Gallery与ImageSwitcher的图片显示

来源：互联网发布：mac打开app store很慢编辑：程序博客网时间：2024/05/22 03:15

一、Gallery图片显示

1、在activity_main.xml中正常定义一个Gallery:

<Gallery
        android:id="@+id/gallery"
        android:layout_height="200dp"
        android:layout_width="200dp"
        />
2、在drawable_hdpi中添加图片准备；

3、在MainActivity.java中实现：
package com.example.gallerytest;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.ViewSwitcher.ViewFactory;

public class MainActivity extends Activity{
    int[] pics ={
           R.drawable.pic1,
           R.drawable.pic2,
           R.drawable.pic3,
           R.drawable.pic4,
           R.drawable.pic5,
           R.drawable.pic6,
           R.drawable.pic7,
           R.drawable.pic1,
    };
   @Override
   protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_main);
       Gallery gallery = (Gallery)findViewById(R.id.gallery);
       MyAdapter adapter = new MyAdapter(MainActivity.this);
       gallery.setAdapter(adapter);



   @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;
   }

   private class MyAdapter extends BaseAdapter{
       Context c;

       public MyAdapter(Context c){
           this.c = c;
       }
       @Override
       public int getCount() {
           // TODO Auto-generated method stub
           return pics.length;
       }

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

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

       @Override
       public View getView(int position, View convertView, ViewGroup parent) {
           // TODO Auto-generated method stub
           ImageView view = null;
           if(convertView!=null){
               view = (ImageView) convertView;
           }else{
               view = new ImageView(c);
               view.setImageResource(pics[position]);
               view.setScaleType(ImageView.ScaleType.CENTER);
               view.setLayoutParams(new Gallery.LayoutParams(200,200));
           }
           return view;
       }

   }

}

二、Gallery与ImageSwitcher结合显示图片

1、在activity_main.xml中正常定义一个Gallery:

    <Gallery
        android:id="@+id/gallery"
        android:layout_height="200dp"
        android:layout_width="200dp"
        />

    <ImageSwitcher
         android:id="@+id/switcher"
        android:layout_height="200dp"
        android:layout_width="200dp"
        />
2、在drawable_hdpi中添加图片准备；

3、Activity实现ViewFactory,即：implements ViewFactory;

4、在MainActivity.java中实现：
package com.example.gallerytest;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.ViewSwitcher.ViewFactory;

public class MainActivity extends Activity implements ViewFactory{
    int[] pics ={
           R.drawable.pic1,
           R.drawable.pic2,
           R.drawable.pic3,
           R.drawable.pic4,
           R.drawable.pic5,
           R.drawable.pic6,
           R.drawable.pic7,
           R.drawable.pic1,
    };
   @Override
   protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_main);
       Gallery gallery = (Gallery)findViewById(R.id.gallery);
       MyAdapter adapter = new MyAdapter(MainActivity.this);
       gallery.setAdapter(adapter);
       final ImageSwitcher switcher = (ImageSwitcher)findViewById(R.id.switcher);
       Log.d("test","switcher="+switcher);
       switcher.setFactory(this);

       gallery.setOnItemSelectedListener(new OnItemSelectedListener() {

           @Override
           public void onItemSelected(AdapterView<?> arg0, View arg1,
                   int arg2, long arg3) {
               // TODO Auto-generated method stub
               Log.d("test","position="+arg2);
               Log.d("test","switcher="+switcher);
               switcher.setImageResource(pics[arg2]);
           }

           @Override
           public void onNothingSelected(AdapterView<?> arg0) {
               // TODO Auto-generated method stub

           }
       });
   }

   @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;
   }

   private class MyAdapter extends BaseAdapter{
       Context c;
       //初始化成员变量
       //构建一个对象
       //构造方法被调用一定会创建新的对象吗？不一定   通过继承来回答
       //任何一个类的间接父类是Object ？
       //任何一个类在创建对象时是否会调用父类的构造方法？
       //调用父类的构造方法是否创建了父类的对象？
       //如果创建了父类的对象违背了什么原则？
       //如果没有创建父类对象那么构造方法调用一定会创建对象吗？
       //一定？不一定？
       public MyAdapter(Context c){
           this.c = c;
       }
       @Override
       public int getCount() {
           // TODO Auto-generated method stub
           return pics.length;
       }

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

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

       @Override
       public View getView(int position, View convertView, ViewGroup parent) {
           // TODO Auto-generated method stub
           ImageView view = null;
           if(convertView!=null){
               view = (ImageView) convertView;
           }else{
               view = new ImageView(c);
               view.setImageResource(pics[position]);
               view.setScaleType(ImageView.ScaleType.CENTER);
               view.setLayoutParams(new Gallery.LayoutParams(200,200));
           }
           return view;
       }

   }

   @Override
   public View makeView() {
       // TODO Auto-generated method stub
       ImageView view = null;
       view = new ImageView(MainActivity.this);
       //view.setImageResource(pics[position]);
       view.setScaleType(ImageView.ScaleType.CENTER);
       view.setLayoutParams(new ImageSwitcher.LayoutParams(200,200));
       Log.d("test","view="+view);
       return view;
   }

}

0 0