好的 - 我正在使用以下教程：“如何将Android与PHP，MySQL连接”
然而，几乎所有尝试本教程的人（从评论中判断）都有强制关闭问题，因为应用程序只能在API级别8或更早版本上运行。
有几个用户为此开发了一个修复程序，包括在EditProductActivity.java文件中添加以下代码行
//此部分仅用于标识工作代码的放置位置
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.edit_product);
// NB *在EditProductActivity.java的import部分插入以下行 // import android.os.StrictMode;
//现在代码可以避免NetworkOnMainThreadException错误
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
.permitAll().build();
StrictMode.setThreadPolicy(policy);
但是我在我的logcat中收到消息，说明StrictMode无法解析，并且StrictMode无法解析为某种类型。我对此进行了一些研究，StrictMode包含在API级别8及更高级别中。考虑到这一点，我已将AndroidManifest.xml中的API级别提升为：
<uses-sdk android:minSdkVersion="9"
android:targetSdkVersion="9"/>
然后清理了我的项目 - 但是我仍然得到StrictMode无法解析为类型错误。
logcat的：
03-17 14:06:57.924: D/AndroidRuntime(18472): Shutting down VM
03-17 14:06:57.924: W/dalvikvm(18472): threadid=1: thread exiting with uncaught exception (group=0x41604930)
03-17 14:06:57.924: E/AndroidRuntime(18472): FATAL EXCEPTION: main
03-17 14:06:57.924: E/AndroidRuntime(18472): java.lang.Error: Unresolved compilation problems:
03-17 14:06:57.924: E/AndroidRuntime(18472): The import android.os.StrictMode cannot be resolved
03-17 14:06:57.924: E/AndroidRuntime(18472): StrictMode cannot be resolved to a type
03-17 14:06:57.924: E/AndroidRuntime(18472): StrictMode cannot be resolved to a type
03-17 14:06:57.924: E/AndroidRuntime(18472): StrictMode cannot be resolved
03-17 14:06:57.924: E/AndroidRuntime(18472): at com.example.androidhive.NewProductActivity.<init>(NewProductActivity.java:10)
03-17 14:06:57.924: E/AndroidRuntime(18472): at java.lang.Class.newInstanceImpl(Native Method)
03-17 14:06:57.924: E/AndroidRuntime(18472): at java.lang.Class.newInstance(Class.java:1319)
03-17 14:06:57.924: E/AndroidRuntime(18472): at android.app.Instrumentation.newActivity(Instrumentation.java:1054)
03-17 14:06:57.924: E/AndroidRuntime(18472): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2097)
03-17 14:06:57.924: E/AndroidRuntime(18472): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
03-17 14:06:57.924: E/AndroidRuntime(18472): at android.app.ActivityThread.access$600(ActivityThread.java:141)
03-17 14:06:57.924: E/AndroidRuntime(18472): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
03-17 14:06:57.924: E/AndroidRuntime(18472): at android.os.Handler.dispatchMessage(Handler.java:99)
03-17 14:06:57.924: E/AndroidRuntime(18472): at android.os.Looper.loop(Looper.java:137)
03-17 14:06:57.924: E/AndroidRuntime(18472): at android.app.ActivityThread.main(ActivityThread.java:5039)
03-17 14:06:57.924: E/AndroidRuntime(18472): at java.lang.reflect.Method.invokeNative(Native Method)
03-17 14:06:57.924: E/AndroidRuntime(18472): at java.lang.reflect.Method.invoke(Method.java:511)
03-17 14:06:57.924: E/AndroidRuntime(18472): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
03-17 14:06:57.924: E/AndroidRuntime(18472): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
03-17 14:06:57.924: E/AndroidRuntime(18472): at dalvik.system.NativeStart.main(Native Method)
JAVA：
import java.util.ArrayList;
import java.util.List;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONArray;
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;
import android.os.StrictMode;
public class EditProductActivity extends Activity {
EditText txtName;
EditText txtPrice;
EditText txtDesc;
EditText txtCreatedAt;
Button btnSave;
Button btnDelete;
String pid;
// Progress Dialog
private ProgressDialog pDialog;
// JSON parser class
JSONParser jsonParser = new JSONParser();
// single product url
private static final String url_product_detials = "http://linkingmanager.zxq.net/get_product_details.php";
// url to update product
private static final String url_update_product = "http://linkingmanager.zxq.net/update_product.php";
// url to delete product
private static final String url_delete_product = "http://linkingmanager.zxq.net/delete_product.php";
// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_PRODUCT = "product";
private static final String TAG_PID = "pid";
private static final String TAG_NAME = "name";
private static final String TAG_PRICE = "price";
private static final String TAG_DESCRIPTION = "description";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.edit_product);
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
.permitAll().build();
StrictMode.setThreadPolicy(policy);
// save button
btnSave = (Button) findViewById(R.id.btnSave);
btnDelete = (Button) findViewById(R.id.btnDelete);
// getting product details from intent
Intent i = getIntent();
// getting product id (pid) from intent
pid = i.getStringExtra(TAG_PID);
// Getting complete product details in background thread
new GetProductDetails().execute();
// save button click event
btnSave.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// starting background task to update product
new SaveProductDetails().execute();
}
});
// Delete button click event
btnDelete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// deleting product in background thread
new DeleteProduct().execute();
}
});
}
/**
* Background Async Task to Get complete product details
* */
