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我有1個活動從服務器（數據庫）接收json對象，並且每個活動都稱爲視圖（TableLayout，但在ScrollView中）會自動更新。但是，當我刪除數據庫中的數據（從當前活動或直接從數據庫中）時，佈局不會更新。在android上刷新視圖或活動
我曾嘗試使用removeView方法，「再」叫setContentView並重新初始化的佈局，最後我用startActivity和finish方法。但是我認爲如果每10秒使用一次類似setInterval方法（但是在Android上），這將會很奇怪。
任何人都知道如何刷新視圖或活動，而無需用戶注意視圖已刷新？
謝謝你的回覆，對不起，如果我錯了。讓我知道我犯的錯誤。我在Google上搜索整整一天，但沒有找到解決方案。
我使用的測試和Linux OS模擬器的Android 2.2，這裏是我的代碼：
package com.player;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.entity.BufferedHttpEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
import org.json.JSONException;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import com.maestro.Mylist.SideMenuClick;
import com.maestro.libs.Functions;
import com.maestro.libs.SQLiteDatabaseConnector;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.DialogInterface.OnCancelListener;
import android.database.Cursor;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.view.WindowManager;
import android.view.ViewGroup.LayoutParams;
import android.widget.ImageButton;
import android.widget.ScrollView;
import android.widget.TableLayout;
import android.widget.TableRow;
import android.widget.TextView;
import android.widget.Toast;
public class Playlist extends Activity {
private int page = 0;
private TableLayout tblContainer;
private int totalPage;
private String selectedItemIndex;
private TableRow selectedItem;
private Drawable rowColor;
// info to request page
private String roomName;
private String serverAddress;
private String playerUsername;
private String layoutUsername;
private Bundle stateTmp;
/**
*
*/
public Playlist() {
// TODO Auto-generated constructor stub
}
public void getSong(){
this.tblContainer = new TableLayout(this);
StringBuilder builder = new StringBuilder();
HttpClient httpClient = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(this.serverAddress + "/index.php?m=playlist&a=list&room=" + this.roomName +
"&p=" + page + "&ax=ok");
Functions.showAlert(this, this.serverAddress + "/index.php?m=playlist&a=list&room=" + this.roomName +
"&p=" + page + "&ax=ok");
try{
HttpResponse response = httpClient.execute(httpGet);
// httpClient.notify();
HttpEntity ht = response.getEntity();
InputStream content = ht.getContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(content));
String line;
while ((line = reader.readLine()) != null) {
builder.append(line);
}
try {
JSONArray obj = new JSONArray(builder.toString());
for(int i=1, j=0; i<obj.length(); i++, j++){
TableRow tr = new TableRow(this);
tr.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
// Functions.showAlert(getRef(), arg0.getTag().toString());
selectedItem = (TableRow) arg0;
rowColor = arg0.getBackground();
arg0.setBackgroundColor(0xFFFFA500);
selectedItemIndex = arg0.getTag().toString();
showDialog(0);
}
});
if((j % 2) == 0){
tr.setBackgroundColor(0xff00ffff);
}
tr.setTag(obj.getJSONObject(i).getString("id"));
TextView td = new TextView(this);
td.setText(obj.getJSONObject(i).getString("songtitle"));
td.setTextSize(30);
td.setTextColor(0xff000000);
tr.addView(td, 350, 40);
TextView td2 = new TextView(this);
td2.setText(obj.getJSONObject(i).getString("artist"));
td2.setTextSize(30);
td2.setTextColor(0xff000000);
tr.addView(td2, 350, 40);
this.tblContainer.addView(tr);
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}catch(ClientProtocolException cpe){
Functions.showAlert(this, cpe.toString());
}catch(IOException e){
Functions.showAlert(this, e.toString());
}
}
/**
*
*/
public void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated constructor stub
