Question

可以在适配器中放入if / else语句吗？这是代码：
我希望将textview的可见性设置为在其为空时消失，否则它将可见。

package daily.diary;

import java.util.ArrayList;
import java.util.HashMap;

import android.app.ListActivity;
import android.content.Intent;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextUtils;
import android.text.TextWatcher;
import android.view.ContextMenu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ContextMenu.ContextMenuInfo;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.TextView;

public class MainActivity extends ListActivity {
Intent intent;
public static ArrayList<HashMap<String, String>> listresults;
public static int val = 2;
DBHelper controller = new DBHelper(this);
public int entry;
ArrayAdapter<String> myadapter;
public ListView lv;
TextView Id, counter, title, content;
private int count;
private EditText searchtext;
private Button cancel, btnsearch,settings;
public static String searchkeyword;
private ArrayList<HashMap<String, String>> EntryList;

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

    counter = (TextView) findViewById(R.id.cnt);
    searchtext = (EditText) findViewById(R.id.searchtext);
    cancel = (Button) findViewById(R.id.cancel);
    btnsearch = (Button) findViewById(R.id.search);
    settings = (Button) findViewById(R.id.settings);
    lv = (ListView) findViewById(android.R.id.list);

    registerForContextMenu(getListView());

    EntryList = controller.getAllEntry();
    if (EntryList.size() != 0) {
        ListView lv = getListView();
        lv.setOnItemClickListener(new OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                val = 0;
                Id = (TextView) view.findViewById(R.id.Id);
                String valId = Id.getText().toString();
                MainActivity.this.onDestroy();
                Intent objIndent = new Intent(getApplicationContext(),
                        EditEntry.class);
                objIndent.putExtra("Id", valId);
                startActivity(objIndent);
            }
        });

        lv.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {

            public boolean onItemLongClick(AdapterView<?> arg0, View v,
                    int index, long arg3) {
                Id = (TextView) v.findViewById(R.id.Id);
                title = (TextView) v.findViewById(R.id.title);
                content = (TextView) v.findViewById(R.id.content);
                return false;
            }
        });

        viewentry();

        count = lv.getCount();
        counter.setText("Entries:" + count);
    }

}


/*@Override
public void onBackPressed() {
        Toast.makeText(getBaseContext(), "Press back again to exit", Toast.LENGTH_LONG).show();
        super.onBackPressed();
    }*/





public void viewentry() {
    EntryList = controller.getAllEntry();
    ListAdapter adapter = new SimpleAdapter(
        MainActivity.this, 
        EntryList,
        R.layout.timeline,
        new String[] { "Id", "title", "content", "date", "time", "category", "tag", "location", "mood" }, 
        new int[] { R.id.Id, R.id.title, R.id.content, R.id.date, R.id.time, R.id.category, R.id.tag, R.id.location, R.id.mood }
    );

        if (TextUtils.isEmpty(title.getText())){

               title.setVisibility(View.GONE);
            } 
    setListAdapter(adapter);
}

public void onCancel(View view) {
    searchtext.setText("");
    searchtext.setVisibility(View.GONE);
    cancel.setVisibility(View.GONE);
    settings.setVisibility(View.VISIBLE);
    btnsearch.setVisibility(View.VISIBLE);
    btnsearch.setEnabled(true);
}

public void onSearch(View view) {
    if (searchtext.getVisibility() == View.GONE) {
        btnsearch.setEnabled(false);
        cancel.setVisibility(View.VISIBLE);
        searchtext.setVisibility(View.VISIBLE);
        btnsearch.setVisibility(View.INVISIBLE);
        settings.setVisibility(View.GONE);

        TextWatcher textWatcher = new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence charSequence, int i,
                    int i1, int i2) {

            }

            @Override
            public void onTextChanged(CharSequence charSequence, int i,
                    int i1, int i2) {
                searchlist();
            }