class GetProductDetails extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(EditProductActivity.this);
pDialog.setMessage("Loading product details. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
/**
* Getting product details in background thread
* */
protected String doInBackground(String... params) {
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
// Check for success tag
int success;
try {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("pid", pid));
// getting product details by making HTTP request
// Note that product details url will use GET request
JSONObject json = jsonParser.makeHttpRequest(
url_product_detials, "GET", params);
// check your log for json response
Log.d("Single Product Details", json.toString());
// json success tag
success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// successfully received product details
JSONArray productObj = json
.getJSONArray(TAG_PRODUCT); // JSON Array
// get first product object from JSON Array
JSONObject product = productObj.getJSONObject(0);
// product with this pid found
// Edit Text
txtName = (EditText) findViewById(R.id.inputName);
txtPrice = (EditText) findViewById(R.id.inputPrice);
txtDesc = (EditText) findViewById(R.id.inputDesc);
// display product data in EditText
txtName.setText(product.getString(TAG_NAME));
txtPrice.setText(product.getString(TAG_PRICE));
txtDesc.setText(product.getString(TAG_DESCRIPTION));
}else{
// product with pid not found
}
} 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 got all details
pDialog.dismiss();
}
}
/**
* Background Async Task to Save product Details
* */
class SaveProductDetails extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(EditProductActivity.this);
pDialog.setMessage("Saving product ...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
/**
* Saving product
* */
protected String doInBackground(String... args) {
// getting updated data from EditTexts
String name = txtName.getText().toString();
String price = txtPrice.getText().toString();
String description = txtDesc.getText().toString();
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair(TAG_PID, pid));
params.add(new BasicNameValuePair(TAG_NAME, name));
params.add(new BasicNameValuePair(TAG_PRICE, price));
params.add(new BasicNameValuePair(TAG_DESCRIPTION, description));
// sending modified data through http request
// Notice that update product url accepts POST method
JSONObject json = jsonParser.makeHttpRequest(url_update_product,
"POST", params);
// check json success tag
try {
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// successfully updated
Intent i = getIntent();
// send result code 100 to notify about product update
setResult(100, i);
finish();
} else {
// failed to update 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 product uupdated
pDialog.dismiss();
}
}
/*****************************************************************
* Background Async Task to Delete Product
* */
class DeleteProduct extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(EditProductActivity.this);
pDialog.setMessage("Deleting Product...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
/**
* Deleting product
* */
protected String doInBackground(String... args) {
// Check for success tag
int success;
try {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair> ();
params.add(new BasicNameValuePair("pid", pid));
// getting product details by making HTTP request
JSONObject json = jsonParser.makeHttpRequest(
url_delete_product, "POST", params);
// check your log for json response
Log.d("Delete Product", json.toString());
// json success tag
success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// product successfully deleted
// notify previous activity by sending code 100
Intent i = getIntent();
// send result code 100 to notify about product deletion
setResult(100, i);
finish();
}
} 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 product deleted
pDialog.dismiss();
}
}
}
答案 0 :(得分：2)
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
.permitAll().build();
StrictMode.setThreadPolicy(policy);
由于您使用AsyncTask，因此无需设置ThreadPolicy。请不要忘记StrictMode从2.3版本开始可用。
您的应用未被很好地指定。看看这个
protected String doInBackground(String... params) {
runOnUiThread(new Runnable() {
...
txtName = (EditText) findViewById(R.id.inputName);
txtPrice = (EditText) findViewById(R.id.inputPrice);
txtDesc = (EditText) findViewById(R.id.inputDesc);
// display product data in EditText
txtName.setText(product.getString(TAG_NAME));
txtPrice.setText(product.getString(TAG_PRICE));
txtDesc.setText(product.getString(TAG_DESCRIPTION));
...
}
}
你为什么这样做？ doInBackground()直接设计用于执行后台操作，也已在后台线程上运行，您不应该从中执行UI更新。你不应该混合它。
如果您想更新用户界面，AsyncTask提供了实现它的正确方法：
因此，如果您想要使用自动调用publishProgress(<data>)方法及其更新UI的后台任务调用onProgressUpdate()方法的进度更新您的UI。
在您的情况下，您正在使用UI方法初始化doInBackground()元素，而不应该这样做。
我建议你这样做：
onCreate()方法初始化您的小部件。doInBackground()方法，调用publishProgress()调用
onProgressUpdate()方法，此处执行更新以下是示例：
@Override
protected void onProgressUpdate(String... params) {
txtName.setText(<value>);
...
}
根据上面提到的事情，我猜你需要阅读AsyncTask教程：
答案 1 :(得分：0)
只需确保您的服务器和Android设备都连接到相同的wifi连接，将IP地址更改为您的服务器地址，例如：将其更改为192.168.1.102（无论您的服务器上显示什么
代码运行良好，我尝试过它