); et_name.setText(user.getName()); et_phone.setText(user.getPhone()); String findId = user.getId(); AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this); builder.setIcon(R.drawable.icon) .setTitle("修改联系人") .setView(dialogView) .setPositiveButton("确定", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { String name = et_name.getText().toString(); String phone = et_phone.getText().toString(); if (phone.length()!=11){ showToast("电话号码长度不符合要求"); }else { User user=dbHelper.get(name); if (user.getName()==null){ if (dbHelper.update(findId,name,phone)){ showToast("修改成功"); updateListView(); }else{ showToast("修改失败"); } }else { showToast("该联系人已存在"); } } } }) .setNegativeButton("取消", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.dismiss(); } }); AlertDialog alertDialog = builder.create(); alertDialog.show(); } public void updateListView(){ userList=dbHelper.query(); myAdapter=new MyAdapter(userList,MainActivity.this); lv_show.setAdapter(myAdapter); } public void showToast(String msg){ Toast.makeText(MainActivity.this,msg,Toast.LENGTH_SHORT).show(); } }