android平台仿pinterest瀑布流展现方式实现

package com.cascade; import java.io.IOException; import java.util.Arrays; import java.util.List; import android.app.Activity; import android.content.Context; import android.content.res.AssetManager; import android.graphics.drawable.Drawable; import android.os.Bundle; import android.util.Log; import android.view.Display; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.view.ViewGroup.LayoutParams; import android.widget.BaseAdapter; import android.widget.ImageView; import android.widget.LinearLayout; import android.widget.ListView; import com.cascade.DrawableManager.ImageCallback; public class TestCascadeActivity extends Activity { private static final String TAG = "TestCascadeActivity"; private LinearLayout llCcasecade; private LinearLayout lvCasecade1; private LinearLayout lvCasecade2; private LinearLayout lvCasecade3; private Display display; private AssetManager assetManager; private List<String> iamgePaths; private static final String imgspath = "imgs"; private int casecadeWidth; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); display = this.getWindowManager().getDefaultDisplay(); casecadeWidth = display.getWidth()/3; assetManager = this.getAssets(); findView(); } private void findView(){ llCcasecade = (LinearLayout)this.findViewById(R.id.llCcasecade); lvCasecade1 = (LinearLayout)this.findViewById(R.id.casecade1); lvCasecade2 = (LinearLayout)this.findViewById(R.id.casecade2); lvCasecade3 = (LinearLayout)this.findViewById(R.id.casecade3); LayoutParams lp1 = lvCasecade1.getLayoutParams(); lp1.width = casecadeWidth; lvCasecade1.setLayoutParams(lp1); LayoutParams lp2 = lvCasecade2.getLayoutParams(); lp2.width = casecadeWidth; lvCasecade2.setLayoutParams(lp2); LayoutParams lp3 = lvCasecade3.getLayoutParams(); lp3.width = casecadeWidth; lvCasecade3.setLayoutParams(lp3); try { iamgePaths = Arrays.asList(assetManager.list("imgs")); } catch (IOException e) { e.printStackTrace(); } int j = 0; for (int i = 0; i < iamgePaths.size(); i++) { addImgToCasecade(iamgePaths.get(i), j); j++; if(j>=3) j = 0; } } private void addImgToCasecade(String filename,int j){ ImageView iv = (ImageView)LayoutInflater.from(this).inflate(R.layout.item, null); if(j==0){ lvCasecade1.addView(iv); }else if(j==1){ lvCasecade2.addView(iv); }else{ lvCasecade3.addView(iv); } String imgPath = imgspath+"/"+filename; iv.setTag(imgPath); Drawable drawable = DrawableManager.getInstance().fetchDrawableOnThread(imgPath, assetManager, new ImageCallback() { @Override public void imageLoaded(Drawable imageDrawable, String imageUrl) { ImageView iv = (ImageView)llCcasecade.findViewWithTag(imageUrl); if(iv!=null && imageDrawable!=null){ int oldwidth = imageDrawable.getIntrinsicWidth(); int oldheight = imageDrawable.getIntrinsicHeight(); LayoutParams lp = iv.getLayoutParams(); lp.height = (oldheight * casecadeWidth)/oldwidth; iv.setPadding(0, 2, 0, 0); iv.setLayoutParams(lp); iv.setImageDrawable(imageDrawable); } } }); if(drawable!=null){ int oldwidth = drawable.getIntrinsicWidth(); int oldheight = drawable.getIntrinsicHeight(); LayoutParams lp = iv.getLayoutParams(); lp.height = (oldheight * casecadeWidth)/oldwidth; iv.setPadding(0, 2, 0, 0); iv.setLayoutParams(lp); iv.setImageDrawable(drawable); } } }