如何在回收站视图中删除项目而不删除位置？

Question

我真的需要你的帮助。我已经用很多关键字搜索Google了很多天，但我听不懂。所以，我决定问你。

就在这里。实际上，我在RecyclerView中有一个按钮，但是该按钮会重复使用尽可能多的可用数据，有：带有文本“ Baca 3x”，“ Baca 4x”等的按钮。我想要，如果单击带有文本“ Baca 3x”的按钮3次，它将变为“ Baca 2x” >>“ Baca 1x” >>删除项目。另外，如果我单击带有文本“ Baca 4x”的按钮4次，它将变为“ Baca 3x” >>“ Baca 2x” >>“ Baca 1x” >>删除项目。

但是我的问题是，不能对每个按钮进行不同的处理，因为每次删除该项目时，数据的位置都会自动更改。因此，我无法获得特定的按钮。例如：有两个按钮，

 1. Button "Baca 3x" on position 0
 2. Button "Baca 4x" on position 1

如果位置0上的按钮“ Baca 3x”已被删除，则按钮“ Baca 4x”会自动将其位置更改为0。问题出在这里。

直到现在，我只获得每个按钮基于其位置的信息，这对我来说是个问题。因此，我正在考虑如何在回收器视图中删除项目而不删除位置？你们能解决我的问题吗？我应该使用DiffUtil吗？如何使用？在我使用的完整代码下面：

ModelDoa.java

public class ModelDoa {

public static final int DOA_PAGI = 0;
public static final int DOA_SORE = 1;
public static final int DOA_MASJID = 2;
public static final int DOA_BANGUNT = 3;
public static final int DOA_MAU_TIDUR = 4;

private String mName;
private String bName;
private int mType;

public ModelDoa(String name, String butong, int type) {
    this.mName = name;
    this.bName = butong;
    this.mType = type;
}

public String getName() {
    return mName;
}

public void setName(String name) {
    this.mName = name;
}


public int getType() {
    return mType;
}

public void setType(int type) { this.mType = type; }


public String ambilName() {
    return bName;
}

public void setNama(String butonk) {
    this.bName = butonk;
}

}

AdapterDoa.java

public class AdapterDoa extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

public List<ModelDoa> mList;

public AdapterDoa(List<ModelDoa> list) {

    this.mList = list;
}

@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

    switch (viewType) {

        case DOA_PAGI:
            View vieu = LayoutInflater.from(parent.getContext()).inflate(R.layout.content_doa, parent, false);
            PagiViewHolder rcv = new PagiViewHolder(vieu, this);
            return rcv;

        case DOA_SORE:
            View doa = LayoutInflater.from(parent.getContext()).inflate(R.layout.content_doa, parent, false);
            SoreViewHolder mdoa = new SoreViewHolder(doa);
            return mdoa;

        case DOA_MASJID:
            View dMasjid = LayoutInflater.from(parent.getContext()).inflate(R.layout.content_doa, parent, false);
            MasjidViewHolder mMasjid = new MasjidViewHolder(dMasjid);
            return mMasjid;

        case DOA_BANGUNT:
            View dBangunt = LayoutInflater.from(parent.getContext()).inflate(R.layout.content_doa, parent, false);
            BanguntViewHolder mBangunt = new BanguntViewHolder(dBangunt);
            return mBangunt;

        case DOA_MAU_TIDUR:
            View regut = LayoutInflater.from(parent.getContext()).inflate(R.layout.content_doa, parent, false);
            MauTidurViewHolder turu = new MauTidurViewHolder(regut);
            return turu;
    }
    return null;
}

