android --- listview 优化+复杂UI 《中航信android客户端实战 经验》

list view 在android UI 中起着很大的作用。 listview 要是书写不好会极大影响程序的性能。

这里有一个 项目实战 listview 例子。 关键是ListView 复杂UI 的实现。

最终的效果如：

package com.test.list;

import android.app.ListActivity;
import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.TreeSet;

public class MultipleItemsList extends ListActivity {

private MyCustomAdapter mAdapter;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mAdapter = new MyCustomAdapter();
for (int i = 1; i < 50; i++) {
mAdapter.addItem("item " + i);
if (i % 4 == 0) {
mAdapter.addSeparatorItem("separator " + i);
}
}
setListAdapter(mAdapter);
}

private class MyCustomAdapter extends BaseAdapter {

private static final int TYPE_ITEM = 0;
private static final int TYPE_SEPARATOR = 1;
private static final int TYPE_MAX_COUNT = TYPE_SEPARATOR + 1;

private ArrayList<String> mData = new ArrayList<String>();
private LayoutInflater mInflater;

private TreeSet<Integer> mSeparatorsSet = new TreeSet<Integer>();

public MyCustomAdapter() {
mInflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

public void addItem(final String item) {
mData.add(item);
notifyDataSetChanged();
}

public void addSeparatorItem(final String item) {
mData.add(item);
// save separator position
mSeparatorsSet.add(mData.size() - 1);
notifyDataSetChanged();
}

@Override
public int getItemViewType(int position) {
return mSeparatorsSet.contains(position) ? TYPE_SEPARATOR : TYPE_ITEM;
}

@Override
public int getViewTypeCount() {
return TYPE_MAX_COUNT;
}

@Override
public int getCount() {
return mData.size();
}

@Override
public String getItem(int position) {
return mData.get(position);
}

@Override
public long getItemId(int position) {
return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
int type = getItemViewType(position);
System.out.println("getView " + position + " " + convertView + " type = " + type);
if (convertView == null) {
holder = new ViewHolder();
switch (type) {
case TYPE_ITEM:
convertView = mInflater.inflate(R.layout.item1, null);
holder.textView = (TextView)convertView.findViewById(R.id.text);
break;
case TYPE_SEPARATOR:
convertView = mInflater.inflate(R.layout.item2, null);
holder.textView = (TextView)convertView.findViewById(R.id.textSeparator);
break;
}
convertView.setTag(holder);
} else {
holder = (ViewHolder)convertView.getTag();
}
holder.textView.setText(mData.get(position));
return convertView;
}

}

public static class ViewHolder {
public TextView textView;
}
}

两个xml UI配置文件：

1： item1.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="wrap_content"
android:layout_width="fill_parent">
<!-- android:gravity="center_vertical" -->
<TextView
android:id="@+id/text"
android:layout_height="50dp"
android:gravity="center"
android:text="text"
android:visibility="visible"
android:layout_width="fill_parent"
android:textColor="#FF000000"
android:background="#FFFFFFFF" />
</LinearLayout>

2: item2.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="wrap_content"
android:layout_width="fill_parent">
<TextView
android:id="@+id/textSeparator"
android:layout_height="wrap_content"
android:gravity="center_vertical"
android:text="text"
android:visibility="visible"
android:layout_width="fill_parent"
android:textColor="#FFFFFFFF"
android:background="#FFFF0000" />
</LinearLayout>

原文地址：

http://android.amberfog.com/?p=296