Android 上千张图片的列表滑动加载

一般项目中图片加载用的比较多的是ImageLoader 但是需求自己配置一些参数 上手有些复杂

对于手机图库中有上千张图片需要加载时 一个使用性能很好的库Glide可以解决 效果图如下

滑动非常流畅 加载速度也很快 而且使用也非常简单 个人感觉比手机自带的图库效果更佳

上图上代码

Code

public class MainActivity extends Activity {
  
  ArrayList fileNames = new ArrayList(); //本地图片路径

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    
    initData();
    
    GridView listView = (GridView) findViewById(R.id.gridview);
    //ImageAdapter imageAdapter = new ImageAdapter(getApplicationContext(),Images.imageUrls);
    ImageAdapter imageAdapter = new ImageAdapter(getApplicationContext(), fileNames);
    
    listView.setAdapter(imageAdapter);
  }

  private void initData() {
    
    fileNames.clear();
    Cursor cursor = getContentResolver().query(Media.EXTERNAL_CONTENT_URI, null, null, null, null);
    while (cursor.moveToNext()) {
      byte[] data = cursor.getBlob(cursor.getColumnIndex(Media.DATA)); //图片的保存位置的数据
      fileNames.add(new String(data, 0, data.length - 1));
    }
  }
  
}

activity_main

<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="com.example.imagelist.MainActivity" >

    <GridView
        android:id="@+id/gridview"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:numColumns="3" 
        android:horizontalSpacing="2dp"
        android:verticalSpacing="2dp"
        >
    GridView>

RelativeLayout>

ImageAdapter

public class ImageAdapter extends BaseAdapter {

  private Context context;
  private String[] imageUrls;
  ArrayList fileNames;
  private LinearLayout.LayoutParams mImageViewLayoutParams;

  /*
   * public ImageAdapter(Context context, String[] imageUrls) { super();
   * this.context = context; this.imageUrls = imageUrls; }
   */

  public ImageAdapter(Context context, ArrayList fileNames) {
    super();
    this.context = context;
    this.fileNames = fileNames;
    
    DisplayMetrics dm = context.getResources().getDisplayMetrics();  
    int wh = dm.widthPixels;

    int w = (wh - context.getResources().getDimensionPixelSize(R.dimen.test) * 2) / 3;
    mImageViewLayoutParams = new LinearLayout.LayoutParams(w, w);
  }

  @Override
  public int getCount() {
    return fileNames.size();
  }

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

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

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

    View view;
    if (convertView == null) {
      view = LayoutInflater.from(context).inflate(R.layout.item, null);
    } else {
      view = convertView;
    }
    ImageView image = (ImageView) view.findViewById(R.id.image);
    image.setLayoutParams(mImageViewLayoutParams);

    Glide.with(context).load(fileNames.get(position)).centerCrop().placeholder(R.color.test).crossFade()
        .into(image);

    return view;

  }
}

item

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:orientation="vertical" >
    
    <ImageView 
        android:id="@+id/image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:scaleType="centerCrop"
        />

LinearLayout>

Demo见github

https://github.com/huanyi0723/ImageList

转载于:https://www.cnblogs.com/huanyi0723/p/4816393.html