数据在列表视图中不可见

我尝试了所有可能的情况，但数据没有显示在数据库的列表中。我的开始活动有列表视图，它在启动时为空，当用户填充数据并将其从另一个活动保存时，ANS按后退按钮数据，应在第一项活动中显示具有列表视图，但每次的数据没有显示数据在列表视图中不可见

MainActivty.java

package com.example.smscampaign; 

import java.util.ArrayList; 
import java.util.HashMap; 
import java.util.List; 
import java.util.Map; 
import android.app.Activity; 
import android.content.Context; 
import android.content.Intent; 
import android.database.Cursor; 
import android.os.Bundle; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.AdapterView; 
import android.widget.ArrayAdapter; 
import android.widget.Button; 
import android.widget.ListView; 
import android.widget.TextView; 



public class Campaign_Details extends Activity { 

    private Demo selectedAdapter; 
    private ArrayList<String> list; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_list_demostration); 
     TextView text1=(TextView) findViewById(R.id.text1); 
     TextView text2=(TextView) findViewById(R.id.text1); 
     DataBaseHandler info= new DataBaseHandler(this); 
     info.open(); 
     String data=info.getData(); 
     info.close(); 
     String[] values= new String[]{ data }; 
     //txt.setText(data); 
     // Button next=(Button) findViewById(R.id.next); 
     // Map<String, String[]> storage = new HashMap<String, String[]>(); 
    // String[] tableItems = storage.get("ContactTable"); 


     // next.setOnClickListener(this); 
    // final ListView listview = (ListView) findViewById(R.id.listview); 


     ListView listview1 = (ListView) findViewById(R.id.listview1); 
     // TextView emptyText = (TextView)findViewById(android.R.id.empty); 


     //listview.setEmptyView(findViewById(R.id.empty)); 
    // TextView emptyText = (TextView)findViewById(android.R.id.empty); 
     // listview .setEmptyView(emptyText); 

     final ArrayList<String> list = new ArrayList<String>(); 
     for (int i = 0; i < values.length; ++i) { 

      list.add(values[i]); 
     } 
     selectedAdapter = new Demo(this,values); 
     ListView listview = (ListView) findViewById(R.id.listview); 
     listview.setAdapter(selectedAdapter); 

     listview.setOnItemClickListener(new AdapterView.OnItemClickListener() { 

      @Override 
      public void onItemClick(AdapterView<?> parent, final View view, 
       int position, long id) { 
       Intent n = new Intent(getApplicationContext(), SmsSend.class); 
      startActivity(n); 

      } 
     }); 
    } 







    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 

     // TODO Auto-generated method stub 
     getMenuInflater().inflate(R.menu.main2, menu); 
     return true; 

    } 

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     // TODO Auto-generated method stub 

     switch (item.getItemId()) { 
     case R.id.nextPage: 
      Intent i = new Intent(this,SmsSend.class); 
      startActivity(i); 
      break; 

     } 
     return super.onOptionsItemSelected(item); 
    } 
    }

demo.java

package com.example.smscampaign; 

import android.content.Context; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.ArrayAdapter; 
import android.widget.ImageView; 
import android.widget.LinearLayout; 
import android.widget.TextView; 

public class Demo extends ArrayAdapter{ 
    private Campaign_Details list1; 
     // used to keep selected position in ListView 
     private int selectedPos = -1; // init value for not-selected 
     private Context context; 
     private String[] values; 

     public Demo(Context context, String[] values) { 
      super(context, R.layout.list); 
      this.context = context; 
      this.values = values; 
     } 




     public void setSelectedPosition(int pos){ 
     selectedPos = pos; 
      // inform the view of this change 
      notifyDataSetChanged(); 
     } 
     public int getSelectedPosition(){ 
      return selectedPos; 
     } 
     @Override 
     public View getView(int position, View convertView, ViewGroup parent) { 
       View v = convertView; 
         LayoutInflater vi = (LayoutInflater)this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
         v = vi.inflate(R.layout.list, null); 

       // get text view 
        TextView label = (TextView)v.findViewById(R.id.data); 

        if (convertView == null) {    
         v = vi.inflate(R.layout.list, parent, false); 
        } 
        else 
         v = convertView; 
        TextView text1 = (TextView) v.findViewById(R.id.data); 
       text1.setText(values[position]); 
        return v; 
       } 
     }

activity_list_demonstration.xml

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

    <TableLayout 
     android:layout_width="fill_parent" 
     android:layout_height="wrap_content" 
     android:orientation="horizontal" 
     android:stretchColumns="3" > 

     <TableRow 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" > 

      <TextView 
       android:id="@+id/textcolour" 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:layout_gravity="left" 
       android:background="@drawable/green_circle" /> 

      <TextView 
       android:id="@+id/text1" 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:layout_gravity="center" 
       android:paddingLeft="10dp" 
       android:text="Active Campaign" 
       android:textAppearance="?android:attr/textAppearanceLarge" 
       android:textColor="#4AE56B" /> 