            @Override
            public void afterTextChanged(Editable editable) {

            }
        };
        searchtext.addTextChangedListener(textWatcher);

    }

}

public void searchlist() {
    searchkeyword = searchtext.getText().toString();
    if (!searchtext.getText().toString().equals("")) {
        listresults = controller.getAllEntryfromsearch();
    } else {
        listresults = controller.getAllEntry();
    }
    ListAdapter adapter = new SimpleAdapter(MainActivity.this, listresults,
            R.layout.timeline,
            new String[] { "Id", "title", "content", "date", "time",
                    "category", "tag", "location", "mood" }, new int[] {
                    R.id.Id, R.id.title, R.id.content, R.id.date,
                    R.id.time, R.id.category, R.id.tag, R.id.location,
                    R.id.mood });
    setListAdapter(adapter);
    count = lv.getCount();
    counter.setText("Entries:" + count);

}

public void onAdd(View view) {
    val = 1;
    Intent objIntent = new Intent(getApplicationContext(), NewEntry.class);
    startActivity(objIntent);
    MainActivity.this.onDestroy();

}

@Override
public void onCreateContextMenu(ContextMenu menu, View v,
        ContextMenuInfo itemId) {
    super.onCreateContextMenu(menu, v, itemId);
    MenuInflater mi = getMenuInflater();
    mi.inflate(R.menu.action_list, menu);
    menu.setHeaderTitle("Choose Action");
    menu.setHeaderIcon(R.drawable.ic_action_warning);

}

@Override
public boolean onContextItemSelected(MenuItem item) {
    switch (item.getItemId()) {
    case R.id.delete:
        SQLiteDatabase database = controller.getWritableDatabase();
        database.execSQL("DELETE FROM Entry Where Id="
                + Id.getText().toString() + "");
        viewentry();
        count = lv.getCount();
        counter.setText("Entries:" + count);
        Toast.makeText(getApplication(), "Deleted Successfully",
                Toast.LENGTH_LONG).show();
        break;
    case R.id.mail:
        final Intent send = new Intent(android.content.Intent.ACTION_SEND);

        send.setType("text/plain");

        send.putExtra(android.content.Intent.EXTRA_SUBJECT, title.getText()
                .toString());

        send.putExtra(android.content.Intent.EXTRA_TEXT, content.getText()
                .toString());

        MainActivity.this.startActivity(android.content.Intent
                .createChooser(send, "Send via"));
        break;
    case R.id.cancel:
        break;
    }
    return super.onContextItemSelected(item);
}

}

有人能帮助我吗？

Answer 1

有很多方法可以做到这一点。我使用这样的东西：

if (tv.length() == 0) {
    tv.setVisibility(View.GONE)
}

Answer 2

根据你的问题答案是

if (tv.length() == 0) {
 tv.setVisibility(View.GONE);

}

或者您可以使用

 if (TextUtils.isEmpty(tv.getText()){

   tv.setVisibility(View.GONE);
}

的更新： 的

将此代码移至onCreate（）方法。

Id = (TextView) v.findViewById(R.id.Id); title = (TextView) v.findViewById(R.id.title); content = (TextView) v.findViewById(R.id.content);

到

Id = (TextView)findViewById(R.id.Id); title = (TextView)findViewById(R.id.title); content = (TextView)findViewById(R.id.content);

Answer 3

在文本视图中添加文本观察器。当文本为空时，将visibilty设置为GONE。

textview.setTextWatcher(new TextWatcher(){

    private void hideIfEmpty(String s){
        if(s.length == 0){
            textview.setVisibility(View.GONE);
        }
    }

    public void afterTextChanged(Editable s){
        hideIfEmpty(s.toString());
    }

    public void beforeTextChanged(CharSequence s, int start, int count, int after){
        hideIfEmpty(s.toString());
    }

    public void onTextChanged(CharSequence s, int start, int count){
        hideIfEmpty(s.toString());
    }
});

TextView在空时设置可见性

3 个答案: