[Android]联系人-删除修改

1. 界面显示

添加按钮点击，holder.imgDelete.setlog();具体代码

 public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        //映射布局文件，生成相应的组件
        View v = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.data_item, parent, false);
        MyViewHolder vh = new MyViewHolder(v);
        vh.txtName = v.findViewById(R.id.txtNameMainItem);
        vh.txtTel = v.findViewById(R.id.txtTelMainItem);
        vh.imgView = v.findViewById(R.id.imgMainItem);
        vh.imdDelete=v.findViewById(R.id.imgDelete);
        vh.imgEdit=v.findViewById(R.id.imgEdit);

        vh.imdDelete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                String s=(String)view.getTag();
                AlertDialog dlg=new AlertDialog.Builder(view.getContext())
                        .setTitle("删除提示：")
                        .setIcon(R.drawable.down)
                        .setMessage("是否删除"+s+"?")
                        .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialogInterface, int i) {
                                String ss="delete from contacts where name='"+s+"';";
                                db.execSQL(ss);
                                updateData();
                            }
                        })
                        .setNegativeButton("取消",null)
                        .create();
                    dlg.show();

                    }
        });

        vh.imgEdit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String s=(String)view.getTag();
                Log.d("test","Edit"+s);
            }
        });
        return vh;
    }

设置每个数据项的View组件的属性

public void onBindViewHolder(@NonNull MyViewHolder holder, int position) {
        cursor.moveToFirst();//先移动到第0条记录
        cursor.move(position);//再移动到第position条记录
        holder.txtName.setText(cursor.getString(0));
        holder.txtTel.setText(cursor.getString(1));
        if (1 == cursor.getInt(2))
            holder.imgView.setImageResource(R.drawable.avatar_male);
        else
            holder.imgView.setImageResource(R.drawable.avatar_female);

        holder.imdDelete.setTag(1,cursor.getString(0));
        holder.imgEdit.setTag(1,cursor.getString(0));
    }

1. 准备主键修改

2. 链接数据库，实时更新，指定主键where

3. 改变之后联系人信息更改

4. 详细代码

   package com.example.testcontacts;
   
   import androidx.appcompat.app.AppCompatActivity;
   
   import android.database.Cursor;
   import android.os.Bundle;
   import android.view.View;
   import android.widget.Button;
   import android.widget.EditText;
   import android.widget.RadioButton;
   import android.widget.Toast;
   
   public class EditActivity extends AppCompatActivity {
       private EditText dtName, dtTel, dtAddress, dtEmail;
       private RadioButton rbtnMale, rbtnFemale;
       private Button btnEdit, btnCancel;
       private String sName;
       @Override
       protected void onCreate(Bundle savedInstanceState) {
           super.onCreate(savedInstanceState);
           setContentView(R.layout.activity_edit);
           initView();
   
           btnCancel.setOnClickListener(new View.OnClickListener() {
               @Override
               public void onClick(View view) {
                   finish();
               }
           });
           sName = getIntent().getStringExtra("name");
           String s = "select name,gender,tel,address,email from contacts where name='" + sName+"';";
           Cursor cursor = MyAdapter.db.rawQuery(s, null);
           if (!cursor.moveToNext()) {
               Toast.makeText(this, "找不到"+sName+"的记录", Toast.LENGTH_SHORT).show();
               finish();
               return;
           }
   
           dtName.setText(cursor.getString(0));
           int iGender = cursor.getInt(1);
           if (iGender > 0)
               rbtnMale.setChecked(true);
           else
               rbtnFemale.setChecked(true);
           dtTel.setText(cursor.getString(2));
           dtAddress.setText(cursor.getString(3));
           dtEmail.setText(cursor.getString(4));
   
           btnEdit.setOnClickListener(new View.OnClickListener() {
               @Override
               public void onClick(View view) {
                   String sGender = "true";
                   if (rbtnFemale.isChecked())
                       sGender = "false";
                   String name = dtName.getText().toString();
                   String sTel = dtTel.getText().toString();
                   String sAddress = dtAddress.getText().toString();
                   String sEmail = dtEmail.getText().toString();
   
                   String s = "update contacts set name='" + name+"', gender="+sGender+",tel='" + sTel+
                           "',address='"+sAddress+"',email='"+sEmail+"' where name='"+ sName + "';";
                   MyAdapter.db.execSQL(s);
                   finish();
               }
           });
       }
   
       private void initView()
       {
           dtName = findViewById(R.id.dtEditName);
           dtTel = findViewById(R.id.dtEditTel);
           dtAddress = findViewById(R.id.dtEditAddress);
           dtEmail = findViewById(R.id.dtEditEmail);
           rbtnMale = findViewById(R.id.rEditBtnMale);
           rbtnFemale = findViewById(R.id.rEditBtnFemale);
           btnEdit = findViewById(R.id.btnEdit);
           btnCancel = findViewById(R.id.btnEditCancel);
       }
   }