      <TextView 
       android:id="@+id/textnum1" 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:layout_gravity="center" 
       android:layout_marginRight="130dp" 
       android:background="@drawable/green_badge" 
       android:gravity="center" 
       android:text=" 0 " 
       android:textColor="@color/white" /> 
     </TableRow> 
    </TableLayout> 

    <LinearLayout 
     android:layout_width="fill_parent" 
     android:layout_height="240dp" 
     android:orientation="vertical" > 

     <ListView 
      android:id="@+id/listview" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" /> 
    </LinearLayout> 

    <TableLayout 
     android:layout_width="fill_parent" 
     android:layout_height="wrap_content" 
     android:orientation="horizontal" 
     android:stretchColumns="3" > 

     <TableRow 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" > 

      <TextView 
       android:id="@+id/textcolour" 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:layout_gravity="left" 
       android:background="@drawable/grey_circle" /> 

      <TextView 
       android:id="@+id/text2" 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:paddingLeft="10dp" 
       android:text="Closed Campaign" 
       android:textAppearance="?android:attr/textAppearanceLarge" /> 

      <TextView 
       android:id="@+id/textnum2" 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:layout_gravity="center" 
       android:layout_marginRight="130dp" 
       android:background="@drawable/grey_badge" 
       android:gravity="center" 
       android:text=" 0 " 
       android:textColor="@color/white" /> 
     </TableRow> 
    </TableLayout> 

    <LinearLayout 
     android:layout_width="fill_parent" 
     android:layout_height="140dp" 
     android:orientation="vertical" > 

     <ListView 
      android:id="@+id/listview1" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" /> 
    </LinearLayout> 

</LinearLayout>

list.xml

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:orientation="vertical" > 


    <TextView 
      android:id="@+id/data" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:text="text" > 
     </TextView> 

</LinearLayout>

DatabaseHandler.java// databaseclass

package com.example.smscampaign; 

import android.content.ContentValues; 
import android.content.Context; 
import android.database.Cursor; 
import android.database.SQLException; 
import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteDatabase.CursorFactory; 
import android.database.sqlite.SQLiteOpenHelper; 



public class DataBaseHandler{ 

    public static final String KEY_ROWID="_id"; 
    public static final String KEY_NAME="person_name"; 
    public static final String KEY_SCALE="scale_person"; 

    private static final String DATABASE_NAME="Scaledb"; 
    private static final String DATABASE_TABLE="peopleTable"; 
    private static final int DATABASE_VERSION=1; 

    private DbHelper ourHepler; 
    private final Context ourContext; 
    private SQLiteDatabase ourDatabase; 
    public class DbHelper extends SQLiteOpenHelper{ 

     public DbHelper(Context context) { 
      super(context,DATABASE_NAME,null,DATABASE_VERSION); 
      // TODO Auto-generated constructor stub 
     } 

     @Override 
     public void onCreate(SQLiteDatabase db) { 
      // TODO Auto-generated method stub 
      db.execSQL("CREATE TABLE " + DATABASE_TABLE + " (" + 
        KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + 
        KEY_NAME + " TEXT NOT NULL, " + 
        KEY_SCALE + " TEXT NOT NULL);" 
        ); 
      } 

     @Override 
     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
      // TODO Auto-generated method stub 
      db.execSQL("DROP TABLE IF EXISTS" + DATABASE_TABLE); 
      onCreate(db); 
     } 

    } 

    public DataBaseHandler(Context c){ 
     ourContext=c; 
    } 


    public DataBaseHandler open() throws SQLException{ 
     ourHepler = new DbHelper(ourContext); 
     ourDatabase= ourHepler.getWritableDatabase(); 
     return this; 
    } 
    public void close() 
    { 
     ourHepler.close(); 
    } 


    public long entryCreate(String name, String scale) { 
     // TODO Auto-generated method stub 

     ContentValues cv=new ContentValues(); 
     cv.put(KEY_NAME, name); 
     cv.put(KEY_SCALE, scale); 
     return ourDatabase.insert(DATABASE_TABLE, null, cv); 

