我正在创建一个包含ListView的应用，只需点击ListView中的任意一项，就会弹出AlertDialog个自定义{{1}这将为用户提供更多选项。现在，自定义View中有一个TextView，它显示项目的名称，该名称已被用户长按。但是，当我第二次长按View中的任何项目时，会出现问题。
让我用一个例子清楚地解释这个 -
假设列表中有四个项目 -
让我们说用户长按了数学＆＃34;数学＆＃34; ListView加载后（第一次）。结果，Activity弹出AlertDialog说＆＃34;英语＆＃34;。
现在，在用户取消之前的对话框并再次长按，例如＆＃34; Geography＆＃34;之后。结果，TextView再次弹出AlertDialog说＆＃34;英语＆＃34;！然而，它应该显示＆＃34;地理＆＃34;。
这是我使用的代码 -
TextView：
Add_Topics.java package com.Swap.StudyBuddy;
import java.util.ArrayList;
import android.os.Bundle;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.AlertDialog.Builder;
import android.app.Dialog;
import android.content.Context;
import android.content.DialogInterface;
import android.graphics.Typeface;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.view.inputmethod.InputMethodManager;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemLongClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
public class Add_Topics extends Activity {
AddTopics_MenuAdapter adapter;
ListView topics_list;
ArrayList<Topic> the_subjects = new ArrayList<Topic>();
String new_subject;
SubjectsDatabase sd = new SubjectsDatabase(this);
EditText tpc_nm;
InputMethodManager imm;
ImageView list_bg;
ImageView bg_shadow;
TextView itemTitle;
int whereArgs2;
View dialog;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add__topics);
topics_list = (ListView) findViewById(R.id.topics_list);
topics_list.setOnItemLongClickListener(new OnItemLongClickListener() {
public boolean onItemLongClick(AdapterView<?> arg0, View arg1,
int arg2, long arg3) {
whereArgs2 = arg2;
showDialog(1);
return false;
}
});
sd.getWritableDatabase();
the_subjects = sd.getTopics();
overridePendingTransition(R.anim.reverse_in_left, R.anim.reverse_out_left);
Animation enter = AnimationUtils.loadAnimation(getBaseContext(), R.anim.upcoming_menu);
Animation enter_slow = AnimationUtils.loadAnimation(getBaseContext(), R.anim.enter_l2r_slide);
TextView des = (TextView)findViewById(R.id.des_at);
TextView title = (TextView)findViewById(R.id.title_at);
Button add_topic = (Button)findViewById(R.id.add_topic_button);
Typeface roboto_lt = Typeface.createFromAsset(getAssets(), "Roboto-Light.ttf");
des.setTypeface(roboto_lt);
title.setTypeface(roboto_lt);
add_topic.setTypeface(roboto_lt);
title.startAnimation(enter);
des.startAnimation(enter_slow);
adapter = new AddTopics_MenuAdapter(this, the_subjects);
topics_list.setAdapter(adapter);
backgroundChanges();
}
public void onClickAddTopic(View v) {
showDialog(0);
tpc_nm.requestFocus();
getBaseContext();
imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
imm.toggleSoftInput(InputMethodManager.SHOW_FORCED, 0);
}
protected Dialog onCreateDialog(int id) {
switch(id) {
case 0:
tpc_nm = new EditText(this);
tpc_nm.setHint("New Topic/Subject Name");
Typeface roboto_lt = Typeface.createFromAsset(getAssets(), "Roboto-Light.ttf");
tpc_nm.setTypeface(roboto_lt);
Builder bld = new AlertDialog.Builder(this);
bld.setIcon(R.drawable.ic_launcher);
bld.setTitle("Add Topic/Subject");
bld.setView(tpc_nm);
bld.setPositiveButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButon) {
String new_topic_name = tpc_nm.getText().toString();
new_subject = new_topic_name;
adapter = null;
the_subjects.add(new Topic(new_topic_name));
sd.addTopic(new Topic(new_topic_name));
sd.close();
adapter = new AddTopics_MenuAdapter(getBaseContext(), the_subjects);
imm.toggleSoftInput(InputMethodManager.RESULT_HIDDEN, 0);
tpc_nm.setText("");
backgroundChanges();
adapter.notifyDataSetChanged();
}
});
bld.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
imm.toggleSoftInput(InputMethodManager.RESULT_HIDDEN, 0);
tpc_nm.setText("");
backgroundChanges();
}
});
return bld.create();
case 1:
String item = the_subjects.get(whereArgs2).getTopic();
final Builder build = new AlertDialog.Builder(this);
LayoutInflater li = this.getLayoutInflater();
dialog = li.inflate(R.layout.topics_dialog, null);
itemTitle = (TextView) dialog.findViewById(R.id.itemTitle);
itemTitle.setText(item);
Toast.makeText(getBaseContext(), String.valueOf(whereArgs2) , Toast.LENGTH_SHORT).show();
build.setView(dialog);
return build.create();
case 2:
final EditText edited_topic_name = new EditText(this);
Typeface roboto_light = Typeface.createFromAsset(getAssets(), "Roboto-Light.ttf");
edited_topic_name.setTypeface(roboto_light);
edited_topic_name.setHint("New Topic Name");
Builder bld1 = new AlertDialog.Builder(this);
bld1.setView(edited_topic_name);
bld1.setPositiveButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface arg0, int arg1) {
sd.getWritableDatabase();
sd.updateTopic(new Topic(edited_topic_name.getText().toString()));
sd.close();
the_subjects.clear();
adapter = null;
