學習RecyclerView

對RecyclerView還是很不瞭解，所以看鴻洋大神的視頻來補充下這方面知識

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RecyclerView？啥玩意？

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RecyclerView實現ListView

public class MainActivity extends AppCompatActivity {
    private RecyclerView mRecyclerView;
    private List<String> data;


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

        initView();
        initData();

        //設置RecyclerView的管理器
        LinearLayoutManager manager = new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false);

        //設置RecyclerView的item分割線

        mRecyclerView.setAdapter(new RecyclerViewAdapter(this,data));


    }
    private void initView() {
        mRecyclerView  = (RecyclerView)findViewById(R.id.recyView);
    }

    private void initData() {
        data = new ArrayList<>();
        for (int i = 'A'; i < 'z'; i++) {
            data.add((char)i +"");
        }
    }
}


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public class RecyclerViewAdapter extends RecyclerView.Adapter<MyRecyclerViewHolder> {
    //上下文
    private Context mContext;
    //數據源
    private List<String> data;
    //佈局填充對象
    private LayoutInflater layoutInflater;

    public RecyclerViewAdapter(Context mContext, List<String> data) {
        this.mContext = mContext;
        this.data = data;
        //獲取到layoutInflater對象　後面好填充佈局
        layoutInflater = LayoutInflater.from(mContext);
    }

    //創建ViewHolder
    @Override
    public MyRecyclerViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        //添加布局
        View view = layoutInflater.inflate(R.layout.item_recycler, parent, false);
        //把視圖給ViewHolder
        MyRecyclerViewHolder holder = new MyRecyclerViewHolder(view);
        return holder;
    }

    //綁定ViewHolder 適配數據
    @Override
    public void onBindViewHolder(MyRecyclerViewHolder holder, int position) {
        //獲取該條目的字符串,並給控件設置
        String str = data.get(position);
        holder.mText.setText(str);
    }

    @Override
    public int getItemCount() {
        return data.size();
    }
}

class MyRecyclerViewHolder extends RecyclerView.ViewHolder {
    public TextView mText;

    public MyRecyclerViewHolder(View itemView) {
        super(itemView);
        mText = itemView.findViewById(R.id.id_text);
    }
}

以上簡單的實現了ListView 但是沒有ListView的分割線。

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增加分割線

  dividerPaint = new Paint();
        dividerPaint.setColor(getResources().getColor(R.color.fenge));
        dividerHeight = 10;
    @Override
            public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
                super.getItemOffsets(outRect, view, parent, state);
                    outRect.bottom= 10;
            }

            @Override
            public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
                int childCount = parent.getChildCount();
                int left = parent.getPaddingLeft();
                int right = parent.getWidth() - parent.getPaddingRight();

                for (int i = 0; i < childCount ; i++) {
                    View view = parent.getChildAt(i);
                    float top = view.getBottom();
                    float bottom = view.getBottom() + dividerHeight;
                    c.drawRect(left, top, right, bottom, dividerPaint);
                }
            }
        });
回調繪製方法,給線條設置間距和線條。

待續。。