我对为Android编写应用程序非常非常陌生，所以我希望这不会被视为浪费其他人的时间。我也非常确定我的代码不是很好，所以尽量不要笑。
我正在尝试将值从我的应用程序发送到远程 PHP 表单。虽然我所拥有的似乎在将信息发送到表单方面工作得很好，但如果应用程序没有连接到互联网并且我无法发送任何内容，我无法弄清楚我应该如何处理错误，所以我不确定如何让它显示 Toast 或错误消息以通知用户该消息从未发送以及原因。
我也不确定在显示已发送的确认或错误时如何将所有内容暂停约 3-4 秒。在过去的 4 个小时里，我一直在为这些事情而苦苦挣扎，并浏览了 stackoverflow 和其他一些论坛，试图找到一些代码示例来给我"啊哈！"时刻，但没有这样的运气。
我希望有人可以帮助我或指出我做错了什么。谢谢！
我的整个代码如下：
package net.testapp.commenter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import android.app.Activity;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.RelativeLayout;
import android.widget.Toast;
public class suptest extends Activity implements OnClickListener{
private EditText name, email, phone, comment;
private Button postbutton;
private ProgressBar pbfirst;
private RelativeLayout pbdark, pbsent;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.suptest);
// stuff in the layout
name=(EditText)findViewById(R.id.editText1);
email=(EditText)findViewById(R.id.editText2);
phone=(EditText)findViewById(R.id.editText3);
comment=(EditText)findViewById(R.id.editText4);
postbutton=(Button)findViewById(R.id.sendButton);
pbfirst=(ProgressBar)findViewById(R.id.progressBar1);
pbdark=(RelativeLayout)findViewById(R.id.pbdark);
pbsent=(RelativeLayout)findViewById(R.id.pbsent);
// hide some stuff up front
pbfirst.setVisibility(View.GONE);
pbdark.setVisibility(View.GONE);
pbsent.setVisibility(View.GONE);
// post button listener thingy
postbutton.setOnClickListener(this);
// Go back button
Button goback = (Button) findViewById(R.id.goback);
goback.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
Intent intent = new Intent();
setResult(RESULT_OK, intent);
finish();
}
});
};
// clicking the send button
public void onClick(View v) {
if(email.getText().toString().length()<1){
// TODO LEARN HOW TO APPLY THIS TO OTHER FIELDS AS WELL
// Remind user to fill in text fields
Toast.makeText(this, "Please fill in all fields.", Toast.LENGTH_LONG).show();
}else{
//show my progress bar and dark fullscreen layout for "Sending" text to overlay
pbdark.setVisibility(View.VISIBLE);
pbfirst.setVisibility(View.VISIBLE);
new MyAsyncTask().execute();
}
}
// Where all the http post magic happens
private class MyAsyncTask extends AsyncTask<String, Integer, Double>{
@Override
protected Double doInBackground(String... params) {
// TODO Auto-generated method stub
postData();
return null;
}
protected void onPostExecute(Double result){
//make progress bar and dark background for "Sending" test vanish
pbfirst.setVisibility(View.GONE);
pbdark.setVisibility(View.GONE);
//make sent confirmation appear
pbsent.setVisibility(View.VISIBLE);
// TODO FIGURE OUT HOW TO PAUSE ON SENT CONFIRMATION MESSAGE JUST LONG ENOUGH TO READ IT BEFORE FINISH()
finish();
}
protected void onProgressUpdate(Integer... progress){
pbfirst.setProgress(progress[0]);
}
public void postData() {
// Strings for the layout stuff
String namer = name.getText().toString();
String emailer = email.getText().toString();
String phoner = phone.getText().toString();
String commenter = comment.getText().toString();
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://www.mysite.net/commentform.php");
try {
// talk to the PHP script
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(4);
nameValuePairs.add(new BasicNameValuePair("name", namer));
nameValuePairs.add(new BasicNameValuePair("email", emailer));
nameValuePairs.add(new BasicNameValuePair("number", phoner));
nameValuePairs.add(new BasicNameValuePair("comments", commenter));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
// execute the http post
@SuppressWarnings("unused")
HttpResponse response = httpclient.execute(httppost);
} catch (ClientProtocolException e) {
} catch (IOException e) {
}
}
}
}
您可以通过在 ClientProtocolException 和 IOException 的 catch 块中添加代码来做到这一点，不是吗？ 使用如下所示的代码来显示对话框，或者您可以只使用 android toasts...
public void showDialog(final Activity activity, final String title, final String message) {
activity.runOnUiThread(new Runnable() {
public void run() {
// 1. Instantiate an AlertDialog.Builder with its constructor
AlertDialog.Builder builder = new AlertDialog.Builder(activity);
// 2. Chain together various setter methods to set the dialog
// characteristics
builder.setMessage(message).setTitle(title);
// 3. Get the AlertDialog from create()
AlertDialog dialog = builder.create();
dialog.show();
}
});
}
好的，
我想我设法弄清楚了它崩溃的原因。显然，AsyncTask 是一个不同的线程，无法操纵 UI 的东西，所以我不得不把它放在我的捕获中以显示错误消息等等......
runOnUiThread(new Runnable() {
public void run() {
//And now for my one line of code to display the error message
pber2.setVisibility(View.VISIBLE);
}
});
我希望这至少在未来对其他人有所帮助！