无法在未调用 Looper.prepare()3 的线程内创建处理程序
Can't create handler inside thread that has not called Looper.prepare()3
public class AddStudentActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_student);
}
public void add2(View view){
//create 3 editText , 1 Textview
EditText et_name, et_age;
RadioButton rb_male;
TextView tv_msg;
//bind with xml widget
et_name = (EditText)findViewById(R.id.et_name);
et_age = (EditText)findViewById(R.id.et_age);
rb_male = (RadioButton)findViewById(R.id.rb_male);
tv_msg = (TextView)findViewById(R.id.tv_msg);
//retrieve values
String name = et_name.getText().toString();
String age = et_age.getText().toString();
String gender = "";
if (rb_male.isChecked())
gender = "male";
else
gender = "female";
//call php
new AddStudent(this, tv_msg).execute(name, age, gender);
}
}
class AddStudent extends AsyncTask<String, Void, String> {
private Context context;
//CHANGE HERE....ADD PARAMATER
TextView tv_msg;
public AddStudent(Context context,TextView tv_msg) {
this.context = context;
this.tv_msg = tv_msg;
}
@Override
protected String doInBackground(String[] arg) {
//CHANGE HERE ...... RETRIEVE STRING ARGUMENTS
String name = arg[0];
String age = arg[1];
String gender = arg[2];
String link;
String data;
BufferedReader bufferedReader;
String result;
try {
//CHANGE HERE .... PARAMETERS
data = "?name=" + URLEncoder.encode(name, "UTF-8");
data += "&age="+ URLEncoder.encode(age, "UTF-8");
data += "&gender="+ URLEncoder.encode(gender, "UTF-8");
//CHANGE HERE .... PHP PAGE
link = "http://10.0.2.2/fashionstudio/ADD3.php" + data;
URL url = new URL(link);
HttpURLConnection con = (HttpURLConnection) url.openConnection();
bufferedReader = new BufferedReader(new InputStreamReader(con.getInputStream(), "UTF-8"));
result = bufferedReader.readLine();
return result;
} catch (Exception e) {
Log.d("msg here", e.getMessage());
Toast.makeText(context, "Error Exception", Toast.LENGTH_SHORT).show();
return new String("Exception: " + e.getMessage());
}
}
@Override
protected void onPostExecute(String result) {
if (result != null) {
try {
JSONObject reader = new JSONObject(result);
//CHANGE HERE... RETRIEVE VALUES
String msg = reader.getString("msg");
tv_msg.setText(msg);
} catch (Exception e) {
e.printStackTrace();
Log.d("msg here", e.getMessage());
Toast.makeText(context, "Error parsing JSON data.", Toast.LENGTH_SHORT).show();
}
} else {
Toast.makeText(context, "Couldn't get any JSON data.", Toast.LENGTH_SHORT).show();
}
}
}
我在 android
中单击添加学生时出现错误
E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #1
Process: com.example.lenovo.yuwilson, PID: 22199
java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask.done(AsyncTask.java:300)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:231)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:841)
Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
at android.os.Handler.(Handler.java:208)
at android.os.Handler.(Handler.java:122)
at android.widget.Toast$TN.(Toast.java:341)
at android.widget.Toast.(Toast.java:96)
at android.widget.Toast.makeText(Toast.java:245)
at com.example.lenovo.yuwilson.AddStudent.doInBackground(AddStudentActivity.java:94)
at com.example.lenovo.yuwilson.AddStudent.doInBackground(AddStudentActivity.java:54)
at android.os.AsyncTask.call(AsyncTask.java:288)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:231)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:841)
有人帮我解决吗?
你不能
Toast.makeText(context, "Error Exception", Toast.LENGTH_SHORT).show();
在 doInBackground
方法中。 Toast.makeText(...)
必须在 UI 线程中执行。
试试这个:
runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(context, "Error Exception", Toast.LENGTH_SHORT).show();
}
});
您需要从 UI 线程调用 Toast.makeText(...)
