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相信大家平常在项目中遇到过画廊的效果，网上也有多种方式，类似viewPager、recyclerview等等方式实现，今天推荐一个三方库GalleryLayoutManager，便于快速实现，以解燃眉之急。
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依赖
gradle依赖
compile 'github.hellocsl:GalleryLayoutManager:1.0.6'
实现
布局文件
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.RecyclerView
android:id="@+id/recycler"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</RelativeLayout>
recyclerView设置的adapter
private class Adapter extends RecyclerView.Adapter<RecyclerHolder> {
private Context context;
private Adapter(Context context) {
this.context = context;
}
@Override
public RecyclerHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(context).inflate(R.layout.item_view, null);
//自定义view的宽度，控制一屏显示个数
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
int width = context.getResources().getDisplayMetrics().widthPixels;
params.width = width / 3;
view.setLayoutParams(params);
return new RecyclerHolder(view);
}
@Override
public void onBindViewHolder(RecyclerHolder holder, int position) {
}
@Override
public int getItemCount() {
return 10;
}
}
private class RecyclerHolder extends RecyclerView.ViewHolder {
private View view;
public RecyclerHolder(View itemView) {
super(itemView);
view = itemView;
}
public View getView() {
return view;
}
}
每个item简单的放置一个布局
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:orientation="vertical">
<ImageView
android:layout_width="100dp"
android:layout_height="wrap_content"
android:src="@mipmap/dota" />
</LinearLayout>
采用第三方的GalleryLayoutManager 与 recyclerView绑定，设置为横向滑动布局
GalleryLayoutManager manager = new GalleryLayoutManager(GalleryLayoutManager.HORIZONTAL);
manager.attach(recycler);
//设置滑动缩放效果
manager.setItemTransformer(new Transformer());
recycler.setAdapter(new Adapter(this));
缩放效果处理
//滑动过程中的缩放
public class Transformer implements GalleryLayoutManager.ItemTransformer {
@Override
public void transformItem(GalleryLayoutManager layoutManager, View item, float fraction) {
//以圆心进行缩放
item.setPivotX(item.getWidth() / 2.0f);
item.setPivotY(item.getHeight() / 2.0f);
float scale = 1 - 0.3f * Math.abs(fraction);
item.setScaleX(scale);
item.setScaleY(scale);
}
}
可以自定义RecyclerView里每项view的宽度，控制一屏显示效果，adapter的onCreateViewHolder里操作
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(context).inflate(R.layout.item_view, null);
//自定义view的宽度，控制一屏显示个数
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
int width = context.getResources().getDisplayMetrics().widthPixels;
params.width = width / 3;
view.setLayoutParams(params);
return new RecyclerHolder(view);
}
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滑动监听
滑动监听最终停止的位置
manager.setOnItemSelectedListener(new GalleryLayoutManager.OnItemSelectedListener() {
@Override
public void onItemSelected(RecyclerView recyclerView, View item, int position) {
//滑动到某一项的position
}
});
同时支持点击每一项滑动切换，adapter的onBindViewHolder方法里
@Override
public void onBindViewHolder(RecyclerHolder holder, final int position) {
holder.getView().setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
recycler.smoothScrollToPosition(position);
}
});
}
至此，一个简单的画廊效果实现，如果你项目正好需要这个，而我正好有。
当然这里只是简单介绍了画廊效果的实现，这个库还提供支持上下滑动的效果，贴上github地址 https://github.com/BCsl/GalleryLayoutManager， 便于大家进一步研究
同时欢迎关注微信公众号
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