如何仅在列表菜单中显示列表标题，而不是 listview android studio 中列表项的全部内容？

Question

我正在尝试制作一个简单的笔记应用程序。 我试图在列表视图中显示笔记。 但是当我向笔记添加更多内容时，它会在列表视图的主菜单中显示全部内容。 如何只让列表的标题在Listview中可见，而内容只有在我们打开列表项时才可见？

MainActivity.java

package com.example.notes;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
public class MainActivity extends AppCompatActivity {
    static   ArrayList<String> notes=new ArrayList<>();
    static ArrayAdapter arrayAdapter;
    @Override
    public boolean onCreateOptionsMenu(Menu menu){
        MenuInflater menuInflater=getMenuInflater();
        menuInflater.inflate(R.menu.add_note_menu,menu);
        return super.onCreateOptionsMenu(menu);
    }
    @Override
    public boolean onOptionsItemSelected(@NonNull MenuItem item) {
         super.onOptionsItemSelected(item);
         if(item.getItemId()==R.id.add_note){
             Intent intent=new Intent(getApplicationContext(),NoteEditorActivity.class);
             startActivity(intent);
             return true;
         }
         return false;
    }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ListView listview=(ListView) findViewById(R.id.listView);
        SharedPreferences sharedPreferences=getApplicationContext().getSharedPreferences("com.robpercival.notes", Context.MODE_PRIVATE);
        HashSet<String> set=(HashSet<String>)sharedPreferences.getStringSet("notes",null);
        if(set==null) {
            notes.add("Example note");
        }
        else{
            notes=new ArrayList(set);
        }
        notes.add("Note 1");
     arrayAdapter=new ArrayAdapter(this,android.R.layout.simple_list_item_1,notes) ;
        listview.setAdapter(arrayAdapter);
listview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int i, long l) {
        Intent intent=new Intent(getApplicationContext(),NoteEditorActivity.class);
        intent.putExtra("noteId",i);
        startActivity(intent);
    }
});
listview.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
    @Override
    public boolean onItemLongClick(AdapterView<?> parent, View view, int i, long l) {
 final int itemToDelete=i;
        new AlertDialog.Builder(MainActivity.this)
                .setIcon(android.R.drawable.ic_dialog_alert)
                .setTitle("are you sure?")
                .setMessage("do you want to delete?")
                .setPositiveButton("yes", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialogInterface, int i) {
                        notes.remove(itemToDelete);
                        arrayAdapter.notifyDataSetChanged();
                        SharedPreferences sharedPreferences=getApplicationContext().getSharedPreferences("com.robpercival.notes", Context.MODE_PRIVATE);
                        HashSet<String> set=new HashSet<>(MainActivity.notes);
                        sharedPreferences.edit().putStringSet("notes",set).apply();
                    }
                })
                .setNegativeButton("no",null)
                .show();
        return true;
    }
});
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/note1"
    tools:context=".MainActivity">
    <ListView
        android:id="@+id/listView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

note_editor_activity.java

package com.example.notes;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.widget.EditText;
import com.google.android.material.textfield.TextInputLayout;
import java.util.HashSet;
public class NoteEditorActivity extends AppCompatActivity {
int noteId;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_note_editor);
        EditText editText=(EditText) findViewById(R.id.editText);
        Intent intent=getIntent();
        noteId=intent.getIntExtra("noteId",-1);
if(noteId!=-1){
    editText.setText(MainActivity.notes.get(noteId));
}
else{
    MainActivity.notes.add("");
    noteId=MainActivity.notes.size()-1;
    MainActivity.arrayAdapter.notifyDataSetChanged();
}
editText.addTextChangedListener(new TextWatcher() {
    @Override
    public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
    }
    @Override
    public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
MainActivity.notes.set(noteId,String.valueOf(charSequence));
MainActivity.arrayAdapter.notifyDataSetChanged();
        SharedPreferences sharedPreferences=getApplicationContext().getSharedPreferences("com.robpercival.notes", Context.MODE_PRIVATE);
        HashSet<String> set=new HashSet<>(MainActivity.notes);
        sharedPreferences.edit().putStringSet("notes",set).apply();
    }
    @Override
    public void afterTextChanged(Editable editable) {
    }
});
    }
}

acitivity_node-editor.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/olo"
tools:context=".NoteEditorActivity">
<EditText
    android:id="@+id/editText"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:ems="10"
    android:gravity="start|top"
    android:inputType="textMultiLine"
    android:padding="0dp"
    tools:layout_editor_absoluteX="118dp"
    tools:layout_editor_absoluteY="91dp" />
    </androidx.constraintlayout.widget.ConstraintLayout>

add_note_menu.xml

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
<item android:id="@+id/add_note" android:title="Add note"></item>
</menu>

Answer 1

在我看来，我认为您应该使用两个edittext，一个用于标题，一个用于内容，然后将两者都保存在hasmap中。 使用标题作为键，然后将其用于列表视图内容。

Answer 2

note_create.java

EditText title=findViewById(R.id.title);
EditText body=findViewById(R.id.body);
HashMap<String,String>all=new HashMap<String,String>();
all.put(title.getText().toString(),body.getText().toString());
ArrayList<String>head=new ArrayList<String>();
head.addAll(all.keySet());

Answer 3

note_create.java

EditText title=findViewById(R.id.title);
EditText body=findViewById(R.id.body);
HashMap<String,String>all=new HashMap<String,String>();
all.put(title.getText().toString(),body.getText().toString());
ArrayList<String>head=new ArrayList<String>();
head.addAll(all.keySet());

然后将头 ArrayList 添加到您的列表视图

供观赏

    shs.setOnItemClickListener(new AdapterView.OnItemClickListener(){
    @Override
    public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
String read=(String)getItemAtPosition(arg2);
if(head.contains(read);
{
String reads=all.get(read);
}
});

Answer 4

您可以将读取的字符串传递给另一个意图查看这就是我的做法

Answer 5

抱歉，关于前一种，我没有正确解释使用另一种格式使用两个edittext，一个用于标题，一个用于正文。使用正文键作为标题将它们保存在不同的首选项中 将标题首选项传递给列表视图。