我在Listview中有一个 CustomAdapter 。 Listview有一个两个Button和Textview。我想通过（+）按钮和（ - ）按钮在Textview中设置文本。当我点击（+）按钮时， Textview 中的数字会增加。但是当我点击（ - ）按钮时，这是一个错误。
BtnArtir表示 - ＆gt;增加| BtnAzalt意味着 - ＆gt;减少
public View getView(final int position, View view, ViewGroup parent) {
if (position == 0) {
//Slider
inflater = context.getLayoutInflater();
rowView4 = inflater.inflate(R.layout.custom_anasayfa_slider, null, true);
Row4_Tanimlamalar();
Row4_Fonksiyonlar();
return rowView4;
} else if (position == 1) {
if (KampanyaCinsi.equals("Resim")) {
inflater = context.getLayoutInflater();
rowView3 = inflater.inflate(R.layout.custom_anasayfa_kampanya_resim, null, true);
Row3_Tanimlamalar();
Row3_Fonksiyonlar();
return rowView3;
} else if (KampanyaCinsi.equals("Yazi")) {
inflater = context.getLayoutInflater();
rowView2 = inflater.inflate(R.layout.custom_anasayfa_kampanya_yazi, null, true);
Row2_Tanimlamalar();
Row2_Fonksiyonlar();
return rowView2;
}
} else if (position == MainActivity.listview.getAdapter().getCount() - 1) {
inflater = context.getLayoutInflater();
rowView5 = inflater.inflate(R.layout.custom_site_detay_sayfalari, null, true);
Row5_Tanimlamalar();
Row5_Fonksiyonlar();
return rowView5;
} else {
holder = new Holder();
inflater = context.getLayoutInflater();
rowView = inflater.inflate(R.layout.custom_item_anasayfa_urunleri, null, true);
Row_Tanimlamalar();
if (urunBirimi.get(position).equals("Adet")) {
holder.TxtAdetKg.setText("1");
holder.TxtAdetKgMetin.setText("Adet");
} else {
holder.TxtAdetKg.setText("0.25");
holder.TxtAdetKgMetin.setText("Kg");
}
holder.BtnArtir.setTag(holder);
holder.BtnArtir.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Holder mH = (Holder) v.getTag();
Toast.makeText(context, String.valueOf(urunBirimi.size()), Toast.LENGTH_SHORT).show();
if (urunBirimi.get(position).equals("Adet")) {
adet = Integer.parseInt(urunAdedi.get(position)) + 1;
urunAdedi.set(position, String.valueOf(adet));
mH.TxtAdetKg.setText(String.valueOf(adet));
} else if (urunBirimi.get(position).equals("Kg")) {
kg = Double.parseDouble(urunAdedi.get(position)) + 0.25;
urunAdedi.set(position, String.valueOf(kg));
mH.TxtAdetKg.setText(urunAdedi.get(position));
} else {
Toast.makeText(context, "Beklenmedik bir hata oluştu -", Toast.LENGTH_SHORT).show();
}
}
});
holder.BtnAzalt.setTag(holder);
holder.BtnAzalt.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Holder mH = (Holder) v.getTag();
if (urunBirimi.get(position).equals("Adet")) {
if (Integer.parseInt(urunAdedi.get(position)) == 1) {
} else {
adet = Integer.parseInt(urunAdedi.get(position)) - 1;
urunAdedi.set(position, String.valueOf(adet));
mH.TxtAdetKg.setText(String.valueOf(adet));
}
} else if (urunBirimi.get(position).equals("Kg")) {
if (Double.parseDouble(urunAdedi.get(position)) == 0.25) {
} else {
kg = Double.parseDouble(urunAdedi.get(position)) - 0.25;
urunAdedi.set(position, String.valueOf(kg));
mH.TxtAdetKg.setText(urunAdedi.get(position));
}
} else {
Toast.makeText(context, "Beklenmedik bir hata oluştu -", Toast.LENGTH_SHORT).show();
}
}
});
return rowView;
}
return null;
}
Row_Tanimlamalar
private void Row_Tanimlamalar() {
holder.ImgUrunResmi = (ImageView) rowView.findViewById(R.id.ImgUrunResmi);
holder.TxtUrunAdi = (TextView) rowView.findViewById(R.id.TxtUrunAdi);
holder.TxtAdetKg = (TextView) rowView.findViewById(R.id.TxtAdetKg);
holder.TxtAdetKgMetin = (TextView) rowView.findViewById(R.id.TxtAdetKgMetin);
holder.TxtUrunFiyat1 = (TextView) rowView.findViewById(R.id.TxtUrunFiyat1);
holder.TxtUrunFiyat2 = (TextView) rowView.findViewById(R.id.TxtUrunFiyat2);
holder.BtnAzalt = (Button) rowView.findViewById(R.id.BtnAzalt);
holder.BtnArtir = (Button) rowView.findViewById(R.id.BtnArtir);
holder.BtnSepeteEkle = (Button) rowView.findViewById(R.id.BtnSepeteEkle);
holder.LayoutUrunGorseli = (LinearLayout) rowView.findViewById(R.id.LayoutUrunGorseli);
}
ViewHolder
public static class Holder {
public ImageView ImgUrunResmi;
public TextView TxtUrunAdi;
public TextView TxtAdetKg;
public TextView TxtAdetKgMetin;
public TextView TxtUrunFiyat1;
public TextView TxtUrunFiyat2;
public Button BtnAzalt;
public Button BtnArtir;
public Button BtnSepeteEkle;
public LinearLayout LayoutUrunGorseli;
}
布局
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:clickable="true"
android:orientation="vertical">
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="@drawable/anasayfa_urun_bg"
android:orientation="vertical">
<LinearLayout
android:id="@+id/LayoutUrunGorseli"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<ImageView
android:id="@+id/ImgUrunResmi"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:adjustViewBounds="true" />
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="20dp"
android:layout_marginRight="20dp"
android:gravity="center"
android:orientation="horizontal">
<TextView
