[英]onClickListener on a button that is added through a layout inflator
到目前為止,這是我的代碼,基於對SO相關問題的各種答案。
在我的活動中
GridView gv = (GridView) findViewById(R.id.gridView1);
MyCustomAdapter mAdapter = new MyCustomAdapter();
mAdapter.addItem("Action1");
mAdapter.addItem("Action2");
mAdapter.addItem("Action3");
gv.setAdapter(mAdapter);
我的適配器
private class MyCustomAdapter extends BaseAdapter {
private ArrayList<String> mData = new ArrayList<String>();
private LayoutInflater mInflater;
public MyCustomAdapter() {
mInflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
public void addItem(final String item) {
mData.add(item);
notifyDataSetChanged();
}
@Override
public int getCount() {
return mData.size();
}
@Override
public String getItem(int position) {
return mData.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
NumericViewHolder holder = new NumericViewHolder();
if (convertView == null) {
convertView = mInflater.inflate(R.layout.horizontalnumberpicker, null);
holder.textView = (TextView)convertView.findViewById(R.id.txtNPTitle);
holder.minus = (Button)convertView.findViewById(R.id.btnMinus);
holder.plus = (Button)convertView.findViewById(R.id.btnPlus);
holder.value = (TextView)convertView.findViewById(R.id.txtNPValue);
holder.minus.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
TextView tv = (TextView) v.findViewById(R.id.txtNPValue);
int value = Integer.parseInt(tv.getText().toString());
Toast.makeText(getApplicationContext(), Integer.toString(value), Toast.LENGTH_SHORT).show();
if (value > 0) {
value = value - 1;
tv.setText(Integer.toString(value));
}
}
});
holder.plus.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
TextView tv = (TextView) v.findViewById(R.id.txtNPValue);
int value = Integer.parseInt(tv.getText().toString()); <--Error is here
Toast.makeText(getApplicationContext(), Integer.toString(value), Toast.LENGTH_SHORT).show();
value = value + 1;
tv.setText(Integer.toString(value));
}
});
convertView.setTag(holder);
} else {
holder = (NumericViewHolder)convertView.getTag();
}
holder.textView.setText(mData.get(position));
return convertView;
}
}
XML-Main_Activity
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/rlAddProduct"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<Button
android:id="@+id/btnSaveProduct"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentEnd="true"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:layout_marginEnd="20dp"
android:layout_marginRight="20dp"
android:layout_marginTop="20dp"
android:text="@string/Save" />
<TextView
android:id="@+id/lblSelectCategory"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/btnSaveProduct"
android:layout_alignBottom="@+id/btnSaveProduct"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginLeft="20dp"
android:layout_marginStart="20dp"
android:text="@string/selectCategory" />
<Spinner
android:id="@+id/spCategory"
android:layout_width="250dp"
android:layout_height="40dp"
android:layout_alignBottom="@+id/lblSelectCategory"
android:layout_marginLeft="33dp"
android:layout_marginStart="33dp"
android:layout_toEndOf="@+id/lblSelectCategory"
android:layout_toRightOf="@+id/lblSelectCategory" />
<GridView
android:id="@+id/gridView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/lblSelectCategory"
android:layout_below="@+id/btnSaveProduct"
android:layout_marginTop="14dp"
android:numColumns="auto_fit" >
</GridView>
</RelativeLayout>
XML-HorizontalNumberpicker
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/RelativeLayout1"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<TextView
android:id="@+id/txtNPTitle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:text="EnterTextHere"
android:layout_marginTop="5dp" />
<Button
android:id="@+id/btnPlus"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_alignBaseline="@+id/txtNPValue"
android:layout_alignBottom="@+id/txtNPValue"
android:layout_toRightOf="@+id/txtNPValue"
android:text="+" />
<TextView
android:id="@+id/txtNPValue"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_alignTop="@+id/btnMinus"
android:layout_toRightOf="@+id/btnMinus"
android:gravity="center"
android:text="0"
android:textAppearance="@style/AppBaseTheme"
android:textSize="20dp" />
<Button
android:id="@+id/btnMinus"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_alignParentLeft="true"
android:layout_below="@+id/txtNPTitle"
android:layout_marginTop="2dp"
android:text="-" />
</RelativeLayout>
要求是當我按下加號按鈕時,我需要增加相應的txtNPValue中的值。 與減號按鈕類似,我需要減少txtNPValue中的值。
錯誤是
01-31 22:40:10.854:E / AndroidRuntime(32198):java.lang.NullPointerException:嘗試在空對象引用上調用虛擬方法'java.lang.CharSequence android.widget.TextView.getText()'
我也不知道這是否是編寫此類要求的正確方法,並且需要一些指針。
TextView tv = (TextView) v.findViewById(R.id.txtNPValue);
這將返回空指針異常,因為您獲得的視圖是按鈕或單擊的項目。
用這個 :-
RelativeLayout rlLayout =(RelativeLayout)v.getParent();
TextView電視=(TextView)rlLayout.findViewById(R.id.txtNPValue);
請刪除:
TextView tv = (TextView) v.findViewById(R.id.txtNPValue);
從onClick解決nullpointerException
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