super.onCreate(savedInstanceState);
this.stateTmp = savedInstanceState;
getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setTitle("Maestro - Playlist");
setContentView(R.layout.playlist);
// get room name(location)
if(savedInstanceState == null){
Bundle tmp = this.getIntent().getExtras();
if(tmp != null){
this.roomName = tmp.getString("room_name");
this.serverAddress = tmp.getString("server_address");
this.playerUsername = tmp.getString("player_username");
this.layoutUsername = tmp.getString("layout_username");
}
}
/*SideMenuClick changeMenu = new SideMenuClick();
ImageButton sideMenuSonglist = (ImageButton) findViewById(R.id.songlist);
sideMenuSonglist.setOnClickListener(changeMenu);
ImageButton sideMenuKeyControl = (ImageButton) findViewById(R.id.keycontrol);
sideMenuKeyControl.setOnClickListener(changeMenu);
ImageButton sideMenuMylist = (ImageButton) findViewById(R.id.mylist);
sideMenuMylist.setOnClickListener(changeMenu);
getSong();
ScrollView sc = (ScrollView) findViewById(R.id.listcontainer);
sc.addView(this.tblContainer);
TextView txt = (TextView) findViewById(R.id.pagedesc);
txt.setText((this.page+1) + "/" + this.totalPage);
txt.setTextColor(0xff000000);
ImageButton next = (ImageButton) findViewById(R.id.next);
next.setOnClickListener(changeMenu);
ImageButton prev = (ImageButton) findViewById(R.id.prev);
prev.setOnClickListener(changeMenu);*/
drawLayout(true);
}
public void drawLayout(boolean isFirst){
if(isFirst == true){
// getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
// requestWindowFeature(Window.FEATURE_NO_TITLE);
// setTitle("Maestro - Playlist");
}
SideMenuClick changeMenu = new SideMenuClick();
ImageButton sideMenuSonglist = (ImageButton) findViewById(R.id.songlist);
sideMenuSonglist.setOnClickListener(changeMenu);
ImageButton sideMenuKeyControl = (ImageButton) findViewById(R.id.keycontrol);
sideMenuKeyControl.setOnClickListener(changeMenu);
ImageButton sideMenuMylist = (ImageButton) findViewById(R.id.mylist);
sideMenuMylist.setOnClickListener(changeMenu);
getSong();
ScrollView sc = (ScrollView) findViewById(R.id.listcontainer);
sc.addView(this.tblContainer);
TextView txt = (TextView) findViewById(R.id.pagedesc);
txt.setText((this.page+1) + "/" + this.totalPage);
txt.setTextColor(0xff000000);
ImageButton next = (ImageButton) findViewById(R.id.next);
next.setOnClickListener(changeMenu);
ImageButton prev = (ImageButton) findViewById(R.id.prev);
prev.setOnClickListener(changeMenu);
}
public Context getRef(){
return this;
}
public void changeActivity(int layoutId){
Intent newActivity = new Intent();
newActivity.putExtra("room_name", this.roomName);
newActivity.putExtra("server_address", this.serverAddress);
newActivity.putExtra("player_username", this.playerUsername);
newActivity.putExtra("layoyt_username", this.layoutUsername);
if(R.id.songlist == layoutId){
newActivity.setClass(this, ListSongs.class);
startActivity(newActivity);
}else if(R.id.keycontrol == layoutId){
newActivity.setClass(this, KeyControl.class);
startActivity(newActivity);
}else if(R.id.mylist == layoutId){
newActivity.setClass(this, Mylist.class);
startActivity(newActivity);
}else if(R.id.prev == layoutId){
if(page > 0){
page--;
}
ScrollView sc = (ScrollView) findViewById(R.id.listcontainer);
sc.removeView(this.tblContainer);
getSong();
sc.addView(this.tblContainer);
TextView txt = (TextView) findViewById(R.id.pagedesc);
txt.setText((this.page+1) + "/" + this.totalPage);
}else if(R.id.next == layoutId){
if(this.page < this.totalPage){
page++;
}