android:id="@+id/TxtUrunAdi"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="15dp"
android:layout_marginRight="15dp"
android:background="@drawable/urun_adi_bg"
android:gravity="center"
android:text="Ürün Adı"
android:textColor="@color/RenkGenelSiteSiyah"
android:textSize="18dp"
android:textStyle="bold" />
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="20dp"
android:layout_marginRight="20dp"
android:gravity="center"
android:orientation="horizontal"
android:weightSum="100">
<LinearLayout
android:id="@+id/LayoutAdetKg"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginRight="5dp"
android:layout_weight="50"
android:gravity="center"
android:orientation="horizontal"
android:weightSum="100">
<LinearLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="33"
android:gravity="center"
android:orientation="horizontal">
<Button
android:id="@+id/BtnAzalt"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="25"
android:background="@drawable/buton_artirma_azaltma_style"
android:gravity="center"
android:text="-"
android:textColor="@color/RenkGenelSiteFiyatRengiAcikSari"
android:textSize="25dp"
android:textStyle="bold" />
</LinearLayout>
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="34"
android:background="@drawable/adetkg_bg"
android:gravity="center"
android:orientation="vertical"
android:weightSum="100">
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="0dp"
android:layout_weight="40"
android:gravity="center"
android:orientation="horizontal">
<TextView
android:id="@+id/TxtAdetKg"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="25"
android:gravity="center"
android:text="1"
android:textColor="@color/RenkGenelSiteBeyaz"
android:textSize="15dp" />
</LinearLayout>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="0dp"
android:layout_weight="30"
android:gravity="center|bottom"
android:orientation="horizontal">
<TextView
android:id="@+id/TxtAdetKgMetin"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="25"
android:gravity="center"
android:text="Adet"
android:textColor="@color/RenkGenelSiteBeyaz"
android:textSize="10dp" />
</LinearLayout>
</LinearLayout>
<LinearLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="33"
android:gravity="center"
android:orientation="horizontal">
<Button
android:id="@+id/BtnArtir"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="25"
android:background="@drawable/buton_artirma_azaltma_style"
android:gravity="center"
android:text="+"
android:textColor="@color/RenkGenelSiteFiyatRengiAcikSari"
android:textSize="25dp"
android:textStyle="bold" />
</LinearLayout>
</LinearLayout>
<RelativeLayout
android:id="@+id/LayoutFiyat"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginLeft="5dp"
android:layout_weight="50"
android:background="@drawable/fiyat_bg"
android:gravity="center">
<TextView
android:id="@+id/TxtUrunFiyat1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="30,"
android:textColor="@color/RenkGenelSiteFiyatRengiAcikSari"
android:textSize="22dp"
android:textStyle="bold" />
<TextView
android:id="@+id/TxtUrunFiyat2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_toEndOf="@+id/TxtUrunFiyat1"
android:layout_toRightOf="@+id/TxtUrunFiyat1"
android:text="30"
android:textColor="@color/RenkGenelSiteFiyatRengiAcikSari"
android:textSize="13dp"
android:textStyle="bold" />
<TextView
android:id="@+id/Layout3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="@+id/TxtUrunFiyat2"
android:layout_toEndOf="@+id/TxtUrunFiyat2"
android:layout_toRightOf="@+id/TxtUrunFiyat2"
android:text=" TL"
android:textColor="@color/RenkGenelSiteFiyatRengiAcikSari"
android:textSize="20dp"
android:textStyle="bold" />
</RelativeLayout>
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:orientation="horizontal">
<LinearLayout
android:id="@+id/LayoutSepeteEkle"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="5dp"
android:layout_marginRight="5dp"
android:gravity="center">
<Button
android:id="@+id/BtnSepeteEkle"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="@drawable/buton_sepete_ekle"
android:text="Sepete Ekle"
android:textColor="#ffffff"
android:textStyle="bold" />
</LinearLayout>
</LinearLayout>
</LinearLayout>
</LinearLayout>
日志
Process: com.mikepenz.materialdrawer.app.debug, PID: 18695
java.lang.NullPointerException: Attempt to read from field 'android.widget.TextView com.mikepenz.materialdrawer.app.adapter.CustomAnasayfaAdapter$Holder.TxtAdetKg' on a null object reference
at com.mikepenz.materialdrawer.app.adapter.CustomAnasayfaAdapter$2.onClick(CustomAnasayfaAdapter.java:232)
at android.view.View.performClick(View.java:5697)
at android.widget.TextView.performClick(TextView.java:10826)
at android.view.View$PerformClick.run(View.java:22526)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:7225)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)