RecyclerView简单使用
package com.example.recyclerviewtest; import androidx.appcompat.app.AppCompatActivity; import androidx.recyclerview.widget.DefaultItemAnimator; import androidx.recyclerview.widget.GridLayoutManager; import androidx.recyclerview.widget.LinearLayoutManager; import androidx.recyclerview.widget.RecyclerView; import androidx.recyclerview.widget.StaggeredGridLayoutManager; import android.annotation.SuppressLint; import android.os.Bundle; import android.util.Log; import android.view.View; import android.widget.Button; import android.widget.Toast; import java.util.ArrayList; import java.util.List; public class RecyclerViewActivity extends AppCompatActivity implements View.OnClickListener { RecyclerView recyclerView; Button btn_add; Button btn_del; Button btn_list; Button btn_grid; Button btn_flow; List<String> datas; private MyRecyclerViewAdapter adapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_recycler_view); initViews(); initdatas(); //设置adapter adapter = new MyRecyclerViewAdapter(RecyclerViewActivity.this, datas); recyclerView.setAdapter(adapter); //设置分割线 recyclerView.addItemDecoration(new DividerListItemDecoration(RecyclerViewActivity.this, DividerListItemDecoration.HORIZONTAL_LIST)); recyclerView.addItemDecoration(new DividerListItemDecoration(RecyclerViewActivity.this, DividerListItemDecoration.VERTICAL_LIST)); adapter.setOnItemClickListener(new MyRecyclerViewAdapter.OnItemclickListner() { @Override public void OnItemClick(View view, String data) { Toast.makeText(RecyclerViewActivity.this, "data = " + data, Toast.LENGTH_SHORT).show(); } }); //设置动画s recyclerView.setItemAnimator(new DefaultItemAnimator()); } private void initdatas() { datas = new ArrayList<>(); for (int i = 0; i < 100; i++) { datas.add("content_" + i); } } @SuppressLint("WrongConstant") private void initViews() { btn_add = findViewById(R.id.btn_add); btn_del = findViewById(R.id.btn_del); btn_list = findViewById(R.id.btn_list); btn_grid = findViewById(R.id.btn_grid); btn_flow = findViewById(R.id.btn_flow); btn_add.setOnClickListener(this); btn_del.setOnClickListener(this); btn_list.setOnClickListener(this); btn_grid.setOnClickListener(this); btn_flow.setOnClickListener(this); recyclerView = findViewById(R.id.recyclerview); recyclerView.setLayoutManager(new LinearLayoutManager(RecyclerViewActivity.this, LinearLayoutManager.VERTICAL, false)); } @SuppressLint("WrongConstant") @Override public void onClick(View view) { switch (view.getId()) { case R.id.btn_add: adapter.addData(0, "zhangsan"); recyclerView.scrollToPosition(0); break; case R.id.btn_del: adapter.removeData(0); break; case R.id.btn_list: //设置LayoutManager //最后一位代表时顺序还是倒序 recyclerView.setLayoutManager(new LinearLayoutManager(RecyclerViewActivity.this, LinearLayoutManager.VERTICAL, false)); //recyclerView.scrollToPosition(datas.size()/2);//定位到中间位置 break; case R.id.btn_grid: //设置成3列 //最后一位代表时顺序还是倒序 recyclerView.setLayoutManager(new GridLayoutManager(RecyclerViewActivity.this, 3, GridLayoutManager.VERTICAL, false)); break; case R.id.btn_flow: recyclerView.setLayoutManager(new StaggeredGridLayoutManager(4, StaggeredGridLayoutManager.VERTICAL)); break; } } }
定义Adapter
package com.example.recyclerviewtest; import android.content.Context; import android.view.View; import android.view.ViewGroup; import android.widget.ImageView; import android.widget.TextView; import android.widget.Toast; import androidx.annotation.NonNull; import androidx.recyclerview.widget.RecyclerView; import java.util.List; public class MyRecyclerViewAdapter extends RecyclerView.Adapter<MyRecyclerViewAdapter.MyViewHolder> { private Context context; private List<String> datas; public MyRecyclerViewAdapter(Context context, List<String> datas) { this.context = context; this.datas = datas; } /** * 相当于getView方法中船舰view和viewHodler * * @param parent * @param viewType * @return */ @NonNull @Override public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) { View itemView = View.inflate(context, R.layout.item_layout, null); return new MyViewHolder(itemView); } /** * 相当于getview绑定数据的部分 * * @param holder * @param position */ @Override public void onBindViewHolder(@NonNull MyViewHolder holder, int position) { //根据位置得到的数据 String data = datas.get(position); holder.tv_text.setText(data); } @Override public int getItemCount() { return datas.size(); } private OnItemclickListner ItemClickListener; public