Android实战简易教程<二十一>（GridView动态添加Item）

本例子实现在GridView的最后显示一个增加图片，点击图片动态增加内容item。

1.main.xml:

[html] view
plaincopy

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent" >



<GridView

android:id="@+id/gv_test"

android:numColumns="3"

android:layout_width="match_parent"

android:layout_height="match_parent" />



</RelativeLayout>

2.grid_item.xml：

[html] view
plaincopy

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical" >



<ImageView

android:id="@+id/item"

android:layout_width="wrap_content"

android:layout_height="wrap_content" />



</LinearLayout>

3.GridViewAdapter.java:

[java] view
plaincopy

package com.yayun.gridviewdemo;



import java.util.List;



import android.content.Context;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.BaseAdapter;

import android.widget.ImageView;



public class GridViewAdapter extends BaseAdapter {

private Context context;

private List<Integer> list;

LayoutInflater layoutInflater;

private ImageView mImageView;



public GridViewAdapter(Context context, List<Integer> list) {

this.context = context;

this.list = list;

layoutInflater = LayoutInflater.from(context);

}



@Override

public int getCount() {

return list.size()+1;//注意此处

}



@Override

public Object getItem(int position) {

return list.get(position);

}



@Override

public long getItemId(int position) {

return position;

}



@Override

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



convertView = layoutInflater.inflate(R.layout.grid_item, null);

mImageView = (ImageView) convertView.findViewById(R.id.item);

if (position < list.size()) {

mImageView.setBackgroundResource(list.get(position));

}else{

mImageView.setBackgroundResource(R.drawable.pic3);//最后一个显示加号图片

}

return convertView;

}



}

4.MainActivity.java:

[java] view
plaincopy

package com.yayun.gridviewdemo;



import java.util.ArrayList;

import java.util.List;



import android.os.Bundle;

import android.support.v7.app.ActionBarActivity;

import android.view.View;

import android.widget.AdapterView;

import android.widget.AdapterView.OnItemClickListener;

import android.widget.GridView;

import android.widget.Toast;



public class MainActivity extends ActionBarActivity {

private List<Integer> mDatas;

private GridView mGridView;

private GridViewAdapter adapter;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

mGridView=(GridView) findViewById(R.id.gv_test);



initDatas();

adapter=new GridViewAdapter(MainActivity.this,mDatas);

mGridView.setAdapter(adapter);

mGridView.setOnItemClickListener(new OnItemClickListener() {



@Override

public void onItemClick(AdapterView<?> parent, View view,

int position, long id) {

if(position==parent.getChildCount()-1){

mDatas.add(R.drawable.pic1);

Toast.makeText(MainActivity.this, "您点击了添加", 1).show();

adapter=new GridViewAdapter(MainActivity.this, mDatas);

mGridView.setAdapter(adapter);

adapter.notifyDataSetChanged();

}



}

});



}

private void initDatas() {

mDatas=new ArrayList<>();

mDatas.add(R.drawable.pic1);

mDatas.add(R.drawable.pic1);

mDatas.add(R.drawable.pic1);

mDatas.add(R.drawable.pic1);

mDatas.add(R.drawable.pic1);



}





}

5.运行项目：