Android布局之GridView使用展示

<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"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.android_gridview.MainActivity" >

<GridView
android:id="@+id/gridview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:columnWidth="90dp"
android:gravity="center"
android:horizontalSpacing="10dp"
android:numColumns="auto_fit"
android:stretchMode="columnWidth"
android:verticalSpacing="10dp"
/>

</RelativeLayout>

package com.example.android_gridview;

import android.support.v7.app.ActionBarActivity;
import android.app.ActionBar.LayoutParams;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.Toast;

public class MainActivity extends ActionBarActivity {

private GridView gridView;
private ImageAdapter imageAdapter;//自定义的适配器

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
gridView = (GridView) this.findViewById(R.id.gridview);

// 需要设置适配器，所以声明一个适配器，供使用
imageAdapter=new ImageAdapter();
gridView.setAdapter(imageAdapter);
gridView.setOnItemClickListener(new OnItemClickListener() {

@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
// TODO Auto-generated method stub
Toast.makeText(MainActivity.this, "点击了"+position, 1).show();
}
});

}

//图片资源，还可以用异步任务下载图片，放到此处
private int[] images = { R.drawable.p1, R.drawable.p2, R.drawable.p3,
R.drawable.p4, R.drawable.p5, R.drawable.p6, R.drawable.p7,
R.drawable.p8 };

// 声明一个适配器
public class ImageAdapter extends BaseAdapter {

public ImageAdapter() {
// TODO Auto-generated constructor stub
}

@Override
public int getCount() {
// TODO Auto-generated method stub
return images.length;
}

@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return images[position];
}

@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}

/**
* 在这里面重绘布局，有两种方法：
* 第一种，一般控件比较简单的就手工创建View的对象，第二种，图文混排，美化布局就要加载XML文件
*/
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
ImageView imageView=null;
if(convertView==null){
imageView=new ImageView(MainActivity.this);
}else{
imageView=(ImageView) convertView;
}
/**
* 设置GridView的显示的格子的间距
*
*/
//这句话写错，会出现闪退的情况，LayoutParams(100,100)里面的参数是设置图片在布局中显示的大小
imageView.setLayoutParams(new GridView.LayoutParams(200,200));
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
imageView.setPadding(8, 8, 8, 8);
//加载图片的三种方式：drawable，BitMap，从资源文件中取
imageView.setImageResource(images[position]);
return imageView;
}

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}