the_subjects = sd.getTopics();
adapter = new AddTopics_MenuAdapter(getBaseContext(), the_subjects);
edited_topic_name.setText("");
adapter.notifyDataSetChanged();
}
});
bld1.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface arg0, int arg1) {
edited_topic_name.setText("");
}
});
}
return null;
}
/*public void onPause() {
super.onPause();
the_subjects.clear();
}
public void onStop() {
super.onStop();
the_subjects.clear();
}
public void onDestroy() {
super.onDestroy();
the_subjects.clear();
} */
public void backgroundChanges() {
list_bg = (ImageView) findViewById(R.id.list_bg);
bg_shadow = (ImageView) findViewById(R.id.bg_shadow);
int topic_list_length = the_subjects.size();
switch(topic_list_length) {
case 0:
break;
default:
list_bg.setImageResource(R.drawable.round);
bg_shadow.setImageResource(R.drawable.shadow);
}
}
public void onClickRemove(View v) {
sd.getWritableDatabase();
sd.removeTopic(new Topic(the_subjects.get(whereArgs2).toString()));
adapter = null;
the_subjects = null;
the_subjects = sd.getTopics();
sd.close();
adapter = new AddTopics_MenuAdapter(this, the_subjects);
dismissDialog(1);
adapter.notifyDataSetChanged();
topics_list.setAdapter(adapter);
}
public void onClickEdit(View v) {
showDialog(2);
}
@Override
public void onBackPressed() {
super.onBackPressed();
overridePendingTransition(R.anim.slide_in_left, R.anim.slide_out_left);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_add__topics, menu);
return true;
}
}
：
AddTopics_MenuAdapter.java package com.Swap.StudyBuddy;
import java.util.ArrayList;
import android.content.Context;
import android.graphics.Typeface;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.ArrayAdapter;
import android.widget.TextView;
public class AddTopics_MenuAdapter extends ArrayAdapter<Topic> {
private final Context context;
final ArrayList<Topic> topics;
public AddTopics_MenuAdapter(Context context, ArrayList<Topic> topics) {
super(context, R.layout.add_topics_menu, topics);
this.context = context;
this.topics = topics;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View topicsView = inflater.inflate(R.layout.add_topics_menu, parent, false);
final TextView topic_name = (TextView) topicsView.findViewById(R.id.topic_title);
Typeface rbt_lt = Typeface.createFromAsset(getContext().getAssets(), "Roboto-Light.ttf");
Animation enter = AnimationUtils.loadAnimation(getContext(), R.anim.upcoming_menu_fast);
Topic topic = topics.get(position);
topic_name.setText(topic.getTopic());
topic_name.setTypeface(rbt_lt);
topic_name.setAnimation(enter);
return topicsView;
}
}
：
SubjectsDatabase.java package com.Swap.StudyBuddy;
import java.util.ArrayList;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class SubjectsDatabase extends SQLiteOpenHelper{
private static final String SUBJECT_ID = "id";
private static final String SUBJECT_NAME = "name";
private static final String DATABASE_NAME = "topicsDatabase";
private static final String TABLE_TOPICS = "topics";
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_CREATE = "CREATE_TABLE" + TABLE_TOPICS + "(" +
SUBJECT_ID + "INTEGER_PRIMARY_KEY, " + SUBJECT_NAME + "TEXT" + ")";
public SubjectsDatabase(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
try {
db.execSQL(DATABASE_CREATE);
}
catch(SQLException e) {
e.printStackTrace();
}
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXSISTS topics");
onCreate(db);
}
public void addTopic(Topic topic) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues topics = new ContentValues();
topics.put(SUBJECT_NAME, topic.getTopic());
db.insert(TABLE_TOPICS, null, topics);
db.close();
}
public void removeTopic(Topic topic) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_TOPICS, SUBJECT_ID + " = ?",
new String[] {String.valueOf(topic.get_id())});
db.close();
}
public ArrayList<Topic> getTopics(){
ArrayList<Topic> topics = new ArrayList<Topic>();
String selectQuery = "SELECT * FROM " + TABLE_TOPICS;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cur = db.rawQuery(selectQuery, null);
if(cur.moveToFirst()) {
do {
Topic topic = new Topic();
topic.set_id(Integer.parseInt(cur.getString(0)));
topic.setTopic(cur.getString(1));
topics.add(topic);
} while(cur.moveToNext());
}
db.close();
return topics;
}
public void updateTopic(Topic topic_name) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues topic = new ContentValues();
topic.put(SUBJECT_NAME, topic_name.getTopic());
db.update(TABLE_TOPICS, topic, SUBJECT_ID + " = ?",
new String[] {String.valueOf(topic_name.get_id())});
db.close();
}
}
Topic.java请帮我解决这个问题。在此先感谢!!
答案 0 :(得分：1)
onCreateDialog创建并缓存对话框。对showDialog的第二次调用仅重新显示原始缓存对话框。如果要在显示之前修改对话框内容，则需要覆盖onPrepareDialog。