RecyclerView使用詳解（一）

一、前言

RecyclerView是谷歌V7包下新增的控件,用來替代ListView的使用,在RecyclerView標準化了ViewHolder類似於ListView中convertView用來做視圖緩.

先來說說RecyclerView的有點就是,他可以通過設置LayoutManager來快速實現listview、gridview、瀑布流的效果，而且還可以設置橫向和縱向顯示，添加動畫效果也非常簡單(自帶了ItemAnimation，可以設置加載和移除時的動畫，方便做出各種動態瀏覽的效果),也是官方推薦使用的.以下是官方的說明:

RecyclerView is a more advanced and flexible version of ListView. This widget is a container for large sets of views that can be recycled and scrolled very efficiently. Use the RecyclerView widget when you have lists with elements that change dynamically. 簡單說就是當你需要動態展示一組數據的時候就會需要用到它。

講了這麼多虛的，接下來我們看看在代碼中怎麼來實現.

二、實現

首先要用這個控件，你需要在gradle文件中添加包的引用（配合官方CardView使用）

compile 'com.android.support:cardview-v7:21.0.3'
compile 'com.android.support:recyclerview-v7:21.0.3'

然後是在XML文件用使用它

<android.support.v7.widget.RecyclerView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/recycler_view"
    android:layout_centerVertical="true"
    android:layout_centerHorizontal="true"/>

接着在Activity中設置它

public class MainActivity extends ActionBarActivity {
    @InjectView(R.id.recycler_view)
    RecyclerView mRecyclerView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.inject(this);

        mRecyclerView.setLayoutManager(new LinearLayoutManager(this));//這裏用線性顯示 類似於listview
//        mRecyclerView.setLayoutManager(new GridLayoutManager(this, 2));//這裏用線性宮格顯示 類似於grid view
//        mRecyclerView.setLayoutManager(new StaggeredGridLayoutManager(2, OrientationHelper.VERTICAL));//這裏用線性宮格顯示 類似於瀑布流
        mRecyclerView.setAdapter(new NormalRecyclerViewAdapter(this));
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();

        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

然後是適配器代碼

public class NormalRecyclerViewAdapter extends RecyclerView.Adapter<NormalRecyclerViewAdapter.NormalTextViewHolder> {
    private  LayoutInflater mLayoutInflater;
    private  Context mContext;
    private String[] mTitles;

    public NormalRecyclerViewAdapter(Context context) {
        mTitles = context.getResources().getStringArray(R.array.titles);
        mContext = context;
        mLayoutInflater = LayoutInflater.from(context);
    }

    @Override
    public NormalTextViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        return new NormalTextViewHolder(mLayoutInflater.inflate(R.layout.item_text, parent, false));
    }

    @Override
    public void onBindViewHolder(NormalTextViewHolder holder, int position) {
        holder.mTextView.setText(mTitles[position]);
    }

    @Override
    public int getItemCount() {
        return mTitles == null ? 0 : mTitles.length;
    }

    public static class NormalTextViewHolder extends RecyclerView.ViewHolder {
        @InjectView(R.id.text_view)
        TextView mTextView;

        NormalTextViewHolder(View view) {
            super(view);
            ButterKnife.inject(this, view);
            view.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Log.d("NormalTextViewHolder", "onClick--> position = " + getPosition());
                }
            });
        }
    }
}