我有一个 Activity 。我正在创建一个文件,该文件在创建 Activity 时包含一些数据。正确创建所有文件并正确写入数据。 以下是我的代码
public class MyRecordingsActivity extends AppCompatActivity {
private RecyclerView recyclerView;
private RecordingsAdapter recordingsAdapter;
private ArrayList<Recording> recordingArrayList;
private File userRecordingFile;
private static final String USER_MIX_DIR = "UserMix";
private String lines[]=new String[]{};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my_recordings);
for(int i=0;i<5;i++){
try{
userRecordingFile = new File(createRecordingFiles(), "Recording"+i+".txt");
FileWriter writer = new FileWriter(userRecordingFile);
writer.append("DEF"+i+"\nHIJ "+i);
writer.flush();
writer.close();
}
catch (Exception e){
e.printStackTrace();
}
}
getSupportActionBar().hide();
recordingArrayList=new ArrayList<>();
recyclerView=findViewById(R.id.recyclerView);
recyclerView.setLayoutManager(new LinearLayoutManager(getApplicationContext()));
recyclerView.setHasFixedSize(true);
readFiles();
Toast.makeText(getApplicationContext(),lines[0],Toast.LENGTH_SHORT).show();
Toast.makeText(getApplicationContext(),lines[1],Toast.LENGTH_SHORT).show();
recordingArrayList.add(new Recording(R.drawable.ic_launcher,lines[0],lines[1]));
recordingArrayList.add(new Recording(R.drawable.ic_launcher,lines[2],lines[3]));
recordingArrayList.add(new Recording(R.drawable.ic_launcher,lines[4],lines[5]));
recordingArrayList.add(new Recording(R.drawable.ic_launcher,lines[6],lines[7]));
recordingArrayList.add(new Recording(R.drawable.ic_launcher,lines[8],lines[9]));
recordingsAdapter=new RecordingsAdapter(recordingArrayList);
recyclerView.setAdapter(recordingsAdapter);
}
public File createRecordingFiles() {
File dirRoot = getExternalCacheDir();
File workDir = new File(dirRoot, USER_MIX_DIR);
//Toast.makeText(getApplicationContext(), "HI", Toast.LENGTH_SHORT).show();
if (!workDir.exists()) {
workDir.mkdirs();
File recordingFile = new File(workDir, "Recording File ");
try {
recordingFile.createNewFile();
} catch (IOException e) {
}
}
return workDir;
}
public void readFiles(){
StringBuilder text = new StringBuilder();
BufferedReader br=null;
try {
File dirRoot = getExternalCacheDir();
File workDir = new File(dirRoot, USER_MIX_DIR);
for(int i=0;i<5;i++){
File file = new File(workDir,"Recording"+i+".txt");
br = new BufferedReader(new FileReader(file));
String line;
while ((line = br.readLine()) != null) {
text.append(line);
text.append('\n');
lines=text.toString().split("\n");
}
}
br.close() ;
}catch (IOException e) {
e.printStackTrace();
}
}
}
我写的 Toast 正确显示了 DEF0 和 HIJ 0,但它们没有显示在 recyclerview 中。以下是屏幕截图
以下是我的适配器类
public class RecordingsAdapter extends RecyclerView.Adapter<RecordingsAdapter.RecyclerViewHolder> {
public static final int TYPE_HEAD=0;
public static final int TYPE_LIST=1;
private ArrayList<Recording> recordingArrayList;
public RecordingsAdapter(ArrayList<Recording> recordingArrayList) {
this.recordingArrayList = recordingArrayList;
}
@Override
public RecyclerViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view;
RecyclerViewHolder recyclerViewHolder;
if(viewType == TYPE_LIST){
view= LayoutInflater.from(parent.getContext()).inflate(R.layout.cell_my_recordings,parent,