@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {

    ModelDoa object = mList.get(position);

    if (object != null) {

        switch (object.getType()) {

            case DOA_PAGI:
                ((PagiViewHolder) holder).mTitle.setText(object.getName());
                ((PagiViewHolder) holder).tombolbaca.setText(object.ambilName());
                break;

            case DOA_SORE:
                ((SoreViewHolder) holder).mTitle.setText(object.getName());
                ((SoreViewHolder) holder).tombolbaca.setText(object.ambilName());
                break;

            case DOA_MASJID:
                ((MasjidViewHolder) holder).mTitle.setText(object.getName());
                ((MasjidViewHolder) holder).tombolbaca.setText(object.ambilName());
                break;

            case DOA_BANGUNT:
                ((BanguntViewHolder) holder).mTitle.setText(object.getName());
                ((BanguntViewHolder) holder).tombolbaca.setText(object.ambilName());
                break;

            case DOA_MAU_TIDUR:
                ((MauTidurViewHolder) holder).mTitle.setText(object.getName());
                ((MauTidurViewHolder) holder).tombolbaca.setText(object.ambilName());
                break;
        }
    }
}

public void deleteItem(int position) {
    mList.remove(position); // hapus list
    notifyItemRemoved(position); // hapus tampilan
    // notifyItemRangeChanged( position, mList.size());
}

@Override
public int getItemCount() {
    if (mList == null)
        return 0;
    return mList.size();
}

@Override
public int getItemViewType(int position) {
    if (mList != null) {
        ModelDoa object = mList.get(position);
        if (object != null) {
            return object.getType();
        }
    }
    return 0;
}


}

PagiViewHolder.java

public class PagiViewHolder extends RecyclerView.ViewHolder {
public TextView mTitle;
public Button tombolbaca;
public Button teksbaca;
public Button tombolshare;
private RelativeLayout rl2;
private int klik10 = 10;
private AdapterDoa myAdapter;

public PagiViewHolder(View itemView, AdapterDoa myAdapter) {
    super(itemView);
    this.myAdapter = myAdapter;

    itemView.setOnClickListener(mainViewClickListener);
    mTitle = (TextView) itemView.findViewById(R.id.titleTextView);
    tombolbaca = (Button) itemView.findViewById(R.id.buttonbaca);
    tombolshare = (Button) itemView.findViewById(R.id.buttonshare);
    tombolbaca.setOnClickListener(bacaClickListener);
    tombolshare.setOnClickListener(shareClickListener);
    rl2 = (RelativeLayout) itemView.findViewById(R.id.relmasjid);
}

private View.OnClickListener bacaClickListener = new View.OnClickListener() {

    @Override
    public void onClick(View v) {

        teksbaca = (Button) v.findViewById(R.id.buttonbaca);

        // Baca 10x
        if( getAdapterPosition() ==0 ) {
            klik10--;
            teksbaca.setText("Baca " + klik10 + "x");

            if (klik10 <= 0)
            {
                // modify listItems however you want... add, delete, shuffle, etc
                myAdapter.deleteItem(getAdapterPosition());
            }
        }

    } // onclick
};

private View.OnClickListener shareClickListener = new View.OnClickListener() {

    @Override
    public void onClick(View v) {
        // Do button click handling here
            Intent sendIntent = new Intent();
            sendIntent.setAction(Intent.ACTION_SEND);
            sendIntent.putExtra(Intent.EXTRA_TEXT, mTitle.getText().toString() + "\n \n download aplikasinya di: http://www.tauhid.or.id" );
            sendIntent.setType("text/plain");
            Intent.createChooser(sendIntent,"Share via");
            v.getContext().startActivity(sendIntent);
    }
};

private View.OnClickListener mainViewClickListener = new View.OnClickListener() {

    @Override
    public void onClick(View v) {
        // Do button click handling here
    }
};


}

DoaPagi.java

public class DoaPagi extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_doa_pagi);

    // toolbar
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    //this line shows back button
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);

    List<ModelDoa> rowListItem =  getData();
    LinearLayoutManager linearLayoutManager = new LinearLayoutManager(DoaPagi.this);
    RecyclerView mRecyclerView = (RecyclerView) findViewById(R.id.recyclerView);
    mRecyclerView.setLayoutManager(linearLayoutManager);
    mRecyclerView.setHasFixedSize(true);
    AdapterDoa rcAdapter = new AdapterDoa(rowListItem);
    mRecyclerView.setAdapter(rcAdapter);

