一个adapter实现多个itemView

要想实现这个功能，有两个函数比较重要getItemViewType和getViewTypeCount



我先说明一下我的这个demo的功能。一共有两个按钮，一个用来添加字符串，一个用来添加图像。

先给出布局main.xml（就一个listview和两个button）

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/LinearLayout1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.example.listviewbutton.MainActivity" >

<ListView
android:id="@+id/listView1"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1" >
</ListView>

<LinearLayout
android:layout_width="match_parent"
android:layout_height="50dp" >

<Button
android:id="@+id/button1"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="match_parent"
style="?android:attr/buttonBarButtonStyle"
android:text="@string/adapter1" />

<Button
android:id="@+id/button2"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="match_parent"
style="?android:attr/buttonBarButtonStyle"
android:text="@string/adapter2" />

</LinearLayout>

</LinearLayout>

接下来是MainActivity

package com.example.listviewbutton;

import java.util.Random;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ListView;

public class MainActivity extends Activity {
private ListView listView;
private MyAdapter adapter;
private Button button1, button2;

private static int count = 0;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

listView = (ListView) findViewById(R.id.listView1);
adapter = new MyAdapter(getApplicationContext());
listView.setAdapter(adapter);

// button1添加字符串
button1 = (Button) findViewById(R.id.button1);
button1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
adapter.addString("adapter1+" + (count++));
adapter.notifyDataSetChanged();
}
});

// button2添加bitmap。通过随机数来确定添加哪一张
button2 = (Button) findViewById(R.id.button2);
button2.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Random random = new Random();
int i = random.nextInt(2);
if (i == 0) {
adapter.addImg(R.drawable.ic_launcher);
} else {
adapter.addImg(R.drawable.boss);
}
adapter.notifyDataSetChanged();
}
});
}
}

最后就是重点MyAdapter.java

package com.example.listviewbutton;

import java.util.ArrayList;
import java.util.List;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.BitmapDrawable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;

public class MyAdapter extends BaseAdapter {
private static final int MSG = 1;
private static final int IMG = 2;

private List<Object> data = new ArrayList<Object>();

private Context context;
private LayoutInflater inflater;

public MyAdapter(Context context) {
super();
this.context = context;
inflater = LayoutInflater.from(this.context);
}

//添加字符串。将字符串存入List<Object> data中
public void addString(String string) {
data.add(string);
}

//添加bitmap。将bitmap的id存入List<Object> data中
public void addImg(int id) {
Bitmap bitmap = BitmapFactory
.decodeResource(context.getResources(), id);
data.add(bitmap);
}

//判断itemView类型
@Override
public int getItemViewType(int position) {
int type;
if (data.get(position) instanceof Bitmap) {
type = IMG;
} else {
type = MSG;
}
return type;
}

// 种类+1。这里尤其要注意，必须+1.具体为什么我也不清楚
@Override
public int getViewTypeCount() {
return 3;
}

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

@Override
public Object getItem(int position) {
return data.get(position);
}

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

//根据itemview判断加载的布局
@Override
public View getView(int position, View convertView, ViewGroup parent) {
int type = getItemViewType(position);
if (type == MSG) {
convertView = inflater.inflate(R.layout.itemmsg, null);
TextView tv = (TextView) convertView.findViewById(R.id.textView1);
tv.setText((String) data.get(position));
} else if (type == IMG) {
convertView = inflater.inflate(R.layout.itemimg, null);
ImageView iv = (ImageView) convertView.findViewById(R.id.imageView);
iv.setBackground(new BitmapDrawable(context.getResources(),
(Bitmap) data.get(position)));
}
return convertView;
}
}