Android左右滑动切换图片

ImageUtils.java:

 

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Environment;
import android.util.Log;
import android.widget.ImageView;

/**  
 * @ClassName: ImageUtils  
 * @Description: 处理图片的工具类 
 * @author chenzheng
 * @date 2014-4-17 下午3:11:08  
 */
public class ImageUtils {

  /**
   * 图片基准路径
   */
  private static final String BASE_SDCARD_IMAGES = "/mnt/sdcard/weijie/images/";

  private static final String TAG = "ImageUtils";

  /**
   * 判断文件是否存在
   *
   * @param 文件在本地的完整名
   * @return
   */
  private static boolean judgeExists(String fullName) {

    File file = new File(fullName);

    return file.exists();
  }

  /**
   * 获取最后的‘/’后的文件名
   *
   * @param name
   * @return
   */
  private static String getLastName(String name) {
    int lastIndexOf = 0;
    try {
      lastIndexOf = name.lastIndexOf('/');
    } catch (Exception e) {
      e.printStackTrace();
    }
    return !name.equals("") ? name.substring(lastIndexOf + 1) : "";
  }

  /**
   * 拼接一个完整的本地文件名
   * @param 文件的网络路径
   * @return
   */
  private static String getImageFullName(String name) {
    return BASE_SDCARD_IMAGES + getLastName(name);
  }

  /**
   * 通过该网络路径获取Bitmap
   * @param 该图片的网络路径
   */
  public static Bitmap getBitmap(String urlPath) {

    Bitmap bitmap = null;
    String fullName = getImageFullName(urlPath);
    if (ImageUtils.judgeExists(fullName)) {
      /* 存在就直接使用 */
      Log.i(TAG, "使用了sdcard里的图片");
      bitmap = BitmapFactory.decodeFile(fullName);
    } else {
      /* 去下载图片,下载完成之后返回该对象 */
      Log.i(TAG, "去下载了图片");
      bitmap = downloadAndSaveBitmap(urlPath, fullName);
    }
    return bitmap;
  }

  /**
   * 下载保存图片
   *
   * @param urlPath
   *            下载路径
   * @param fullName
   *            文件保存路径+文件名
   * @return
   */
  private static Bitmap downloadAndSaveBitmap(String urlPath, String fullName) {

    Bitmap bitmap = downloadImage(urlPath);

    /* 首先判断是否挂载了sdcard */
    if (Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {

      if (bitmap != null) {

        saveBitmap(fullName, bitmap);

      }
    } else {
      Log.e(TAG, "没有sdcard无法保存图片");
    }

    return bitmap;
  }

  /**
   * 保存图片
   *
   * @param fullName
   * @param bitmap
   */
  private static void saveBitmap(String fullName, Bitmap bitmap) {

    if (bitmap != null) {

      try {
        File file = new File(fullName);
        if (!file.exists()) {
          creatFolder(fullName);
          file.createNewFile();
        }
        FileOutputStream fos = new FileOutputStream(file);
        bitmap.compress(Bitmap.CompressFormat.PNG, 100, fos);
        fos.flush();
      } catch (IOException e) {
        e.printStackTrace();
        Log.e(TAG, "图片保存失败，异常信息是：" + e.toString());
      }
    } else {
      Log.e(TAG, "没有下载成功图片，无法保存");
    }
  }

  /**
   * 创建保存文件的文件夹
   *
   * @param fullName
   *            带文件名的文件路径
   * @return
   */
  private static void creatFolder(String fullName) {
    if (getLastName(fullName).contains(".")) {
      String newFilePath = fullName.substring(0, fullName
          .lastIndexOf('/'));
      File file = new File(newFilePath);
      file.mkdirs();
    }
  }

  /**
   * 下载图片
   *
   * @param urlPath
   * @return
   */
  private static Bitmap downloadImage(String urlPath) {

    try {
      byte[] byteData = getImageByte(urlPath);
      if (byteData == null) {
        Log.e(TAG, "没有得到图片的byte，问题可能是path：" + urlPath);
        return null;
      }
      int len = byteData.length;

      BitmapFactory.Options options = new BitmapFactory.Options();
      options.inPreferredConfig = Bitmap.Config.RGB_565;
      options.inPurgeable = true;
      options.inInputShareable = true;
      options.inJustDecodeBounds = false;
      if (len > 200000) {// 大于200K的进行压缩处理
        options.inSampleSize = 2;
      }

      return BitmapFactory.decodeByteArray(byteData, 0, len);
    } catch (Exception e) {
      e.printStackTrace();
      Log.e(TAG, "图片下载失败，异常信息是：" + e.toString());
      return null;
    }
  }

