如何删除 CardView 布局中的冗余项
How to remove redundancy item in CardView layout
我在 RecyclerView 中使用 CardView 布局，JSON 将加载数据并填充适配器。我的布局包括一个 ImageView、一个 TextView，一切正常。
这是适配器 class（已更新）：
public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> {
private static final int TYPE_HEADER = 4;
private static final int TYPE_ITEM = 1;
Context context;
List<CarData> getCarData; // getDataAdapter
ImageLoader imageThumbLoader;
public RecyclerViewAdapter(List<CarData> getCarData, Context context){
super();
this.getCarData = getCarData;
this.context = context;
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.recyclerview_items, parent, false);
ViewHolder viewHolder = new ViewHolder(v);
return viewHolder;
}
@Override
public void onBindViewHolder(ViewHolder Viewholder, int position) {
// if (!isPositionHeader(position)) {
CarData getCarData1 = getCarData.get(position - 1);
imageThumbLoader = ServerImageParseAdapter.getInstance(context).getImageLoader();
imageThumbLoader.get(getCarData1.getImageThumb(),
ImageLoader.getImageListener(
Viewholder.imageThumb,//Server Image
R.mipmap.ic_launcher,//Before loading server image the default showing image.
android.R.drawable.ic_dialog_alert //Error image if requested image dose not found on server.
)
);
Viewholder.imageThumb.setImageUrl(getCarData1.getImageThumb(), imageThumbLoader);
Viewholder.titleName.setText(getCarData1.getTitleName());
Viewholder.doorName.setText(Html.fromHtml("<b>Số cửa:</b> " + getCarData1.getDoorName()));
Viewholder.seatName.setText(Html.fromHtml("<b>Số ghế:</b> " + getCarData1.getSeatName()));
Viewholder.cityName.setText(Html.fromHtml(getCarData1.getCityName()));
Viewholder.districtName.setText(Html.fromHtml(getCarData1.getDistrictName()));
// }
}
public int getDataAdapter() {
return getCarData == null ? 0 : getCarData.size();
}
@Override
public int getItemViewType(int position) {
if (isPositionHeader(position)) {
return TYPE_HEADER;
}
return TYPE_ITEM;
}
@Override
public int getItemCount() {
return getDataAdapter(); // + 1
}
private boolean isPositionHeader(int position) {
return position == 0;
}
class ViewHolder extends RecyclerView.ViewHolder{
public TextView titleName;
public NetworkImageView imageThumb;
public TextView doorName;
public TextView seatName;
public TextView cityName;
public TextView districtName;
public ViewHolder(View itemView) {
super(itemView);
titleName = (TextView) itemView.findViewById(R.id.titleName);
imageThumb = (NetworkImageView) itemView.findViewById(R.id.imageThumb);
doorName = (TextView) itemView.findViewById(R.id.doorName);
seatName = (TextView) itemView.findViewById(R.id.seatName);
cityName = (TextView) itemView.findViewById(R.id.cityName);
districtName = (TextView) itemView.findViewById(R.id.districtName);
}
}
}
我的布局:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:id="@+id/cardview1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
card_view:cardElevation="3dp"
card_view:contentPadding="3dp"
card_view:cardCornerRadius="3dp"
card_view:cardMaxElevation="3dp"
card_view:cardUseCompatPadding="true">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<com.android.volley.toolbox.NetworkImageView
android:id="@+id/imageThumb"
android:layout_width="400dp"
android:layout_height="230dp"
android:src="@mipmap/ic_launcher"
android:gravity="top"
android:scaleType="centerCrop"/>
<TextView
android:id="@+id/titleName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Image View"
