Gallery控件学习

自我认识：Gallery就是我们手机中经常用的相册的意思，用这个空间可以通过左右滑动显示图片

首先附上学习Gallery时候的目录列表，下面会详细附上各部分的代码

运行结果如下图：

下面是详细的代码部分,还是按照布局文件-Java代码-manifests这个顺序

activity_main.xml代码

说明：这里面仍用的是自己创建项目 时候的相对布局，里面只有一个Gallery控件

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

    <Gallery
        android:id="@+id/gallery_id"
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:unselectedAlpha="0.5"
        android:spacing="20dp"
        android:gravity="center_horizontal"
        ></Gallery>

</RelativeLayout>

grideviewtest.xml代码

说明：线性布局嵌套线性布局，里面的线性布局里面放一个ImageView和TextView。。。主体线性布局有一个10dp的padding.

<?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:padding="10dp"
    android:orientation="vertical" >

    <LinearLayout

        android:id="@+id/linearlayout_id"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        >

         <ImageView
        android:id="@+id/image_grideview"
        android:layout_width="80dp"
        android:layout_height="80dp"

        />
    <TextView 
        android:id="@+id/text_fruitname"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="水果名字"
        android:layout_gravity="center_horizontal"

        />

    </LinearLayout>



</LinearLayout>

MyGalleryViewAdapter.java中的代码

说明：MyGalleryViewAdapter仍然是继承自BaseAdaper,这里使用的都是效率最高的、最节约内存的ViewHolder

package com.example.administrator.mygallery.adapter;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;


import com.example.administrator.mygallery.R;
import com.example.administrator.mygallery.model.Fruit;

import java.util.List;

public class MyGalleryViewAdapter extends BaseAdapter{

    private List<Fruit> mFruit;
    private LayoutInflater inflater;


    public MyGalleryViewAdapter(List<Fruit> mFruit, LayoutInflater inflater)
    {
            this.mFruit=mFruit;
            this.inflater=inflater;
    }


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

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

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

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

        ViewHolder viewHolder=null;
        if(convertView==null)
        {
            convertView=inflater.inflate(R.layout.grideviewtest, null);
            viewHolder=new ViewHolder();
            viewHolder.imageView = (ImageView) convertView.findViewById(R.id.image_grideview);
            viewHolder.textView=(TextView) convertView.findViewById(R.id.text_fruitname);

            convertView.setTag(viewHolder);
        }else
        {
            viewHolder=(ViewHolder)convertView.getTag();
        }

        Fruit fruit=mFruit.get(position);
        viewHolder.imageView.setImageResource(fruit.getImg());
        viewHolder.textView.setText(fruit.getName());

        return convertView;
    }

        class   ViewHolder
        {
            ImageView imageView;
            TextView textView;
        }

}

Fruit.java中的代码：

说明：就是一个简单的类，里面有两个属性，添加上get和set方法，还有构造方法

package com.example.administrator.mygallery.model;

public class Fruit {
    private String name;
    private int img;

    public Fruit(String name, int img)
    {
        this.name = name;
        this.img = img;
    }

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getImg() {
        return img;
    }
    public void setImg(int img) {
        this.img = img;
    }

}

MainActivity中的代码。。这是项目最重要的代码部分

说明：私有化本类中用到的属性，利用MyGalleryViewAdapter.java的构造方法生成一个adapter。

package com.example.administrator.mygallery;

import android.app.Activity;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Gallery;
import android.widget.GridView;

import com.example.administrator.mygallery.adapter.MyGalleryViewAdapter;
import com.example.administrator.mygallery.model.Fruit;

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

public class MainActivity extends Activity {
    private Gallery gallery;
    private List<Fruit> mFruit;
    private LayoutInflater inflater;
    private MyGalleryViewAdapter adapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        gallery=(Gallery) findViewById(R.id.gallery_id);
        inflater=getLayoutInflater();
        ininFruit();
        adapter=new MyGalleryViewAdapter(mFruit, inflater);
        gallery.setAdapter(adapter);
    }
    public List<Fruit> ininFruit()
    {
        mFruit = new ArrayList<Fruit>();


        for (int i = 0; i < 5; i++) {

            Fruit fish = new Fruit("鱼", R.mipmap.fish);
            Fruit jellyfish = new Fruit("jelly鱼", R.mipmap.jelly_fish);
            Fruit kbugbuster = new Fruit("kbugbuster", R.mipmap.kbugbuster);
            Fruit penguin = new Fruit("penguin", R.mipmap.penguin);
            Fruit pig = new Fruit("penguin", R.mipmap.penguin);
            Fruit poweranimal = new Fruit("poweranimal", R.mipmap.power_animal);

            mFruit.add(fish);
            mFruit.add(jellyfish);
            mFruit.add(kbugbuster);
            mFruit.add(penguin);
            mFruit.add(pig);
            mFruit.add(poweranimal);


        }



        return mFruit;

    }

}

AndroidManifest.xml代码如下：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.administrator.mygallery" >

    <application
        android:allowBackup="true"
        android:icon="@mipmap/album"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

总结：
学习Gallery控件，没有什么难的，就是生成一个adapter，这个才是项目的难点。

说明：

项目中用到的图片在这里就不添加了。