您好我已按照此链接How to highlight filtered text in RecyclerView when using SearchView widget在recyclerview中制作自定义过滤列表。但它对我的情况不起作用，我的代码有什么问题？如果你能看起来和帮助我，我真的会感到骄傲。
感谢SaravInfern关注我的案例，过滤是成功但不改变颜色
这是我的适配器：
public class TanamanAdapter extends RecyclerView.Adapter<DaftarTanamanVH>{
private List<Tanaman> mTanaman;
private ImageLoader imageLoader;
private Context context;
String searchText = "";
public TanamanAdapter(List<Tanaman> mTanaman, Context context){
this.mTanaman = mTanaman;
this.context = context;
}
@Override
public DaftarTanamanVH onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_tanaman,parent,false);
return new DaftarTanamanVH(v);
}
@Override
public void onBindViewHolder(DaftarTanamanVH holder, int position) {
final Tanaman tanaman = mTanaman.get(position);
String namaTanaman = tanaman.getNama_tanaman();
String namaIlmiah = tanaman.getNama_ilmiah();
String urlGambar = tanaman.getUrlGambar();
imageLoader = CustomVolleyRequest.getInstance(context).getImageLoader();
imageLoader.get(urlGambar,ImageLoader.getImageListener(holder.networkImageView,R.mipmap.ic_launcher,android.R.drawable.ic_dialog_alert));
//holder.bind(tanaman);
holder.tv_nama_tanaman.setText(namaTanaman);
holder.networkImageView.setImageUrl(urlGambar,imageLoader);
if(searchText.length() > 0){
int index = namaIlmiah.indexOf(searchText);
while(index > 0){
SpannableStringBuilder sb = new SpannableStringBuilder(namaIlmiah);
ForegroundColorSpan fcs = new ForegroundColorSpan(Color.BLUE);
sb.setSpan(fcs,index,searchText.length(),Spanned.SPAN_INCLUSIVE_EXCLUSIVE);
index = namaIlmiah.indexOf(searchText,index+1);
holder.tv_nama_ilmiah.setText(sb);
}
}else{
holder.tv_nama_ilmiah.setText(namaIlmiah);
}
/*
holder.cardView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(v.getContext(), DetailTanaman.class);
intent.putExtra("KEY_ID",tanaman.getId_tanaman());
intent.putExtra("KEY_NAMA",tanaman.getNama_tanaman());
intent.putExtra("KEY_ILMIAH",tanaman.getNama_ilmiah());
intent.putExtra("KEY_GAMBAR",tanaman.getUrlGambar());
v.getContext().startActivity(intent);
}
});*/
}
@Override
public int getItemCount() {
return mTanaman.size();
}
public void setFilter(List<Tanaman> tanamanList, String searchText){
mTanaman = new ArrayList<>();
mTanaman.addAll(tanamanList);
this.searchText = searchText;
notifyDataSetChanged();
}
}
这是我的活动：
public class DaftarTanaman extends AppCompatActivity implements SearchView.OnQueryTextListener{
private RecyclerView recyclerView;
private List<Tanaman> mTanaman;
private TanamanAdapter tanamanAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_daftar_tanaman);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
ActionBar actionBar = getSupportActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
recyclerView = (RecyclerView) findViewById(R.id.rv_daftar_tanaman);
LinearLayoutManager layoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(layoutManager);
mTanaman = new ArrayList<>();
getDataTanaman();
}
private void getDataTanaman() {
final ProgressDialog loading = ProgressDialog.show(this,"Mohon tunggu ...","Sedang mengambil data...",false,false);
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(ConfigTanaman.DATA_URL_TANAMAN, new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray jsonArray) {
loading.dismiss();
parseData(jsonArray);
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError volleyError) {
}
});
RequestQueue requestQueue = Volley.newRequestQueue(this);
requestQueue.add(jsonArrayRequest);
}
private void parseData(JSONArray jsonArray) {
for(int i=0;i<jsonArray.length();i++){
Tanaman tanaman = new Tanaman();
JSONObject jsonObject = null;
try{
jsonObject = jsonArray.getJSONObject(i);
tanaman.setId_tanaman(jsonObject.getString(ConfigTanaman.TAG_ID));
tanaman.setNama_tanaman(jsonObject.getString(ConfigTanaman.TAG_NAMA));
tanaman.setNama_ilmiah(jsonObject.getString(ConfigTanaman.TAG_ILMIAH));
tanaman.setUrlGambar(jsonObject.getString(ConfigTanaman.TAG_URL_GAMBAR));
}catch(JSONException e){
e.printStackTrace();
}
mTanaman.add(tanaman);
}
tanamanAdapter = new TanamanAdapter(mTanaman,this);
recyclerView.setAdapter(tanamanAdapter);
}
@Override
public boolean onQueryTextSubmit(String query) {
final List<Tanaman> filteredTanaman = filter(mTanaman,query);
tanamanAdapter.setFilter(filteredTanaman,query);
if(filteredTanaman.size() == 0){
Toast.makeText(DaftarTanaman.this, "Maaf, data dengan kata kunci "+query+" tidak ditemukan", Toast.LENGTH_SHORT).show();
return false;
}
return true;
}
private List<Tanaman> filter(List<Tanaman> models, String query) {
query = query.toLowerCase();
final List<Tanaman> filteredTanaman = new ArrayList<>();
KMP kmp = new KMP();
for(Tanaman model: models){
