Android初级教程_图片混排效果和ViewPager的使用

前段时间公司需要实现图片混排的效果,类似"美丽说"那样,宽度一样,高度不一.总共有3列.每次加载更多的时候都是往最低的那列添加图片,这样就不会出现有的列非常多的图片,而有的列图片很少.首先申明的是这个例子是根据别人的程序基础上改的:https://github.com/dodola/android_waterfall再次感谢.!
效果如下图所示:



当滑倒底部的时候如果还有图片则自动加载下一页.

代码实现如下:

首先自定义布局:

[java]
view plaincopy

public class MyLinearLayout extends LinearLayout {

private Map<Integer, Integer> map;
private ArrayList<LinearLayout> waterfall_items;
private Context context;
private Display display;
private int itemWidth;

public MyLinearLayout(Context context, AttributeSet attrs) {
super(context, attrs);
}
public MyLinearLayout(Context context) {
super(context);
}

/**
* 初始化容器
* @param columnCount
* 列数
* @param paddingLeft
* @param paddingTop
* @param paddingRight
* @param paddingBottom
*/
public void initLayout(int columnCount, int paddingLeft, int paddingTop,
int paddingRight, int paddingBottom) {

if (columnCount < 1)
columnCount = 3;

Constans.COLUMN_COUNT = columnCount;

waterfall_items = new ArrayList<LinearLayout>();
map = new HashMap<Integer, Integer>();
for (int i = 0; i < columnCount; i++) {
map.put(i, 0);
}
context = getContext();
WindowManager windowManager = (WindowManager) context
.getSystemService(Context.WINDOW_SERVICE);
display = windowManager.getDefaultDisplay();
itemWidth = display.getWidth() / columnCount;// 根据屏幕大小计算每列大小
for (int i = 0; i < columnCount; i++) {
LinearLayout itemLayout = new LinearLayout(context);
LinearLayout.LayoutParams itemParam = new LinearLayout.LayoutParams(
itemWidth, LayoutParams.WRAP_CONTENT);
itemLayout.setPadding(1, 2, 1, 2);
itemLayout.setOrientation(LinearLayout.VERTICAL);
itemLayout.setLayoutParams(itemParam);
waterfall_items.add(itemLayout);
this.addView(itemLayout);
}
}
/**
* 贴图
* @param article 文章实体
* @param columnIndex 列索引
*/
private void addImage(final Article article, int columnIndex) {
ImageView item = (ImageView) LayoutInflater.from(context).inflate(
R.layout.waterfallitem, null);
waterfall_items.get(columnIndex).addView(item);
//int inSampleSize = 1;
int h = 0;
// int originalWidth = article.getWidth();
int originalHieght = article.getHeight();
//
// int screenHeight = display.getHeight() / 7;
// int screenWidth = display.getWidth() / 7;
// float heightRatio = (float) Math.ceil(article.getHeight()
// / screenHeight);
// float widthRatio = (float) (Math.ceil(originalWidth / screenWidth));
// if (heightRatio >= 1 && widthRatio >= 1) {
// if (heightRatio > widthRatio) {
// inSampleSize = (int) heightRatio;
// } else {
// inSampleSize = (int) widthRatio;
// }
// h = originalHieght;// inSampleSize;
// } else {
// h = originalHieght;
// }
h = originalHieght;
int value = map.get(columnIndex);
map.put(columnIndex, value+h);

TaskParam param = new TaskParam();
param.setItemWidth(itemWidth);
Bitmap defaultImage = BitmapFactory.decodeResource(getResources(),
R.drawable.loading);
ImageLoaderTask task = new ImageLoaderTask(item, display,
article.getImage(), article, defaultImage, param);
task.execute(param);
item.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent();
intent.setClassName(context.getPackageName(),
GirlDetailActivity.class.getName());
intent.putExtra("id", article.getId());
context.startActivity(intent);
}
});


}

/**
* 把图片集合填充到容器里
* @param articles
*/
public void setAdapter(List<Article> articles) {
for (int i = 0; i < articles.size(); i++) {
Article article = articles.get(i);
addImage(article, getLowestColumn());
}
}

public int getLowestColumn(){
List<Integer> list = new ArrayList<Integer>();
list.addAll(map.values());
Collections.sort(list);
int min = list.get(0);
Set<Map.Entry<Integer, Integer>> entrySet = map.entrySet();
for (Map.Entry<Integer, Integer> entry : entrySet) {
if(min==entry.getValue()){
return entry.getKey();
}
}
return 0;
}
}

界面Activity:

[java]
view plaincopy

Handler handler = new Handler() {
public void handleMessage(android.os.Message msg) {
waterfall_container.setAdapter(articles);//设置数据
if(countImage==currentCount){
System.out.println("已经到最后");
textView.setVisibility(View.VISIBLE);
}
}
};

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
initLayout();

}

private void initLayout() {

textView = (TextView) findViewById(R.id.tv_tip);
waterfall_scroll = (LazyScrollView) findViewById(R.id.waterfall_scroll);
waterfall_scroll.getView();
waterfall_scroll.setOnScrollListener(new OnScrollListener() {

@Override
public void onTop() {
Log.d("LazyScroll", "Scroll to top");
}
@Override
public void onScroll() {
Log.d("LazyScroll", "Scroll");
}
@Override
public void onBottom() {
// 滚动到最底端
if(countImage!=currentCount) {
new Thread(new LoadMyArticle()).start();//加载下一页
}
}
});
waterfall_container = (MyLinearLayout) this
.findViewById(R.id.waterfall_container);

//初始化容器
waterfall_container.initLayout(3, 2, 2, 2, 2);

// 加载所有图片路径
new Thread(new LoadMyArticle()).start();