  /**
   * 获取图片的byte数组
   *
   * @param urlPath
   * @return
   */
  private static byte[] getImageByte(String urlPath) {
    InputStream in = null;
    byte[] result = null;
    try {
      URL url = new URL(urlPath);
      HttpURLConnection httpURLconnection = (HttpURLConnection) url
          .openConnection();
      httpURLconnection.setDoInput(true);
      httpURLconnection.connect();
      if (httpURLconnection.getResponseCode() == 200) {
        in = httpURLconnection.getInputStream();
        result = readInputStream(in);
        in.close();
      } else {
        Log
            .e(TAG, "下载图片失败，状态码是："
                + httpURLconnection.getResponseCode());
      }
    } catch (Exception e) {
      Log.e(TAG, "下载图片失败，原因是：" + e.toString());
      e.printStackTrace();
    } finally {
      if (in != null) {
        try {
          in.close();
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
    }
    return result;
  }

  /**
   * 将输入流转为byte数组
   *
   * @param in
   * @return
   * @throws Exception
   */
  private static byte[] readInputStream(InputStream in) throws Exception {

    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    byte[] buffer = new byte[1024];
    int len = -1;
    while ((len = in.read(buffer)) != -1) {
      baos.write(buffer, 0, len);
    }
    baos.close();
    in.close();
    return baos.toByteArray();

  }

  /**
   * 此方法用来异步加载图片
   * @param imageview
   * @param path
   */
  public static void downloadAsyncTask(final ImageView imageview,
      final String path) {
    new AsyncTask<String, Void, Bitmap>() {

      @Override
      protected Bitmap doInBackground(String... params) {
        return getBitmap(path);
      }

      @Override
      protected void onPostExecute(Bitmap result) {
        super.onPostExecute(result);
        if (result != null && imageview != null) {
          imageview.setImageBitmap(result);
        } else {
          Log.e(TAG, "在downloadAsyncTask里异步加载图片失败！");
        }
      }

    }.execute(new String[] {});

  }

}

 

 

 

 

 

ProductDetailIndex.java:

 

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

import android.app.Activity;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.os.Parcelable;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.view.View;
import android.widget.ImageView;
import android.widget.ImageView.ScaleType;

import com.weijie.app_user.R;
import com.weijie.app_user.utility.ImageUtils;

public class ProductDetailIndex extends Activity {

  private ViewPager viewPager; // android-support-v4中的滑动组件
  private int default_bg=R.drawable.a;
  private List<ImageView> imageViews; // 滑动的图片集合

  private String[] imageResUrl; // 图片url
  private List<ImageView> dots; // 图片标题正文的那些点

  private int currentItem = 0; // 当前图片的索引号

  private Handler handler = new Handler() {

    public void handleMessage(android.os.Message msg) {

      if (msg.what == 0) {
        @SuppressWarnings("unchecked")
        List<Bitmap> bmList=(List<Bitmap>) msg.obj;
        for(int i=0;i<bmList.size();i++){
          Bitmap bitmap=bmList.get(i);
          ImageView imageView = new ImageView(getApplicationContext());
          if (bitmap != null) {
            imageView.setImageBitmap(bitmap);
          } else {
            imageView.setImageResource(default_bg);
          }
          imageView.setScaleType(ScaleType.CENTER_CROP);
          imageViews.add(imageView);
        }
        
        viewPager = (ViewPager) findViewById(R.id.img_viewpager);
        viewPager.setAdapter(new MyPagerAdapter());// 设置填充ViewPager页面的适配器
        // 设置一个监听器，当ViewPager中的页面改变时调用
        viewPager.setOnPageChangeListener(new MyPageChangeListener());
      }
    };

  };

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.product_detail_index);
    
    imageViews = new ArrayList<ImageView>();
    
    new Thread() {

      @SuppressWarnings("unchecked")
      public void run() {
        List<Bitmap> bitmapList = new ArrayList<Bitmap>();
        Message msg = new Message();
        Bitmap bitmap=null;
        imageResUrl = new String[] {
            "http://imgt8.bdstatic.com/it/u=2,1200870009&fm=19&gp=0.jpg",
            "http://imgt3.bdstatic.com/it/u=2483720495,3389680904&fm=21&gp=0.jpg",
            "http://imgt6.bdstatic.com/it/u=2,936516090&fm=19&gp=0.jpg" };
        for (int i = 0; i < imageResUrl.length; i++) {
          bitmap=ImageUtils.getBitmap(imageResUrl[i]);
          bitmapList.add(bitmap);
          