final String source = model.getNama_tanaman().toLowerCase();
int pos = kmp.postMatch(source,query);
if(pos != -1){
filteredTanaman.add(model);
}
}
return filteredTanaman;
}
@Override
public boolean onQueryTextChange(String newText) {
return false;
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menu_main,menu);
final MenuItem item = menu.findItem(R.id.action_search);
final SearchView searchView = (SearchView) MenuItemCompat.getActionView(item);
searchView.setOnQueryTextListener(this);
MenuItemCompat.setOnActionExpandListener(item, new MenuItemCompat.OnActionExpandListener() {
@Override
public boolean onMenuItemActionExpand(MenuItem item) {
return true;
}
@Override
public boolean onMenuItemActionCollapse(MenuItem item) {
tanamanAdapter.setFilter(mTanaman,"");
return true;
}
});
return super.onCreateOptionsMenu(menu);
}
}
这是显示错误的日志猫：
FATAL EXCEPTION: main
Process: id.tanamanobat.skripsi.qori.ensiklopeditanamanobat, PID: 2927
java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.length()' on a null object reference
at id.tanamanobat.skripsi.qori.ensiklopeditanamanobat.Adapter.TanamanAdapter.onBindViewHolder(TanamanAdapter.java:67)
at id.tanamanobat.skripsi.qori.ensiklopeditanamanobat.Adapter.TanamanAdapter.onBindViewHolder(TanamanAdapter.java:35)
at android.support.v7.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:5471)
at android.support.v7.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:5504)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4741)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4617)
at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:1994)
at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1390)
at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1353)
at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:574)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3028)
at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:2906)
at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:3283)
at android.view.View.layout(View.java:15596)
at android.view.ViewGroup.layout(ViewGroup.java:4966)
at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1076)
at android.view.View.layout(View.java:15596)
at android.view.ViewGroup.layout(ViewGroup.java:4966)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:573)
at android.widget.FrameLayout.onLayout(FrameLayout.java:508)
at android.view.View.layout(View.java:15596)
at android.view.ViewGroup.layout(ViewGroup.java:4966)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1703)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1557)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1466)
at android.view.View.layout(View.java:15596)
at android.view.ViewGroup.layout(ViewGroup.java:4966)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:573)
at android.widget.FrameLayout.onLayout(FrameLayout.java:508)
at android.view.View.layout(View.java:15596)
at android.view.ViewGroup.layout(ViewGroup.java:4966)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1703)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1557)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1466)
at android.view.View.layout(View.java:15596)
at android.view.ViewGroup.layout(ViewGroup.java:4966)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:573)
at android.widget.FrameLayout.onLayout(FrameLayout.java:508)
at android.view.View.layout(View.java:15596)
at android.view.ViewGroup.layout(ViewGroup.java:4966)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2072)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1829)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1054)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5779)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
at android.view.Choreographer.doCallbacks(Choreographer.java:580)
at android.view.Choreographer.doFrame(Choreographer.java:550)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.jav
以下是截图：
答案 0 :(得分：0)
Attempt to invoke virtual method 'int java.lang.String.length()' on a null object reference我可以说，当您创建适配器时，searchText为空，您在调用setFilter时将值存储在其中，因此最简单的解决方案是为您的searchText 指定空白值
String searchText = "";
答案 1 :(得分：0)
您必须像这样String searchText = "";初始化searchText或进行空检查
if(searchText.length() > 0 && searchText!=null){
int index = namaIlmiah.indexOf(searchText);
while(index > 0){
SpannableStringBuilder sb = new SpannableStringBuilder(namaIlmiah);
ForegroundColorSpan fcs = new ForegroundColorSpan(Color.BLUE);
sb.setSpan(fcs,index,searchText.length(),Spanned.SPAN_INCLUSIVE_EXCLUSIVE);
index = namaIlmiah.indexOf(searchText,index+1);
holder.tv_nama_ilmiah.setText(sb);
}
}else{
holder.tv_nama_ilmiah.setText(namaIlmiah);
}