false);
recyclerViewHolder=new RecyclerViewHolder(view,viewType);
return recyclerViewHolder;
}else if(viewType == TYPE_HEAD){
view= LayoutInflater.from(parent.getContext()).inflate(R.layout.head_layout,parent,
false);
recyclerViewHolder=new RecyclerViewHolder(view,viewType);
return recyclerViewHolder;
}
return null;
}
@Override
public void onBindViewHolder(RecyclerViewHolder holder, int position) {
Recording recording;
if(holder.view_type==TYPE_LIST){
recording=recordingArrayList.get(position);
holder.imageView.setImageResource(recording.getImage_id());
holder.typeTextView.setText(recording.getTitle());
holder.dateTimeTextView.setText(recording.getDatetime());
}else if (holder.view_type == TYPE_HEAD){
holder.typeHeaderTextView.setText("TYPE");
holder.titleHeaderTextView.setText("TITLE");
holder.dateTimeHeaderTextView.setText("DATE/TIME");
}
}
@Override
public int getItemCount() {
return recordingArrayList.size();
}
@Override
public int getItemViewType(int position) {
if(position==0){
return TYPE_HEAD;
}
return TYPE_LIST;
}
public static class RecyclerViewHolder extends RecyclerView.ViewHolder{
int view_type;
ImageView imageView;
TextView typeTextView,dateTimeTextView;
TextView typeHeaderTextView,titleHeaderTextView,dateTimeHeaderTextView;
public RecyclerViewHolder(View itemView, int viewType) {
super(itemView);
if(viewType==TYPE_LIST){
typeTextView=itemView.findViewById(R.id.tv_cell_recording_recording_name);
imageView=itemView.findViewById(R.id.iv_cell_recordings);
dateTimeTextView=itemView.findViewById(R.id.tv_cell_recording_date_time);
view_type=1;
}else if(viewType==TYPE_HEAD){
typeHeaderTextView=itemView.findViewById(R.id.tv_type_head_layout);
titleHeaderTextView=itemView.findViewById(R.id.tv_title_head_layout);
dateTimeHeaderTextView=itemView.findViewById(R.id.tv_date_time_head_layout);
view_type=0;
}
}
}
}
DEf0 和 HIJ 0 没有显示在 recyclerview 中。我不明白为什么它们没有显示在我的回收站 View 中。我的日志中没有错误。任何帮助将不胜感激
最佳答案
你做错了....
您要在 recyclerview
中添加五个项目,但首先要考虑的是标题。
所以这会将您的第一个项目作为标题,您会看到其他四个项目。
您需要做的是,将虚拟项目作为第一个项目传递,然后添加您的 5 个项目。
这样你就可以解决你的问题。
你可以这样试试:
recordingArrayList.add(new Recording(R.drawable.ic_launcher,"", ""));
recordingArrayList.add(new Recording(R.drawable.ic_launcher,lines[0],lines[1]));
recordingArrayList.add(new Recording(R.drawable.ic_launcher,lines[2],lines[3]));
recordingArrayList.add(new Recording(R.drawable.ic_launcher,lines[4],lines[5]));
recordingArrayList.add(new Recording(R.drawable.ic_launcher,lines[6],lines[7]));
recordingArrayList.add(new Recording(R.drawable.ic_launcher,lines[8],lines[9]));
或者你也可以按照下面的方式进行:
更改适配器代码
@Override
public int getItemCount() {
return recordingArrayList.size() + 1;
}
@Override
public void onBindViewHolder(RecyclerViewHolder holder, int position) {
Recording recording;
if(holder.view_type==TYPE_LIST){
recording=recordingArrayList.get(position - 1);
...
}else if (holder.view_type == TYPE_HEAD){
holder.typeHeaderTextView.setText("TYPE");
holder.titleHeaderTextView.setText("TITLE");
holder.dateTimeHeaderTextView.setText("DATE/TIME");
}
}
但是你需要用这种方式验证空列表
关于android - RecyclerView 的第一项丢失,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/48501732/