RecylerView能够灵活地实现大数据集的展示,视图的复用管理比ListView更好,能够显示列表,网格,瀑布流等形式,且不同的ViewHolder能够实现item多元化的功能.
使用准备，添加依赖implementation 'androidx.recyclerview:recyclerview:1.1.0'下列例子所有依赖
dependencies {
implementation 'androidx.appcompat:appcompat:1.2.0'
implementation 'com.google.android.material:material:1.3.0'
implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
testImplementation 'junit:junit:4.+'
androidTestImplementation 'androidx.test.ext:junit:1.1.2'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
implementation 'androidx.recyclerview:recyclerview:1.1.0'
}
RecyclerView 的简单使用
一:RecyclerView 的初始化
recyclerView = findViewById(R.id.recycler1);
recyclerView.setLayoutManager(new LinearLayoutManager(LinearRecycleActivity.this));
//recyclerView.setAdapter(new CLinearAdapter(LinearRecycleActivity.this));简单使用
recyclerView.setAdapter(new CLinearAdapter(LinearRecycleActivity.this, new CLinearAdapter.onItemClickListener() {
@Override
public void click(int pos) {
Toast.makeText(LinearRecycleActivity.this,"InActivity cilik is "+pos,Toast.LENGTH_SHORT).show();
}
}));//这里嵌入了一个lambda表达式，用于实现监听功能
//xml:
- 二:RecyclerView 的 Adapter
public class CLinearAdapter extends RecyclerView.Adapter这里体现了一个RecyclerView 和 ListView的不同点:在ListView中,可以直接调用监听事件,但RecyclerView需要自己去定义实现监听{ private Context context; private onItemClickListener listener; CLinearAdapter(Context context,onItemClickListener listener){ this.context = context; this.listener = listener; } @Override public CLinearAdapter.LinearViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) { LinearViewHolder linearViewHolder = new LinearViewHolder(LayoutInflater.from(context).inflate(R.layout.linear_item,parent,false)); return linearViewHolder; } @Override public void onBindViewHolder(@NonNull CLinearAdapter.LinearViewHolder holder, int position) { //设置item holder.textView.setText("onBindViewHolder"); holder.itemView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) {//点击事件 // Toast.makeText(context,"inAdapter onClick is "+position,Toast.LENGTH_SHORT).show(); listener.click(position); } }); } @Override public int getItemCount() { return 20; }//设置item的个数 class LinearViewHolder extends RecyclerView.ViewHolder{//item的样式 TextView textView; public LinearViewHolder(@NonNull View itemView) { super(itemView); textView = itemView.findViewById(R.id.linear_text); } } public interface onItemClickListener{//给外部的接口,以实现点击事件 void click(int pos); } } //xml
效果(上述代码没有分割线):
- 二:设为水平滚动
public class HorRecyleActivity extends AppCompatActivity {
private RecyclerView recyclerView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_hor);
recyclerView = findViewById(R.id.recycler_hor);
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(HorRecyleActivity.this);
linearLayoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
recyclerView.setLayoutManager(linearLayoutManager);
recyclerView.setAdapter(new CLinearAdapter(HorRecyleActivity.this, new CLinearAdapter.onItemClickListener() {
@Override
public void click(int pos) {
Toast.makeText(HorRecyleActivity.this,"InActivity cilik is "+pos,Toast.LENGTH_SHORT).show();
}
}));
}
}
- 三:item设为网格布局
public class GridRecyleActivity extends AppCompatActivity {
private RecyclerView recyclerView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_grid_recyle);
recyclerView = findViewById(R.id.recycler_grid);
recyclerView.setLayoutManager(new GridLayoutManager(GridRecyleActivity.this,5));//一行5个
recyclerView.setAdapter(new CLinearAdapter(GridRecyleActivity.this, new CLinearAdapter.onItemClickListener() {
@Override
public void click(int pos) {
Toast.makeText(GridRecyleActivity.this,"InActivity cilik is "+pos,Toast.LENGTH_SHORT).show();
}
}));
}
}
效果:
- 四:RecyclerView扩展:瀑布流
public class FallRecyleActivity2 extends AppCompatActivity {
private RecyclerView recyclerView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_fall_recyle2);
recyclerView = findViewById(R.id.recycler_fall);
recyclerView.setLayoutManager(new StaggeredGridLayoutManager(5,StaggeredGridLayoutManager.VERTICAL));//5列
recyclerView.setAdapter(new CLinearAdapter(FallRecyleActivity2.this, new CLinearAdapter.onItemClickListener() {
@Override
public void click(int pos) {
Toast.makeText(FallRecyleActivity2.this,"InActivity cilik is "+pos,Toast.LENGTH_SHORT).show();
}
}));
}
}
//Adpater继承的对象不同
public class StaggerdAdapter extends RecyclerView.Adapter {
效果:
- 五:多种viewHolder
public class CLinearAdapter extends RecyclerView.Adapter{ private Context context; private onItemClickListener listener; CLinearAdapter(Context context,onItemClickListener listener){ this.context = context; this.listener = listener; } @Override public int getItemViewType(int position){ return position&1; } @Override public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) { if(viewType==1) { LinearViewHolder linearViewHolder = new LinearViewHolder(LayoutInflater.from(context).inflate(R.layout.linear_item,parent,false)); return linearViewHolder; } else { LinearViewHolder2 linearViewHolder = new LinearViewHolder2(LayoutInflater.from(context).inflate(R.layout.linear2_item,parent,false)); return linearViewHolder; } } @Override public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder,final int position) { //设置item if(getItemViewType(position)==1){ ((LinearViewHolder)holder).textView.setText("onBindViewHolder1"); }else{ ((LinearViewHolder2)holder).textView.setText("onBindViewHolder2"); } holder.itemView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) {//点击事件 // Toast.makeText(context,"inAdapter onClick is "+position,Toast.LENGTH_SHORT).show(); listener.click(position); } }); } @Override public int getItemCount() { return 20; }//设置item的个数 class LinearViewHolder extends RecyclerView.ViewHolder{//item的样式 TextView textView; public LinearViewHolder(@NonNull View itemView) { super(itemView); textView = itemView.findViewById(R.id.linear_text); } } class LinearViewHolder2 extends RecyclerView.ViewHolder{//item的样式 TextView textView; public LinearViewHolder2(@NonNull View itemView) { super(itemView); textView = itemView.findViewById(R.id.linear_text2); } } public interface onItemClickListener{//给外部的接口 void click(int pos); } }
效果:
