[英]My Custom ListView display nothing
我是android的新手。 我想創建一個自定義listview arrayadapter。 我已經按照一些教程,但我的模擬器沒有為Custom ListView顯示任何內容。 誰能幫我弄清楚我的代碼出了什么問題? 提前致謝。
這是我的custom_listview_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ListView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/customListView" />
</LinearLayout>
這是我的custom_listview_row.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center_vertical"
android:minHeight="64dp">
<!-- <ImageView
android:id="@+id/clv_imageView"
android:layout_width="32dp"
android:layout_height="32dp"
android:contentDescription="@string/empty"
android:layout_alignParentLeft="true"
android:layout_marginLeft="9dp"
android:layout_alignParentTop="true"/> -->
<TextView
android:id="@+id/clv_textView2"
android:layout_width="97dp"
android:layout_height="32dp"
android:layout_alignParentRight="true"
android:gravity="center_vertical"
android:text="@string/tv_definition"
android:textIsSelectable="true" />
<TextView
android:id="@+id/clv_textView"
android:layout_width="97dp"
android:layout_height="32dp"
android:layout_alignParentLeft="true"
android:gravity="center_vertical"
android:text="@string/tv_word"
android:textIsSelectable="true" />
</RelativeLayout>
這是我的MyPerformanceArrayAdapter.java
import java.util.List;
import android.app.Activity;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;
public class MyPerformanceArrayAdapter extends ArrayAdapter<DefinitionObject>{
private List<DefinitionObject> entries;
private Activity activity;
public MyPerformanceArrayAdapter(Activity a, int textViewResourceId, List<DefinitionObject> entries) {
super(a, textViewResourceId, entries);
this.entries = entries;
this.activity = a;
}
public static class ViewHolder{
public TextView item1;
public TextView item2;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
ViewHolder holder;
if (v == null) {
LayoutInflater vi =
(LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = vi.inflate(R.layout.custom_listview_row, null);
holder = new ViewHolder();
holder.item1 = (TextView) v.findViewById(R.id.clv_textView);
holder.item2 = (TextView) v.findViewById(R.id.clv_textView2);
v.setTag(holder);
}
else
holder=(ViewHolder)v.getTag();
final DefinitionObject custom = entries.get(position);
if (custom != null) {
holder.item1.setText(custom.getWord());
holder.item2.setText(custom.getFav());
}
return v;
}
}
最后,這是我的名為TempCLV.java的Activity
package com.example.myidictionary;
import java.util.List;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.ListView;
public class TempCLV extends Activity {
private MySQLiteDefinitionHelper db;
String tblName = "";
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.custom_listview_main);
Intent msjIntent = getIntent();
tblName = msjIntent.getStringExtra(WordDefinitionHomeActivity.TABLENAME2);
}
public void refresh()
{
db = new MySQLiteDefinitionHelper(this);
final List<DefinitionObject> values = db.getAllWords(tblName);
ListView mylist = (ListView)findViewById(R.id.customListView);
MyPerformanceArrayAdapter adapter = new MyPerformanceArrayAdapter(this, R.id.customListView, values);
mylist.setAdapter(adapter);
}
}
您需要在onCreate
調用refresh
,因為您要將適配器設置為列表視圖。
確保您的values
包含一些數據
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.custom_listview_main);
Intent msjIntent = getIntent();
tblName = msjIntent.getStringExtra(WordDefinitionHomeActivity.TABLENAME2);
refresh();
}
您還可以將inflater初始化移動到適配器類的構造函數。 無需在getView
初始化
LayoutInflater vi;
public MyPerformanceArrayAdapter(Activity a, int textViewResourceId,List<DefinitionObject> entries) {
super(a, textViewResourceId, entries);
this.entries = entries;
vi =(LayoutInflater)a.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
請至少在第一次調用refresh方法,在MainActivity的onCreate
方法中設置適配器。
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