我有1个活动从服务器（数据库）接收一个json对象，每个名为view（TableLayout但在ScrollView中）的活动都会自动更新。但是当我删除数据库中的数据时（从当前活动或直接从数据库中删除），布局将不会更新。
我尝试使用removeView方法，再次调用setContentView'并重新初始化布局，最后我使用了startActivity和finish方法。但是我认为如果每隔10秒使用setInterval方法（但在Android上）就会很奇怪。
任何人都知道如何在没有用户注意到视图已刷新的情况下刷新视图或活动吗？
感谢您的回复，对不起，如果我错了。让我知道我犯的错误。我在Google上搜索了一整天但没有找到解决方案。
我在测试和Linux OS模拟器上使用Android 2.2，这是我的代码：
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());
}
}
}
答案 0 :(得分：1)
Android中的视图有一个Invalidate和PostInvalidate方法，它会在某些时候调用OnDraw方法。
因此，如果您使用某些数据填充了View，则可以通过调用其中一个来重绘自身。