android:layout_centerVertical="true"
android:layout_toRightOf="@+id/imageThumb"
android:layout_toEndOf="@+id/imageThumb"
android:layout_marginLeft="20dp"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:weightSum="2">
<TextView
android:id="@+id/doorName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginLeft="20dp"/>
<TextView
android:id="@+id/seatName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginLeft="20dp"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:weightSum="2">
<TextView
android:id="@+id/cityName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginLeft="20dp"/>
<TextView
android:id="@+id/districtName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginLeft="20dp"/>
</LinearLayout>
<TextView
android:id="@+id/checkStatus"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="KIỂM TRA TÌNH TRẠNG XE"
android:textColor="@color/color_primary_green_dark"
android:textStyle="bold"
android:textSize="12dp"
android:layout_centerVertical="true"
android:layout_toRightOf="@+id/textView_item32"
android:layout_toEndOf="@+id/textView_item32"
android:layout_marginLeft="20dp"/>
</LinearLayout>
但是当我第一次加载数据时，有一个冗余项。请看以下附件：
更新代码时出现异常：
E/AndroidRuntime: FATAL EXCEPTION: main
Process: pl.michalz.hideonscrollexample, PID: 9794
java.lang.ArrayIndexOutOfBoundsException: length=18; index=-1
at java.util.ArrayList.get(ArrayList.java:310)
at pl.michalz.hideonscrollexample.RecyclerViewAdapter$override.onBindViewHolder(RecyclerViewAdapter.java:54)
at pl.michalz.hideonscrollexample.RecyclerViewAdapter$override.access$dispatch(RecyclerViewAdapter.java)
at pl.michalz.hideonscrollexample.RecyclerViewAdapter.onBindViewHolder(RecyclerViewAdapter.java:0)
at pl.michalz.hideonscrollexample.RecyclerViewAdapter.onBindViewHolder(RecyclerViewAdapter.java:20)
at android.support.v7.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:5768)
at android.support.v7.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:5801)
如何删除 CardView 中的这个冗余项目？
您的重写 getItemCount() 方法中有 + 1。这会导致您的列表中多了一项。
然后你有方法 isPositionHeader，你在 onBindViewHolder 方法中调用它来找出位置是否是 header 位置。如果它不是 header 位置，则您正在用数据填充 cardview。但是如果是header这个位置，你直接跳过就行了。所以第一项是空白的，实际上是 header 使用与其他项目相同的卡片视图。
尝试删除 + 1 和此条件 if (!isPositionHeader(position))。
我在 RecyclerView 中使用 CardView 布局，JSON 将加载数据并填充适配器。我的布局包括一个 ImageView、一个 TextView，一切正常。
这是适配器 class（已更新）：
public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> {
private static final int TYPE_HEADER = 4;
private static final int TYPE_ITEM = 1;
Context context;
List<CarData> getCarData; // getDataAdapter
ImageLoader imageThumbLoader;
public RecyclerViewAdapter(List<CarData> getCarData, Context context){
super();
this.getCarData = getCarData;
this.context = context;
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.recyclerview_items, parent, false);
ViewHolder viewHolder = new ViewHolder(v);
return viewHolder;
}
@Override
public void onBindViewHolder(ViewHolder Viewholder, int position) {
// if (!isPositionHeader(position)) {
CarData getCarData1 = getCarData.get(position - 1);
imageThumbLoader = ServerImageParseAdapter.getInstance(context).getImageLoader();
imageThumbLoader.get(getCarData1.getImageThumb(),
ImageLoader.getImageListener(
Viewholder.imageThumb,//Server Image
R.mipmap.ic_launcher,//Before loading server image the default showing image.
android.R.drawable.ic_dialog_alert //Error image if requested image dose not found on server.
