具有不同的布局的ListView行 [英] ListView rows with different layouts
问题描述
我试图做到的,是有不同的布局每一行。在code在我的 ArrayAdapter
如下:
What I am trying to achieve is to have different layouts for each row. The code in my ArrayAdapter
is as follows:
@Override
public int getCount() {
return contentList.size();
}
@Override
public MyContents getItem(int position) {
return content.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public int getViewTypeCount() {
// TODO Auto-generated method stub
return 2;
}
@Override
public int getItemViewType(int position) {
// TODO Auto-generated method stub
return super.getItemViewType(position);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
final MyContents entry = content.get(position);
View row = convertView;
LayoutInflater inflater = null;
boolean _haschild_ = entry.testBoolean();
if (row == null) {
if (entry.testBoolean()) {
inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
row = inflater
.inflate(R.layout.contents_layout, null);
} else {
inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
row = inflater.inflate(R.layout.test_layout, null);
}
}
if (entry.testBoolean()) {
TextView txtView = (TextView) row
.findViewById(R.id.txtView);
//.....
} else {
((TextView) row.findViewById(R.id.txtView_test)) //**LOE**
.setText("test: " + position); //**LOE**
}
return row;
}
在布局文件* test_layout.xml *:
The layout file for *test_layout.xml*:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/layout_test"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_margin="12dp"
android:background="@color/grey_five"
android:orientation="vertical"
android:padding="@dimen/padding_small" >
<TextView
android:id="@+id/txtView_test"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:text="@string/lorem__ipsum"
android:textAppearance="?android:attr/textAppearanceMedium"
android:textColor="@color/grey" />
</RelativeLayout>
但每当我执行它抛出一个 NullPointerException异常
(检查与注释行// LOE )。
But whenever I execute it throws a NullPointerException
(check the line with the comment //LOE).
任何建议怎么办?我挣扎与它过去的一天。
Any suggestion what to do? I am struggling with it for past one day.
推荐答案
这 NullPointerException异常
是因为你没有执行 getItemViewType
。现在您返回的行布局的第一种类型,不管是什么,这是不具备* txtView_test * 布局的TextView
)。您的code应该是这样的:
That NullPointerException
occurs because you didn't implement the getItemViewType
. Right now you return the first type of row layout no matter what and this is a layout that doesn't have the *txtView_test* TextView
). Your code should be something like this:
// some fields
public static final int FIRST_TYPE = 0;
public static final int SECOND_TYPE = 1;
@Override
public int getItemViewType(int position) {
MyContents item = getItem(position);
if (item.testBoolean()) {
return FIRST_TYPE;
} else {
return SECOND_TYPE;
}
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
final MyContents entry = content.get(position);
View row = convertView;
LayoutInflater inflater = null;
int type = getItemViewType(position);
boolean _haschild_ = entry.testBoolean();
if (row == null) {
if (type == FIRST_TYPE) {
inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
row = inflater
.inflate(R.layout.contents_layout, null);
} else {
inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
row = inflater.inflate(R.layout.test_layout, null);
}
}
if (type == FIRST_TYPE) {
TextView txtView = (TextView) row
.findViewById(R.id.txtView);
//.....
} else {
((TextView) row.findViewById(R.id.txtView_test)) //**LOE**
.setText("test: " + position); //**LOE**
}
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