ANDROID 学习笔记(三) UI THREAD AsyncTask 使用
一般获取验证码，用户登录验证，上传头像，获取消息，发消息，评论 都可以使用
1.先上官网实例代码
private class DownloadFilesTask extends AsyncTask<URL, Integer, Long> {
protected Long doInBackground(URL... urls) {
int count = urls.length;
long totalSize = 0;
for (int i = 0; i < count; i++) {
totalSize += Downloader.downloadFile(urls[i]);
publishProgress((int) ((i / (float) count) * 100));
// Escape early if cancel() is called
if (isCancelled()) break;
}
return totalSize;
}
protected void onProgressUpdate(Integer... progress) {
setProgressPercent(progress[0]);
}
protected void onPostExecute(Long result) {
showDialog("Downloaded " + result + " bytes");
}
}
上面代码是：下载文件的AsyncTask
doInBackground 方法：
根据传入的url,下载文件，显示下载进度，判断是否取消下载，返回。
onProgressUpdate:
显示下载进度？
onPostExecute:
下载完成，执行该方法。
new DownloadFilesTask().execute(url1, url2, url3);
上面是调用 DownloadFilesTask。
2.AsyncTask 参数分析
android.os.AsyncTask<Params, Progress, Result>
Params 定义onProgressUpdate传入参数类型，Result 是onProgressUpdate返回参数类型
Progress 定义onProgressUpdate
Result 是onPostExecute传入参数类型。
3.下面是一个登录实例
package com.lanbeizi.secret.net;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import android.os.AsyncTask;
import com.lanbeizi.secret.Config;
public class NetConnection {
public NetConnection(final String url,final HttpMethod method,final SuccessCallback successCallback,final FailCallback failCallback,final String ... kvs){
new AsyncTask<Void,Void,String>(){
@Override
protected String doInBackground(Void... params) {
// TODO Auto-generated method stub
StringBuffer paramsStr = new StringBuffer();
for(int i=0;i < kvs.length ; i+=2){
paramsStr.append(kvs[i]).append("=").append(kvs[i+1]).append("&");
}
try {
URLConnection uc ;
switch(method){
case POST:
// post 方式上传参数，以流的方式上传
uc = new URL(url).openConnection();
uc.setDoOutput(true);
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(uc.getOutputStream(),Config.CHARSET));
bw.write(paramsStr.toString());
bw.flush();
break;
default:
//get 方式 将参数写入url 不安全
uc = new URL(url+"?"+paramsStr.toString()).openConnection();
break;
}
System.out.println("Request url: " + uc.getURL());
System.out.println("Request data: " + paramsStr);
//按行读取数据
BufferedReader br = new BufferedReader(new InputStreamReader(uc.getInputStream(),Config.CHARSET));
String line = null;
StringBuffer result = new StringBuffer();
while((line=br.readLine())!= null){
result.append(line);
}
System.out.println("Result : " + result);
return result.toString();
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
// 传参 result 是 doInBackground 的返回值
@Override
protected void onPostExecute(String result) {
if(result != null)
{
if (successCallback != null){
successCallback.onSuccess(result);
}
}else
{
if (failCallback != null){
failCallback.onFail();
}
}
super.onPostExecute(result);
}
}.execute();
}
public static interface SuccessCallback{
void onSuccess(String result);
}
public static interface FailCallback{
void onFail();
}
}
package com.lanbeizi.secret.net;
import org.json.JSONException;
import org.json.JSONObject;
import com.lanbeizi.secret.Config;
public class Login {
public Login(String phone_md5,String code, final SuccessCallback successCallback,final FailCallback failCallback){
new NetConnection(Config.SERVER_URL, HttpMethod.POST,new NetConnection.SuccessCallback() {
@Override
public void onSuccess(String result) {
try {
JSONObject obj = new JSONObject(result);
switch (obj.getInt(Config.KEY_STATUS)) {
case Config.RESUTL_STATUS_SUCCESS:
if(successCallback != null){
successCallback.onSuccess(obj.getString(Config.KEY_TOKEN));
}
break;
default:
if(failCallback != null){
failCallback.onFail();
}
break;
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
if(failCallback != null){
failCallback.onFail();
}
}
}
}, new NetConnection.FailCallback() {
@Override
public void onFail() {
if(failCallback != null){
failCallback.onFail();
}
}
} , Config.KEY_ACTION,Config.ACTION_LOGIN,Config.KEY_PHONE_MD5,phone_md5,Config.KEY_CODE,code);
}
public static interface SuccessCallback{
void onSuccess(String token);
}
public static interface FailCallback{
void onFail();
}
}
package com.lanbeizi.secret.atys;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;
import com.lanbeizi.secret.Config;
import com.lanbeizi.secret.R;
import com.lanbeizi.secret.net.GetCode;
import com.lanbeizi.secret.net.Login;
import com.lanbeizi.secret.tools.MD5Tool;
public class AtyLogin extends Activity {
private EditText etPhone = null;
private EditText etCode = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.aty_login);
etPhone = (EditText) findViewById(R.id.etPhoneNum);
etCode = (EditText) findViewById(R.id.etCode);
findViewById(R.id.btnGetCode).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if(TextUtils.isEmpty(etPhone.getText())){
Toast.makeText(AtyLogin.this,R.string.phone_num_can_not_be_empty, Toast.LENGTH_LONG).show();
return;
}
final ProgressDialog pd = ProgressDialog.show(AtyLogin.this,getResources().getString( R.string.connecting), getResources().getString(R.string.connecting_to_server));
new GetCode(etPhone.getText().toString(), new GetCode.SuccessCallback() {
@Override
public void onSuccess() {
// TODO Auto-generated method stub
pd.dismiss();
Toast.makeText(AtyLogin.this,R.string.succ_to_get_code, Toast.LENGTH_LONG).show();
}
}, new GetCode.FailCallback() {
@Override
public void onFail() {
pd.dismiss();
// TODO Auto-generated method stub
Toast.makeText(AtyLogin.this,R.string.fail_to_get_code, Toast.LENGTH_LONG).show();
}
});// end GetCode
}
}); //end findViewById(R.id.btnGetCode)
findViewById(R.id.btnLogin).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(TextUtils.isEmpty(etPhone.getText().toString())){
Toast.makeText(AtyLogin.this,R.string.phone_num_can_not_be_empty, Toast.LENGTH_LONG).show();
return;
}
if(TextUtils.isEmpty(etCode.getText().toString())){
Toast.makeText(AtyLogin.this,R.string.code_can_not_be_empty, Toast.LENGTH_LONG).show();
return;
}
final ProgressDialog pd = ProgressDialog.show(AtyLogin.this,getResources().getString( R.string.connecting), getResources().getString(R.string.connecting_to_server));
new Login(MD5Tool.md5(etPhone.getText().toString()), etCode.getText().toString(), new Login.SuccessCallback() {
@Override
public void onSuccess(String token) {
pd.dismiss();
Config.cacheToken(AtyLogin.this, token);
Config.cachePhoneNum(AtyLogin.this, etPhone.getText().toString());
Intent i = new Intent(AtyLogin.this,AtyTimeLine.class);
i.putExtra(Config.KEY_TOKEN, token);
i.putExtra(Config.KEY_PHONE_NUM, etPhone.getText().toString());
startActivity(i);
finish();// 关闭当前登陆的ACTIVITY 这样按返回键就不会回到登陆页面了
}
}, new Login.FailCallback() {
@Override
public void onFail() {
pd.dismiss();
Toast.makeText(AtyLogin.this, R.string.fail_to_login, Toast.LENGTH_LONG).show();
}
}); // end new Login
}
});// end findViewById(R.id.btnLogin)
}
}
三个类 NetConnection.class Login.class AtyLogin.class
NetConnection.class 是网络链接通用类
Login.class 登录网络通信类
AtyLogin.class 登录窗口