如何在Android中单击向下/向上单击时缩小/缩小回收器查看卡项?

Question

我有一个回收器视图，里面每个项目都是卡片视图。 我想在按下卡片项目时缩小(调整(卡片项目，并在单击时放大。

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

你需要创建一个动画来做到这一点，类似于

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%" />

然后打电话给 Kotlin

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

或者没有 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)

持续时间：动画将持续数的毫秒数

FromXScale/FromYScale：起始 X 和 Y 位置(1 是视图的原始大小(

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

PivotX/PivotY：动画的起源(在本例中，50% 是视图的中心(

最后，您需要在适配器中使用此动画，因为这是访问每个项目视图的位置，对于您来说，这可以DataObjectHolder OnClick()

Answer 2

可以在RecyclerView.OnItemTouchListener#onTouch中检测到新闻和发布操作：

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;
}
// ...
});

return falseinonTouch()不会停止事件，因此您设置的onItemClick()也会正常工作。
您还可以轻松对缩放进行动画处理(在此处查找更多信息(：

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

请注意，如果不返回正确的值，mRecyclerView.OnItemTouchListener和mRecyclerView.OnTouchListener可能会相互干扰，对于缩放项目，第一个值就足够了。