)
);
Viewholder.imageThumb.setImageUrl(getCarData1.getImageThumb(), imageThumbLoader);
Viewholder.titleName.setText(getCarData1.getTitleName());
Viewholder.doorName.setText(Html.fromHtml("<b>Số cửa:</b> " + getCarData1.getDoorName()));
Viewholder.seatName.setText(Html.fromHtml("<b>Số ghế:</b> " + getCarData1.getSeatName()));
Viewholder.cityName.setText(Html.fromHtml(getCarData1.getCityName()));
Viewholder.districtName.setText(Html.fromHtml(getCarData1.getDistrictName()));
// }
}
public int getDataAdapter() {
return getCarData == null ? 0 : getCarData.size();
}
@Override
public int getItemViewType(int position) {
if (isPositionHeader(position)) {
return TYPE_HEADER;
}
return TYPE_ITEM;
}
@Override
public int getItemCount() {
return getDataAdapter(); // + 1
}
private boolean isPositionHeader(int position) {
return position == 0;
}
class ViewHolder extends RecyclerView.ViewHolder{
public TextView titleName;
public NetworkImageView imageThumb;
public TextView doorName;
public TextView seatName;
public TextView cityName;
public TextView districtName;
public ViewHolder(View itemView) {
super(itemView);
titleName = (TextView) itemView.findViewById(R.id.titleName);
imageThumb = (NetworkImageView) itemView.findViewById(R.id.imageThumb);
doorName = (TextView) itemView.findViewById(R.id.doorName);
seatName = (TextView) itemView.findViewById(R.id.seatName);
cityName = (TextView) itemView.findViewById(R.id.cityName);
districtName = (TextView) itemView.findViewById(R.id.districtName);
}
}
}
我的布局:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:id="@+id/cardview1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
card_view:cardElevation="3dp"
card_view:contentPadding="3dp"
card_view:cardCornerRadius="3dp"
card_view:cardMaxElevation="3dp"
card_view:cardUseCompatPadding="true">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<com.android.volley.toolbox.NetworkImageView
android:id="@+id/imageThumb"
android:layout_width="400dp"
android:layout_height="230dp"
android:src="@mipmap/ic_launcher"
android:gravity="top"
android:scaleType="centerCrop"/>
<TextView
android:id="@+id/titleName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Image View"
android:layout_centerVertical="true"
android:layout_toRightOf="@+id/imageThumb"
android:layout_toEndOf="@+id/imageThumb"
android:layout_marginLeft="20dp"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:weightSum="2">
<TextView
android:id="@+id/doorName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginLeft="20dp"/>
<TextView
android:id="@+id/seatName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginLeft="20dp"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:weightSum="2">
<TextView
android:id="@+id/cityName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginLeft="20dp"/>
<TextView
android:id="@+id/districtName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginLeft="20dp"/>
</LinearLayout>
<TextView
android:id="@+id/checkStatus"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="KIỂM TRA TÌNH TRẠNG XE"
android:textColor="@color/color_primary_green_dark"
android:textStyle="bold"
android:textSize="12dp"
android:layout_centerVertical="true"
android:layout_toRightOf="@+id/textView_item32"
android:layout_toEndOf="@+id/textView_item32"
android:layout_marginLeft="20dp"/>
</LinearLayout>
但是当我第一次加载数据时，有一个冗余项。请看以下附件：
更新代码时出现异常：
E/AndroidRuntime: FATAL EXCEPTION: main
Process: pl.michalz.hideonscrollexample, PID: 9794
java.lang.ArrayIndexOutOfBoundsException: length=18; index=-1
at java.util.ArrayList.get(ArrayList.java:310)
at pl.michalz.hideonscrollexample.RecyclerViewAdapter$override.onBindViewHolder(RecyclerViewAdapter.java:54)
at pl.michalz.hideonscrollexample.RecyclerViewAdapter$override.access$dispatch(RecyclerViewAdapter.java)
at pl.michalz.hideonscrollexample.RecyclerViewAdapter.onBindViewHolder(RecyclerViewAdapter.java:0)
at pl.michalz.hideonscrollexample.RecyclerViewAdapter.onBindViewHolder(RecyclerViewAdapter.java:20)
at android.support.v7.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:5768)
at android.support.v7.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:5801)
如何删除 CardView 中的这个冗余项目？
您的重写 getItemCount() 方法中有 + 1。这会导致您的列表中多了一项。
然后你有方法 isPositionHeader，你在 onBindViewHolder 方法中调用它来找出位置是否是 header 位置。如果它不是 header 位置，则您正在用数据填充 cardview。但是如果是header这个位置，你直接跳过就行了。所以第一项是空白的，实际上是 header 使用与其他项目相同的卡片视图。
尝试删除 + 1 和此条件 if (!isPositionHeader(position))。