    } 


    public String getData() { 
     // TODO Auto-generated method stub 
     String[] col= new String[]{KEY_ROWID,KEY_NAME,KEY_SCALE}; 
     Cursor c= ourDatabase.query(DATABASE_TABLE, col, null, null, null, null, null); 
     String run=""; 
     int iRow=c.getColumnIndex(KEY_ROWID); 
     int iName=c.getColumnIndex(KEY_NAME); 
     int iScale=c.getColumnIndex(KEY_SCALE); 

     for(c.moveToFirst();!c.isAfterLast();c.moveToNext()){ 
      run=run+c.getString(iRow)+ " " + c.getString(iName) + " " + c.getString(iScale) + "\n"; 
     } 

     return run; 
    } 


    public String getScale(long l) { 
     // TODO Auto-generated method stub 
     String[] col= new String[]{KEY_ROWID,KEY_NAME,KEY_SCALE}; 
     Cursor c= ourDatabase.query(DATABASE_TABLE, col,KEY_ROWID + "-" + l, null, null, null, null); 

     if(c != null){ 
      c.moveToFirst(); 
      String scale=c.getString(2); 
      return scale; 
     } 
     return null; 
    } 


    public String getName(long l) { 
     // TODO Auto-generated method stub 
     String[] col= new String[]{KEY_ROWID,KEY_NAME,KEY_SCALE}; 
     Cursor c= ourDatabase.query(DATABASE_TABLE, col,KEY_ROWID + "-" + l, null, null, null, null); 

     if(c != null){ 
      c.moveToFirst(); 
      String name=c.getString(1); 
      return name; 

     } 
     return null; 
    } 


    public void updateEntry(long lt, String mName, String mScale) { 
     // TODO Auto-generated method stub 
      ContentValues cvUpdate=new ContentValues(); 
      cvUpdate.put(KEY_NAME,mName); 
      cvUpdate.put(KEY_SCALE,mScale); 
      ourDatabase.update(DATABASE_TABLE, cvUpdate, KEY_ROWID + "-" + lt, null); 
    } 


    public void deleteEntry(long ltt) throws SQLException{ 
     // TODO Auto-generated method stub 
     ourDatabase.delete(DATABASE_TABLE, KEY_ROWID + "=" + ltt,null); 

    } 
}

来源

2014-03-12 Himani

哪里是activity_list_demostration.xml ... – Ranjit

我把它写成activity.xml – Himani

好..你可以显示你的数据库类.. – Ranjit

您需要在某些地方更换。你已经宣布你的ArrayList全球作为

private ArrayList<String> list;

后再次声明了上onCreate（）方法

final ArrayList<String> list = new ArrayList<String>();

所以更换由

list = new ArrayList<String>();

现在，在您的所有数据在您的列表中添加，但在您的适配器中您已通过值字符串数组。所以，你也需要改变从

selectedAdapter = new Demo(this,values);

到

selectedAdapter = new Demo(this,list);

来源

2014-03-12 11:52:00 Piyush

不工作....如果我做出改变，它也会影响我的演示班，所以我们也必须在那里改变。我也是这样做了，但没有工作。没有显示任何数据 – Himani

更改getview方法的内容。

public static class ViewHolder{ 

       public TextView text; 

      } 

      public View getView(int position, View convertView, ViewGroup parent) { 

       View vi = convertView; 
       ViewHolder holder; 

       if(convertView==null){ 

        vi = inflater.inflate(R.layout.list, null); 

        holder = new ViewHolder(); 
        holder.text = (TextView) vi.findViewById(R.id.data); 

        vi.setTag(holder); 
       } 
       else 
        holder=(ViewHolder)vi.getTag();

此外，如果您不是自定义布局[只使用textview]通过选择默认布局使用arrayadapter直通车。

来源

2014-03-12 11:07:08 Shriram

按后退按钮数据，应在第一个活动显示

你写你的数据库加载代码onCreate()方法，它在它的生命周期，即执行一次时，当活动摧毁了你的应用程序启动或像在方向变化。

所以当你按下后退按钮onCreate()没有调用，并将继续列表。

一些suggessions：

它的好，如果你写的所有数据库的东西你onResume()

否则调用finish（）在您的主要活动的onPause()方法，再通过按下回意向启动你的second_activity的方法.. finish()杀死活动，当你去下一个..再次重新创建时，你从第二通过strtaActivity及其相应的意图。

而且它更好，如果您使用StringTokenizer当您从数据库中获取数据并将其放入字符串数组。

来源

2014-03-12 11:12:21 Ranjit

在

ArrayAdapter你写

if (convertView == null) { 
    v = vi.inflate(R.layout.list, parent, false); 
} else 
    v = convertView;

删除else语句。或者完全删除完整的if-else声明。此外 TextView text1 = (TextView) v.findViewById(R.id.data);是多余的，你已经在label

编辑错误已经定义了这个特定TextView

public Demo(Context context, String[] values) { 
     super(context, R.layout.list); 
     this.context = context; 
     this.values = values; 
    }

到

public Demo(Context context, String[] values) { 
     super(context, R.layout.list,values); 
     this.context = context; 
     this.values = values; 
    }

来源

2014-03-12 12:03:21

这也没有帮助。像往常一样工作 – Himani

@ user3359315请注意，只有当您点击文本时，您的当前代码才会填充第一个“ListView”，即低于[b] Active Campaign [/ b]并且只会触发OnitemClickListener（）。 –

我知道..，bt数据在列表视图中不可见 – Himani

数据在列表视图中不可见

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