我只是将我的listview设置为空..但现在将数据从另一个活动添加到数据库后，并尝试在列表视图中显示该数据，它给出了相同的emptyview ..它没有显示数据，如何检索数据在listview .. ??
Campaign.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 listview = (ListView) findViewById(R.id.listview);
ListView listview1 = (ListView) findViewById(R.id.listview1);
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) {
selectedAdapter = new Demo(this,values);
selectedAdapter.setNotifyOnChange(true);
listview.setAdapter(selectedAdapter);
list.add(values[i]);
}
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 //自定义适配器
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;
}
}
DatabaseHandler.java
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);
}
public void getWritableDatabase() {
// TODO Auto-generated method stub
}
}
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" >
<TextView
android:id="@+id/text1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Active Campaign"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textColor="#4AE56B" />
<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" />
<TextView
android:id="@+id/empty"
style="@android:style/TextAppearance.Large"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_gravity="center"
android:text="Tab on Icon to start a Campaign" >
</TextView>
</LinearLayout>
<TextView
android:id="@+id/text2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Closed Campaign"
android:textAppearance="?android:attr/textAppearanceLarge" />
<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" />
<TextView
android:id="@+id/empty"
style="@android:style/TextAppearance.Large"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_gravity="center"
android:text="No Closed Campaign" >
</TextView>
</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" >
</TextView>
</LinearLayout>
答案 0 :(得分：1)
检查String []数据是否为空。
其次，您的数据库返回一个长字符串而不是String数组，并且在ListView中只能获得一行
for(c.moveToFirst();!c.isAfterLast();c.moveToNext()){
run=run+c.getString(iRow)+ " " + c.getString(iName) + " " + c.getString(iScale) + "\n";
}
你也只获得最后一行或空行
将其更改为此类
List<String> dataArray = new ArrayList<String>();
for(c.moveToFirst();!c.isAfterLast();c.moveToNext()){
dataArray.add(run+c.getString(iRow)+ " " + c.getString(iName) + " " + c.getString(iScale) + "\n");
}
return dataArray;
将您的适配器设置为使用List数组;
公共类SampleAdapter扩展了BaseAdapter {
private Context context;
private List<String> dataArray;
public SampleAdapter(Context context,List<String> dataArray){
this.context = context;
this.dataArray = dataArray;
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return dataArray.size();
}
@Override
public Object getItem(int arg0) {
// TODO Auto-generated method stub
return null;
}
@Override
public long getItemId(int arg0) {
// TODO Auto-generated method stub
return 0;
}
static class ViewHolder
{
TextView txt1;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder viewHolder;
if(convertView==null){
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.grid_row_item_layout,parent, false);
viewHolder = new ViewHolder();
viewHolder.txt1 = (TextView) convertView.findViewById(R.id.textView1);
convertView.setTag(viewHolder);
}
else{
viewHolder = (ViewHolder) convertView.getTag();
}
viewHolder.txt1.setText(dataArray.get(position));
return convertView;
}
}
MainActivity
public class MainActivity extends Activity {
SampleAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
List<String> array = new ArrayList<String>();
array.add("data line 1");
array.add("data line 2");
array.add("data line 3");
array.add("data line 4");
array.add("data line 5");
adapter = new SampleAdapter(this,array);
ListView listView = (ListView) findViewById(R.id.listView1);
listView.setAdapter(adapter);
}
}
答案 1 :(得分：0)
先解决这个问题
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.setAdapter(selectedAdapter);
您的适配器也需要此方法
@Override
public int getCount() {
// TODO Auto-generated method stub
return values.length();
}