        }
        msg.what = 0;
        msg.obj = bitmapList;
        handler.sendMessage(msg);
      }

    }.start();
    
    dots = new ArrayList<ImageView>();  
        dots.add((ImageView) findViewById(R.id.v_dot1));  
        dots.add((ImageView) findViewById(R.id.v_dot2));  
        dots.add((ImageView) findViewById(R.id.v_dot3)); 
        dots.get(currentItem).setImageResource(R.drawable.orange_btn); 
  }



  /**
   * 填充ViewPager页面的适配器
   * 
   * @author Administrator
   * 
   */
  private class MyPagerAdapter extends PagerAdapter {

    @Override
    public int getCount() {
      return imageResUrl.length;
    }

    @Override
    public Object instantiateItem(View arg0, int arg1) {
      ((ViewPager) arg0).addView(imageViews.get(arg1));
      return imageViews.get(arg1);
    }

    @Override
    public void destroyItem(View arg0, int arg1, Object arg2) {
      ((ViewPager) arg0).removeView((View) arg2);
    }

    @Override
    public boolean isViewFromObject(View arg0, Object arg1) {
      return arg0 == arg1;
    }

    @Override
    public void restoreState(Parcelable arg0, ClassLoader arg1) {

    }

    @Override
    public Parcelable saveState() {
      return null;
    }

    @Override
    public void startUpdate(View arg0) {

    }

    @Override
    public void finishUpdate(View arg0) {

    }
  }

  /**
   * 当ViewPager中页面的状态发生改变时调用
   * 
   * @author Administrator
   * 
   */
  private class MyPageChangeListener implements OnPageChangeListener {
    private int oldPosition = 0;

    public void onPageSelected(int position) {
      currentItem = position;
      dots.get(oldPosition).setImageResource(R.drawable.white_btn);  
            dots.get(position).setImageResource(R.drawable.orange_btn); 
      oldPosition = position;
    }

    public void onPageScrollStateChanged(int arg0) {

    }

    public void onPageScrolled(int arg0, float arg1, int arg2) {

    }
  }

}

 

 

 

 

 

product_detail_index.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="@color/white"
    android:orientation="vertical" >

    <RelativeLayout
        android:layout_width="fill_parent"
        android:layout_height="50dp"
        android:background="@color/orange"
        android:orientation="horizontal" >

        <ImageView
            android:id="@+id/header_back"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerVertical="true"
            android:layout_marginLeft="10dp"
            android:src="@drawable/reg_back" />
        <!-- 商品详情 -->

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerVertical="true"
            android:layout_marginLeft="10dp"
            android:layout_toRightOf="@id/header_back"
            android:text="商品详情"
            android:textColor="@color/white"
            android:textSize="24sp" />

        <ImageView
            android:id="@+id/three_dot"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentRight="true"
            android:layout_centerVertical="true"
            android:layout_marginLeft="15dp"
            android:layout_marginRight="10dp"
            android:src="@drawable/shop_threedot" />

        <LinearLayout
            android:id="@+id/goods_share"
            android:layout_width="wrap_content"
            android:layout_height="fill_parent"
            android:layout_toLeftOf="@id/three_dot"
            android:gravity="center"
            android:orientation="vertical" >

            <ImageView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:src="@drawable/goods_share" />

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="分享"
                android:textColor="@color/white"
                android:textSize="14sp" />
        </LinearLayout>
    </RelativeLayout>

    <FrameLayout
        android:layout_width="fill_parent"
        android:layout_height="240dp" >

        <android.support.v4.view.ViewPager
            android:id="@+id/img_viewpager"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent" />

        <LinearLayout
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:gravity="center_horizontal"
            android:layout_gravity="bottom"  
            android:layout_marginBottom="8dp"
            android:orientation="horizontal" >
            <ImageView
                android:id="@+id/v_dot1"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:src="@drawable/white_btn" />
            <ImageView
                android:id="@+id/v_dot2"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginLeft="15dp"
                android:layout_marginRight="15dp"
                android:src="@drawable/white_btn" />
            <ImageView
                android:id="@+id/v_dot3"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:src="@drawable/white_btn" />
        </LinearLayout>
    </FrameLayout>

</LinearLayout>