Android 两个活动之间的进度条
我正在做一个非常简单的程序。我只想显示第一个和第二个活动之间的进度条Android 两个活动之间的进度条,android,android-progressbar,Android,Android Progressbar,我正在做一个非常简单的程序。我只想显示第一个和第二个活动之间的进度条 活动1只包含一个按钮,我一单击它,它就会在同一活动中显示一个进度条,并一直显示,直到第二个活动出现,其中只包含一条正在显示的消息。在做繁重的工作之前,调用第二个活动并从那里显示进度条会更有效。 看看AsyncTask类是如何工作的。我假设您希望在转到第二个活动时实现长时间运行的后台任务。如果是这种情况,则实施 AsyncTask有4种方法可以实现,但您可以执行以下操作: doInBackground()-在此处执行长期运行的任
活动1只包含一个按钮,我一单击它,它就会在同一活动中显示一个进度条,并一直显示,直到第二个活动出现,其中只包含一条正在显示的消息。在做繁重的工作之前,调用第二个活动并从那里显示进度条会更有效。
看看AsyncTask类是如何工作的。我假设您希望在转到第二个活动时实现长时间运行的后台任务。如果是这种情况,则实施 AsyncTask有4种方法可以实现,但您可以执行以下操作:
doInBackground()
-在此处执行长期运行的任务onPostExecute()
-移动到第二个活动每当有任何流程需要花费更多时间时,就会使用ProgressBar,然后我们应该使用异步任务并显示进度对话框,直到完成任务为止 如果您有任何类似的要求,请遵循以下要求
private class LongOperation extends AsyncTask<String, Void, String>
{
protected void onPreExecute()
{
progressDialog = new ProgressDialog(activity.this);
progressDialog.setTitle("Processing...");
progressDialog.setMessage("Please wait...");
progressDialog.setCancelable(true);
progressDialog.show();
}
protected String doInBackground(String... params)
{
try
{
//BackGround process();
}
catch (Exception e) {
e.printStackTrace();
}
return null;
}
protected void onPostExecute(String result)
{
progressDialog.dismiss();
Intent n = new Intent(firstactivity.this, secondactivity.class);
startActivity(n);
}
}
看看这个例子,这将清除所有与概念相关的进度条和异步任务
import java.io.BufferedInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.net.URLConnection;
import android.app.Activity;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class download extends Activity {
public static final int DIALOG_DOWNLOAD_PROGRESS = 0;
private Button startBtn;
private ProgressDialog mProgressDialog;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
startBtn = (Button)findViewById(R.id.startBtn);
startBtn.setOnClickListener(new OnClickListener(){
public void onClick(View v) {
startDownload();
}
});
}
private void startDownload() {
String url = "http://farm1.static.flickr.com/114/298125983_0e4bf66782_b.jpg";
new DownloadFileAsync().execute(url);
}
@Override
protected Dialog onCreateDialog(int id) {
switch (id) {
case DIALOG_DOWNLOAD_PROGRESS:
mProgressDialog = new ProgressDialog(this);
mProgressDialog.setMessage("Downloading file..");
mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
mProgressDialog.setCancelable(false);
mProgressDialog.show();
return mProgressDialog;
default:
return null;
}
}
class DownloadFileAsync extends AsyncTask<String, String, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
showDialog(DIALOG_DOWNLOAD_PROGRESS);
}
@Override
protected String doInBackground(String... aurl) {
int count;
try {
URL url = new URL(aurl[0]);
URLConnection conexion = url.openConnection();
conexion.connect();
int lenghtOfFile = conexion.getContentLength();
Log.d("ANDRO_ASYNC", "Lenght of file: " + lenghtOfFile);
InputStream input = new BufferedInputStream(url.openStream());
OutputStream output = new FileOutputStream("/sdcard /some_photo_from_gdansk_poland.jpg");
byte data[] = new byte[1024];
long total = 0;
while ((count = input.read(data)) != -1) {
total += count;
publishProgress(""+(int)((total*100)/lenghtOfFile));
output.write(data, 0, count);
}
output.flush();
output.close();
input.close();
} catch (Exception e) {}
return null;
}
protected void onProgressUpdate(String... progress) {
Log.d("ANDRO_ASYNC",progress[0]);
mProgressDialog.setProgress(Integer.parseInt(progress[0]));
}
@Override
protected void onPostExecute(String unused) {
dismissDialog(DIALOG_DOWNLOAD_PROGRESS);
}
}
}
import java.io.BufferedInputStream;
导入java.io.FileOutputStream;
导入java.io.InputStream;
导入java.io.OutputStream;
导入java.net.URL;
导入java.net.URLConnection;
导入android.app.Activity;
导入android.app.Dialog;
导入android.app.ProgressDialog;
导入android.os.AsyncTask;
导入android.os.Bundle;
导入android.util.Log;
导入android.view.view;
