关于gridview水平居中，平均布局

首先是布局

activity_main.xml

gridview的padding可以通过在外边嵌套一层布局添加 paddinng，例如：LinearLayout。

gridview的父控件也必须用match_parrent,  gridview必须用 match_parent,才能获得它的实际宽高

<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"    tools:context="${relativePackage}.${activityClass}" >    <LinearLayout        android:id="@+id/linearLayout"        android:layout_width="match_parent"        android:layout_height="60dp"        android:layout_alignParentBottom="true"        android:layout_alignParentLeft="true"        android:background="#999999"        android:orientation="horizontal" >    </LinearLayout>    <LinearLayout        android:layout_width="match_parent"        android:layout_height="match_parent"        android:layout_above="@+id/linearLayout"        android:orientation="horizontal"        android:paddingLeft="20dp"         android:paddingRight="20dp"         android:paddingTop="25dp"         android:paddingBottom="25dp"                 >        <GridView            android:id="@+id/gridView1"            android:layout_width="match_parent"            android:layout_height="match_parent"            android:background="#666666"            android:numColumns="4"            android:scrollbars="none" >        </GridView>    </LinearLayout></RelativeLayout>

griditem_app.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:gravity="center"    android:orientation="vertical" >    <ImageView        android:id="@+id/imageView1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:src="@drawable/ic_launcher" />    <TextView        android:id="@+id/textView1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="TextView" /></LinearLayout>

2 GridViewAdapter.java

package com.example.gridviewtest;import android.annotation.SuppressLint;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;public class GridViewAdapter extends BaseAdapter {private int itemWidth = 0;private int count = 3;@Overridepublic int getCount() {return count;}public void setCount(int count) {this.count = count;}public void setItemHeight(int itemWidth) {this.itemWidth = itemWidth;}@Overridepublic Object getItem(int position) {return null;}@Overridepublic long getItemId(int position) {return 0;}@SuppressLint("InflateParams")@Overridepublic View getView(int position, View convertView, ViewGroup parent) {if (convertView == null) {LayoutInflater inflater = LayoutInflater.from(parent.getContext());convertView = inflater.inflate(R.layout.griditem_app, null);}

//从外部传进来计算好的item 高度进行设置convertView.setMinimumHeight(itemWidth);return convertView;}}

MainActivity.java

package com.example.gridviewtest;import android.app.Activity;import android.os.Bundle;import android.util.DisplayMetrics;import android.widget.GridView;public class MainActivity extends Activity {private GridView gridview;private GridViewAdapter adapter;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);gridview = (GridView) findViewById(R.id.gridView1);

//获得手机密度DisplayMetrics dm = new DisplayMetrics();getWindowManager().getDefaultDisplay().getMetrics(dm);final float denScale = (float) dm.densityDpi / (float) DisplayMetrics.DENSITY_DEFAULT;adapter = new GridViewAdapter();

//在主线程绘图渲染的时候计算gridview宽高gridview.post(new Runnable() {@Overridepublic void run() {int width = gridview.getMeasuredWidth();int height = gridview.getMeasuredHeight();int itemWidth = (int) (denScale * 80);

//计算一行能容纳的item个数int count = width / itemWidth;

//设置一行能放下的item个数gridview.setNumColumns(count);

//计算gridview可见高度所能容纳的item行数int rowCount = height / itemWidth;

//设置item高度adapter.setItemHeight((int) ((float) height / (float) rowCount));adapter.setCount(count * rowCount-9);gridview.setAdapter(adapter);}});}}

效果图