Question

如何在不使用动画的情况下重新启动活动，同时保持回收器视图适配器内的滚动位置。我的主要活动java code`

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.Menu;
import android.view.MenuItem;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {
    private RecyclerView mRecyclerView;
    private RecyclerView.Adapter mAdapter;
    private RecyclerView.LayoutManager mLayoutManager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mRecyclerView = (RecyclerView) findViewById(R.id.my_recycler_view);

        // use this setting to improve performance if you know that changes
        // in content do not change the layout size of the RecyclerView
        mRecyclerView.setHasFixedSize(true);

        // use a linear layout manager
        mLayoutManager = new LinearLayoutManager(this);
        mRecyclerView.setLayoutManager(mLayoutManager);
        ArrayList<MyData> data= new ArrayList<MyData>();
        for (int i=0;i<10;i++){
            data.add(new MyData(
                    "Title"+i,
                    "description"+i,
                    R.drawable.ic_favorite_black_24dp
            ));
        }

        // specify an adapter (see also next example)
        mAdapter = new MyAdapter(data);
        mRecyclerView.setAdapter(mAdapter);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

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

        return super.onOptionsItemSelected(item);
    }
}

myData代码：

public class MyData {
String title;
String description;
int image;

public MyData(String title, String description, int image) {
    this.title = title;
    this.description = description;
    this.image = image;
}

public String getTitle() {
    return title;
}

public String getDescription() {
    return description;
}

public int getImage() {
    return image;
}
}

我的适配器：

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {
private ArrayList<MyData> data;


public static class ViewHolder extends RecyclerView.ViewHolder {
    // each data item is just a string in this case
    public View view;
    public ViewHolder(View v) {
        super(v);
        view = v;
    }
}

// Provide a suitable constructor (depends on the kind of dataset)
public MyAdapter(ArrayList<MyData> data) {
    this.data = data;
}

// Create new views (invoked by the layout manager)
@Override
public MyAdapter.ViewHolder onCreateViewHolder(ViewGroup parent,
                                               int viewType) {
    // create a new view
    View v = LayoutInflater.from(parent.getContext())
            .inflate(R.layout.custom_row, parent, false);
    // set the view's size, margins, paddings and layout parameters

    ViewHolder vh = new ViewHolder(v);
    return vh;
}

// Replace the contents of a view (invoked by the layout manager)
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
    // - get element from your dataset at this position
    // - replace the contents of the view with that element
    TextView title = (TextView) holder.view.findViewById(R.id.mainText);
    TextView description = (TextView) holder.view.findViewById(R.id.descriptionText);
    ImageView image= (ImageView) holder.view.findViewById(R.id.icon);
    title.setText(data.get(position).getTitle());
    description.setText(data.get(position).getDescription());
    image.setImageResource(data.get(position).getImage());
    title.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            ...
        }
    });

}

// Return the size of your dataset (invoked by the layout manager)
@Override
public int getItemCount() {
    return data.size();
}
}

在recyclerview适配器中重新启动/刷新活动

0 个答案: