基于列表项位置的java替换片段
我正在为我的片段使用一个两行列表视图。如何根据所选列表视图项的位置执行必要的步骤?下面是替换细节片段的代码,但它与位置无关
- 如果mTwoPane为true,我希望用片段替换细节容器(使用该列表项中的片段名称)
- 如果mTwoPane为false,我希望启动活动(使用该列表项中的活动名称)
更换细节容器
FragmentLineChooserList newFragment = new FragmentLineChooserList();
FragmentTransaction transaction = FragmentMainList.this.getActivity().getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.detail_container, newFragment);
transaction.commit();
碎片线。java
public class FragmentWCLine extends 安卓.support.v4.app.Fragment {
ListView listView;
private class WC {
private CharSequence station;
private CharSequence zone;
private Class<? extends Activity> activityClass;
private Class<? extends 安卓.support.v4.app.Fragment> fragmentClass;
public WC(int stationResId, int zoneResId, Class<? extends Activity> activityClass, Class<? extends 安卓.support.v4.app.Fragment> fragmentClass) {
this.fragmentClass = fragmentClass;
this.activityClass = activityClass;
this.station = getResources().getString(stationResId);
this.zone = getResources().getString(zoneResId);
}
@Override
public String toString() { return station.toString(); }
public String getzone(){ return zone.toString(); }
}
private static WC[] mWC;
private boolean mTwoPane;
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
View v = inflater.inflate(R.layout.fragment_wc_line, container, false);
mWC = new WC[]{
new WC(R.string.bank, R.string.zone_1, WCBankActivity.class, FragmentWCBank.class),
new WC(R.string.wat, R.string.zone_1, WCWATActivity.class, FragmentWCWAT.class)
};
listView = (ListView)v.findViewById(R.id.list_wc);
listView.setAdapter(new MyAdapter(getActivity(), mWC));
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
if (mTwoPane) {
startActivity(new Intent(getActivity(), mWC[position].fragmentClass));
} else {
startActivity(new Intent(getActivity(), mWC[position].activityClass));
}
}
});
return v;
}
static class MyAdapter extends BaseAdapter {
static class ViewHolder {
TextView station;
TextView zone;
}
LayoutInflater inflater;
WC[] mWC;
public MyAdapter(Context contexts, WC[] samples) {
this.mWC = samples;
inflater = LayoutInflater.from(contexts);
}
@Override
public int getCount() {
return mWC.length;
}
@Override
public Object getItem(int position) {
return mWC[position];
}
@Override
public long getItemId(int position) {
return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder viewHolder;
if (convertView == null) {
convertView = inflater.inflate(R.layout.list_item_dualline, null);
viewHolder = new ViewHolder();
viewHolder.station = (TextView) convertView.findViewById(R.id.list_item_station);
viewHolder.zone = (TextView) convertView.findViewById(R.id.list_item_zone);
convertView.setTag(viewHolder);
} else {
viewHolder = (ViewHolder) convertView.getTag();
}
viewHolder.station.setText(mWC[position].station);
viewHolder.zone.setText(mWC[position].getzone());
return convertView;
}
}
}
FragmentWCLine-更新0
public class FragmentWCLine extends 安卓.support.v4.app.Fragment {
ListView listView;
private class WC {
private CharSequence station;
private CharSequence zone;
private Class<? extends Activity> activityClass;
private Class<? extends 安卓.support.v4.app.Fragment> fragmentClass;
public WC(int stationResId, int zoneResId, Class<? extends Activity> activityClass, Class<? extends 安卓.support.v4.app.Fragment> fragmentClass) {
this.fragmentClass = fragmentClass;
this.activityClass = activityClass;
this.station = getResources().getString(stationResId);
this.zone = getResources().getString(zoneResId);
}
@Override
public String toString() { return station.toString(); }
public String getzone(){ return zone.toString(); }
}
private static WC[] mWC;
private boolean mTwoPane;
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
View v = inflater.inflate(R.layout.fragment_wc_line, container, false);
mWC = new WC[]{
new WC(R.string.bank, R.string.zone_1, WCBankActivity.class, FragmentWCBank.class),
new WC(R.string.wat, R.string.zone_1, WCWATActivity.class, FragmentWCWAT.class)
};