void setOnItemClickListener(OnItemclickListner itemClickListener) { this.ItemClickListener = itemClickListener; } public void addData(int position, String data) { datas.add(position, data); notifyItemInserted(position); } public void removeData(int i) { if (datas.size() > 0) { datas.remove(i); notifyItemRemoved(i); } } public interface OnItemclickListner { void OnItemClick(View view, String data); } class MyViewHolder extends RecyclerView.ViewHolder { private ImageView iv_icon; private TextView tv_text; public MyViewHolder(@NonNull final View itemView) { super(itemView); iv_icon = itemView.findViewById(R.id.iv_icon); tv_text = itemView.findViewById(R.id.tv_text); itemView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { if (ItemClickListener != null) { ItemClickListener.OnItemClick(itemView, datas.get(getLayoutPosition())); } } }); } } }
设置分隔符 DividerListItemDecoration
package com.example.recyclerviewtest; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Canvas; import android.graphics.Rect; import android.graphics.drawable.Drawable; import android.view.View; import androidx.recyclerview.widget.LinearLayoutManager; import androidx.recyclerview.widget.RecyclerView; public class DividerListItemDecoration extends RecyclerView.ItemDecoration { private static final int[] ATTRS = new int[]{ android.R.attr.listDivider }; public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL; public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL; private Drawable mDivider; private int mOrientation; public DividerListItemDecoration(Context context, int orientation) { final TypedArray a = context.obtainStyledAttributes(ATTRS); mDivider = a.getDrawable(0); a.recycle(); setOrientation(orientation); } public void setOrientation(int orientation) { if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST) { throw new IllegalArgumentException("invalid orientation"); } mOrientation = orientation; } @Override public void onDraw(Canvas c, RecyclerView parent) { // Log.e("recyclerview - itemdecoration", "onDraw()"); if (mOrientation == VERTICAL_LIST) { drawVertical(c, parent); } else { drawHorizontal(c, parent); } } public void drawVertical(Canvas c, RecyclerView parent) { final int left = parent.getPaddingLeft(); final int right = parent.getWidth() - parent.getPaddingRight(); final int childCount = parent.getChildCount(); for (int i = 0; i < childCount; i++) { final View child = parent.getChildAt(i); RecyclerView v = new RecyclerView(parent.getContext()); final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child .getLayoutParams(); final int top = child.getBottom() + params.bottomMargin; final int bottom = top + mDivider.getIntrinsicHeight(); mDivider.setBounds(left, top, right, bottom); mDivider.draw(c); } } public void drawHorizontal(Canvas c, RecyclerView parent) { final int top = parent.getPaddingTop(); final int bottom = parent.getHeight() - parent.getPaddingBottom(); final int childCount = parent.getChildCount(); for (int i = 0; i < childCount; i++) { final View child = parent.getChildAt(i); final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child .getLayoutParams(); final int left = child.getRight() + params.rightMargin; final int right = left + mDivider.getIntrinsicHeight(); mDivider.setBounds(left, top, right, bottom); mDivider.draw(c); } } @Override public void getItemOffsets(Rect outRect, int itemPosition, RecyclerView parent) { if (mOrientation == VERTICAL_LIST) { outRect.set(0, 0, 0, mDivider.getIntrinsicHeight()); } else { outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0); } } }
设置分割线xml文件
首先定义个drawable
divider_bg.xml
<?xml version="1.0" encoding="utf-8"?> <shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle"> <gradient android:centerColor="#ff00ff00" android:endColor="#ff0000ff" android:startColor="#ffff0000" android:type="linear" /> <size android:height="2dp" /> </shape>
设置style
<style name="listDividerTheme" parent="Theme.AppCompat.Light.DarkActionBar"> <!-- Customize your theme here. --> <item name="colorPrimary">@color/colorPrimary</item> <item name="colorPrimaryDark">@color/colorPrimaryDark</item> <item name="colorAccent">@color/colorAccent</item> <item name="android:listDivider">@drawable/divider_bg</item> </style>
AndroidManifest.xml中设置Activity的分割
<activity
android:name=".RecyclerViewActivity"
android:theme="@style/listDividerTheme"></activity>