导入android.view.view.OnClickListener;
导入android.widget.Button;
公共类下载扩展了活动{
公共静态最终整型对话框\u下载\u进度=0;
专用按钮startBtn;
private ProgressDialog mProgressDialog;
/**在首次创建活动时调用*/
@凌驾
创建时的公共void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
startBtn=(按钮)findViewById(R.id.startBtn);
setOnClickListener(新的OnClickListener(){
公共void onClick(视图v){
startDownload();
}
});
}
私有void startDownload(){
字符串url=”http://farm1.static.flickr.com/114/298125983_0e4bf66782_b.jpg";
新建DownloadFileAsync().execute(url);
}
@凌驾
受保护的对话框onCreateDialog(int id){
开关(id){
案例对话框\u下载\u进度:
mProgressDialog=新建进度对话框(此);
设置消息(“下载文件…”);
mProgressDialog.setProgressStyle(ProgressDialog.STYLE_水平);
mProgressDialog.setCancelable(假);
mProgressDialog.show();
返回mProgressDialog;
违约:
返回null;
}
}
类DownloadFileAsync扩展AsyncTask{
@凌驾
受保护的void onPreExecute(){
super.onPreExecute();
showDialog(对话框下载进度);
}
@凌驾
受保护的字符串背景(字符串…aurl){
整数计数;
试一试{
URL=新URL(aurl[0]);
URLConnection conexion=url.openConnection();
conexion.connect();
int lenghtOfFile=conexion.getContentLength();
Log.d(“ANDRO_ASYNC”,“文件长度:“+lenghtOfFile”);
InputStream输入=新的BufferedInputStream(url.openStream());
OutputStream output=新文件OutputStream(“/sdcard/some_photo_from_gdansk_poland.jpg”);
字节数据[]=新字节[1024];
长总计=0;
而((计数=输入。读取(数据))!=-1){
总数+=计数;
出版进度(“+(int)((总计*100)/长度文档));
输出.写入(数据,0,计数);
}
output.flush();
output.close();
input.close();
}捕获(例外e){}
返回null;
}
受保护的void onProgressUpdate(字符串…进度){
Log.d(“ANDRO_ASYNC”,progress[0]);
mProgressDialog.setProgress(Integer.parseInt(progress[0]));
}
@凌驾
受保护的void onPostExecute(字符串未使用){
dismissDialog(对话框下载进度);
}
}
}
在切换到新活动之前或在显示新活动之后显示ProgressDialog,但数据仍在加载。你可以查一下。。。
在这里:
在进行过程中应该发生什么?
import java.io.BufferedInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.net.URLConnection;
import android.app.Activity;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class download extends Activity {
public static final int DIALOG_DOWNLOAD_PROGRESS = 0;
private Button startBtn;
private ProgressDialog mProgressDialog;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
startBtn = (Button)findViewById(R.id.startBtn);
startBtn.setOnClickListener(new OnClickListener(){
public void onClick(View v) {
startDownload();
}
});
}
private void startDownload() {
String url = "http://farm1.static.flickr.com/114/298125983_0e4bf66782_b.jpg";
new DownloadFileAsync().execute(url);
}
@Override
protected Dialog onCreateDialog(int id) {
switch (id) {
case DIALOG_DOWNLOAD_PROGRESS:
mProgressDialog = new ProgressDialog(this);
mProgressDialog.setMessage("Downloading file..");
mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
mProgressDialog.setCancelable(false);
mProgressDialog.show();
return mProgressDialog;
default:
return null;
}
}
class DownloadFileAsync extends AsyncTask<String, String, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
showDialog(DIALOG_DOWNLOAD_PROGRESS);
}
@Override
protected String doInBackground(String... aurl) {
int count;
try {
URL url = new URL(aurl[0]);
URLConnection conexion = url.openConnection();
conexion.connect();
int lenghtOfFile = conexion.getContentLength();
Log.d("ANDRO_ASYNC", "Lenght of file: " + lenghtOfFile);
InputStream input = new BufferedInputStream(url.openStream());
OutputStream output = new FileOutputStream("/sdcard /some_photo_from_gdansk_poland.jpg");
byte data[] = new byte[1024];
long total = 0;
while ((count = input.read(data)) != -1) {
total += count;
publishProgress(""+(int)((total*100)/lenghtOfFile));
output.write(data, 0, count);
}
output.flush();
output.close();
input.close();
} catch (Exception e) {}
return null;
}
protected void onProgressUpdate(String... progress) {
Log.d("ANDRO_ASYNC",progress[0]);
mProgressDialog.setProgress(Integer.parseInt(progress[0]));
}
@Override
protected void onPostExecute(String unused) {
dismissDialog(DIALOG_DOWNLOAD_PROGRESS);
}
}
}