:因为 UI 线程处理 UI 相关函数而不是工作线程
public class AddStudentActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_student);
}
public void add2(View view){
//create 3 editText , 1 Textview
EditText et_name, et_age;
RadioButton rb_male;
TextView tv_msg;
//bind with xml widget
et_name = (EditText)findViewById(R.id.et_name);
et_age = (EditText)findViewById(R.id.et_age);
rb_male = (RadioButton)findViewById(R.id.rb_male);
tv_msg = (TextView)findViewById(R.id.tv_msg);
//retrieve values
String name = et_name.getText().toString();
String age = et_age.getText().toString();
String gender = "";
if (rb_male.isChecked())
gender = "male";
else
gender = "female";
//call php
new AddStudent(this, tv_msg).execute(name, age, gender);
}
}
class AddStudent extends AsyncTask<String, Void, String> {
private Context context;
//CHANGE HERE....ADD PARAMATER
TextView tv_msg;
public AddStudent(Context context,TextView tv_msg) {
this.context = context;
this.tv_msg = tv_msg;
}
@Override
protected String doInBackground(String[] arg) {
//CHANGE HERE ...... RETRIEVE STRING ARGUMENTS
String name = arg[0];
String age = arg[1];
String gender = arg[2];
String link;
String data;
BufferedReader bufferedReader;
String result;
try {
//CHANGE HERE .... PARAMETERS
data = "?name=" + URLEncoder.encode(name, "UTF-8");
data += "&age="+ URLEncoder.encode(age, "UTF-8");
data += "&gender="+ URLEncoder.encode(gender, "UTF-8");
//CHANGE HERE .... PHP PAGE
link = "http://10.0.2.2/fashionstudio/ADD3.php" + data;
URL url = new URL(link);
HttpURLConnection con = (HttpURLConnection) url.openConnection();
bufferedReader = new BufferedReader(new InputStreamReader(con.getInputStream(), "UTF-8"));
result = bufferedReader.readLine();
return result;
} catch (Exception e) {
Log.d("msg here", e.getMessage());
Toast.makeText(context, "Error Exception", Toast.LENGTH_SHORT).show();
return new String("Exception: " + e.getMessage());
}
}
@Override
protected void onPostExecute(String result) {
if (result != null) {
try {
JSONObject reader = new JSONObject(result);
//CHANGE HERE... RETRIEVE VALUES
String msg = reader.getString("msg");
tv_msg.setText(msg);
} catch (Exception e) {
e.printStackTrace();
Log.d("msg here", e.getMessage());
Toast.makeText(context, "Error parsing JSON data.", Toast.LENGTH_SHORT).show();
}
} else {
Toast.makeText(context, "Couldn't get any JSON data.", Toast.LENGTH_SHORT).show();
}
}
}
我在 android
中单击添加学生时出现错误E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #1 Process: com.example.lenovo.yuwilson, PID: 22199 java.lang.RuntimeException: An error occured while executing doInBackground() at android.os.AsyncTask.done(AsyncTask.java:300) at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355) at java.util.concurrent.FutureTask.setException(FutureTask.java:222) at java.util.concurrent.FutureTask.run(FutureTask.java:242) at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:231) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) at java.lang.Thread.run(Thread.java:841) Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare() at android.os.Handler.(Handler.java:208) at android.os.Handler.(Handler.java:122) at android.widget.Toast$TN.(Toast.java:341) at android.widget.Toast.(Toast.java:96) at android.widget.Toast.makeText(Toast.java:245) at com.example.lenovo.yuwilson.AddStudent.doInBackground(AddStudentActivity.java:94) at com.example.lenovo.yuwilson.AddStudent.doInBackground(AddStudentActivity.java:54) at android.os.AsyncTask.call(AsyncTask.java:288) at java.util.concurrent.FutureTask.run(FutureTask.java:237) at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:231) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) at java.lang.Thread.run(Thread.java:841)
有人帮我解决吗?
你不能
Toast.makeText(context, "Error Exception", Toast.LENGTH_SHORT).show();
在 doInBackground
方法中。 Toast.makeText(...)
必须在 UI 线程中执行。
试试这个:
runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(context, "Error Exception", Toast.LENGTH_SHORT).show();
}
});
您需要从 UI 线程调用 Toast.makeText(...)
:因为 UI 线程处理 UI 相关函数而不是工作线程