将数据从另一个活动添加到listview

Question

我真的很困惑如何从另一个活动中添加，我在代码的这一部分不断收到错误：

Emails a = new Emails(intent.getStringExtra("inputEmail"), intent.getStringExtra("inputBody"), intent.getStringExtra("inputSubject"));

所以错误说"；实际的和形式的自变量列表在长度上不同"；。如果有人能帮我，那将是一个巨大的帮助，谢谢：(

这是我的代码：

主要活动：

import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ListView;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
private Button newEmail;
private ListView listView;
private EmailAdapter emailAdapter;
private ArrayList<Emails> emailsArrayList;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
init();

emailAdapter = new EmailAdapter(this, emailsArrayList);
listView.setAdapter(emailAdapter);
updateList();

newEmail.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, SendActivity.class);
startActivity(intent);
}
});
}
private void init(){
newEmail = (Button) findViewById(R.id.newBtn);
listView = (ListView) findViewById(R.id.list);
emailsArrayList = new ArrayList<>();
Emails emails = new Emails ();
emails.setEmails("[e-mail]");
emails.setSubject("Sample Data");
emails.setBody("this is the sample data");
emailsArrayList.add(emails);

}
private void updateList()
{
Bundle bundle = getIntent().getExtras();
Intent intent = getIntent();
if(bundle != null)
{
Emails a = new Emails(intent.getStringExtra("inputEmail"), intent.getStringExtra("inputBody"), intent.getStringExtra("inputSubject"));
emailAdapter.add(a);
emailAdapter.notifyDataSetChanged();
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent intent)
{
super.onActivityResult(requestCode, resultCode, intent);
if(requestCode == 1 && resultCode == RESULT_OK)
{
Emails a = new Emails(intent.getStringExtra("inputEmail"), intent.getStringExtra("inputBody"), intent.getStringExtra("inputSubject"));
emailAdapter.add(a);
emailAdapter.notifyDataSetChanged();
}
}
@Override
protected void onStart() {
super.onStart();
Log.d("MainActivity","onStart invoked");
}
@Override
protected void onResume() {
super.onResume();
Log.d("MainActivity","onResume invoked");
}
@Override
protected void onPause() {
super.onPause();
Log.d("MainActivity","onPause invoked");
}
@Override
protected void onStop() {
super.onStop();
}
@Override
protected void onRestart() {
super.onRestart();
}
@Override
protected void onDestroy() {
super.onDestroy();
}
}

这是添加项目活动：

import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Toast;
import java.util.ArrayList;
public class SendActivity extends AppCompatActivity {
private Button send;
private Button discard;
private EditText email;
private EditText subject;
private EditText body;
private ArrayList<Emails> emailsArrayList;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_send);
send = (Button) findViewById(R.id.sendBtn);
discard = (Button) findViewById(R.id.discardBtn);
email = (EditText) findViewById(R.id.inputEmail);
subject = (EditText) findViewById(R.id.inputSubject);
body = (EditText) findViewById(R.id.inputBody);

discard.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(SendActivity.this, MainActivity.class);
startActivity(intent);
}
});

send.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String inputEmail = email.getText().toString();
String inputSubject = subject.getText().toString();
String inputBody = body.getText().toString();
if (inputBody.isEmpty() || inputEmail.isEmpty() || inputEmail.isEmpty()){
Toast.makeText(SendActivity.this, "Please enter the following data", Toast.LENGTH_SHORT).show();
}
else {
emailsArrayList = new ArrayList<>();
Emails newEmails = new Emails ();
newEmails.setEmails(inputEmail);
newEmails.setSubject(inputSubject);
newEmails.setBody(inputBody);
emailsArrayList.add(newEmails);
Intent intent = new Intent();
getIntent().putExtra("inputEmail", inputEmail);
getIntent().putExtra("inputSubject", inputSubject);
getIntent().putExtra("inputBody", inputBody);
setResult(RESULT_OK, intent);
finish();
}

}
});
}


}

Answer 1

我也会更改以下内容：

private void updateList()
{
Bundle bundle = getIntent().getExtras();
Intent intent = getIntent();
if(bundle != null)
{
Emails a = new Emails(intent.getStringExtra("inputEmail"), intent.getStringExtra("inputBody"), intent.getStringExtra("inputSubject"));
emailAdapter.add(a);
emailAdapter.notifyDataSetChanged();
}
}

至

private void updateList()
{
Intent intent = getIntent();        
Bundle bundle = intent.getExtras();
if(bundle != null)
{
Emails a = new Emails(String)bundle.get("inputEmail"), (String)bundle.get("inputBody"), (String)bundle.get("inputSubject"));
emailAdapter.add(a);
emailAdapter.notifyDataSetChanged();
}
}

我会先尝试一下：您可以使用现有的，只需更改updateList((中的Bundle Bundle和Intent Intent行即可。再说一遍，没有专家，但先尝试一下，然后再超过第二次。我希望它对你有用。