在列表视图中，所有值都被插入到第一个位置

Question

下面是我的javaclass

字符串s的值来自数据库缓冲区，我希望每当值出现时，我都会作为第一个可点击元素存储在列表视图中。但是发生的是所有值都作为项目 1

存储在列表视图的第一个位置

             import android.database.Cursor;
             import android.os.Bundle;
              import android.support.v7.app.AppCompatActivity;
              import android.widget.ArrayAdapter;
              import android.widget.ListView;
              import android.widget.TextView;

              import java.util.ArrayList;
               import java.util.Arrays;


      public class HistoryActivity extends AppCompatActivity {

 ListView lv;
String s= null;
TextView tv1;
DatabaseHelper mydb;
StringBuffer buffer;
private ArrayAdapter<String> listAdapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.acticity_history);
    lv = (ListView) findViewById(R.id.listView);
    mydb = new DatabaseHelper(this);

    Cursor res = mydb.getAllData();
    if(res.getCount() == 0)
    {
        return;

    }

    buffer = new StringBuffer();
    while(res.moveToNext()){
        buffer.append(""+ res.getString(1)+ "\n");
    }
    s = buffer.toString();

    String[] values = new String[]{s};


    ArrayList<String> planetList = new ArrayList<String>();
    planetList.addAll( Arrays.asList(values) );

    listAdapter = new ArrayAdapter<String>(this, R.layout.simpleraw, planetList);

    lv.setAdapter(listAdapter);} }

下面是我的 xml 列表视图布局

    <?xml version="1.0" encoding="utf-8"?>

    <LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="fill_parent"
android:isScrollContainer="true">

<ListView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/listView"
    android:layout_gravity="center_horizontal"
    android:background="#000000"/>
</LinearLayout>

下面是我的 textview 的简单布局文件

      <?xml version="1.0" encoding="utf-8"?>

<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/rowTextView"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:padding="10dp"
    android:textColor="#FFFFFF"
    android:textSize="16sp" >
</TextView>

Answer 1

您正在将数据库的字符串附加到字符串缓冲区并且以下代码不会为您提供数组中的所有项目。该数组将只有一项。

String[] values = new String[]{s};

请使用以下代码。

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.acticity_history);
        lv = (ListView) findViewById(R.id.listView);
        mydb = new DatabaseHelper(this);

        Cursor res = mydb.getAllData();
        if(res.getCount() == 0)
        {
            return;

        }

        ArrayList<String> planetList = new ArrayList<String>();
        while(res.moveToNext()){
            planetList.add( res.getString(1));
        }

        listAdapter = new ArrayAdapter<String>(this, R.layout.simpleraw, planetList);

   }

Answer 2

您的所有值都将附加到 String s。用以下内容替换您的代码，

 @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.acticity_history);
lv = (ListView) findViewById(R.id.listView);
mydb = new DatabaseHelper(this);

Cursor res = mydb.getAllData();
if(res.getCount() == 0)
{
    return;
}

else
{
  ArrayList<String> planetList = new ArrayList<String>();
  while(res.moveToNext()){
    planetList.add(res.getString(1));
    }

    listAdapter = new ArrayAdapter<String>(this, R.layout.simpleraw, planetList);

   lv.setAdapter(listAdapter);
  }
 } 
}

为您的 listView 设置一个 OnItemClickListener，

lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id)
        {
            String itemName = (String) lv.getItemAtPosition(position);
            Intent intent = new Intent(currentActivity.this,newActivity.class);
            intent.putExtra("some_string", itemName);
            startActivity(intent);
        }               
  }

在列表视图中，所有值都被插入到第一个位置

In listview all the values are getting inserted at firs position

java

android

listview

android-listview