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() {@Overridepublic 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() {@Overridepublic 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() {@Overridepublic 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);elseholder.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;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_edit);initView();btnCancel.setOnClickListener(new View.OnClickListener() {@Overridepublic 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);elserbtnFemale.setChecked(true);dtTel.setText(cursor.getString(2));dtAddress.setText(cursor.getString(3));dtEmail.setText(cursor.getString(4));btnEdit.setOnClickListener(new View.OnClickListener() {@Overridepublic 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);}
   }