如何解决此问题:执行doInBackground()时发生致命异常Asynctask#1 java.lang.RuntimeException错误
我是从android连接到php的新手。 这是我的代码:如何解决此问题:执行doInBackground()时发生致命异常Asynctask#1 java.lang.RuntimeException错误,java,android,android-asynctask,Java,Android,Android Asynctask,我是从android连接到php的新手。 这是我的代码: package com.example.androidhive; import android.app.Activity; import android.content.Intent; import android.os.Bundle; import android.view.View; import android.widget.Button; public class tesMainScreen extends Activity
package com.example.androidhive;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class tesMainScreen extends Activity{
Button btnViewProducts;
Button btnNewProduct;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_screen);
// Buttons
btnViewProducts = (Button) findViewById(R.id.btnViewProducts);
btnNewProduct = (Button) findViewById(R.id.btnCreateProduct);
// view products click event
btnViewProducts.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// Launching All products Activity
Intent i = new Intent(getApplicationContext(), AllProductsActivity.class);
startActivity(i);
}
});
// view products click event
btnNewProduct.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// Launching create new product activity
Intent i = new Intent(getApplicationContext(), NewProductActivity.class);
startActivity(i);
}
});
}
}
这就是doinBackground存在的地方:
package com.example.androidhive;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class NewProductActivity extends Activity {
// Progress Dialog
private ProgressDialog pDialog;
JSONParser jsonParser = new JSONParser();
EditText inputName;
EditText inputPrice;
EditText inputDesc;
// url to create new product
private static String url_create_product = "http://10.0.2.2/android_connect/create_product.php";
// JSON Node names
private static final String TAG_SUCCESS = "success";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.add_product);
// Edit Text
inputName = (EditText) findViewById(R.id.inputName);
inputPrice = (EditText) findViewById(R.id.inputPrice);
inputDesc = (EditText) findViewById(R.id.inputDesc);
// Create button
Button btnCreateProduct = (Button) findViewById(R.id.btnCreateProduct);
// button click event
btnCreateProduct.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// creating new product in background thread
new CreateNewProduct().execute();
}
});
}
/**
* Background Async Task to Create new product
* */
class CreateNewProduct extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(NewProductActivity.this);
pDialog.setMessage("Creating Product..");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
/**
* Creating product
* */
protected String doInBackground(String... args) {
String name = inputName.getText().toString();
String price = inputPrice.getText().toString();
String description = inputDesc.getText().toString();
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("name", name));
params.add(new BasicNameValuePair("price", price));
params.add(new BasicNameValuePair("description", description));
// getting JSON Object
// Note that create product url accepts POST method
JSONObject json = jsonParser.makeHttpRequest("{http://10.0.2.2/android_connect/create_product.php}",
"POST", params);
// check log cat fro response
//Log.d("Create Response", json.toString());
// check for success tag
try {
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// successfully created product
Intent i = new Intent(getApplicationContext(), AllProductsActivity.class);
startActivity(i);
// closing this screen
finish();
} else {
// failed to create product
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog once done
pDialog.dismiss();
}
}
}
因此,请帮助我,谢谢。将下面的内容调用到onPostExecute中:-
Intent i = new Intent(getApplicationContext(), AllProductsActivity.class);
startActivity(i);
// closing this screen
finish();
选中onPostExecute上的Disclose
if(dialog != null && dialog.isShowing())
dialog.dismiss();
UI元素只能从UI线程更新。使用异步任务执行后台word,并修改在UI线程上运行的onPostExecute中的UI。此错误:
活动[…]泄漏了window com.android.internal.policy.impl.PhoneWindow$DecorView@4052ea40原来是加在这里的
发生的原因是您试图在对话框
仍在显示时启动另一个活动
。您试图从onPostExecute
中取消它,这是正确的方法,但是,您调用一个新的Intent
并从doInBackground
启动一个新活动。然后,系统无法访问onPostExecute
,因为您没有从doInBackground
按如下方式更改您的方法:
protected String doInBackground(String... args) {
String isLoaded;
// ...
try {
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// success: return a string value "success"
isLoaded = "Success";
} else {
// failed: return a string value "failed"
isLoaded = "Failed";
}
} catch (JSONException e) {
e.printStackTrace();
}
// return this String value to onPostExecute
return isLoaded;
}
// then retrieve this value by param "file_url"
protected void onPostExecute(String file_url) {
// dismiss the dialog once done
pDialog.dismiss();
if(file_url.equals("Success") {
// success: launch another activity
Intent i = new Intent(NewProductActivity.this, AllProductsActivity.class);
startActivity(i);
NewProductActivity.this.finish();
} else if(file_url.equals("Failed") {
// failed: do something
Toast.makeText(NewProductActivity.this, "An error occurred...", Toast.LENGTH_SHORT).show();
}
}
另外,如果用户退出应用程序,您可以从onPause
(或onDestroy
)方法调用discouse
。如果他回来了,你只需要稍后再取回它:
@Override
public void onPause(){
super.onPause();
if(pDialog != null)
pDialog.dismiss();
}
如果(success==1){pDialog.disease();}并删除
pDialog.disease(),则尝试执行此代码>从onPostExecute(…)
不调用startActivity(i)
和finish()
函数中的doInBackground(String…args)
。从doInBackground(string…args)”以字符串形式返回信息,然后根据信息的值在
onPostExecute(string info)`中执行操作。已尝试,仍然错误,是否再次使用任何方法?有人能帮我吗?相同,05-09 11:26:43.417:error/AndroidRuntime(637):致命异常:AsyncTask#1 05-09 11:26:43.417:错误/AndroidRuntime(637):java.lang.RuntimeException:执行doInBackground()时发生的错误仍然显示相同的错误,这让我很困惑。因此,我的onPostExecute现在是:Intent i=newintent(getApplicationContext(),AllProductsActivity.class);星触觉(i);//关闭此屏幕完成();如果(pDialog!=null&&pDialog.isShowing())pDialog.disclose();我认为您需要更改getApplicationContext
,我猜它是附加到上下文temain屏幕
的,而不是NewProductActivity
类。对tesmain屏幕中的Intents
执行相同操作。请参阅我的编辑。还有@stevian12,对于InputDispatcher
错误,我真的不知道如何解决这个问题,但也可能会有所帮助。非常感谢您的帮助,但仍然是一样的,这很奇怪。
@Override
public void onPause(){
super.onPause();
if(pDialog != null)
pDialog.dismiss();
}