}

public final class LoadMyArticle implements Runnable {
@Override
public void run() {
try {
url_article_list.append("&page=").append(page++);
InputStream inputStream = GsonJsonParser
.getIputStream(url_article_list.toString());
ArticleJson articleJson = (ArticleJson) GsonJsonParser
.parseStreamToObject(inputStream, ArticleJson.class);
countImage = articleJson.getTotal();
articles = articleJson.getData();
currentCount += articles.size();
handler.sendEmptyMessage(1);
} catch (IOException e) {
e.printStackTrace();
}
}
}

当点击某一张图片的时候,进入图片详情.这里使用了VIewPager来实现的.效果如下:







实现如下:

[java]
view plaincopy

private ViewPager viewPager;
private List<ImageView> imageViews = new ArrayList<ImageView>();
private List<Photo> photos;
private Map<Integer,SoftReference<Bitmap>> cache = new HashMap<Integer,SoftReference<Bitmap>>();
private ProgressBar pb;
private MyAsyncTask myAsyncTask;
int screenWidth ;
int screenHeight;
Handler handler = new Handler(){
public void handleMessage(android.os.Message msg) {
switch (msg.what) {
case 1:
if(photos!=null&&photos.size()>0){
for (int i = 0; i < photos.size(); i++) {
ImageView imageView = new ImageView(GirlDetailActivity.this);
imageViews.add(imageView);
}
viewPager.setAdapter(new AwesomePagerAdapter());
myAsyncTask = new MyAsyncTask(0);
myAsyncTask.execute(photos.get(0).getImage());
}
break;
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.girls_detail);
Display display = getWindowManager().getDefaultDisplay();
display = getWindowManager().getDefaultDisplay();
screenWidth = display.getWidth();
screenHeight = display.getHeight();
init();
Intent intent = getIntent();
String id = intent.getStringExtra("id");
StringBuffer url = new StringBuffer(url);
url.append("?id=").append(id).append("&type=2");
new Thread(new LoadImagePath(url.toString())).start();

}

public void init(){

pb = (ProgressBar) findViewById(R.id.widget);

viewPager = (ViewPager) findViewById(R.id.awesomepager);

viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageSelected(final int position) {
String image_path = photos.get(position).getImage();
pb.setVisibility(View.GONE);
if(cache.containsKey(position)){
Bitmap bitmap = cache.get(position).get();
if(bitmap!=null){
imageViews.get(position).setImageBitmap(bitmap);
}else {
if(!myAsyncTask.isCancelled()){
System.out.println("任务被取消");
myAsyncTask.cancel(true);
}
myAsyncTask = new MyAsyncTask(position);
myAsyncTask.execute(image_path);
}
}else {
if(!myAsyncTask.isCancelled()){
System.out.println("任务被取消");
myAsyncTask.cancel(true);
}
myAsyncTask = new MyAsyncTask(position);
myAsyncTask.execute(image_path);
}
}

@Override
public void onPageScrolled(int position, float positionOffset,
int positionOffsetPixels) {

}

@Override
public void onPageScrollStateChanged(int arg0) {

}
});
}




public class AwesomePagerAdapter extends PagerAdapter {
@Override
public int getCount() {
return imageViews.size();
}

@Override
public Object instantiateItem(View collection, int position) {

ImageView imageView = imageViews.get(position);
((ViewPager) collection).addView(imageView, 0);
return imageViews.get(position);
}

@Override
public void destroyItem(View collection, int position, Object view) {
((ViewPager) collection).removeView(imageViews.get(position));
}

@Override
public boolean isViewFromObject(View view, Object object) {
// System.out.println("isViewFromObject");
return view == (object);
}

@Override
public void finishUpdate(View arg0) {
// System.out.println("finishUpdate");
}

@Override
public void restoreState(Parcelable arg0, ClassLoader arg1) {
// System.out.println("restoreState");
}

@Override
public Parcelable saveState() {
// System.out.println("saveState");
return null;
}

@Override
public void startUpdate(View arg0) {
}

}

@Override
public void onStop() {
super.onStop();
}

@Override
protected void onDestroy() {
super.onDestroy();
}

private final class LoadImagePath implements Runnable{
private String url;
public LoadImagePath(String url){
this.url = url;
}
@Override
public void run() {
try {
InputStream in = JsonParse.getIputStream(url);
PhotoDetailJson photoDetailJson = (PhotoDetailJson) GsonJsonParser.parseStreamToObject(in, PhotoDetailJson.class);
PhotoDetail detail = photoDetailJson.getData();
photos = detail.getPhoto();
handler.sendEmptyMessage(1);
} catch (IOException e) {
e.printStackTrace();
}
}
}

public final class MyAsyncTask extends AsyncTask<String, Void, Bitmap>{

private int position;
public MyAsyncTask(int position){
this.position = position;
}
@Override
protected Bitmap doInBackground(String... params) {
String path = params[0];
try {
InputStream in = JsonParse.getIputStream(path);
//如果屏幕超过800*480
if(screenWidth>480&&screenHeight>800){//960x540
screenWidth = 480;
screenHeight = 800;
}
Bitmap bitmap = ImageUtil.getSizedBitmap(screenWidth, screenHeight, in);
cache.put(position, new SoftReference<Bitmap>(bitmap));
return bitmap;
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
return null;
}

@Override
protected void onPostExecute(Bitmap result) {
super.onPostExecute(result);
imageViews.get(position).setImageBitmap(result);
pb.setVisibility(View.GONE);
}

@Override
protected void onPreExecute() {
super.onPreExecute();
pb.setVisibility(View.VISIBLE);
imageViews.get(position).setImageResource(R.drawable.wait_girl_detail);
}

}

完毕!

欢迎转载,转载请注明出处:http://blog.csdn.net/johnny901114/article/details/7835139

谢谢大家.希望对你有帮助.有事请留言....