}

private List<ModelDoa> getData() {

    String[] data = getResources().getStringArray(R.array.doapagi);
    String[] baca = getResources().getStringArray(R.array.bacapagi);

    List<ModelDoa> list = new ArrayList<ModelDoa>();

    for (int i = 0; i < data.length; i++) {
            list.add(new ModelDoa(data[i], baca[i], ModelDoa.DOA_PAGI));
    }

    return list;
}

// Agar back button pada halaman induk settings berfungsi
@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case android.R.id.home:
            this.finish();
            return true;
    }
    return super.onOptionsItemSelected(item);
}

}

更新（固定码）作者：Krishna Sharma： https://github.com/seadclark/RecyclerViewWithButtonClicks

Answer 1

有两种方法可以代替列表中的项目和更新界面。其中一个（deleteItem）仅删除项目，另一个（deleteItemAndUpdate）将删除项目并更新接口。

public void deleteItem(int position) {
    mList.remove(position); // hapus list
}

public void deleteItemAndUpdate(int position) {
    mList.remove(position); // hapus list
    notifyItemRemoved(position); // hapus tampilan
}

将来，您可以决定是只从列表中删除项目，还是删除项目并更新UI。

编辑1：

您需要跟踪每个项目的点击次数。我们可以将此值称为readCount。每次单击该项目，我们都会从该值中减去1。当该值达到0时，我们将从列表中将其删除。

ModelDoa：

public class ModelDoa {

    private int readCount = 10;

    public int getReadCount() {
        return this.readCount;
    }

    public void setReadCount(int readCount) {
        this.readCount = readCount;
    }
}

PagiViewHolder：

private View.OnClickListener bacaClickListener = new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        teksbaca = (Button) v.findViewById(R.id.buttonbaca);
        ModelDoa modelDoa = mAdapter.getItem(getAdapterPosition());

        if (modelDoa != null) {
            modelDoa.setReadCount(modelDoa.getReadCount() - 1);
            if (modelDoa.getReadCount() <= 0) {
                myAdapter.deleteItem(getAdapterPosition());
            }
            teksbaca.setText("Baca " + modelDoa.getReadCount() + "x");
        }
    }
};

AdapterDoa：

public ModelDoa getItem(int position) {
    if (position > -1 && position < getItemCount()) {
        return this.mList.get(position);
    } else {
        return null;
    }
}

编辑2：

这个想法是在实例化对象时设置readCount变量。您没有执行相同操作的多个变量。您只需在创建变量时将单个readCount变量更改为7或10，并在检索模型本身（而不是变量！）时使用相同的getItem方法即可。

ModelDoa：

public class ModelDoa {

    private String name;
    private String butong;
    private int type;
    private int readCount;

    public ModelDoa(String name, String butong, int type, int readCount) {
        this.mName = name;
        this.bName = butong;
        this.mType = type;
        this.readCount = readCount;
    }

    public int getReadCount() {
        return this.readCount;
    }

    public void setReadCount(int readCount) {
        this.readCount = readCount;
    }
}

DoaPagi：

private List<ModelDoa> getData() {
    String[] data = getResources().getStringArray(R.array.doapagi);
    String[] baca = getResources().getStringArray(R.array.bacapagi);

    List<ModelDoa> list = new ArrayList<ModelDoa>();

    for (int i = 0; i < data.length; i++) {
        // Here is where you would set the value of readCount.
        list.add(new ModelDoa(data[i], baca[i], ModelDoa.DOA_PAGI, i));
    }

    return list;
}

Answer 2

这是解决方法。只需更新ModelDoa构造函数，如下所示。我已经验证了自己，并且现在可以按预期工作。 也向您发送了github上的拉取请求。

public ModelDoa(String name, String butong, int type) {
    this.mName = name;
    this.bName = butong;
    this.mType = type;
    String[] data = butong.split("\\s");
    if (data.length > 0) {
        String count = data[1].substring(0, data[1].length() - 1);
        read10 = Integer.parseInt(count);
    }
}