如何在Android中點擊向下/向上縮小/放大回收器視圖卡項目？

Question

我有一個回收站視圖，在里面，每個項目都是一個卡片視圖。 我想在按下項目時縮小（大小）卡片項目，並在單擊時放大。

以下是CardViewActivity.java

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.MotionEvent;
import android.view.View;
import android.widget.Toast;

import java.util.ArrayList;

public class CardViewActivity 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_card_view);

        mRecyclerView = (RecyclerView) findViewById(R.id.my_recycler_view);
        mRecyclerView.setHasFixedSize(true);
        mLayoutManager = new LinearLayoutManager(this);
        mRecyclerView.setLayoutManager(mLayoutManager);
        mAdapter = new MyRecyclerViewAdapter(getDataSet());
        mRecyclerView.setAdapter(mAdapter);
    }


    @Override
    protected void onResume() {
        super.onResume();
        ((MyRecyclerViewAdapter) mAdapter).setOnItemClickListener(new MyRecyclerViewAdapter
                .MyClickListener() {
            @Override
            public void onItemClick(int position, View v) {
                Toast.makeText(getApplicationContext(), " Clicked on Item " + position, Toast.LENGTH_SHORT).show();
            }

        });

        mRecyclerView.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {

                return false;
            }
        });
        mRecyclerView.addOnItemTouchListener(new RecyclerView.OnItemTouchListener() {
            @Override
            public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
                return false;
            }

            @Override
            public void onTouchEvent(RecyclerView rv, MotionEvent event) {

            }

            @Override
            public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {

            }
        });


    }

    private ArrayList<DataObject> getDataSet() {
        ArrayList results = new ArrayList<DataObject>();
        for (int index = 0; index < 20; index++) {
            DataObject obj = new DataObject("Some Primary Text " + index,
                    "Secondary " + index);
            results.add(index, obj);
        }
        return results;
    }
}

和MyRecyclerViewAdapter.java

import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import java.util.ArrayList;

public class MyRecyclerViewAdapter extends RecyclerView
        .Adapter<MyRecyclerViewAdapter
        .DataObjectHolder> {
    private static String LOG_TAG = "MyRecyclerViewAdapter";
    private ArrayList<DataObject> mDataset;
    private static MyClickListener myClickListener;

    public static class DataObjectHolder extends RecyclerView.ViewHolder
            implements View
            .OnClickListener {
        TextView label;
        TextView dateTime;

        public DataObjectHolder(View itemView) {
            super(itemView);
            label = (TextView) itemView.findViewById(R.id.textView);
            dateTime = (TextView) itemView.findViewById(R.id.textView2);
            Log.i(LOG_TAG, "Adding Listener");
            itemView.setOnClickListener(this);
        }

        @Override
        public void onClick(View v) {
            myClickListener.onItemClick(getAdapterPosition(), v);
        }
    }

    public void setOnItemClickListener(MyClickListener myClickListener) {
        this.myClickListener = myClickListener;
    }

    public MyRecyclerViewAdapter(ArrayList<DataObject> myDataset) {
        mDataset = myDataset;
    }

    @Override
    public DataObjectHolder onCreateViewHolder(ViewGroup parent,
                                               int viewType) {
        View view = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.card_view_row, parent, false);

        DataObjectHolder dataObjectHolder = new DataObjectHolder(view);
        return dataObjectHolder;
    }

    @Override
    public void onBindViewHolder(DataObjectHolder holder, int position) {
        holder.label.setText(mDataset.get(position).getmText1());
        holder.dateTime.setText(mDataset.get(position).getmText2());
    }

    public void addItem(DataObject dataObj, int index) {
        mDataset.add(index, dataObj);
        notifyItemInserted(index);
    }

    public void deleteItem(int index) {
        mDataset.remove(index);
        notifyItemRemoved(index);
    }

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

    public interface MyClickListener {
        public void onItemClick(int position, View v);
    }
}

card_view_row.xml -

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:card_view="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <android.support.v7.widget.CardView
        android:id="@+id/card_view"
        android:layout_width="fill_parent"
        android:layout_height="100dp"
        android:layout_gravity="center"
        android:layout_margin="5dp"
        card_view:cardCornerRadius="2dp"
        card_view:contentPadding="10dp">

        <RelativeLayout
            android:layout_width="fill_parent"
            android:layout_height="fill_parent">

            <TextView
                android:id="@+id/textView"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_alignParentTop="true"
                android:textStyle="bold"/>

            <TextView
                android:id="@+id/textView2"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_below="@+id/textView"
                android:layout_marginTop="10dp"/>
        </RelativeLayout>
    </android.support.v7.widget.CardView>


</LinearLayout>

Answer 1

您需要創建一個動畫來執行此操作，例如

item_click.xml

<?xml version="1.0" encoding="utf-8"?>
<scale
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:duration="100"
    android:fromXScale="1.0"
    android:toXScale="0.9"
    android:fromYScale="1.0"
    android:toYScale="0.9"
    android:pivotX="50%"
    android:pivotY="50%" />

然后調用 Kotlin

val anim: Animation = AnimationUtils.loadAnimation(context, R.anim.item_click)
view.startAnimation(anim)

或者沒有 xml

 val anim: Animation = ScaleAnimation(
        1f,
        0.9f,
        1f,
        0.9f,
        Animation.RELATIVE_TO_SELF, 0.5f,
        Animation.RELATIVE_TO_SELF, 0.5f)
    anim.duration = 100
    view.startAnimation(anim)

持續時間：動畫將持續的毫秒數

FromXScale/FromYScale：起始 X 和 Y 位置（1 是視圖的原始大小）

ToXScale/ToYScale：結束 X 和 Y 位置（0.9 比原始大小略小）

PivotX/PivotY：動畫的原點（在這種情況下，50% 是視圖的中心）

最后你需要在你的適配器中使用這個動畫，因為這是訪問每個項目視圖的地方，對你來說這可以是DataObjectHolder OnClick()

Answer 2

在RecyclerView.OnItemTouchListener#onTouch可以檢測按下和釋放動作：

mRecyclerView.addOnItemTouchListener(new RecyclerView.OnItemTouchListener() {

    //...

    @Override
    public boolean onTouch(View v, MotionEvent event) {
        switch(event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                v.setScale(0.9f);
                break;
            case MotionEvent.ACTION_UP:
                v.setScale(1f);
                break;
        }
        return false;
    }

    // ...

});

在onTouch() return false不會停止事件，因此您設置的onItemClick()也將起作用。
您還可以輕松地為縮放設置動畫（在此處找到更多信息）：

Animation anim = new ScaleAnimation(/* Scale down/up animation */);
anim.setFillAfter(true);
anim.setDuration(/* ... */);
v.startAnimation(anim);

請注意，如果您沒有返回正確的值，則mRecyclerView.OnItemTouchListener和mRecyclerView.OnTouchListener可能會相互干擾，並且對於縮放項目，第一個就足夠了。