ScrollView sc = (ScrollView) findViewById(R.id.listcontainer);
sc.removeView(this.tblContainer);
getSong();
sc.addView(this.tblContainer);
TextView txt = (TextView) findViewById(R.id.pagedesc);
txt.setText((this.page+1) + "/" + this.totalPage);
}
}
protected Dialog onCreateDialog(int id){
LayoutInflater inflater = (LayoutInflater) this.getSystemService(LAYOUT_INFLATER_SERVICE);
View layout = inflater.inflate(R.layout.playlist_popup, (ViewGroup) findViewById(R.id.layout_root));
ImageButton ib0 = (ImageButton) layout.findViewById(R.id.back);
ib0.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
selectedItem.setBackgroundDrawable(rowColor);
dismissDialog(0);
}
});
ImageButton ib1 = (ImageButton) layout.findViewById(R.id.del);
ib1.setOnClickListener(new View.OnClickListener(){
public void onClick(View arg0){
Toast.makeText(getRef(), selectedItemIndex, 60000);
HttpClient ajax = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(serverAddress + "/index.php?m=playlist&a=del&room=" + roomName + "&to=" + playerUsername +
"&username=" + layoutUsername + "&id=" + selectedItemIndex);
//Functions.showAlert(getRef(), serverAddress + "/index.php?m=playlist&a=del&room=" + roomName + "&to=" + playerUsername +
// "&username=" + layoutUsername + "&id=" + selectedItemIndex);
try {
ajax.execute(httpGet);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
selectedItem.setBackgroundDrawable(rowColor);
dismissDialog(0);
// ScrollView sc = (ScrollView) findViewById(R.id.listcontainer);
// sc.removeView(tblContainer);
// sc.removeAllViewsInLayout();
// sc.destroyDrawingCache();
// tblContainer.removeAllViewsInLayout();
// setContentView(R.layout.playlist);
// setContentView(R.layout.playlist);
// drawLayout(false);
Intent newActivity = new Intent();
newActivity.putExtra("room_name", roomName);
newActivity.putExtra("server_address", serverAddress);
newActivity.putExtra("player_username", playerUsername);
newActivity.putExtra("layoyt_username", layoutUsername);
newActivity.setClass(getRef(), Playlist.class);
startActivity(newActivity);
finish();
// getSong();
// sc = (ScrollView) findViewById(R.id.listcontainer);
// tblContainer = new TableLayout(getRef());
// sc.addView(tblContainer);
}
});
ImageButton ib2 = (ImageButton) layout.findViewById(R.id.top);
ib2.setOnClickListener(new View.OnClickListener(){
public void onClick(View arg0){
Toast.makeText(getRef(), selectedItemIndex, 60000);
HttpClient ajax = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(serverAddress + "/index.php?m=playlist&a=top&room=" + roomName + "&to=" + playerUsername +
"&username=" + layoutUsername + "&id=" + selectedItemIndex);
try {
ajax.execute(httpGet);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
selectedItem.setBackgroundDrawable(rowColor);
dismissDialog(0);
ScrollView sc = (ScrollView) findViewById(R.id.listcontainer);
sc.removeView(tblContainer);
tblContainer = new TableLayout(getRef());
getSong();
sc.addView(tblContainer);
}
});
layout.setLayoutParams(new LayoutParams(170, 90));
layout.setMinimumWidth(0);
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setView(layout);
AlertDialog alertDialog = builder.create();
alertDialog.setCancelable(true);
alertDialog.setOnCancelListener(new OnCancelListener(){
@Override
public void onCancel(DialogInterface arg0) {
// TODO Auto-generated method stub
selectedItem.setBackgroundDrawable(rowColor);
dismissDialog(0);
}});
return alertDialog;
}
public class SideMenuClick implements View.OnClickListener{
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
// changeList();
changeActivity(arg0.getId());
}
}
}