Go语言视频零基础入门到精通

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GridView 宫格视图实践
BaseAdapter 与 GridView


①新建工程
②在 res/drawable 目录下添加名称为 a.png---p.png 的图片
③修改 main.xml 布局，添加一个 GridView、一个 ImageView
<?xml version="1.0" encoding="utf-8"?>

<AbsoluteLayout

android:id="@+id/widget0"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

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

<GridView

android:id="@+id/grid"

android:layout_width="fill_parent"

android:padding="30dip"

android:columnWidth="52px"

android:layout_height="210px"

android:numColumns="5">

<!-- GridView设置为五列 边距为30pid-->

</GridView>

<ImageView

android:id="@+id/ImageView_Big"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_x="95px"

android:layout_y="250px">

</ImageView>

</AbsoluteLayout>
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④GridView 的定义与实例化

/*定义类对象*/

private GridView my_gridview;

/*从xml中获取UI资源对象*/

my_gridview = (GridView) findViewById(R.id.grid);
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⑤GridView 的图像内容设置与 ImageAdapter
/*新建一个自定义的ImageAdapter*/

myImageViewAdapter = new ImageAdapter(this);

/*为GridView对象设置一个ImageAdapter*/

my_gridview.setAdapter(myImageViewAdapter);
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⑥内部类 ImageAdapter，实现了 BaseAdapter
private class myImageAdapter extends BaseAdapter{

@Override

public int getCount() {

// TODO Auto-generated method stub

return 0;

}

@Override

public Object getItem(int position) {

// TODO Auto-generated method stub

return null;

}

@Override

public long getItemId(int position) {

// TODO Auto-generated method stub

return 0;

}

@Override

public View getView(int position,

View convertView, ViewGroup parent) {

// TODO Auto-generated method stub

return null;

}

}
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⑦GridView 的图片 Items 点击事件处理
/*为GridView添加图片Items点击事件监听器*/

my_gridview.setOnItemClickListener(this);

@Override

public void onItemClick(AdapterView<?> arg0,

View arg1, int arg2, long arg3) {

// TODO Auto-generated method stub

/*点击GridView中图片Items事件处理*/

}
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⑧GridView 移动后选中图片 Items 的事件处理
/*为GridView添加图片Items移动选中事件监听器*/

my_gridview.setOnItemSelectedListener(this);

@Override

public void onItemSelected(AdapterView<?> arg0,

View arg1, int arg2,long arg3) {



//



TODO Auto-generated method stub



/*GridView中的图片移动焦点选中时事件处理*/

}

/*未选中GridView中的图片Items事件处理*/

@Override

public void onNothingSelected(AdapterView<?> arg0) {

// TODO Auto-generated method stub

}
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⑨修改 mainActivity.java 来实现图片点击和图片移动选中的效果
package zyf.GridViewTest;

/*导入要使用的包*/

import android.app.Activity;

import android.app.AlertDialog;

import android.content.Context;

import android.content.DialogInterface;

import android.content.DialogInterface.OnClickListener;

import android.os.Bundle;

import android.view.View;

import android.view.ViewGroup;

import android.widget.AdapterView;

import android.widget.BaseAdapter;

import android.widget.GridView;

import android.widget.ImageView;

public class GridViewTest extends Activity implements

GridView.OnItemClickListener,

GridView.OnItemSelectedListener {

/** Called when the activity is first created. */

/*定义类对象*/

private GridView my_gridview;

private ImageView big_imageView;

private ImageAdapter myImageViewAdapter;

/*内部类，实现一个图片适配器*/

public class ImageAdapter extends BaseAdapter {

/*myContext为上下文*/

private Context myContext;

/*GridView用来加载图片的ImageView*/

private ImageView the_imageView;



// 这是图片资源ID的数组

private Integer[] mImageIds = {



R.drawable.a, R.drawable.b,R.drawable.c,

R.drawable.e, R.drawable.f,R.drawable.g,

R.drawable.i, R.drawable.j,R.drawable.k,

R.drawable.m, R.drawable.n,R.drawable.o,



R.drawable.d,

R.drawable.h,

R.drawable.l,

R.drawable.p



};

/*构造方法*/

public ImageAdapter(Context myContext) {

// TODO Auto-generated constructor stub

this.myContext = myContext;

/*传入一个Context，本例中传入的是GridViewTest */

}

/*返回资源ID数组长度*/

@Override

public int getCount() {

// TODO Auto-generated method stub

return mImageIds.length;

}

/*得到Item*/

@Override

public Object getItem(int position) {

// TODO Auto-generated method stub

return position;

}

/*获取Items的ID*/

@Override

public long getItemId(int position) {

// TODO Auto-generated method stub

return position;

}

/*获取要显示的View对象*/

@Override

public View getView(int position,

View convertView, ViewGroup parent) {

// TODO Auto-generated method stub

/*创建一个ImageView*/

the_imageView = new ImageView(myContext);

// 设置图像源于资源ID。

the_imageView.setImageResource(mImageIds[position]);

/*使ImageView与边界适应*/

the_imageView.setAdjustViewBounds(true);



/*设置背景图片的风格*/

the_imageView.setBackgroundResource(

android.R.drawable.picture_frame);

/*返回带有多个图片ID的ImageView*/

return the_imageView;

}

/*自定义获取对应位置的图片ID*/

public Integer getcheckedImageIDPostion(int theindex) {

return mImageIds[theindex];

}

}

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

/*设置主屏布局*/

setContentView(R.layout.main);

/*从xml中获取UI资源对象*/

my_gridview = (GridView) findViewById(R.id.grid);

big_imageView =

(ImageView) findViewById(R.id.ImageView_Big);

/*新建一个自定义的ImageAdapter*/

myImageViewAdapter = new ImageAdapter(this);

/*为GridView对象设置一个ImageAdapter*/

my_gridview.setAdapter(myImageViewAdapter);

/*为GridView添加图片Items点击事件监听器*/

my_gridview.setOnItemClickListener(this);

/*为GridView添加图片Items移动选中事件监听器*/

my_gridview.setOnItemSelectedListener(this);

}

@Override

public void onItemClick(AdapterView<?> arg0,

View arg1, int arg2, long arg3) {

/*点击GridView中图片Items后显示一个AlterDialog提示框*/

new AlertDialog.Builder(this)

.setTitle("图片浏览")

/*获得对应的图片并显示*/

.setIcon(myImageViewAdapter.getcheckedImageIDPostion(arg2))

/*添加一个按钮*/

.setPositiveButton("返回", new OnClickListener() {

@Override

public void onClick(DialogInterface dialog,

int which) {

}

/*显示提示框*/



}).show();

}

@Override

public void onItemSelected(AdapterView<?> arg0,

View arg1, int arg2,long arg3) {

// TODO Auto-generated method stub

/*GridView中的图片移动焦点选中时，

*下面的大图ImageView显示相应的大图片*/

big_imageView.setImageResource(myImageViewAdapter

.getcheckedImageIDPostion(arg2));

}

/*未选中GridView中的图片Items事件处理*/

@Override

public void onNothingSelected(AdapterView<?> arg0) {

// TODO Auto-generated method stub

}

}
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结果：