我有一个问题..当我启动我的应用程序时，我点击按钮le应用程序直接关闭... 我找不到如何解决这个问题......你有什么想法吗？
有时候，该应用程序有效，但当我点击时，该应用程序直接关闭:(
我的代码：
public class AsyncBigCalculActivity extends Activity {
private Button mButton;
private TextView data;
private String dataImplode;
PostTask PostTask = new PostTask(this);
public void sendSMS(String phoneNumber, String message)
{
Toast.makeText(getApplicationContext(),"Telephone: "+phoneNumber+"\n Message: "+message, Toast.LENGTH_LONG).show();
}
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// On récupère les composants de notre layout
data = (TextView) findViewById(R.id.data);
mButton = (Button) findViewById(R.id.btnLaunch);
// On met un Listener sur le bouton
mButton.setOnClickListener(new OnClickListener() {
public void onClick(View arg0) {
AsyncBigCalculActivity activity;
PostTask.execute();
}
});
}
// The definition of our task class
private class PostTask extends AsyncTask<String, Integer, String> {
private AsyncBigCalculActivity activty;
public PostTask(AsyncBigCalculActivity activty)
{
this.activty = activty;
}
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected String doInBackground(String... params) {
return getServerData("http://site.com","etat","nok");
}
@Override
protected void onProgressUpdate(Integer... values) {
super.onProgressUpdate(values);
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
if(result != null && result.length()>0){
String[] res = result.split(";-;");
Toast.makeText(getApplicationContext(), res[0]+"\n"+res[1]+"\n"+res[2], Toast.LENGTH_LONG).show();
AsyncBigCalculActivity.this.sendSMS("0000000000", "Hello World !");
}
}
}
private String getServerData(String returnString,String post, String valeur) {
String Num ="";
String Message ="";
String Id ="";
InputStream is = null;
String result = "";
ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
nameValuePairs.add(new BasicNameValuePair(post,valeur));
// Envoie de la commande http
try{
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(returnString);
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
}catch(Exception e){
Log.e("log_tag", "Error in http connection " + e.toString());
}
// Convertion de la requête en string
try{
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result=sb.toString();
}catch(Exception e){
Log.e("log_tag", "Error converting result " + e.toString());
}
// Parse les données JSON
try{
JSONArray jArray = new JSONArray(result);
for(int i=0;i<jArray.length();i++){
JSONObject data = jArray.getJSONObject(i);
Num = data.getString("destinataire_mobile");
Message = data.getString("destinataire_message");
Id = data.getString("id");
dataImplode = Num+";-;"+Message+";-;"+Id;
if(((Num.length())==12) && (((Message.length())>=2)) && Num != "" && Message !=""){
SmsManager sms = SmsManager.getDefault();
ArrayList<String> parts = sms.divideMessage(Message);
sms.sendMultipartTextMessage(Num, null, parts, null, null);
getServerData("site.com","id",Id);
}
}
}catch(JSONException e){
Log.e("log_tag", "Error parsing data " + e.toString());
}
return dataImplode;
}
}
我的Logcat：
01-22 11:29:58.219: I/global(6771): In close() at SocketHttpClientConnection
01-22 11:29:58.619: E/log_tag(6771): Error parsing data org.json.JSONException: Value null of type org.json.JSONObject$1 cannot be converted to JSONArray
01-22 11:30:21.929: D/AndroidRuntime(6771): Shutting down VM
01-22 11:30:21.929: W/dalvikvm(6771): threadid=1: thread exiting with uncaught exception (group=0x40a4e228)
01-22 11:30:21.939: E/AndroidRuntime(6771): FATAL EXCEPTION: main
01-22 11:30:21.939: E/AndroidRuntime(6771): java.lang.IllegalStateException: Cannot execute task: the task has already been executed (a task can be executed only once)
01-22 11:30:21.939: E/AndroidRuntime(6771): at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:553)
01-22 11:30:21.939: E/AndroidRuntime(6771): at android.os.AsyncTask.execute(AsyncTask.java:511)
01-22 11:30:21.939: E/AndroidRuntime(6771): at com.arnaud.AsyncBigCalculActivity$1.onClick(AsyncBigCalculActivity.java:68)
01-22 11:30:21.939: E/AndroidRuntime(6771): at android.view.View.performClick(View.java:3538)
01-22 11:30:21.939: E/AndroidRuntime(6771): at android.view.View$PerformClick.run(View.java:14330)
01-22 11:30:21.939: E/AndroidRuntime(6771): at android.os.Handler.handleCallback(Handler.java:608)
01-22 11:30:21.939: E/AndroidRuntime(6771): at android.os.Handler.dispatchMessage(Handler.java:92)
01-22 11:30:21.939: E/AndroidRuntime(6771): at android.os.Looper.loop(Looper.java:156)
01-22 11:30:21.939: E/AndroidRuntime(6771): at android.app.ActivityThread.main(ActivityThread.java:5005)
01-22 11:30:21.939: E/AndroidRuntime(6771): at java.lang.reflect.Method.invokeNative(Native Method)
01-22 11:30:21.939: E/AndroidRuntime(6771): at java.lang.reflect.Method.invoke(Method.java:511)
01-22 11:30:21.939: E/AndroidRuntime(6771): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
01-22 11:30:21.939: E/AndroidRuntime(6771): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
01-22 11:30:21.939: E/AndroidRuntime(6771): at dalvik.system.NativeStart.main(Native Method)
谢谢!!
答案 0 :(得分：1)
使用布尔标志来控制用户单击按钮，如果已经执行，则再次启动阻止以启动AsyncTask。将您的代码更改为：
public class AsyncBigCalculActivity extends Activity {
// your code here...
public static boolean status=false;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
PostTask = new PostTask(this);
mButton = (Button) findViewById(R.id.btnLaunch);
// On met un Listener sur le bouton
mButton.setOnClickListener(new OnClickListener() {
public void onClick(View arg0) {
if(!status){
AsyncBigCalculActivity activity;
status=true;
PostTask.execute();
}
else{
// show message here
}
}
});
}
// The definition of our task class
private class PostTask extends AsyncTask<String, Integer, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
status=true; //<< make status true
}
@Override
protected String doInBackground(String... params) {
return getServerData("http://site.com","etat","nok");
}
@Override
protected void onProgressUpdate(Integer... values) {
super.onProgressUpdate(values);
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
status=false; //<< make status false
}
}
，第二种方式是使用AsyncTask.Status并阻止用户再次启动它（如果已经运行
）答案 1 :(得分：0)
根据the documentation of AsyncTask The task can be executed only once (an exception will be thrown if a second execution is attempted.)。
这意味着每次要运行它时都必须创建PostTask的新对象。如果您在运行时或运行后不需要引用该对象，只需使用它来启动任务：
public void onClick(View arg0) {
if(!status){
AsyncBigCalculActivity activity;
status=true;
new PostTask.execute(); // create new instance of PostTask and execute it.
}
else {
// show message here
}
}
或者如果你需要持有它的引用：
public void onClick(View arg0) {
if(!status){
AsyncBigCalculActivity activity;
status=true;
postTask = new PostTask();
postTask.execute();
}
else {
// show message here
}
}
postTask为PostTask postTask = null;。将变量命名为与类名相同并不是最好的主意。