listView = (ListView)v.findViewById(R.id.list_wc);
listView.setAdapter(new MyAdapter(getActivity(), mWC));
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
if (mTwoPane) {
startActivity(new Intent(getActivity(), mWC[position].fragmentClass));
} else {
startActivity(new Intent(getActivity(), mWC[position].activityClass));
}
}
});
return v;
}
static class MyAdapter extends BaseAdapter {
static class ViewHolder {
TextView station;
TextView zone;
}
LayoutInflater inflater;
WC[] mWC;
public MyAdapter(Context contexts, WC[] samples) {
this.mWC = samples;
}
@Override
public int getCount() {
return mWC.length;
}
@Override
public Object getItem(int position) {
return mWC[position];
}
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder viewHolder;
if (convertView == null) {
convertView = inflater.inflate(R.layout.list_item_dualline, null);
viewHolder = new ViewHolder();
viewHolder.station = (TextView) convertView.findViewById(R.id.list_item_station);
viewHolder.zone = (TextView) convertView.findViewById(R.id.list_item_zone);
convertView.setTag(viewHolder);
} else {
viewHolder = (ViewHolder) convertView.getTag();
}
viewHolder.station.setText(mWC[position].station);
viewHolder.zone.setText(mWC[position].getzone());
return convertView;
}
}
}
碎片线路-更新1
public class FragmentWCLine extends 安卓.support.v4.app.Fragment {
ListView listView;
private class WC {
private CharSequence station;
private CharSequence zone;
private Class<? extends Activity> activityClass;
private Class<? extends 安卓.support.v4.app.Fragment> fragmentClass;
public WC(int stationResId, int zoneResId, Class<? extends Activity> activityClass, Class<? extends 安卓.support.v4.app.Fragment> fragmentClass) {
this.fragmentClass = fragmentClass;
this.activityClass = activityClass;
this.station = getResources().getString(stationResId);
this.zone = getResources().getString(zoneResId);
}
@Override
public String toString() { return station.toString(); }
public String getzone(){ return zone.toString(); }
}
private static WC[] mWC;
private boolean mTwoPane;
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
View v = inflater.inflate(R.layout.fragment_wc_line, container, false);
mWC = new WC[]{
new WC(R.string.bank, R.string.zone_1, WCBankActivity.class, FragmentWCBank.class),
new WC(R.string.wat, R.string.zone_1, WCWATActivity.class, FragmentWCWAT.class)
};
listView = (ListView)v.findViewById(R.id.list_wc);
listView.setAdapter(new MyAdapter(getActivity(), mWC));
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
if (mTwoPane) {
startActivity(new Intent(getActivity(), mWC[position].fragmentClass));
} else {
startActivity(new Intent(getActivity(), mWC[position].activityClass));
}
}
});
return v;
}
static class MyAdapter extends BaseAdapter {
static class ViewHolder {
TextView station;
TextView zone;
}
LayoutInflater inflater;
WC[] mWC;
public MyAdapter(Context contexts, WC[] samples) {
this.mWC = samples;
}
@Override
public int getCount() {
return mWC.length;
}
@Override
public Object getItem(int position) {
return mWC[position];
}
@Override
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder viewHolder;
if (convertView == null) {
convertView = inflater.inflate(R.layout.list_item_dualline, null);
viewHolder = new ViewHolder();
viewHolder.station = (TextView) convertView.findViewById(R.id.list_item_station);
viewHolder.zone = (TextView) convertView.findViewById(R.id.list_item_zone);
convertView.setTag(viewHolder);
} else {
viewHolder = (ViewHolder) convertView.getTag();
}
viewHolder.station.setText(mWC[position].station);
viewHolder.zone.setText(mWC[position].getzone());
return convertView;
}
}
}
# 1 楼答案
我注意到
MyAdapter
构造函数中的代码inflater = LayoutInflater.from(contexts)
中有一个问题。它不应该存在于这种方法中。我从未见过任何示例项目在构造函数中实现这一点。原因是,如果用户翻转手机,或者安卓决定换掉你的应用程序以释放内存,那么构造器不会恢复。测试一下代码建议,在getView中充气:
新代码建议:
注:
contexts
,并将其保存为getView()李>getItemId
()并在适配器中返回0,而不是像position这样的实际值或mWC[position]的成员变量。如果此方法返回0或null,则任何引用它的代码都将与零值混淆李>getItemId
的代码是从ArrayAdapter中的相同方法复制的李>